[House Hearing, 109 Congress]
[From the U.S. Government Publishing Office]
QUESTIONS SURROUNDING THE 'HOCKEY STICK' TEMPERATURE STUDIES:
IMPLICATIONS FOR CLIMATE CHANGE ASSESSMENTS
HEARINGS
BEFORE THE
SUBCOMMITTEE ON OVERSIGHT AND INVESTIGATIONS
OF THE
COMMITTEE ON ENERGY AND
COMMERCE
HOUSE OF REPRESENTATIVES
ONE HUNDRED NINTH CONGRESS
SECOND SESSION
JULY 19 AND JULY 27, 2006
Serial No. 109-128
Printed for the use of the Committee on Energy and Commerce
Available via the World Wide Web: http://www.access.gpo.gov/congress/house
U.S. GOVERNMENT PRINTING OFFICE
31-362 PDF WASHINGTON : 2006
______________________________________________________________________
For sale by the Superintendent of Documents, U.S. Government Printing
Office Internet: bookstore.gpo.gov Phone: toll free (866) 512-1800;
DC area (202) 512-1800 Fax: (202) 512-2250 Mail: Stop SSOP,
Washington, DC 20402-0001
COMMITTEE ON ENERGY AND COMMERCE
Joe Barton, Texas, Chairman
Ralph M. Hall, Texas John D. Dingell, Michigan
Michael Bilirakis, Florida Ranking Member
Vice Chairman Henry A. Waxman, California
Fred Upton, Michigan Edward J. Markey, Massachusetts
Cliff Stearns, Florida Rick Boucher, Virginia
Paul E. Gillmor, Ohio Edolphus Towns, New York
Nathan Deal, Georgia Frank Pallone, Jr., New Jersey
Ed Whitfield, Kentucky Sherrod Brown, Ohio
Charlie Norwood, Georgia Bart Gordon, Tennessee
Barbara Cubin, Wyoming Bobby L. Rush, Illinois
John Shimkus, Illinois Anna G. Eshoo, California
Heather Wilson, New Mexico Bart Stupak, Michigan
John B. Shadegg, Arizona Eliot L. Engel, New York
Charles W. "Chip" Pickering, Mississippi Albert R. Wynn, Maryland
Vice Chairman Gene Green, Texas
Vito Fossella, New York Ted Strickland, Ohio
Roy Blunt, Missouri Diana DeGette, Colorado
Steve Buyer, Indiana Lois Capps, California
George Radanovich, California Mike Doyle, Pennsylvania
Charles F. Bass, New Hampshire Tom Allen, Maine
Joseph R. Pitts, Pennsylvania Jim Davis, Florida
Mary Bono, California Jan Schakowsky, Illinois
Greg Walden, Oregon Hilda L. Solis, California
Lee Terry, Nebraska Charles A. Gonzalez, Texas
Mike Ferguson, New Jersey Jay Inslee, Washington
Mike Rogers, Michigan Tammy Baldwin, Wisconsin
C.L. "Butch" Otter, Idaho Mike Ross, Arkansas
Sue Myrick, North Carolina
John Sullivan, Oklahoma
Tim Murphy, Pennsylvania
Michael C. Burgess, Texas
Marsha Blackburn, Tennessee
Bud Albright, Staff Director
David Cavicke, General Counsel
Reid P. F. Stuntz, Minority Staff Director and Chief Counsel
__________
SUBCOMMITTEE ON OVERSIGHT AND INVESTIGATIONS
Ed Whitfield, Kentucky, Chairman
Cliff Stearns, Florida Bart Stupak, Michigan
Charles W. "Chip" Pickering, Mississippi Ranking Member
Charles F. Bass, New Hampshire Diana DeGette, Colorado
Greg Walden, Oregon Jan Schakowsky, Illinois
Mike Ferguson, New Jersey Jay Inslee, Washington
Michael C. Burgess, Texas Tammy Baldwin, Wisconsin
Marsha Blackburn, Tennessee Henry A. Waxman, California
Joe Barton, Texas John D. Dingell, Michigan
(Ex Officio) (Ex Officio)
II
CONTENTS
Page
Hearings held:
July 19, 2006......................................... 1
July 27, 2006......................................... 603
Testimony of:
Wegman, Dr. Edward J., Center for Computational
Statistics, George Mason University.................. 39
North, Dr. Gerald R., Department of Atmospheric
Sciences, Texas A&M University....................... 52
Karl, Dr. Thomas R., Director, National Climatic
Data Center, National Oceanic and Atmospheric
Administration, U.S. Department of Commerce.......... 127
Crowley, Dr. Thomas J., Nicholas Professor of Earth
Science, Duke University............................. 138
von Storch, Dr. Hans, Director of Institute for Coastal
Research, GKSS Research Center, Germany.............. 215
McIntyre, Stephen, Toronto, Ontario, Canada........... 236
Mann, Dr. Michael E., Associate Professor and
Director, Earth System Science Center, The
Pennsylvania State University........................ 640
Christy, Dr. John R., Professor and Director, Earth
System Science Center, NSSTC, University of Alabama
in Huntsville........................................ 654
Cicerone, Dr. Ralph J., President, National Academy
of Sciences........................................... 674
McIntyre, Stephen, Toronto, Ontario, Canada........... 682
Gulledge, Dr. Jay, Senior Research Fellow, Pew Center
on Global Climate Change............................. 696
Wegman, Dr. Edward J., Center for Computational
Statistics, George Mason University.................. 705
Additional material submitted for the record:
North, Dr. Gerald R., Department of Atmospheric
Sciences, Texas A&M University, response for the
record............................................... 586
Crowley, Dr. Thomas J., Nicholas Professor of Earth
Science, Duke University, response for the record.... 585
Mann, Dr. Michael E., Associate Professor and Director,
Earth System Science Center, The Pennsylvania State
University, response for the record.................. 764
Christy, Dr. John R., Professor and Director, Earth
System Science Center, NSSTC, University of Alabama
in Huntsville, response for the record............... 770
Cicerone, Dr. Ralph J., President, National Academy
of Sciences, response for the record................. 780
McIntyre, Stephen, Toronto, Ontario, Canada, response
for the record....................................... 784
Wegman, Dr. Edward J., Center for Computational
Statistics, George Mason University, response for
the record........................................... 829
QUESTIONS SURROUNDING THE 'HOCKEY STICK' TEMPERATURE STUDIES:
IMPLICATIONS FOR CLIMATE CHANGE ASSESSMENTS
WEDNESDAY, JULY 19, 2006
HOUSE OF REPRESENTATIVES,
COMMITTEE ON ENERGY AND COMMERCE,
SUBCOMMITTEE ON OVERSIGHT AND INVESTIGATIONS,
Washington, DC.
The subcommittee met, pursuant to notice, at 10:07 a.m., in Room 2123
of the Rayburn House Office Building, Hon. Ed Whitfield (Chairman)
presiding.
Members present: Representatives Walden, Bass, Stearns,
Burgess, Blackburn, Barton (ex officio), Stupak, Schakowsky, Inslee,
Baldwin, Waxman, and Whitfield.
Staff present: Mark Paoletta, Chief Counsel for Oversight and
Investigations; Peter Spencer, Professional Staff Member; Tom Feddo,
Counsel; Matt Johnson, Legislative Clerk; Mike Abraham, Legislative
Clerk; Ryan Ambrose, Legislative Clerk; David Vogel, Minority Research
Assistant; Chris Knauer, Minority Investigator; Lorie Schmidt, Minority
Counsel; and Edith Holleman, Minority Counsel.
MR. WHITFIELD. I call this hearing to order this morning.
Albert Gore's first movie, or documentary, entitled "An
Inconvenient Truth" is the most recent of many topics in years and
years of focus on the subject of global warming, and 95 percent of the
American people certainly are familiar with the term "global warming"
and they know basically what it means, I would think. However, 95
percent of the American people and certainly 95 percent of the Members
of the U.S. Congress have not had the time to examine the data used by
scientists, paleoclimatologists, and statisticians nor do they have
the inclination to do so, to look at that data that is used to predict
the probability that the temperature of one century is warmer or
cooler than that of another century.
Now, the United Nations Intergovernmental Panel on Climate
Change is the world body with most of the interest and does focus on
this subject of global warming. And it is the body that most people
look to on this subject. Now, for many years the Intergovernmental
Panel on Climate Change used a chart that clearly shows the
temperature from 1000 A.D. to about 1450 A.D., that the temperatures
during that period were significantly warmer than the latter part of
the 20th Century, or the late 1990s. Now, in 1998 and 1999, a
paleoclimatologist, Dr. Michael Mann, with Raymond Bradley and
Dr. Malcolm Hughes, introduced a new technique to develop more
quantitative estimates of the nature of climate change since 1000
A.D. and concluded that the late 20th Century was the warmest in
1,000 years, that the warming during the late 1990s was the warmest
in over 1,000 years. Now, as a result of that report, the IPCC
incorporated the study with other data which eliminated the warming
period for 1000 A.D. to 1450 A.D. and incorporated a new graph
referred to as the "hockey stick" graph, which shows remarkable
warming in the late 1990s. Now, when Chairman Barton and I wrote a
letter asking that the Mann report be reviewed by some statisticians,
there was a hue and cry around the country among many people in the
news media that we were being totally political, that all we were
trying to do was gut this issue that global warming is occurring.
But I think quite sincerely that we have a responsibility when public
policy decisions being made on reports like the Mann report and others
have such a broad impact on so much of our society and certainly the
Kyoto arguments were primarily based on this new chart, that the U.S.
should be part of Kyoto. That was an important part of that. And so
what we did was, we asked that Dr. Wegman and a team that he had review
these data. Now, when we did that, Sherry Boehlert, who is a good
Republican friend of ours and is Chairman of the Science Committee,
was quite upset about it and he said I think you all are being
political also, and he asked that we ask Dr. North, who is going to
be a witness, and would like for him to be involved in this data
analysis, and he is going to be a witness today also. But the real
purpose of this is that this issue is so important that I think it
is imperative that we hear from all sides and try to get some real
understanding of the strengths and weaknesses of these reports.
Now, Dr. Wegman is going to testify today that the mathematics
used by Mann is incorrect and wrong. Dr. North, I think on page five
of his testimony, says that they have some concerns about it, the
math. But the first witness today is going to be Dr. Edward Wegman,
a statistician from George Mason University, and on his team was Dr.
David Scott from Rice University and Dr. Yasmin Said from Johns
Hopkins, and she is sitting behind him there. Dr. Wegman is Chairman
of the National Academy of Sciences Committee on Applied and
Theoretical Statistics, and at the committee's request he assembled
this ad hoc committee of statisticians to examine the hockey stick
studies and related articles and his committee report prepared for
Chairman Barton and me and the committee and publicly released this
Friday provides important findings for Congress and the public to
consider about the soundness and openness of climate change research
and assessment and I can tell you right now that his document has
been peer reviewed also, and we will get into that later.
In addition to Dr. Wegman, we have Dr. Gerald North of
Texas A&M University, who will testify on the first panel about
the current state of historical temperature understanding. Dr.
North chaired a recent National Research Council panel on
historical temperature reconstructions and we look forward to
hearing his perspective for improving climate change assessments.
And to help us understand some particulars of the IPCC process, we
will hear testimony on the second panel from Dr. Thomas Karl, who
is a coordinating author of the chapter upon which Dr. Mann and his
colleagues worked. Dr. Thomas Crowley of Duke University will be
here and Dr. Hans von Storch, who traveled from Germany to be with
us this morning. Both will provide their views concerning the
questions about the hockey stick study as well as questions
concerning data sharing, transparency and the IPCC process.
Finally, I would like to welcome Mr. Stephen McIntyre, who
will testify about attempting to understanding just what was behind
the hockey stick graphic promoted by the IPCC. His work is a
testament to the value of open debate and scrutiny.
Now, I have talked about Dr. Mann and we invited Dr. Mann to
be here today and he was unable to be here. We are extending another
invitation for him to come and hope that maybe he will be here next
week. Now, even though Dr. Mann could not come, he specifically
asked us to request Dr. Crowley to testify on his behalf and Dr.
Crowley is with us today from Duke University, and we look forward
to his testimony. But as I said, the real purpose of this hearing
is, let us just open the book. Let us look at everything. Let us
look at the criticisms of all parties and see exactly where we are
on this important issue of global climate change.
[The prepared statement of Hon. Ed Whitfield follows:]
PREPARED STATEMENT OF THE HON. ED WHITFIELD, CHAIRMAN, SUBCOMMITTEE
ON OVERSIGHT AND INVESTIGATIONS
Good morning and welcome. We convene this hearing today to consider
questions that begin with and surround the reliability of two
particular studies of historical temperatures that gained an
extraordinary level of public prominence a few years ago, and
recently featured in former Vice President Al Gore's motion
picture, "An Inconvenient Truth."
In 2001, the results of these studies were used to promote the view
that the very recent average temperatures of the northern hemisphere
were likely the warmest in 1,000 years. The temperature history
results were portrayed in what is widely known as the 'hockey stick'
graph, for its resemblance to the shape of a hockey stick. As a
result, these studies are known as the "hockey stick" studies.
With its relatively long and even trend for 900 years and then sharp
up-tick during the 20th Century, the "hockey stick" graph effectively
undermined what had been the prevailing view that we had experienced
periods of similar or even higher average temperatures in the past -
such as when the Vikings inhabited Greenland.
The fact that the United Nation's Intergovernmental Panel on Climate
Change, or IPCC, prominently relied upon the graph lent the graph its
apparent authority. The IPCC is an influential international body
that conducts scientific assessments for use by policymakers.
The graph offered a simple and powerful message for the public
and policymakers to understand. It was also a message that some say
may have been based on faulty methodology. The "hockey stick"
studies formed the basis for the IPCC finding in 2001 that the
1990s were likely the warmest decade of the millennium and 1998
likely the warmest year during that time. Some of today's witnesses
will describe in detail that the "hockey stick" studies were
critically flawed and could not support the findings reached by
these studies.
Had the 'hockey stick' studies remained in the niche of climate
change journals, we would not be holding this hearing. Instead, we
are here because the questions surrounding these studies relate
directly to the strength of the findings in the first place. What
does the "hockey stick" story say about the reliability of these
studies for policymakers?
Last summer, Chairman Barton and I inquired into this matter after
we learned that the lead author of these federally funded studies -
Dr. Michael Mann -- to share the computer code he used to generate
his results with researchers who sought to replicate the result of
Mann's studies. The researchers, one of whom will testify today,
reportedly could not replicate his work based on what the study
said. The researchers nevertheless identified several methodological
and data problems with the work.
How critical were these problems identified by these researchers?
Were the problems undetected because Dr. Mann assessed his own work
in an IPCC report?
These are serious questions, and the answers contain broad
implications for global policy on climate change. We should ensure
that science is providing us with reliable, balanced, well-
considered, and unbiased answers.
Today, our witnesses will help us address these critical questions.
I want to welcome, especially, Dr. Edward Wegman, a statistician
with George Mason University, who will lead off the first panel this
morning. Dr. Wegman is Chairman of the National Academy of Sciences
Committee on Applied and Theoretical Statistics. At the Committee
request, Dr. Wegman assembled an ad-hoc committee of statisticians
to examine the hockey stick studies and related articles. His
committee's report, prepared for Chairman Barton and me and publicly
released this past Friday, provides important findings for Congress -
and the public - to consider about the soundness and openness of
climate change research and assessments. The Wegman Committee not
only identified fundamental flaws in the "hockey stick" studies, it
also addressed the larger point that climate change studies, like
any work with potentially large policy implications, must be subject
to careful and broad scrutiny.
Dr. Wegman and his team performed their work completely independent
of the Committee and without charge. I believe Dr. Wegman's team has
done a great public service and their work should help us improve how
we discuss climate change when crafting policy.
Additionally, Dr. Gerald North, of Texas A&M University, will testify
on the first panel about the current state of historical temperature
understanding. Dr. North chaired a recent National Research Council
panel on historical temperature reconstructions, and I look forward to
hearing his perspective for improving climate change assessments.
To help us understand some particulars of the IPCC process, we'll
hear testimony on the second panel from Dr. Thomas Karl, who was a
coordinating author of the chapter upon which Dr. Mann and his
colleagues worked. Dr. Thomas Crowley, of Duke University, and
Dr. Hans von Storch - who traveled from Germany to be with us this
morning - both can provide their considered views concerning the
questions about the "hockey stick" studies, as well as questions
concerning data sharing, transparency, and the IPCC process.
Finally, I'd like to welcome Mr. Steven McIntyre. Mr. McIntyre will
testify about attempting to understand just what was behind the
hockey stick graphic promoted by the IPCC. His examination of the
facts underlying the assessments' claims really initiated some of
the important questions concerning the scrutiny provided by climate
change assessments. His work is a testament to the value of open
debate and scrutiny. His perseverance should be commended.
Let me add that we did invite Dr. Mann to this hearing, but his
attorney explained that he was unavailable, on family vacation.
Dr. Mann suggested Dr. Crowley could come in his place. We do
hope to have Dr. Mann at a future hearing, however.
At the end of the day, the issues of climate change require open
and objective discussion. Some of the work we'll consider today
points to the value of policy decisions that are informed by sound
science and objective advice.
I'll now yield to Mr. Stupak, our ranking member, for his opening
statement.
MR. WHITFIELD. At this time, I would like to recognize
Mr. Stupak of Michigan for his opening statement.
MR. STUPAK. Thank you, Mr. Chairman.
It is a little bewildering to me why the committee is holding
its very first hearing on global warming to referee a dispute over a
1999 hockey stick graph of global temperatures for the past
millennium. Mr. Chairman, in your opening statement you claim that
Dr. Mann's hockey stick report of 1999 was the basis for the Kyoto
Accord. According to my recollection, Kyoto was in 1997, so it could
not have been the basis for the Kyoto Accord.
So as we will hear at this hearing today, global warming
science has moved on since Dr. Mann put forth his study in 1999.
Dr. Mann, who did this study, has made changes and even such diehard
opponents as President Bush now actually admit that global warming
exists and must be addressed. Congress is particularly ill-suited
to decide scientific debates. There has been no attempt by this
committee to obtain an unbiased view of the work done by Dr. Michael
Mann, the author of the hockey stick research. Dr. Mann, who has
done additional work with his methodology since 1999, is not even
here to confront his critics because the Majority would not even
postpone this hearing until Dr. Mann could be available. Moreover,
it was known from the beginning that Dr. Mann used a new methodology
and proxy material to reconstruct temperatures.
Paleoclimatologists, those who try to reconstruct ancient
climates, are not working with instrumental measurements of
temperature as we have today. Paleoclimatologists are looking at
tree rings, ice cores, bore heads and historical records to attempt
to determine what happened in an earlier time. That is all the
research materials paleoclimatologists have and it is an admittedly
imprecise science. It should not surprise us if the initial work in
a new field can be improved. What should surprise us is that
Dr. Wegman's report focuses on critiques of Dr. Mann's first work
in 1998 and 1999, even though the field of large-scale temperature
reconstruction has advanced since that time.
The Majority paid for a report to independently verify the
critiques of Dr. Mann's 1999 research by a statistician but without
any input from a climatologist. The Majority left it to the Science
Committee to ask the National Academy of Sciences to do a full
review of all the science represented. The Majority made no effort
to verify whether the patterns in global temperatures detected in
the Mann study were valid or coincided with conclusions of other
researchers in global warming.
It is now 7 years since the original work was published and
much additional work has been done by Dr. Mann and others. As we
will hear from Dr. North, who chaired the NAS study, the patterns
were verified with certainty for recent years but less certain for
the years 1000 to 1600 A.D. That is to be expected because there is
less data from this long ago era. Dr. Wegman has an eminent
background in statistics and he believes that statisticians should
be included in the research teams of all these studies because
statisticians can make studies better. Perhaps they can.
Dr. Wegman says Dr. Mann didn't center his data properly. Perhaps he
didn't. But we note that Dr. Wegman's work is not yet published or
peer reviewed so it is very difficult for us to evaluate his work.
Dr. Wegman's criticism of Dr. Mann should have been interdisciplinary
and include a statistician can also be said of Dr. Wegman's work.
Dr. Wegman did not have a climate scientist on his team. However,
Dr. Wegman has decided to go beyond his statistical expertise to
hypothesize that Dr. Mann was allowed to publish and defend his work
because of the small "social network" of paleoclimatologists who
work with each other and protect each other. I want to emphasize
that this is simply a hypothesis. Mr. Chairman, whatever the purpose
of this hearing is, it is not to hypothesize about the impact of
professional scientific relationships on research unless we have
some hard objective evidence.
We in Washington know all about undue influence on government
scientists. A political appointee at NASA just recently tried to
keep James Hanson, a veteran atmosphere scientist, from discussing
the dire consequences of global warming by threatening dire
consequences to Mr. Hanson's employment status. The science content
has been changed on NASA and other government websites because it
didn't fit the Administration's world view. This fact ought to be
of much more interest to this committee, the Oversight and
Investigations Committee, than hypothesis about scientific social
networking.
And with that, Mr. Chairman, I would yield back the balance
of my time.
MR. WHITFIELD. Mr. Stupak, thank you. I also want to thank
you for pointing out an incorrect statement that I made. I said
something about the hockey stick being the impetus for Kyoto. Kyoto
certainly started way before the hockey stick but the hockey stick
graph did add impetus to the argument for the adoption of Kyoto, so I
want to thank you for that. Also, I would point out that the committee
did not pay Mr. Wegman for this report, we simply contacted him asking
him to review it.
At this time I recognize the full committee Chairman, Mr. Barton.
CHAIRMAN BARTON. Thank you, Mr. Chairman. I have a written
statement, I am going to use some of it, but I want to speak
extemporaneously briefly based on what my good friend from Michigan,
Mr. Stupak, just said.
The purpose of oversight and investigation is to do exactly
that, to oversee the jurisdictional issues before this committee and
when it seems to be called for to investigate issues that arise because
of the oversight. There has been a disagreement for a number of years
in the community at large about the issue of global warming. In this
Congress, there has been a disagreement between the Chairman of the
Science Committee and myself about that issue. That is normal and
that is not anything that is a negative. But there were some
statements made about a specific report by a number of people that
basically use that report to come to the conclusion that global
warming was a fact and that the 1990s was the hottest decade on
record and that one year, 1998, was the hottest year in the
millennium. Now, a millennium is a thousand years. That is a pretty
bold statement. So Chairman Whitfield and myself decided, let us take
this report that is the basis for many of these conclusions and has
been circulated widely and once it is in the mainstream, it is
stipulated that because of that, everything else follows and let us
see if it can be replicated. Let us see if in fact the facts as
purported in that report are in truth the facts.
Now, I have not seen Dr. Wegman until I walked in this room.
I have not talked to him on the phone or in person or any of his
collaborators. I may have seen Dr. North at Texas A&M since I went
to Texas A&M. I don't recall it but it is possible. He has got
enough white in his hair that I could have been one of his students
and I wouldn't remember it, so I can't stipulate that I have never met
him but I can stipulate that I have never met Dr. Wegman. We asked to
find some experts to try to replicate Dr. Mann's work. Now, to their
credit, when Dr. Wegman agreed to do it, he asked for no
compensation. I don't think we have even paid him for the fax paper
that he has used. He picked some eminent statisticians in his field
and they studied this thing. Had their report said Dr. Mann's data
can be replicated, his conclusions are right on point, he is totally
correct, we would have reported that, but that is not what they said.
Now, I took statistics at Texas A&M and I also took them in graduate
school. I made A's and B's, but I really didn't understand it but I
kind of understand it. And according to Dr. Wegman, Dr. Mann made a
fundamental error. He decentered the data. Now, to the average
person, that doesn't mean squat. What does "decentered the data"
mean? What it means apparently is, he moved it off center a little
bit by enough that it really makes a difference and then using some
statistical techniques that instead of looking at all the variables
and in a complex system like climate you are going to have lots of
variables, he chose one or two as the principal variables and used
those to explain everything else, and Dr. Wegman and his colleagues
who as far as I know have got no axe to grind, have said the Mann
study is flat wrong. Now, it may be wrong just kind of
unintentionally. Dr. Wegman doesn't say there is any intent to
deceive but he says it is flat wrong. Now, if that is not the
purpose of the Oversight Subcommittee of the Energy and Commerce
Committee that has got jurisdiction over energy and environmental
policy for the United States of America, then I don't know what
this subcommittee should be doing.
So I want to thank Dr. Wegman and his colleagues for giving
us an unvarnished, flat out non-political report. Now, admittedly,
that report is going to be used probably for political purposes but
that is not what he did, and I want to thank Dr. North for the work
that he did in this document. Now, it is a lot thicker than
Dr. Wegman's document, and Dr. North and his colleagues have kind of
looked at the same subject and they have come to a somewhat little--
they are little bit more, I don't want to use the technical term
wishy-washy but they are kind of on both sides of it, but even
Dr. North's report says that the absolute basic conclusion in
Dr. Mann's work cannot be guaranteed. This report says it is
plausible. Lots of things are plausible. Dr. Wegman's report says
it is wrong.
Now, what we are going to do after today's hearing, we are
going to take Dr. Wegman's report, and if my friends on the Minority
want to shop it to their experts, so be it. We are going to put it up
there, let everybody who wants to, take a shot at it. Now, my guess
is that since Dr. Wegman came into this with no political axe to
grind, that it is going to stand up pretty well. If Dr. Mann and
his colleagues are right, their conclusion may be right--Dr. Mann's
conclusion may be right but you can't verify it from his statistics
in his model so if Dr. Mann's conclusion is right, it is incumbent
upon him and his colleagues to go back, get the math right, get the
data points right, get the modeling right. That is what science is
about.
So I want to thank you, Mr. Chairman, for holding this
hearing. I am planning to participate fully and extensively. I have
got a whole series of questions. I stayed up half the night studying
all the various documents so I hope that by the end of today we can
shed some light on a subject that is very, very important to the
future economic and health consequences for this country. Thank
you, sir.
[The prepared statement of Hon. Joe Barton follows:]
PREPARED STATEMENT OF THE HON. JOE BARTON, CHAIRMAN, COMMITTEE ON
ENERGY AND COMMERCE
Thank you, Chairman Whitfield. Today's hearing on the hockey stick
temperature studies will show why we need to question the quality
of climate assessments for policy makers.
This Committee frequently confronts some of our Nation's most
consequential public policy questions affecting the quality of
human health, our economy, and our environment. However, no issue
we deal with has more potential to affect the American people than
climate change.
Meanwhile, the compounding costs to the U.S. economy posed by some
proposals for reducing greenhouse gas emissions could rock our economy,
drive manufacturing off-shore, and spike domestic consumer energy costs.
That is why we need to be sure that we have a solid factual basis for
whatever decisions we make in this area.
The report we are about to receive indicates that the social and
statistical underpinnings of key climate-change work are prone to
produce error.
I look forward to hearing from all of our witnesses because we have
important work to accomplish today. I would especially like to thank
Dr. Edward Wegman who, on his own time and his own expense, assembled
a pro bono committee of statisticians to provide us with independent
and expert guidance concerning the hockey stick studies and the
process for vetting this work.
Dr. Wegman and his committee have done a great public service. Their
report, with clear writing and measured tone, has identified
significant issues concerning the reliability of some of the climate
change work that is transmitted to policymakers and characterized as
well scrutinized. The Wegman Committee report will be the centerpiece
of today's hearing.
These 'hockey stick' studies were the linchpin for what became widely
acclaimed as the consensus view of the earth's temperature history
during the past thousand years. It was presented as part of the
leading climate assessment for public policy makers around the
world - the United Nation's Intergovernmental Panel on Climate
Change, or IPCC.
Both good science and good public policymaking demand that scientific
work withstand independent and impartial scrutiny. Information that is
not scientifically sound is just not acceptable. Indeed, it appears
that some of the authors of the IPCC assessment dealing with global
temperature history were not independent or impartial. They also
happened to be the authors of the hockey stick studies, themselves.
The researchers then declined to provide the information necessary
to replicate their work, a fundamental failure in reliable science.
The "hockey stick" studies were supported by Federal grants and were
central to a prominent finding in an influential assessment. In my
view, if Congress is going to make policy decisions based on the
authority of climate change assessments, we cannot fail to wonder how
they have been formulated. Asking questions is at the core of what
we do.
Our central question is: Can we count on hockey stick studies? That
answer from Dr. Wegman and his panel appears to be, "No." And it
doesn't appear to be a matter of overlooking the researchers' written
caveats about their particular work; rather, the Wegman panel has
identified a fundamental error of methodology. If that finding holds
up, it will highlight a mistake that lay dormant for years as a closed
network of supportive colleagues saw and heard what it wanted. It took
scientists outside the network to identify the core problems, both in
the studies and in the IPCC assessment.
Congress is in the business of making policy decisions that affect
the lives of real people. Science provides us with the answers to
many policy questions, and we need to trust it. I do trust science,
and I trust it most when it is transparent, open to question, and
eager to explain. When research is secretive, automatically and
aggressively defensive, and self-reinforcing, it becomes easy to
distrust.
As Chairman of the Energy and Commerce Committee, which holds a key
role in any policy making relating to climate change, I believe it
is incumbent on this Committee must ensure that the very best
information is available to make its decisions.
Caveats and uncertainty are facts of life, and not only in science. We
deal with complicated science and research-based decisions and
uncertainty in every area of our jurisdiction. Some of the most
troubling work we confront - on bioterror or radiological risks for
example - present very tough and complicated issues for us to assess.
Good science is built on healthy skepticism, and good scientists don't
hide from questions. They invite them. Asking questions to establish
the validity of scientific studies - especially those with enormous
policy implications - is why we are here today. The caveats and
uncertainty are never going to be eliminated, but we would like to
know whether the facts or caveats contained in these sophisticated
climate assessments have been adequately and independently
scrutinized.
Heads-I-win, tails-you-lose science can produce any answer that is
desired, but that's hardly the way to make multi-billion-dollar
decisions. This is a vitally important matter. When we deal with
global warming, we need to know that the underlying studies
constitute reliable science. The taxpayers depend on it. My
grandchildren depend on it. The planet depends on it.
I want to extend my thanks to all the witnesses for appearing today,
and I look forward to their testimony.
MR. WHITFIELD. Thank you, Mr. Chairman. At this time I
recognize Mr. Inslee of Washington.
MR. INSLEE. Thank you, Mr. Chairman.
America is fully capable of dealing with global warming but
not if Congress engages in snipe hunts, arguments about how many
statisticians can dance on the head of a pin rather than figuring out
what our energy policy should be to get a handle on global warming.
Now, why are we in this exercise for doubt? I refer you to the
first slide I have, which is a memo from the tobacco industry when they
were fighting the clear, unalloyed science that tobacco was bad for
you. Here is a memo from one of their people: "Doubt is our
product." And those who decide that America should stay quiescent,
do nothing about global warming, doubt is their product.
Next slide.
Why should we deal with this? What we are going to find out today, I
hope, we can spend weeks debating the statistics behind one particular
study but what we will find is that every single study ever that has
looked at proxy data for temperature has indicated we are in a unique
circumstance and carbon dioxide is going through the roof which you
will see from these studies, multiple of which are on this slide.
Next slide.
What we find now is that CO2 is going through the roof. No
one in this room will say otherwise. The first bottom circle is
where we are today. It is higher CO2 levels than any time in the
last 160,000 years. Every single scientist in the world agrees to
that fact, and by 2100 the circle on top, it will be almost twice as
it has ever been in the last 200,000 years. Every single scientist
in the world agrees to that fact, and because CO2 drives climate,
because it drives temperature, we ought to get out of this posture
of the ostrich and assume the posture of the eagle to do something
about global warming. Next slide, please.
I want to point out something that is very important in today's
discussion. We can spend years debating what the temperature was on
July 18, 972, but what we ought to know is that our putting CO2 into
the atmosphere is destroying the world's oceans regardless of the
temperature. The new science shows that the CO2 that we put in the
atmosphere is acidifying the oceans. The oceans have 23 percent more
hydrogen ions that create acidic conditions than any time ever that
we know of in human history, at least. Next slide, please.
The result of that is that when the oceans become more acidic,
it becomes much more difficult for any life including plankton, coral
reefs, clams, oysters, you name it to form shells including plankton,
which is the basis of the entire food chain of all the protein we get
out of the oceans. Next slide, please.
What this shows is the pH level of acidity is changing. Next
slide, please.
So that by the year 2099, conditions in the ocean may not support any
coral reefs healthy anywhere in the world. This doesn't have anything
to do with Dr. Mann's report. Even if temperatures did not change
one-half a degree, the oceans are becoming acidic that may not support
the protein that we depend on in the world if we don't act and if
this committee continues to act like an ostrich. Next slide, please.
Why are Americans rejecting this doubt they see with their
own eyes? Polar icecaps shrunk in density--next slide, please--in the
last 12 years.
Greenland is melting at unprecedented rates. Next slide, please.
The polar icecap has shrunk 20 percent in the summer. The red line
shows where it used to be. The white is where it is now. Next
slide, please. We have run out of slides. Well, maybe I ought to
talk then.
This is very disturbing to me that when the entire world
scientific community has reached a conclusion with high levels of
certainty that carbon dioxide is going to astrospheric levels,
unprecedented in world history, and that when we know beyond a shadow
of a doubt the levels of carbon dioxide ultimately will drive
temperature changes to areas we do not want to see, that instead of
really engaging Congressional talent in figuring out how to deal with
this problem, we try to poke little pinholes in one particular
statistical conclusion of one particular study where the overwhelming
evidence is that we have to act to deal with this global challenge.
It is not fitting for this Congress, America that should lead
the technology that drives the energy future of the world, to sit here
to ask these fine statisticians to go into mind-numbing detail about
whether this particular year was hotter than it was in 980. I don't
care whether this year or yesterday was the hottest day. It was
pretty hot here yesterday, but I don't care whether it may have been
hotter in 980. What I care about is whether there will be snow in
the mountains for my kids and grandkids to ski on 50 years from now,
and there is not going to be unless this Congress pulls its head out
of the sand and acts.
So I look forward to the day that we have a Congress that will
adopt the position that we need to deal with technology rather than
statistical recreations of the tobacco industry's effort to create
doubt. Thank you.
MR. WHITFIELD. Mr. Bass.
MR. BASS. Thank you, Mr. Chairman, and thank you for holding
this hearing.
I want to start by saying that in my opinion, there is
absolutely nothing inappropriate about the subject of this hearing,
and although the data may be mind-numbing, nonetheless there are
those--I am probably not one of them--who really get into going
through the data and the details and so forth to try to figure out
what the problem is. Ultimately, the issue underlying the hearing
today and any others that we have is not going to be about math, it
is going to be about the effect of the extraction of enormous
quantities of hydrocarbons from the middle of the Earth and from
underground and the combustion of those hydrocarbons and the
resultant impact that that has, if any, on the climate of the world.
Now, in another life when I used to sell architectural panel
products for buildings, I was often asked by a customer whether or
not the panel that I was trying to sell passed the ASTM, American
Society for Testing Materials, E84 test, and I always used to respond
because, of course, we couldn't afford to have that test conducted, I
used to say well, it hasn't but I subjected it to what I called the
elephant foot test and I built--every fall I burned a huge pile of
brush in my field on the farm I live on and one year I just took one
of the panels that I planned to sell and I threw it on top of the pile
and it sat there for 30 minutes and nothing happened. Is that
satisfactory? Well, we can spend I think a productive period of time
talking about the basis upon which the data was developed to determine
the Mann report or the Wegman report or Dr. North's report and so
forth, but ultimately I think we need to recognize that there is a
problem and anyone who denies the existence of any problem associated
with the release of these hydrocarbons I think really needs--I want to
be friendly about this--really needs to rethink that premise. There
is something going on and I think finding out what that something is
and then trying to debate a policy whereby we address that issue is
constructive.
So I want to thank my friend from Kentucky for holding this
hearing and I look forward to hearing the witnesses' testimony, and I
yield back.
MR. WHITFIELD. Thank you, Mr. Bass. At this time I recognize
Mr. Waxman of California.
MR. WAXMAN. Thank you very much, Mr. Chairman.
The party that is in the majority selects the Chairman of the
committees and the subcommittees and they can decide what priorities
ought to be given to different issues and what hearings are to be
called. Now, in the past 12 years, we have had study after study
after study raising genuine concern about global warming and climate
change. The Energy and Commerce Committee is a committee that has
legislative jurisdiction over this issue. So for the past 12 years
this committee has a very amazing record on this issue. This is only
the second hearing in 12 years. The first one was to look at the very
intricate issue of modeling on predictions of climate change and this
one is to look at studies from 1998 and 1999 to see whether those
studies are refuted by the work of the two gentlemen before us today.
We have not held a hearing looking at what is the overwhelming
scientific consensus that global warming is real and is caused by
humans. We have not focused on some of the important recent
scientific news on global warming such as a study showing that climate
change is causing increased wildfires in the American West or the recent
studies that show that global warming is leading to more intense
hurricanes.
The committee could go a step further by examining the practical
solutions that could begin to reduce our greenhouse gas emissions, and
if the committee leadership wanted to conduct important and nonpartisan
oversight, it could investigate why a former employee of ExxonMobil
operated out of the Bush White House to sow doubt in government
publications on global warming. Instead, this committee is doing what
the deniers of global warming would have us do, ignore all the important
questions and divert ourselves to a ridiculous effort to discredit a
climate scientist and two studies he published eight years ago.
Chairman Barton began this dubious investigation in June of
2005 when he sent a letter demanding the funding for every study that
had ever been conducted by Dr. Michael Mann, demanding he turn over all
of the data for all their research and made over burdensome and
intrusive requests. The Washington Post accused our Chairman of
conducting a witch hunt. The Chairman of the Science Committee,
Sherwood Boehlert, called the investigation "misguided" and
"illegitimate." Well, oftentimes when we have scientific disputes we
ask the National Academy of Sciences to review the matter. Instead of
asking them--even though they offered their services to help resolve
controversy--the Academy wasn't called on by this committee but by
Representative Boehlert's committee and the Academy issued its
report last month and they found that they largely upheld the
findings of Dr. Mann.
So I have to submit that I don't find this hearing to be one
about truth. It is about sowing doubt and spreading disinformation,
and I chaired all those committees over the years where I heard from
tobacco executives who always insisted on having their scientists come
in and say it is only coincidental that more cancers and other
diseases seem to afflict smokers but there is no causal relationship.
Not only is this hearing not legit in trying to deal with an important
issue, it isn't even fair. We are going to hear people attacking
Dr. Mann but we are not going to have Dr. Mann here to confront the
accusations against him. That is not science where you hear only one
side. Science is hearing both sides, looking at the evidence, reaching
conclusions based on the evidence. Dr. Mann was willing to testify
before the committee but his schedule would not be accommodated.
Global warming is an incredibly serious problem and this is not a
serious hearing.
I would submit that if you have doubts, fine, but prudent
people would start doing something in case your doubts on the
Republican side of the aisle are wrong. We would start taking
measures to reduce these greenhouse gas emissions that seem to be
causing enormous damage to our planet and a threat to human life.
Instead, we are looking at reports from 8 years ago and trying to
debunk them. That is not an indication to me, that and the 12 years
of inaction by this committee, that there is any interest on behalf
of the Republican leadership to come to terms with what is not a
partisan issue at all but one that is a very important issue for us
to address.
[The prepared statement of Hon. Henry Waxman follows:]
THE PREPARED STATEMENT OF THE HON. HENRY WAXMAN, A REPRESENTATIVE IN
CONGRESS FROM THE STATE OF CALIFORNIA
Today, the Subcommittee holds only the second hearing on global
warming in the Energy and Commerce Committee since the Republicans
took over the House of Representatives in 1995. With so many
important aspects to global warming and twelve years of virtual
inaction, there's a lot of important work for the Committee to do.
It could start by highlighting the overwhelming scientific
consensus that global warming is real and is caused by humans. Or
it could focus on some of the important recent scientific news on
global warming, such as the study showing that climate change is
causing increased wildfires in the American West or the recent
studies that show that global warming is leading to more intense
hurricanes.
The Committee could go a step further by examining the
practical solutions that can begin to reduce our green house gas
emissions. And if it wanted to conduct important and non-partisan
oversight, it could investigate why a former employee of ExxonMobil
operated out of the Bush White House to sow doubt in government
publications on global warming.
Instead, the Committee is doing exactly what the big oil
companies hope for it to do...it ignores the important questions
and diverts to a ridiculous effort to discredit a climate scientist
and a study he published eight years ago.
Chairman Barton began this dubious investigation when he wrote
Dr. Michael Mann and several other researchers in June 2005. He
demanded to know the source of funding for every study they had
ever conducted, demanded they turnover all of the data for all of
their research, and made other burdensome and intrusive requests.
The Washington Post accused Chairman Barton of conducting a witch
hunt. The Chairman of the House Science Committee Sherwood
Boehlert called the investigation "misguided" and "illegitimate."
And the nation's premiere science organizations quickly condemned the
investigation. The American Association for the Advancement of
Science wrote to Chairman Barton stating that his letters "give the
impression of a search for some basis on which to discredit these
particular scientists and findings, rather than a search for
understanding."
The National Academy of Sciences also weighed in, stating that
Chairman Barton's approach was "intimidating" to researchers and
offering the services of the Academy to help resolve the controversy.
Ironically, it wasn't Chairman Barton who took the Academy up on its
offer. Instead, Rep. Boehlert requested the Academy report that was
released last month. The Academy largely upheld the findings of
Dr. Mann.
This hearing isn't about finding the truth. It's about sowing doubt
and spreading disinformation. The closest parallel is the decades-
long campaign of the tobacco industry to deny that nicotine is
addictive and cigarettes cause cancer.
And the hearing isn't even fair. Today we're going to attack the
work of Dr. Mann, but we're not going to give Dr. Mann a chance to
confront the accusations against him. Dr. Mann was willing to
testify before the Committee, but his schedule was not accommodated
and so he is going to be tried in absentia.
Global warming is an incredibly serious problem, but this is not a
serious hearing. It's a diversion and a delaying tactic. And -
worst of all - it is a missed opportunity to begin the process of
protecting our children from the catastrophic effects of global
warming.
I know that the Chairman of this Subcommittee has never accepted the
science about global warming. To bolster his argument over the years,
he has repeatedly brought to the attention of the Committee, the views
of Gregg Easterbrook and his book, "A Moment on the Earth."
So, I just want to make sure that the Chairman is aware of
Mr. Easterbrook's op-ed from May 26, 2006, in which Mr. Easterbrook
announces that he has changed from "a skeptic to a convert." He says
that it is "case closed," and that a strong scientific consensus shows
that global warming "is a real phenomenon posing real danger."
I am glad that Mr. Easterbrook has revisited his views and corrected
them accordingly. I hope the Chairman is willing to do the same.
MR. WHITFIELD. Dr. Burgess, you are recognized.
MR. BURGESS. Thank you, Mr. Chairman, for the recognition.
I thank the Ranking Member for pointing out that partisanship has no
place in this debate and I hope we won't see it again this morning.
I will point out just for the record that Dr. Mann has been
invited to appear before this committee before this hearing this
morning. He couldn't be here. Apparently he is on vacation that
couldn't be interrupted and maybe he can be here next week, and if
he can be here next week, we will certainly be grateful to hear from
him, but fortunately we do have his number one colleague, Dr. Crowley,
on our second panel and I am grateful for that as I am sure the
Minority is as well.
Again, I thank the Chairman for the recognition and I want to
thank all of our witnesses for taking their valuable time to be with
us here today. I know there are many other productive activities you
could have been doing. And we have already heard from our friends on
the other side of the room that there does indeed currently exist an
international consensus that global warming exists and that human
beings have caused it. They didn't say so but I would further
extrapolate that it is Americans that have caused it and it is
probably one American in particular and he lives in the White House.
But I think it is fair to point out that no such consensus exists.
The Earth has been heating and cooling for millions of
years. There have been big ice ages, little ice ages and it is fair
to say that in between those two cooling events it probably even got
a little warm. The Earth's climate is cyclical and we have only been
paying attention during the past few hundred years. With the cyclical
nature of the Earth's climate, it is plausible to say that the Earth's
temperatures would be on the rise today regardless of what humans did
or didn't do. Thirty-five years ago, I was a freshman in a geology
class and we learned how the Earth itself was spun off as a hot ball
of gases and gradually cooled and it was postulated that the Earth had
been cooling ever since and indeed perhaps Armageddon would come one
day not as a fire or as a flood but as we cooled into that last ice
age. Now we have global warming staring us in the face.
I am not saying we should completely dismiss fears of global
warming as an inaccurate science. I think that it merits thoughtful
and serious debate and we owe the subject matter thoughtful and
serious debate. Part of my problem with the whole process is, that
it seems that the cleaner we make our energy generation capability,
and indeed we have cleaned our energy generation capability over the
years, and the Ranking Member can take considerable credit for that
with legislation that he has passed, but now we want to come up
against an obstacle that nothing can come out of those pipes, we
have already taken out the VOX, the NOX, the SOX, the POX, the TOX.
Now it is the carbon dioxide and water that are coming out of those
smokestacks that has to be stopped, and it is interesting that later
today--we have a mechanism to stop the carbon dioxide from coming out
of those stacks and later today we are having a hearing in the Energy
and Air Quality Subcommittee of this same Energy and Commerce
Committee on the Yucca Mountain nuclear waste repository. One of the
reasons why Yucca Mountain is so important is because of the increasing
importance of nuclear power in our national fuel mix as an
emissions-free, carbon-free-emissions source of power.
In fact, I would submit that along with the passage of the Clean
Air Act in the past few decades, perhaps one of the greatest missed
opportunities--if the Clean Air Act was an enacted opportunity, one
of the great missed opportunities was abandonment of nuclear power in
the late 1970s and allowing other countries to get ahead of us in that
regard so now that our dependence on foreign oil--and we knew in the
1974 embargo that dependence on foreign oil was not a good foreign
policy strategy and yet for whatever reason we have lagged with
development of nuclear fuel, so I am grateful we are having that
hearing later on today.
It is false to presume that a consensus exists today or that
human activity has been proven to cause global warming, and that is
the crux of this hearing. What we are here today to discuss is the
broader issue of the use of sound statistical analysis and the peer
review process through the lens of the hockey stick temperature
studies, but the focus of our hearing today is to examine the
statistical analysis and methodology used when evaluating the
influential report on global warming written by Dr. Mann. As the
U.S. Congress and even the international policymaking bodies look
to the scientific community to provide information and analysis, it
is especially important to make certain that the processes are in
place to ensure that we are using sound and unbiased science that
has undergone rigorous peer review process.
I would point out that simply turning off the electrical
generation plants that provide the air conditioning back in my
district would not be a viable option. I would submit that the good
people of California got upset when some people in Texas turned off
their electrical generation plants a few years ago. I don't see that
as a viable option. Should we move to other methods? Perhaps, but
we need to do so in a sound and scientific manner.
With that, Mr. Chairman, I will yield back.
MR. WHITFIELD. At this time I recognize Ms. Baldwin of--
okay, Ms. Schakowsky.
MR. STUPAK. Mr. Chairman, before we do that, if I may, I
would like to put into the record a letter from Georgetown University
Law Center Institute for Public Representation explaining why
Dr. Mann cannot be here on such short notice from the committee and
other dates he was available to testify. I would like to put that
in the record, a follow-up of the statements that he is on vacation,
which is not true.
MR. WHITFIELD. We would be happy to do so unless--
MR. STUPAK. Thank you.
MR. WHITFIELD. --there is objection. Is there objection to
this going in? Thank you.
MR. STUPAK. This letter of July 19 was provided actually by
fax to Mr. Spencer and Mr. Paoletta.
[The information follows:]
MR. WHITFIELD. Ms. Schakowsky.
MS. SCHAKOWSKY. Thank you, Mr. Chairman.
I am glad that we are holding a hearing on global climate
change although I am disappointed in the actual substance of this, and
I have a statement for the record that is prepared but I would like to
just say a couple of things extemporaneously about this issue which I
care so much about.
I guess I would ask about this particular hearing in some ways
is, what is the point? I think that there are certain agreements that
all of the scientific community would adhere to, and one is that
climate change, the question being how much does human activity
contribute to that, but the climate change is definitely happening,
that the Earth is warming right now and there is a large and robust
body of science that documents that, that even in the Middle Ages it
could have been as warm as now although that is not clear at all, that
the temperature is going up and that climate change impacts are being
observed now and are projected to be of enormous consequence, enormous
consequence. If the snow in the Himalayas melts, which provides
water for I think close to a billion people, this is of great concern.
As a grandmother, I am concerned that my grandchildren may
never see or know about a polar bear in the wild and that the coral
reefs are disappearing. The fact that we are seeing stronger
hurricanes and tornadoes and that there is drought and flood and
hunger and displacement as a consequence, these are things that we
know about, and so the question is, even if human activity is not
the principal cause of global warming, which most scientists do
believe that is the case, but even if it weren't but we are simply
contributing to it, why wouldn't we be focusing on now how human
activity could reduce the impact of global warming, how we could help
to stem the tide of these devastating consequences that will hurt all
of humanity. Why wouldn't we be focusing on that instead of trying
to discredit a report that is only one piece of the evidence that
establishes that we are in the midst of a tremendous change that is
going to impact the possibility of life as we know it on this planet.
We don't have to be talking about the kinds of devastating
changes in lifestyle that Americans won't accept. Instead, because
of our ingenuity, always being on the cutting edge of technology and
change, we can manage the changes that are needed in order to sustain
life on this planet. It just makes no sense to me--I mean, we will
talk about it and we will get into it how the Mann statistics that
are going to be discredited actually weren't used in his final report
and we can go into all the details back and forth about the scientific
evidence but it seems to me that this is a waste of time, that what
we ought to be talking about is how are we going to confront what
everyone knows is a real problem, and if human activity can be changed
in some way to ameliorate that problem, for the life of me I can't
understand why all of us together in a bipartisan way wouldn't want
to do that.
I have a young person in my district who really is absolutely
obsessed with the issue of global warming. He is a junior high school
student. His mother is worried about him because he worries about
it so much. To me, the answer isn't explaining to him oh, be happy,
don't worry, this isn't really an issue, there is nothing you can do
about it. The answer is, we need to tell young people, the next
generation, my grandchildren, that there are things that we can do
today, and so I plead with my colleagues on both sides of the aisle,
let us get down to solutions, not discrediting one tiny piece of the
mass of evidence that says that we are in trouble right now and that
literally billions of people, all the people are on our plant, will
suffer if we don't get down to the business of finding a solution,
so I thank you, Mr. Chairman, for the time.
MR. WHITFIELD. Thank you. Mr. Stearns, you are recognized
for 5 minutes.
MR. STEARNS. Thank you, Mr. Chairman. I think Mr. Stupak put
in the letter of July 14 from Mr. Mann's lawyer. I would like
unanimous consent to put in the letter of July 13 that preceded that,
which if without objection I would like that--
MR. STUPAK. Well, I guess I will have to object until we see
it. Can we at least see it?
MR. STEARNS. Oh, sure, sure. Yes. You put a letter that came
after the first letter and I thought it would be appropriate if we
include that letter too since that is a day earlier in which he said he
could not make our committee and for whatever reason he couldn't make
it and in fact he suggested that if we do have this hearing, that we
should have Dr. Thomas J. Crowley, and indeed we took his advice and
we got Dr. Crowley. He is going to be on the second panel, so we
took Dr. Mann's advice, we got the people he wanted, and I am sure,
Mr. Chairman, other people had to cut their vacation short to be here,
perhaps even Dr. North did. This is a time when a lot of us are taking
vacations, not necessarily Members of Congress who are into a
campaign mode but the rest of you perhaps are doing that, and I can
understand that, but the letter Mr. Stupak put in said that he would
not even show up on the 27th. The letter I am putting in says he won't
show up today. Unfortunately, his lawyer from the Georgetown
University Law Center keeps talking about July--I think in his letter--
I don't have it in front of me but he has a typographical error in
both letters in which he cites Friday, July 9. In all calendars,
July 9 is not a Friday.
MR. WHITFIELD. They are not objecting to the letter.
[The information follows:]
MR. STEARNS. Okay. Good. All right. Well, I was just
talking to make sure Mr. Stupak had plenty of time to read it so that
I could go forward.
You know, I think almost everybody in this room and perhaps
everybody on this oversight committee would agree that there is global
warming of some kind. The question is, is it sinusoidal, that is, are
we looking at warming today in which there was warming like this or
similar to this in the Middle Ages and have we seen a warming and a
cooling much like a sinusoidal wave, and so we are trying to look at
Dr. Mann's analysis and we are trying to say, is he absolutely right
that we have this hockey stick effect that is just flat and then
suddenly comes up.
Now, we have Dr. Wegman's analysis concludes that Dr. Mann's
work cannot support the claim that the 1990s were the warmest decade
in the millennium. I mean, that is what he is saying. Some people
are questioning Dr. Mann, his quantitative analysis, and that is fine.
He could be right, he could be wrong. Now, Dr. North, in looking
through his testimony which he is going to give, he sort of confirms
what I think is possible, that this warming and cooling is a sinusoidal
wave and that in fact, let me just read what Dr. North says in his
testimony. He says that it is plausible that the Northern Hemisphere
was warmer during the last few decades of the 20th Century than during
any comparable period over the preceding millennium. That is what he
says. However, the substantial uncertainties currently present in
the quantitative assessment, same thing that Dr. Wegman says, of
large-scale surface temperature changes prior to about 1600 A.D.
lower our confidence in this conclusion compared to the high level
of confidence we place in the Little Ice Age cooling and 20th Century
warming. So we have two distinguished individuals who are
professionals in their fields indicating that it is not absolutely
true that Dr. Mann is correct in his analysis and Dr. North went on
to say even less confidence can be placed in the original conclusions
by Dr. Mann.
So, I mean, for anybody on the other side to say this not a
legitimate hearing is incorrect. We have taken people that Dr. Mann
wanted and we put them on here as witnesses. We have asked Dr. Mann
to come to this hearing. We have asked him to come to the 27th. He
won't come. He has hired a lawyer to spar with our people to say why
he won't come. By golly, if he really is interested in solving this
problem, I would cut my vacation short and whatever he is doing to say
I will be here because I think in the interest of science, I would
like to have an open hearing and talk about it. So I think, one, it
is a legitimate hearing. Two, we have offered Dr. Mann two
opportunities and yet his lawyer has indicated he won't show up. So
this is a very important issue but I think overall, all of us here
are trying to understand this and we would agree that there is
probably global warming. What we want to know is, is this sinusoidal
or is this something that is aberrational.
Let me conclude by saying that yes, we should have further
inquiries into this matter. Perhaps as a result of this hearing we
will. Temperature studies and the effect of climate change, all these
are very important to our very existence. So Mr. Chairman, I commend
what you are doing and I commend the other side too to keep an open
mind here and to hear Dr. Wegman and to hear Dr. North and to read
their opening statements where you will see they have less confidence
and they certainly have as much credibility on this matter as
Dr. Mann, and I am just so sorry, so sorry that Dr. Mann is not
showing up today, he is not showing up on the 27th, and at this
point I am not clear, Mr. Chairman, when you will get him. Thank
you.
MR. WHITFIELD. Ms. Baldwin, you are recognized for 5 minutes.
MR. STUPAK. Mr. Chairman, may I ask unanimous consent that
the letter that we received from Dr. Mann's lawyer indicating he would
like to come at the same time these witnesses are here be entered into
the record.
MR. WHITFIELD. It has been.
MR. STUPAK. Oh, it has been? Oh, okay. Thank you.
MR. WHITFIELD. We have had two letters introduced into the
record from his lawyer, both.
MS. BALDWIN. Thank you, Mr. Chairman. It doesn't take much
more than a quick walk outside today to know that the thermometer has
reached dangerously high levels and government heat alerts are
abounding these days but this summer is not unique. Each year
summers are growing warmer and warmer and so are the winters, falls,
and springs. Of the 20 hottest years on record, 19 have occurred in
the 1980s or later. 2005 was one of the hottest years on records and
so far 2006 has set record levels for its high temperatures.
Unfortunately, despite overwhelming scientific evidence that
our planet is warming at dramatic rates, no political consensus for
bold action has followed and that is the problem. Politicians ignore
sound science showing evidence that the Earth is warming at an
unprecedented rate, that carbon dioxide levels are rising, and that
human activities are largely the cause. But beyond ignoring sound
science, they are doing other disturbing things. I see political
interference in science these days. In fact, time after time, sound
science has been censored in order to maintain a political agenda.
Here are just a few examples.
In 2003, the EPA was ordered by the White House to delete
critical sections relating to climate change from its report on the
environment. In 2005, the White House insisted upon weakening
language relating to the impact of global climate change in a
document that served as the basis of negotiations during the G8
Summit, and just a few months ago the Administration tried to silence
a NASA scientist from talking about the need to reduce greenhouse
gases linked to global warming. I could point to many other examples,
some on this topic, some outside, but it is a disturbing trend indeed.
With all these examples, it only becomes more clear that false
logic will not bring us closer to an understanding of the scientific
truth. The truth is alarming. Sea levels are rising. Glaciers are
melting and storms are becoming more intense, and the result is the
near extinction of animals such as polar bears, the compromising of
coastal ecosystems, and the threatening of human life as heat waves
become prevalent and disease-carrying insects grow more abundant.
Mr. Chairman, I often speak about America's need to take bold
action and the importance of us leading the world on environmental
issues. Now is the time for us to show our commitment for if we do
nothing, we risk an uncertain and unstable future. So I ask, what
are the consequences if the cynics and naysayers and keepers of the
status quo are wrong? We have a moral and an ethical obligation to
act and I just hope that today we will take some steps in that right
direction.
Thank you, Mr. Chairman. I yield back the balance of my time.
MR. WHITFIELD. Thank you, Ms. Baldwin. At this time I
recognize Mrs. Blackburn.
MRS. BLACKBURN. Thank you, Mr. Chairman. Thank you for
holding the hearing. Thank you to the staff for the preparation work
they have done and to our witnesses appearing before us to comment
on the matter. We thank you for being here. We are concerned about
it. I do think it is prudent to address the issue and we are seeking
information. We thank you for being here to supply some.
The ability to obtain and analyze the data and the methods
that a scientist uses to form a theory about the universe is central
to science. For hundreds of years society has placed the utmost
importance on the scientific method to validate theories which is
predicated on the ability to replicate and verify a scientist's work.
If the work cannot be replicated and verified by independent experts,
then that work's conclusions become more speculation and possibly
some will say it should be open to classification as outright
scientific dishonesty.
Last year Chairman Barton inquired into the background of
some recent climate change studies that had been held by scientific
portions of the scientific community as proof of drastic global
warming. Now, I am old enough to remember that as a teen in the
late 1960s, I sat in science classes and in a geology class and I
was warned of a returning and impending ice age. By the time I
reached my current age, the world was going to be covered in ice,
North America would have a 9-month winter, our food supplies would
be short, and I would be freezing to death all the time. Well, I
guess times changed or maybe that old group of scientists had some
kind of political interference in favor of the new group of
scientists who now want the Earth to warm up.
Now, after some independent analysis it seems that all
scientists could possibly be misled on some of their issues. Both
the National Academy of Sciences and Dr. Wegman's committee analyzed
the hockey stick report by Dr. Mann that has become the poster child
for proof of global warming. The committees came to the conclusion
that Dr. Mann's hockey stick report failed verification tests and did
not employ proper statistical methods. Also, it appears that Dr. Mann
is part of a social network or could be part of a social network of
climate scientists who almost always use the same data sets and review
each other's works. There is a contention that they would dismiss
critics who had legitimate concerns, rarely used statistical experts
for the data they used in their reports, and make it very difficult
for reviewers to obtain background data and analysis. These
revelations point to the lack of independent peer review and how it
is practically impossible to replicate or verify Dr. Mann's work by
those not affiliated with the network of scientists, so we are looking
forward to hearing about that work today. Could it be that this
particular work violates the principles of the scientific method
and should be dismissed until it meets the basic qualifications?
Could that have been some of what happened to the Ice Age return
theory of the 1960s?
Climate is affected by numerous causes that interact with
each other. When a scientific paper comes to a conclusion about
climate, its results must be able to be replicated and shown to
have direct causation and not merely correlation. If these steps
cannot be done, then making conclusive statements of how one cause
changes the climate is unwarranted and not real science.
Now, there is strong evidence that the Earth has warmed
about half a degree Fahrenheit from 1900 to 1940 but this is
widely attributed to an increase in solar activity during those
years and there are indications that the Earth warmed another
half degree Fahrenheit from 1940 until the present but that much of
this warming occurred in the past 7 years, and if you look at the
surface record in the satellite data, it is pretty clear and
possible that this warming is mostly due to the 1998 El Nino, so
for the past hundred years the Earth has warmed about one degree
and you can make the cause that it was not caused by human activity
but by natural events. Possibly that is what happened to the return
of that old Ice Age.
Mr. Chairman, if one looks at the data in an objective
manner, I believe that one would conclude that the Earth's climate
is not in serious danger or not standing at the edge of a precipice.
Maybe our focus should be first on getting the information. Maybe
our focus should not be on environmentalism. Maybe the focus should
be on common-sense conservatism. I would challenge my colleagues
on the other side to approach this issue to learn the truth about
the Earth's climate, not to form an agenda.
I am looking forward to our witnesses in the hearing today.
I yield back.
MR. WHITFIELD. Thank you, Mrs. Blackburn. I think that
concludes the opening statements so we will proceed to the first
panel of witnesses, and I would say to you, Dr. North and Dr. Wegman,
that this committee is holding an investigative hearing, and when
doing so we do have the practice of taking testimony under oath,
and I would ask you, do either of you have any objection to
testifying under oath?
Now, Dr. Wegman, accompanying you today is one of the statisticians
that worked with your three-person panel, and would you introduce
her? Although it is my understanding she is not going to be
testifying but she is from Johns Hopkins, I believe.
DR. WEGMAN. That is correct. It is Dr. Yasmin Said.
Dr. Said actually did a tour at Johns Hopkins but has just won a
very prestigious National Institutes of Health postdoctoral
fellowship and she will be with us in George Mason for the next
3 years.
MR. WHITFIELD. And although she is not going to testify,
you may consult with her. Dr. Wegman, if you and Dr. North would
stand up, I would like to swear you in. Of course, under the rules
of the House and the rules of the committee, you are also entitled
to legal counsel and I am assuming you don't need legal counsel
today, but if you do--
DR. WEGMAN. Hopefully not.
MR. WHITFIELD. If you would raise your right hand.
[Witnesses sworn.]
MR. WHITFIELD. Thank you, very much. You are now both under
oath, and Dr. Wegman, you are recognized for your opening statement,
and I would say to both of you, I know both of you have rather
lengthy documents that we appreciate your preparing and those will
be entered into the record in their entirety, and if you all could
keep your statements to 5 to 7 minutes or so, we would appreciate
that. Dr. Wegman, you are recognized.
STATEMENTS OF DR. EDWARD J. WEGMAN, CENTER FOR COMPUTATIONAL
STATISTICS, GEORGE MASON UNIVERSITY; AND DR. GERALD R. NORTH,
DEPARTMENT OF ATMOSPHERIC SCIENCES, TEXAS A&M UNIVERSITY
DR. WEGMAN. Thank you, sir. I would like to begin by
circumscribing the substance of our report. We were asked to
provide independent verification by statisticians of the critiques
of the statistical methodology found in the papers of Drs. Michael
Mann, Raymond Bradley, and Malcolm Hughes published respectively in
Nature in 1998 and in Geophysical Research Letters in 1999. These
two papers have commonly been referred to as MBH98 and MBH99. The
critiques have been made by Stephen McIntyre and Ross McKitrick
published in Energy and Environment in 2003 and again in Energy and
Environment and in Geophysical Research Letters in 2005. We refer
to these are MM02, 05a and 05b, respectively.
We were also asked about the implications of our assessment.
We were not asked to assess the reality of global warming and indeed
this is not an area of our expertise. We do not assume any position
with respect to global warming except to note in our report that the
instrumented record of global average temperature has risen since
1850 according to the MBH99 chart by about 1.2 degrees Centigrade,
and in the NAS panel report chaired by Dr. North, about six-tenths
of a degree Centigrade in several places in that report.
Our panel is composed of myself, Edward Wegman at George
Mason University, David W. Scott at Rice University, and as
mentioned, Yasmin Said at the Johns Hopkins University. This ad
hoc panel has worked on a pro bono basis. We have received no
compensation, not even taxi fare, and no financial interest and
we have no financial interest in this.
Can we see slide one, please? In figure 1, we have a
document, a chart that came out of Dr. Bradley's book on
paleoclimatology, and sort of indicates the kind of things that
are used as proxy data in paleoclimatology. One thing I would
like to point out in particular that is important I think for
understanding this area is the things that are indicated--if you
look--
MR. WHITFIELD. Dr. Wegman, we need for you to use your mic.
I know it is going to be difficult but we could not hear you when
you turned around there.
DR. WEGMAN. I will refrain from doing that. The point of
this graphic is that there are many factors that affect all of the
proxies that are used in paleoclimate temperature reconstruction,
and without carefully teasing out those effects, the tree rings,
the ice cores, and so on, are not by, in and of themselves totally
temperature records.
So MBH98 and 99 use several proxy indicators to measure
global climate change. Primarily these include historical records,
tree rings, ice cores, and coral reefs. More details of the proxies
are given in our report and mentioned in the written testimony.
Could we go to figure 2, please? Some examples of tree ring
proxy series are given in figure 2. Most of the proxy series for
these tree rings show little structure but the last two show the
characteristic hockey stick shape. The principal component-like
methodology in MBH98 and 99 preferentially emphasizes these shapes as
we shall see. Principal component analysis methodology is at the
core of the MBH98 and 99 analysis methodology. Principal component
analysis is a statistical methodology often used for reducing data
sets with many variables into data sets with fewer but composite
variables. The time series proxy data involved are transformed
into their principal components where the first principal component
is intended to explain most of the variation present in the data
variables. Each of the subsequent principal components explains
less and less of the variation. In the methodology of MBH98 and
99, the first principal component is used in the temperature
reconstruction.
Could we have figure 3, please? The two principal methods
for temperature reconstructions have been used. CFR, climate field
construction is used in MBH98/99 although that terminology was
not used formally until 2005, I believe, and the other is CPS,
climate-plus-scale methodology. The CFR is essentially the
principal component-based analysis and the CPS is a simple
averaging of climate proxies. The controversy of the MBH98/99
method lies in that the proxies are incorrectly centered on the
mean period of 1902 to 1995, rather than on the whole time period.
The proxy data exhibiting the hockey stick are actually
decentered low. The updated MBH98/99 reconstruction is given in
figure 3. This fact that the proxies are centered low is apparent
in figure 3 because for most of the thousand years the
reconstruction is below zero. This is temperature anomaly. Because
the hockey stick proxies are centered too low, they will exhibit a
large effective variance, allowing the method to exhibit a
preference for selecting them as the first principal component.
The net effect of decentering the proxy data in MBH98 and MBH99
is to produce the hockey stick shape. Centering on the overall
mean is a critical factor in using principal component methodology
properly.
Could we have figure 4, please? To illustrate this, we
consider the North American tree series and apply the MBH98
methodology. The top panel shows the result from decentering. The
bottom panel shows the result when the principal components are
properly centered. The centering does make a significant
difference in the reconstruction, and as you see, while the top
panel illustrates the temperature rise or purported temperature
rise in the last 100 years or so, the bottom panel when properly
centered does not have this temperature rise.
Could we go to figure 5? To further illustrate this, we
digitized the temperature profile published in the IPCC 1990 report
and we did apply both the CFR and the CPS methods to them. The data
used here are 69 unstructured noise pseudo-proxy series with only
one copy of the 1990 profile. The upper left panel illustrates the
PC1 with proper centering. In other words, no structure is shown.
The other three panels indicate what happens when using principal
components with an increasing amount of decentering. Again, the
single series begins to overwhelm the 69 other pure noise series.
Cleary, this decentering has a big effect.
It is not clear that Dr. Mann and his associates realized
the error in their methodology at the time of publication but our
re-creation supports the critique of the MBH99 methods.
As commentary, in general we found the writing in MBH98 and
99 to be somewhat obscure and incomplete and the criticisms by
MM03/05a and 05b to be valid. The reasons for setting 1902-1995 as
the calibration period presented in the narrative of MBH98 sounds
plausible on the surface and the error may be easily overlooked by
someone not trained in statistical methodology. We note that there
is no evidence that Dr. Mann or any of the other authors in the
paleoclimate studies have significant interactions with mainstream
statisticians.
Because of this apparent isolation, we decided to attempt
to understand the paleoclimate community by exploring the social
network of authorships in the temperature reconstruction area. We
found that at least 43 authors have direct ties to Dr. Mann--and
this should be figure 6, please; thank you--have direct ties to
Dr. Mann by virtue of coauthored papers with him. Our findings
from this analysis suggest that authors in this area of the
relatively narrow field of paleoclimate studies are closely
connected. Dr. Mann has an unusually large reach in terms of
influence. He is the coauthor with every one of these people
which are indicated by the black edge borders on the top and the
side of this graph. In particular, he has a close connection with
Drs. Jones, Bradley, Hughes, Briffa, Rutherford, and Osborne and
those are indicated by the solid block on the upper left-hand
corner.
This area of social networks is based off a graph theoretic
representation, and if we go to figure 7, we can see the graph
theoretic representation. Because of these close connections,
independent studies may not be as independent as they appear to be
on the surface. Although we have no direct data on the functioning
of peer review within the paleoclimate community but, with me having
35 years of experience with peer review in both journals as well as
evaluation of research proposals, peer review may not have been as
independent as would generally be desirable.
Could we have figure 8, please? Figure 8 is a graphic that
depicts a number of papers in the paleoclimate reconstruction area
together with some of the proxies used. We note that many of the
proxies are shared. Some of the same data also suggests a lack of
independence.
The MBH98/99 work has been sufficiently politicized that this
committee can hardly reassess their public positions without losing
credibility. Overall, our community believes that the MBH98/99
assessment that the decade of the 1990s was likely the hottest
decade in the millennium and that 1998 was likely the hottest year
in the millennium cannot be supported by their analysis because of
the mathematical flaws.
We have some recommendations which flowed out of our
analysis. Recommendation one: Especially when massive amounts of
public monies and human lives are at stake, academic work should
have a more intense level of scrutiny and review. It is especially
the case that authors of policy-related documents like the IPCC
report should not be the same people as those that constructed
the academic papers.
We believe that federally funded research agencies should
develop a more comprehensive and concise policy on disclosure.
All of us writing this report have been federally funded. Our
experience with Federal funding agencies has been that they do
not generally articulate clear guidelines to the investigators as
to what must be disclosed. Federally funded work, including code,
should be made available to other researchers upon reasonable
request, especially if the intellectual property has no commercial
value. Some consideration should be granted to the data collectors
to have exclusive use of their data for 1 or 2 years prior to
publication but data collected under Federal support should be made
publicly available.
Recommendation three: With clinical trials for drugs and
devices to be approved for human use by the FDA, review and
consultation with statisticians is expected. Indeed, it is standard
practice to include statisticians in the application for approval
process. We judge this to be a good policy when public health and
also when substantial amounts of monies are involved--for example,
when there are major policy decisions to be made based on statistical
assessments. In such cases, evaluation by statisticians should be
standard practice. The evaluation phase should be a mandatory part
of all grant applications and funded accordingly.
Finally, recommendation four; emphasis should be placed on
the Federal funding of research related to a fundamental understanding
of the mechanisms of climate change. Funding should focus on
interdisciplinary teams and avoid narrowly focused disciple
research. That is a general comment and by interdisciplinary
teams, I mean including teams that involve what I like to call the
enabling sciences such as mathematics, computer science, and
statistics. Thank you, sir.
[The prepared statement of Dr. Edward J. Wegman follows:]
PREPARED STATEMENT OF DR. EDWARD J. WEGMAN, CENTER FOR COMPUTATIONAL
STATISTICS, GEORGE MASON UNIVERSITY
I would like to begin by circumscribing the substance of our report.
We were asked to provide an independent verification by statisticians
of the critiques of the statistical methodology found in the papers
of Drs. Michael Mann, Raymond Bradley and Malcolm Hughes published
respectively in Nature in 1998 and in Geophysical Research Letters
in 1999. These two papers have commonly been referred to as MBH98 and
MBH99. The critiques have been made by Stephen McIntyre and Ross
McKitrick published in Energy and Environment in 2003 and in Energy
and Environment and in Geophysical Research Letters in 2005. We refer
to these as MM03, MM05a, and MM05b respectively. We were also asked
about the implications of our assessment. We were not asked to assess
the reality of global warming and indeed this is not an area of our
expertise. We do not assume any position with respect to global
warming except to note in our report that the instrumented record of
global average temperature has risen since 1850 according to the MBH
99 chart by about 1.2� centigrade. In the NAS panel Report chaired by
Dr. North, .6� centigrade is mentioned in several places.
Our panel is composed of Edward J. Wegman (George Mason University),
David W. Scott (Rice University), and Yasmin H. Said (The Johns
Hopkins University). This Ad Hoc Panel has worked pro bono, has
received no compensation, and has no financial interest in the
outcome of the report.
MBH98, MBH99 use several proxy indicators to measure global climate
change. Primarily, these include historical records, tree rings, ice
cores, and coral reefs. More details of proxies are given in the
report and mentioned in the written testimony. [The width and density
of tree rings vary with climatic conditions (sunlight, precipitation,
temperature, humidity, and carbon dioxide and nitrogen oxides
availability), soil conditions, tree species, tree age, and stored
carbohydrates in the trees. The width and density of tree rings are
dependent on many confounding factors, making isolation of the
climatic temperature signal uncertain. It is usually the case that
width and density of tree rings are monitored in conjunction in order
to more accurately use them as climate proxies. Ice cores are the
accumulation of snow and ice over many years that have recrystallized
and have trapped air bubbles from previous time periods. The
composition of these ice cores, especially the presence of hydrogen
and oxygen isotopes, provides a picture of the climate at the time.
The relative concentrations of the heavier isotopes in the condensate
indicate the temperature of condensation, allowing for ice cores to be
used in global temperature reconstruction. In addition to the isotope
concentration, the air bubbles trapped in the ice cores allow for
measurement of the atmospheric concentrations of trace gases,
including greenhouse gases carbon dioxide, methane, and nitrous
oxide.]
Some examples of tree ring proxy series are given in Figure 2. Most of
the proxy series show little structure, but the last two show the
characteristic 'hockey stick' shape. The principal component-like
methodology in MBH 98/99 preferentially emphasizes these shapes as
we shall see.
Principal component analysis methodology is at the core of the
MBH98/99 analysis methodology. Principal component analysis is a
statistical methodology often used for reducing datasets with many
variables into datasets with fewer, but composite variables. The
time series proxy data involved are transformed into their principal
components, where the first principal component is intended to
explain most of the variation present in the data variables. Each
subsequent principal component explains less and less of the
variation. In the methodology of MBH98/99, the first principal
component is used in the temperature reconstruction.
Two principal methods for temperature reconstructions have been used;
CFR (climate field construction used in MBH98/99) and CPS (climate-
plus-scale). The CFR is essentially the principal component based
analysis and the CPS is a simple averaging of climate proxies. The
controversy of the MBH98/99 methods lies in that the proxies are
incorrectly centered on the mean of the period 1902-1995, rather
than on the whole time period. The proxy data exhibiting the hockey
stick shape are actually decentered low. The updated MBH99
reconstruction is given in Figure 3. This fact that the proxies are
centered low is apparent in Figure 3 because for most of the 1000
years, the reconstruction is below zero. Because the 'hockey stick'
proxies are centered too low, they will exhibit a larger effective
'variance', allowing the method to exhibit a preference for
selecting them as the first principal component. The net effect of
this decentering using the proxy data in MBH98 and MBH99 is to
produce a 'hockey stick' shape. Centering on the overall mean is a
critical factor in using the principal component methodology
properly.
To illustrate this, we consider the North America Tree series and
apply the MBH98 methodology. The top panel shows the result from the
de-centering. The bottom panel shows the result when the principal
components are properly centered. Thus the centering does make a
significant difference to the reconstruction.
To further illustrate this, we digitized the temperature profile
published in the IPCC 1990 report and applied both the CFR and the
CPS methods to them. The data used here are 69 unstructured noise
pseudo-proxy series and only one copy of the 1990 profile. The upper
left panel illustrates the PC1 with proper centering. In other words,
no structure is shown. The other 3 panels indicate what happens using
principal components with an increasing amount of de-centering.
Again, the single series begins to overwhelm the other 69 pure noise
series. Clearly, these have a big effect.
It is not clear that Mann and associates realized the error in their
methodology at the time of publication. Our re-creation supports the
critique of the MBH98 methods.
In general, we found the writing in MBH98 and MBH99 to be somewhat
obscure and incomplete and the criticisms by MM03/05a/05b to be valid.
The reasons for setting 1902-1995 as the calibration period presented
in the narrative of MBH98 sounds plausible, and the error may be easily
overlooked by someone not trained in statistical methodology. We note
that there is no evidence that Dr. Mann or any of the other authors in
paleoclimate studies have had significant interactions with
mainstream statisticians.
Because of this apparent isolation, we decided to attempt to
understand the paleoclimate community by exploring the social
network of authorships in temperature reconstruction.
We found that at least 43 authors have direct ties to Dr. Mann by
virtue of coauthored papers with him. Our findings from this analysis
suggest that authors in the area of this relatively narrow field of
paleoclimate studies are closely connected. Dr. Mann has an
unusually large reach in terms of influence and in particular
Drs. Jones, Bradley, Hughes, Briffa, Rutherford and Osborn.
Because of these close connections, independent studies may not be
as independent as they might appear on the surface. Although we have
no direct data on the functioning of peer review within the
paleoclimate community, but with 35 years of experience with peer
review in both journals as well as evaluation of research proposals,
peer review may not have been as independent as would generally be
desirable.
Figure 8 is a graphic that depicts a number of papers in the
paleoclimate reconstruction area together with some of the proxies
used. We note that many of the proxies are shared. Using the same
data also suggests a lack of independence.
The MBH98/99 work has been sufficiently politicized that this
community can hardly reassess their public positions without losing
credibility. Overall, our committee believes that the MBH99
assessment that the decade of the 1990s was the likely the hottest
decade of the millennium and that 1998 was likely the hottest year
of the millennium cannot be supported by their analysis.
Recommendations
Recommendation 1. Especially when massive amounts of public monies
and human lives are at stake, academic work should have a more
intense level of scrutiny and review. It is especially the case
that authors of policy-related documents like the IPCC report,
Climate Change 2001: The Scientific Basis, should not be the same
people as those that constructed the academic papers.
Recommendation 2. We believe that federally funded research agencies
should develop a more comprehensive and concise policy on
disclosure. All of us writing this report have been federally
funded. Our experience with funding agencies has been that they do
not in general articulate clear guidelines to the investigators as
to what must be disclosed. Federally funded work including code
should be made available to other researchers upon reasonable
request, especially if the intellectual property has no commercial
value. Some consideration should be granted to data collectors to
have exclusive use of their data for one or two years, prior to
publication. But data collected under federal support should be
made publicly available.
Recommendation 3. With clinical trials for drugs and devices to be
approved for human use by the FDA, review and consultation with
statisticians is expected. Indeed, it is standard practice to
include statisticians in the application-for-approval process. We
judge this to be a good policy when public health and also when
substantial amounts of monies are involved, for example, when there
are major policy decisions to be made based on statistical
assessments. In such cases, evaluation by statisticians should be
standard practice. This evaluation phase should be a mandatory
part of all grant applications and funded accordingly.
Recommendation 4. Emphasis should be placed on the Federal funding
of research related to fundamental understanding of the mechanisms
of climate change. Funding should focus on interdisciplinary teams
and avoid narrowly focused discipline research.
MR. WHITFIELD. Thank you, Dr. Wegman, and Dr. North, you
are recognized for your opening statement.
DR. NORTH. Thank you, Mr. Chairman. Before I begin, I would
like to introduce Peter Bloomfield from North Carolina State
University, who is a professor of statistics there, and he was on
our committee, the NAS committee, and so I will use him if I need to
during the course of--
MR. WHITFIELD. Welcome, Dr. Bloomfield.
DR. NORTH. Good morning, Mr. Chairman, and members of the
committee. My name is Jerry North. I am a professor of atmospheric
sciences at Texas A&M University and it is nice to see one Aggie here.
He said he took some statistics there and I suspect he knows more
than he is letting on today. And I served as the Chairman of the
National Research Council's committee on surface temperature
reconstruction for the last 2,000 years.
My comments today will highlight the findings of our
committee's recently released report. Its aim was to asses the
state of scientific efforts to reconstruct surface temperature
records for the Earth over the last few thousand years, and to
comment on the implications of these efforts for our understanding
of global climate change. Surface temperature reconstructions are
only one of many lines of evidence supporting the conclusion that
the climate is warming in response to human activities. These long
records give context and perspective to the issue but they are not
the primary evidence. In fact, human-induced climate change is
quite real.
First some background. Widespread thermometer records only
the last 150 years or so. To extrapolate deeper into the past,
scientists have learned to use proxy evidence such as tree rings,
corals, ocean and lake sediments, ice cores, glacier records,
boreholes, and historical documents. To give one example, the
advances and retreats of glaciers can tell us whether the climate
has been warmer or cooler on the average at that location. Starting
in the 1990s, scientists began combining proxy evidence for many
locations in an effort to estimate temperature changes averaged
over broad geographic regions for the last few thousand years.
Much attention has been concentrated on papers published by
Michael Mann, Raymond Bradley, and Malcolm Hughes in 1998 and 1999.
This is partly because the authors concluded that the Northern
Hemisphere was warmer during the late 20th Century than at any time
during the past millennium. In addition, it was illustrated with a
simple graphic, the so-called hockey stick curve, that was featured
prominently in the 2001 Intergovernmental Panel on Climate Change
report, and you have seen that graphic.
Our committee examined the scientific literature in great
depth, considered written and oral remarks from experts representing
a broad range of perspectives. We reached five major conclusions.
Number one, the warming of about one degree Fahrenheit during the
20th Century is real. No one doubts it.
Number two: Besides the rapid warming in the 20th Century,
two other features appear to be common in the records, a cool period
centered in A.D. 1700 called the Little Ice Age and a warm period
around 1000 known as the Medieval Warm Period, details about the
latter being much less certain.
Number three: It can be said with a high level of
confidence that global mean surface temperature was higher during
the last few decades of the 20th Century than during any comparable
period since 1600. This statement is justified by the consistency
of the evidence from a wide variety of geographically diverse
proxies. If we could put that graphic up. That one. That is
the only one I will show. So here is the kind of diverse evidence
that I would like to just mention. These are different curves from
different investigators. Most of them have come out after the Mann
et al. work, and some of them don't rely on the statistical
techniques at all. The boreholes, for example, come from the
direct physics, no calibration with the instrumental temperatures,
and the same is true for the glacier length records.
Number four: Less confidence can be placed in large-scale
surface temperature reconstructions from A.D. 900 to 1600. We find
that temperatures at many, but not all, locations were higher during
the last 25 years than during any period of comparable length since
A.D. 900, but the uncertainties increase substantially as one moves
backward in time through this period and are not yet fully
quantified. Now, the way we tried to illustrate that on this
graphic is by showing a sort of darkening graying as you go back,
and one of my colleagues on the committee says well, as you go back
beyond the year 1600, things get a little murkier, so the amount of
the kinds of data that we have and so on are much less certain. We
don't understand all of the interrelations and so forth, so I can go
into that in more detail if you need it.
And number five, very little confidence can be assigned to
statements concerning the average surface temperatures prior to about
A.D. 900, so we just don't know enough about that period.
Now, the basic conclusion of the 1999 paper by Mann and his
colleagues was that the late 20th Century warmth in the Northern
Hemisphere was unprecedented during at least the last 1,000 years.
This conclusion has substantially been supported by an array of
evidence, but substantial uncertainties remain for the period before
about 1600, and I can give you some illustrations of other ways of
looking at the problem later if that should come up in questions.
Our main disagreements with the Mann 98/99 papers are related to
the assertions about warmth of individual decades and individual
years. We don't subscribe to that kind of definition of the
problem. We also question some of their statistical methodology,
in fact, some of the same claims that were put forward by
Dr. Wegman and you will hear some later as well.
However, our reservations with some aspects of the original
papers by Mann and colleagues should not undermine the fact that
the climate is warming and will continue to warm as a result of
human activities. In fact, the scientific consensus regarding
human-induced climate warming, global warming, would not be
substantively altered if the global mean surface temperature
1,000 years ago was found to be as warm as it is today although
there is evidence that this really is a very exceptional period
that we are in now, and again, I can come back to that during
questions. This is because we don't know enough about the driving
forces of the climate over that long period.
During the last 150 years, we have considerable evidence
about the increase in greenhouse gas concentrations and we know a
lot about the other things that tend to nudge the climate system
as well. By the way, a lot has been learned about climate in the
last 30 or 40 years. I mean, it is a very rapidly changing field
and we have all the giant computers and satellites now at our
disposal to help us. So we know a lot more about this than we
did 30 years ago. And in the last quarter century, when warming
was particularly steep, we also have good data on the sun because
for the last 25 years we have been measuring the sun very, very
accurately from outside the atmosphere using satellites.
Aerosols--we have a very good idea of how the dust and tiny
particles in the atmosphere have been changing over the last
25 years and probably 50, both of which--both of these two
drivers of climate change, the sun and the aerosols, really are
negligible compared to the forcing from greenhouse gases.
Moreover, climate models can only reproduce the warming of
the 20th Century when greenhouse gases are included. Our knowledge
of the driving forces over the last several thousands of years is
not yet good enough to go back beyond this recent period, so that
is the reason that that early data doesn't really close or finish
off the story.
So now in conclusion, our committee finds that large-scale
surface temperature reconstructions contribute to climate research,
they are important, and that they contain meaningful climate
signals. Our confidence in the reconstructions becomes stronger
when multiple independent lines of evidence point to the same
general result such as the warmth of the last few decades of the
20th Century relative to the last 400 years. Further research,
especially in the collection of additional proxy evidence, would
help to reduce the uncertainties and allow us to make more
definitive conclusions over longer time periods.
I thank you for your attention, and I would be happy to
answer any questions, and I may call on Dr. Bloomfield to help me.
[The prepared statement of Dr. Gerald R. North follows:]
PREPARED STATEMENT OF DR. GERALD R. NORTH, DEPARTMENT OF ATMOSPHERIC
SCIENCES, TEXAS A&M UNIVERSITY
MR. WHITFIELD. Dr. North, thank you and Dr. Wegman both
for your testimony, and Dr. North, now, you are a Ph.D. Are you
a climatologist or--
DR. NORTH. I have a Ph.D. in physics from the University
of Wisconsin.
MR. WHITFIELD. From the University of Wisconsin.
DR. NORTH. Yes.
MR. WHITFIELD. A wonderful school.
DR. NORTH. Yes. It is a wonderful school.
MR. WHITFIELD. Almost as good as Texas A&M.
DR. NORTH. Well, comparable.
MR. WHITFIELD. Now, have you had the opportunity to review
Dr. Wegman's and his associates--
DR. NORTH. Yes, I did receive it a few days ago so I don't
think I have read it in the detail that I should but I have been able
to look through it.
MR. WHITFIELD. And you all don't know each other? You are
not friends or--
DR. NORTH. No, I met him at our briefing a couple of weeks
ago just for a handshake.
MR. WHITFIELD. Well, I was wondering if you might just take
a minute or two to summarize your--as a professional in this area
and your experience in this area. What is your reaction to their
report?
DR. NORTH. Well, I think that on many things we are in
agreement. The studies that--I mean, the examination they did of
the statistical procedures and the Mann et al. papers is not the
way we would--that I would have done it in hindsight, especially
now looking back. It is not the way I would have done it. I don't
think there is anything dishonest about it or anything like that,
but I think that the analyses that the Wegman group did really
were--some of those were examined by the statisticians on our
committee and I don't think that we are in any great disagreement
about it. Let me just mention this, that the criticisms don't mean
that the MBH claims were wrong. They just mean that the MBH claims
are not convincing by themselves. So if you pull together other
information, then that does change the view a bit.
MR. WHITFIELD. Now, Dr. Wegman, I am not a statistician
but obviously a statistician is where you look at data and from
that data you try to look at the probability of something happening
or not happening and whatever. Is that just in a rough layman's
term what statistics is all about, or give me your definition of
statistics or a statistician.
DR. WEGMAN. Well, I think a statistician generally tries
to look at data and represent the meaning, the inferences that are
available from that data as straightforwardly and honestly as
possible.
MR. WHITFIELD. Now, Dr. North said that his group had
reviewed your document and that they agreed with much of what you
said and you have indicated that one of your primary concerns about
the Mann document is the center point that was utilized in his
hockey stick graph. Would you elaborate on that a little bit?
DR. WEGMAN. Yes. They used the period from 1902 to 1995,
which was the instrumented temperature record that they used, so
they used that period to calibrate the proxy data. They centered
their overall proxy data on that period, 1902 to 1995, and of
course temperature was rising in that period, so when you center
on that period, you push the rest of the proxy data below the
axis. That has, as I mentioned, the net effect of increasing the
variance and making the principal component methodology pick out
that kind of shape. So it preferentially attempts to fit those
kind of shapes in the first principal component.
MR. WHITFIELD. And it does establish this hockey stick
showing a rapidly increasing--
DR. WEGMAN. That is essentially the mechanism that creates
the hockey stick. If you do the--as I showed in the one graph, if
you do the centering properly, the hockey stick disappears.
MR. WHITFIELD. Now--
CHAIRMAN BARTON. Would the Chairman yield on that point?
MR. WHITFIELD. Yes.
CHAIRMAN BARTON. Dr. Wegman, you say when you center it
properly. Put in layman's terms that those of us that are not
statisticians, what does that mean, centering it properly?
DR. WEGMAN. Thank you for asking. The principal components
analysis methodology requires that the data be centered on the mean
of the overall series, so if you are doing reconstructions, let us
say, back to year 1000, 1000 to 2000, then you should center on
the average value of the proxy series for the period 1902 to--
CHAIRMAN BARTON. In which there is better data. I mean,
they--there could be a plausible reason why they did what they did,
the more accurate data, they are more certain of it?
DR. WEGMAN. Well, they are more certain of the temperature
data but the net effect of the decentering is to preferentially
pick out these--
CHAIRMAN BARTON. But what they should have done was if they
are going to measure from one 1000 to 2000, they should have used
all the data points and came up with the mean and centered wherever
that mean was?
DR. WEGMAN. That is correct, yes.
CHAIRMAN BARTON. Thank you.
MR. WHITFIELD. And I think the reason that is important is
that when you make a categorical statement that the 1990s were the
warmest decade in a millennium and that 1998 was the warmest year
in the 1,000, I mean, it is difficult to make a statement like that
categorically if the centering is not correct. Would you agree
with that?
DR. WEGMAN. Yes, I agree.
MR. WHITFIELD. And I think that is the whole basis of this
hearing because this hockey stick--all of us are concerned about
global warming but I do think we have an obligation and
responsibility--everyone has latched onto this hockey stick and
almost created a panic in a way, and maybe we should be panicked,
but I think it is important that we understand how the hockey stick
came about, and that is what we are talking about today. Now,
Dr. North, do you agree with Dr. Wegman's centering analysis or not?
DR. NORTH. I do. I think that he is right about that.
However, you know, we have to be careful here and not throw the
baby out with the water.
MR. WHITFIELD. Right.
DR. NORTH. Because there have been other analyses, papers
published after the Mann papers in which people just took a simple
average. Dr. Crowley wrote a paper just a short time after that in
which he didn't use the principal component analysis at all. He got
essentially the same answer. And so--
MR. WHITFIELD. Is that what we refer to as the CPS analysis?
DR. NORTH. I don't know what the initials--but he just took
the average instead of dealing with the data the way one does it in
the principal component analysis, so what I am arguing, and some
other people have also done this same, there have been many studies
later that don't use principal component analysis and the ones that
I showed you, it is not there now--
MR. WAXMAN. Mr. Chairman.
DR. NORTH. They don't all use principal component analysis.
MR. WHITFIELD. Yes?
MR. WAXMAN. Will you yield to me? I am just wondering if
Dr. Wegman is familiar with Dr. Crowley's way of handling the
statistics and if he thinks that the conclusions are suspect in the
Crowley study.
DR. WEGMAN. Well, let me say that simple averaging of
proxies, depending on how the proxies are selected, can yield the
same kind of results. In fact, if--I don't know if you can put up
my backup slide, backup figure number 2, the backup figure number
2 shows--
MR. WHITFIELD. Well, are we putting this graph up? Where
is this graph? Okay. There we go. Okay.
DR. WEGMAN. This is using the CPS, simple averaging proxy
methodology, just like the principal components, and by doing the
simple averaging of proxies appropriately selected, you can
reconstruct the same shape that you had with the principal
component-type methodology. So it is possible depending on how
you approach this.
MR. WHITFIELD. So you can do a lot of things, just
depending upon what data you use, what the centering is and so
forth?
DR. WEGMAN. Exactly.
MR. WHITFIELD. Now, let me just ask both of you one question
quickly. My time has been used by other people.
MR. WAXMAN. I would like to ask unanimous consent that the
chairman be given two additional minutes, but are you critical--
because that was my question--are you critical of his methodology in
reaching the same conclusion?
DR. WEGMAN. I am saying that it is quite possible to use the
CPS, the averaging methodology, and come to the same conclusion that
Dr. Mann had. I am not saying he did that because I haven't studied
his paper in such detail as to be willing to say that.
MR. WHITFIELD. Well, let me just ask you on this whole
issue of scientific analysis and scientific collaboration and so
forth, you mentioned this social networking, for lack of a better
term. I mean, like any other profession, scientists, statisticians,
they deal with each other, they know each other, they write articles
together and so forth. But how serious is this issue of bodies
making scientific reports and getting into a pattern of talking to
the same people all the time about the same thing and they all have
the same views? Is that a significant problem or not?
DR. WEGMAN. I think it potentially can be. It would be
naive to think that there are not competing social networks within
a discipline area. Sometimes the competing social networks keep each
other in check. In the statistical arena, for example, there is a
group of people who view themselves as classical statisticians.
There is a group of people who view themselves as Bayesian
statisticians. As one of our reviewers said, Heaven help you if
you get a reviewer from a competing social network.
MR. WHITFIELD. Okay.
DR. WEGMAN. And I think it would be naive to think that
these things don't exist. They exist in peer review journals,
they exist in reviews of proposals submitted to the NSF and other
organizations.
MR. WHITFIELD. Would you like to make a comment about this
whole issue, Dr. North?
DR. NORTH. Well, I would be pleased to. There are several
matters here. Social networking, it does seem to me to be a little
bit of a problem to pick out that this young scientist got busy and
found himself 43 coauthors. I think a lot of us would look at that
and say my, he is quite a charismatic young man who has gone out and
found himself 43 collaborators. That is something that I would
probably look very favorable on if I were considering him for
tenure. And so there is that. Now, do people collaborate and
think similarly? Of course they do. But, you know, if you look
back at the history of, say, quantum mechanics in the early 1920s,
it was Einstein, Bohr, Heisenberg, all these people. I am sure if
you did a similar analysis, you would probably find something very
like that, but in fact these guys hated each other. I mean, they
were very, very competitive. And if you look at the 43 authors,
I am sure that not all of them like to go out and have a beer
together. This is pretty competitive business, and I will tell
you, if somebody can find a way to knock down someone else's theory,
that is their road to recognition and fame. We all do that. That
is part of the game and we really enjoy that part of the game. So
yes and no.
MR. WHITFIELD. All right. Thank you. My time has expired
and I will recognize Mr. Stupak.
MR. STUPAK. Mr. Chairman, because of time constraints, I
am letting Mr. Waxman go now and I will catch the next round.
MR. WAXMAN. Thank you very much, Mr. Stupak and Mr.
Chairman. That was an interesting analysis, Dr. North. We are
sometimes sheltered by our own politics but it looks like
academics have their politics.
DR. NORTH. They do.
MR. WAXMAN. And I guess we should take that into
consideration, but I don't think we doubt all science because
experts agree with each other or that they are competing with
each other. Is that--
DR. NORTH. That is correct. You know, the process works.
You know, as they say, it is a little like making sausage. You
have heard that one.
MR. WAXMAN. On June 7, 2005, 11 National Science academies
issued a joint statement calling on world leaders "to acknowledge
that the threat of climate change is clear and increasing" and in
their joint statement, the science academies of Brazil, Canada,
China, France, Germany, India, Italy, Japan, Russia, the United
Kingdom, and the United States declared, "There is now strong
evidence that significant global warming is occurring." They
also stated that it is likely that most of the warming in recent
decades can be attributed to human activities. Mr. Chairman, I
would like to ask unanimous consent that this statement from the
premiere scientific institutions be placed in the record.
MR. WHITFIELD. Without objection.
[The information follows:]
MR. WAXMAN. Dr. North, I would like to begin with you. Do you agree
with the statement of these premiere institutions that there is now
strong evidence that significant global warming is occurring and
that it is likely that most of the warming can be attributed to
human activities?
DR. NORTH. Yes, I do.
MR. WAXMAN. And Dr. North, the national science academies
also state that the scientific understanding of climate change is
sufficiently clear to justify nations taking prompt action. They
say it is important that we take cost-effective steps now to reduce
our emissions or else it will be more costly to act in the future.
Again, do you agree with that statement?
DR. NORTH. Well, now you are stepping a little bit beyond
my role here. I will talk about the science but what we ought to
do is somebody else's business.
MR. WAXMAN. I am concerned that some are going to hear about
Dr. Wegman's statistical criticism of the early Mann study and
somehow conclude that global warming is still an open question. In
order to put the overall importance of this issue in context, I
would like to ask you about some of the other evidence of global
warming. Are the Mann studies the basis for the ice core studies
that give us data going back hundreds of thousands of years?
DR. NORTH. No.
MR. WAXMAN. Are the Mann studies the basis for the recorded
atmospheric temperature records that we have maintained for the
last 150 years?
DR. NORTH. No.
MR. WAXMAN. Dr. Crowley is going to testify later today
that although the Mann study was influential in the IPCC's 2001
assessment, the studies, which demonstrated that the instrumental
record and the models could not be reconciled without an
anthropogenic greenhouse influence, were even more influential.
Were those studies based on the Mann studies?
DR. NORTH. I don't think so. I am sorry. I didn't hear
everything you said.
MR. WAXMAN. Well, Dr. Crowley is going to tell us that--
DR. NORTH. He will talk about that, sure.
MR. WAXMAN. --although the Mann study was influential with
the IPCC's 2001--
DR. NORTH. Well, it was part of the report. It was a part
of the report.
MR. WAXMAN. Right.
DR. NORTH. But as I have said, it is only one of several
lines of evidence that are used in drawing those conclusions.
MR. WAXMAN. And so therefore you have further studies that
seem to come to similar conclusions?
DR. NORTH. There are other studies, and they were shown
on the graphic that I showed you.
MR. WAXMAN. And they weren't based on the Mann studies,
were they?
DR. NORTH. They were not based on the Mann studies. Now,
there are cases where they use the same data so there is some
correlation and that is what I think Dr. Wegman referred to and
that is correct. See, there is only a limited amount of data,
so--
MR. WAXMAN. In 2005, two research teams led by scientists
at the Scripps Institution for Oceanography and NASA's Goddard
Institute for Space Studies published studies in Science magazine
that concluded that not only is the Earth's air and land warming,
but the oceans are warming as well and that heating has penetrated
more than 1,000 feet into the ocean's depth. Jim Hanson, director
of the NASA Goddard Institute for Space Studies and the lead author
of one of the studies, called these findings "the smoking gun of
global warming." Dr. North, are these studies in any way based on
the Mann 1998 and 1999 studies?
DR. NORTH. No, not at all.
MR. WAXMAN. In July 2005, Nature magazine published a study
by Dr. Kerry Emanuel of M.I.T. who found that the destructive power
of hurricanes is increasing along with ocean temperatures. Dr.
Emanuel found that the total destructive potential of hurricanes has
increased markedly during the last 30 years. While natural cycles
in the pattern of ocean circulation likely played a role,
Dr. Emanuel attributes at least part of the increase to global
warming. Just last month the publication Geophysical Research
Letters published a new study by Dr. Kevin Trenberth and Dr. Dennis
Shea of the National Center for Atmospheric Research which concludes
that global warming fueled hurricane intensity in the waters of the
tropical North Atlantic in 2005, while natural cycles were only a
minor factor. Dr. North, are these papers by Dr. Emanuel,
Dr. Trenberth, and Dr. Shea in any way based upon Mann's 1998 and
1999 studies?
DR. NORTH. No, no.
MR. WAXMAN. Drs. Mears and Wentz published an article in
Science magazine in August 2005 that resolves a longstanding conflict
in the global warming debate. For years global warming naysayers,
based on the work of Dr. John Christy at the University of Alabama,
have argued that satellite data showed that the Earth's atmosphere
was warming far slower than the Earth's surface. These scientists
reanalyzed the raw satellite data and found that the lower atmosphere
is actually warming slightly faster than the surface in agreement
with the theory and models. These scientists found that the
previous analysis of the satellite data had inaccurately corrected
for changes in the satellite's measurement time resulting from the
decay of their orbit. Dr. Christy has now acknowledged his mistake
and has adjusted his data series, making it much more consistent
with other results. Dr. North, is the Mears and Wentz study in any
way based on Mann's 1998 and 1999 studies?
DR. NORTH. Absolutely not. Dr. Christy was actually on our
committee, by the way.
MR. WAXMAN. He was on--
DR. NORTH. He was on the NAS committee.
MR. WAXMAN. Finally, if we were to--
DR. NORTH. If I may just add one thing. You know, just
because a paper is published, it goes out for the community.
People--the wolves attack, and this particular study by Spencer and
Christy took many years before the error was finally found. It
doesn't mean these guys are villains. It is just that--
MR. WAXMAN. If you knew that Dr. Mears--
DR. NORTH. --they did their best. It took years to find
that mistake.
MR. WAXMAN. If you knew that those two scientists were
friends with--
MR. WHITFIELD. Would the gentleman excuse me one minute?
Did you say it took many years before the error was discovered?
DR. NORTH. Before the error in the Spencer-Christy study
using satellite data was found. It was a good-faith effort on their
part but it turned out to be wrong.
MR. WAXMAN. If you knew that these gentlemen were friends
with Dr. Mann, would that make you suspect their work?
DR. NORTH. I have no idea whether they know him.
MR. WAXMAN. Finally, if we were to sweep away the Mann
studies and forget that they existed, would that in any way erode
the validity of any of the studies I just mentioned?
DR. NORTH. I do not think it would.
MR. WAXMAN. Would there still be--
DR. NORTH. We wouldn't--
MR. WAXMAN. Would there still be a scientific consensus
that global warming is happening, it is being caused by humans and
that some people think it is time to act now?
DR. NORTH. Yes, I think there would be.
MR. WAXMAN. And Dr. North, my point in asking you about
these other studies is simply to illustrate how wrong it would be
for anyone to draw sweeping conclusions from a statistical criticism
of one or two studies from 8 years ago. Unfortunately, the Republican
majority on this committee has been completely content to sit back
and ignore global warming. They ignored it while President Bush
frayed our relationships with our international allies over global
warming. They ignored it while the committee crafted an energy
policy that exacerbates global warming and they continue to ignore
it as evidence piles up about the severity of the situation.
Instead, we spend our time attacking climate researchers who have
infuriated the oil lobby by contributing to our knowledge of this
issue, and apparently that is the one thing that the Majority
simply cannot ignore. My time is just about expired, and we have a
vote on the House floor. I thank the witnesses for their testimony
and Dr. North for responding to my questions.
MR. WHITFIELD. Mr. Chairman, we have 8 minutes to vote on
the floor. Would you like to start your questions and come--
CHAIRMAN BARTON. I would recommend that we recess and let
us go vote, give our witnesses a chance to have a personal convenience
break and then come back.
MR. WHITFIELD. We have two votes on the floor. The first
vote will be over in about 10 minutes and then we will have another
one, so we will reconvene at about 12:15.
[Recess.]
MR. WHITFIELD. At this time I recognize the Chairman for
his 10 minutes of questions.
CHAIRMAN BARTON. Thank you, Mr. Chairman. I appreciate the
courtesy and I appreciate our witnesses here today. My first
question is a personal question to you, Dr. Wegman, and it is not
normally one that I would even think about asking but there has
been some attempt to portray you as a pawn of this committee or me
personally. I am told that you voted for Vice President Gore for
president in the year 2000. Is that correct?
DR. WEGMAN. That is correct.
CHAIRMAN BARTON. So you are by no means a radical, wild-
eyed, hard core, right wing Republican?
DR. WEGMAN. No, sir.
CHAIRMAN BARTON. Okay. How often, if ever, have you been
in Texas?
DR. WEGMAN. I was in Texas in hill country a few weeks ago
but I have been to Houston a few times, interacting in my social
network with David Scott.
CHAIRMAN BARTON. But you are not--you and I until this
morning have had no phone calls, no e-mails, no--
DR. WEGMAN. I didn't even know what you looked like until--
CHAIRMAN BARTON. Which is a blessing for you, right?
DR. WEGMAN. No, sir.
CHAIRMAN BARTON. All right. Now, let me ask you, Dr. North,
obviously you and I went to--I attended the school where you have
been an illustrious professor for a number of years and I asked you
during the break if you and I had met and you said that we had met
on an airplane once.
DR. NORTH. We had a 2-minute--a 30-second conversation.
CHAIRMAN BARTON. So you and I have had some personal
interaction, but that is it. Again, there is no real association in
terms of continuing basis or anything. When Mr. Waxman was here, he
was asking some questions of you, Dr. North, about headlines that had
occurred and papers that had been issued that state the possibility
or the probability that global warming is real and it is caused by
humans, and it is your personal opinion that global warming is real
and that a large part of the reason it is real is because of human
emissions of greenhouse gases. That is a fair statement of yours?
You need to push that button, put your microphone on. Let the record
show that he said yes. But we have some headlines here that have
been purported to be because of global warming. Dr. North, one of
them is that more frogs are dying as the planet warms. Are you aware
of that?
DR. NORTH. I have heard of it.
CHAIRMAN BARTON. You have heard of that. How about because
of global warming, irrigation fuels warmer temperatures in
California's central valley, are you aware of that?
DR. NORTH. I have not heard of that one.
CHAIRMAN BARTON. Okay. How about the irony of global
warming, more rain, less water?
DR. NORTH. I am familiar with that idea. I don't know if
I have seen that headline.
CHAIRMAN BARTON. Global warming could sour the wine
industry?
DR. NORTH. I don't--
CHAIRMAN BARTON. Poison ivy grows faster, bigger, more
irritating?
DR. NORTH. No, I don't--
CHAIRMAN BARTON. Global warming weakens trade winds.
Global warming's next casualty, igloo. Global warming could
overwhelm storm drains. Strange things happening to Pacific
coast marine life. Global warming might create lopsided planet.
Global warming makes seas less salty. Space ring could shade
Earth and stop global warming. My point is, a lot of people are
jumping on the global warming bandwagon and there is no question it
is serious, there is no question that eminent people like yourself
believe the causality of human emissions. I don't have a problem
with that. I mean, you pointed out in your testimony what science
is supposed to be about. My problem is that everybody seems to
think that it is automatically a given and that we shouldn't even
debate the possibility of it and we probably shouldn't debate the
causes of it, and I think that is wrong. That is one of the reasons
that we are holding this hearing.
I want to put up the digitized temperature curve number 2 that
Dr. Wegman was referring to. We determined that you couldn't prove
the hockey stick by using the data points, Dr. Wegman concluded that,
and so Mr. Waxman said well, that is okay but there are other studies
and one of them is the study of a methodology that was not using the
methodology that Dr. Mann used, and that is--it is kind of an S
curve and--that is not?
DR. NORTH. Figure number 2 is the one that--
CHAIRMAN BARTON. That one right there. Now, in that curve
there, Dr. North, the highest point looks to me to be about the year
1300. Would you agree with that?
DR. NORTH. Well, that is what it shows on that graphic.
CHAIRMAN BARTON. Okay. But it is definitely higher than
the 1900s.
DR. NORTH. Higher than--I think that curve goes up to the
middle of the 20th Century although I am not sure.
CHAIRMAN BARTON. But it is obvious--I am not saying that
is the truth, okay, but I am saying, if that is a justification for
global warming in that particular study, which I believe is
purported to be a Crowley study, that is using average temperatures,
that that particular graph shows the warmest period was somewhere
between 1100 and 1400. Is that correct?
DR. NORTH. Well, that is what the curve shows. I cannot
tell you where that one actually came from. We used a graphic like
that in our report just to give some perspective about how people
thought the curve looked 15 year ago, 16 years ago, so we used a
graphic like that. I believe you have replotted it here.
CHAIRMAN BARTON. Now--
DR. WEGMAN. Let me be precise. This is a curve from the
IPCC 1990 report.
DR. NORTH. Sixteen years ago.
CHAIRMAN BARTON. Okay. And let us go to the study--there
is a comparison in Dr. Wegman's testimony of the Mann report and I
believe this curve. There are two--keep going. There are two
documents--yes--no, not that one.
DR. NORTH. Number 4 and 5, I think.
CHAIRMAN BARTON. Well, my question is, something happened
between the chart that we up here that showed the early 1300s being
the warmest period and Dr. Mann's study that obviously shows the
20th Century, and my question is, what changed in the modeling or
the methodology or the data set? Because Dr. Mann wipes out that
early warming period. It is just not there.
DR. NORTH. Is that for me?
CHAIRMAN BARTON. It could be for either one of you.
DR. NORTH. Well, there is more data available 10 years later
than there was in that first report. In fact, I have a feeling that
that first report--I hope you will ask Crowley that later because I
think he will know more about it than--
CHAIRMAN BARTON. Well, is it now the consensus of the
majority of the scientific community that this early warming period
just didn't exist?
DR. NORTH. No, I think that there is good evidence that such
a medieval warm period did exist, however, it may not have existed at
the same time at different locations on the Earth, and I could give
you some information about that. For example, if you look in
Greenland, there was a very distinct warming period in that time
around--between 1000 and 1200. In fact, there were colonies of
people who lived there from Denmark and their civilization
disappeared there. They went back to Denmark or died out, I am not
sure which.
CHAIRMAN BARTON. But I mean, it is striking--
DR. NORTH. So there is evidence, historical and so on, that--
CHAIRMAN BARTON. It is on page 15 of your report, and I have
the prepublication copy. You have the figure 03 at the top and then
you have the figure 04 at the bottom. Oh three is a schematic
description of global warming that is the IPCC report of 1990 and
then the 04 figure is the Mann graph, and it is just striking to me
that there is no correlation between the two, or very little.
DR. NORTH. Oh, actually, if you look at the gray area in
the Mann graph, that is the area where the curve could fall with
some reasonable probability. That is their error margin.
CHAIRMAN BARTON. Let me ask you--
DR. NORTH. If you look at the family of our curves that I
showed in our graphic, the family of curves that were derived by
using several different methods and different sources, you find that
that family of curves really does fall pretty close to where the
gray is here, especially if you put margins of error on each of
those comparable to these.
CHAIRMAN BARTON. Let me ask you--
DR. NORTH. And we would dispute how accurately Mann and
company did that.
CHAIRMAN BARTON. I understand that.
DR. NORTH. That is another matter.
CHAIRMAN BARTON. I understand that. It looks like my time
is expired, so I want to ask one more question. Dr. North, do you
dispute the conclusions or the methodology of Dr. Wegman's report?
DR. NORTH. No, we don't. We don't disagree with their
criticism. In fact, pretty much the same thing is said in our
report. But again, just because the claims are made, doesn't
mean they are false.
CHAIRMAN BARTON. I understand that you can have the right
conclusion and that it not be--
DR. NORTH. It happens all the time in science.
CHAIRMAN BARTON. Yes, and not be substantiated by what you
purport to be the facts but have we established--we know that
Dr. Wegman has said that Dr. Mann's methodology is incorrect. Do
you agree with that? I mean, it doesn't mean Dr. Mann's
conclusions are wrong, but we can stipulate now that we have--and if
you want to ask your statistician expert from North Carolina that
Dr. Mann's methodology cannot be documented and cannot be verified
by independent review.
DR. NORTH. Do you mind if he speaks?
CHAIRMAN BARTON. Yes, if he would like to come to the
microphone.
MR. BLOOMFIELD. Thank you. Yes, Peter Bloomfield. Our
committee reviewed the methodology used by Dr. Mann and his coworkers
and we felt that some of the choices they made were inappropriate.
We had much the same misgivings about his work that was documented
at much greater length by Dr. Wegman.
MR. WHITFIELD. If I may interrupt just one minute. We
didn't swear you in so I want you to swear now that the testimony you
gave was the truth.
[Witness sworn]
MR. WHITFIELD. Thank you.
CHAIRMAN BARTON. I would like to submit for our record an
e-mail that was received, and I would be more than willing to share
it with the Minority if they have not seen it before. They have it?
It is an e-mail from Yasmin Said to Peter Spencer and it says, "To
whom it may concern: I have read the reports of Chairman Barton and
Chairman Whitfield entitled "ad hoc committee report on the hockey
stick global climate reconstruction by Edward J. Wegman, David Scott,
and Yasmin H. Said" and what follows this work of Wegman, Scott, and
Said is simply referred to as Report. The assessment of previous
results given in the Report is correct. The Report is entirely
correct in stating that the most rudimentary additive model, the
model of a simple temperature signal with superimposed noise, is
not adequate to describe the complex relationships involved in
climate dynamics. There is no physical process found in nature
that does not involve feedback in one form or another to regulate
the action of the system. The statistical methods and models
described in the report use more variables and make possible the
construction of more elaborate reconstructions that allow feedback
and interactions. The report represents the correct way to proceed.
It is especially important to bring the professional statistical
community into the picture in order to assure that a sound
analytical foundation is secured in the continuing development of
this program. Sincerely, Enders A. Robinson, member of the National
Academy of the USA, fellow of the European Academy of Scientists,
professor emeritus and the Maurice Ewing and J. Lamar Rozelle,
Chair, Department of Earth and Environment, Columbia University."
And I yield back.
MR. WHITFIELD. Thank you. At this time I recognize Mr. Inslee.
MR. STUPAK. Wait a minute. Did we accept this e-mail that
was read into the record, or what?
MR. WHITFIELD. Well, he asked for unanimous consent if you
all--do you have an objection to it?
MR. STUPAK. Well, let us object for now. We will ask some
questions of it later.
MR. WHITFIELD. They object to it being entered until they
clarify a few things with that.
CHAIRMAN BARTON. But they had the document. I don't want
them to accept it if they have not seen it. I was told that they had
seen it.
MR. WHITFIELD. We were told that you all had it last night
but is that not--
CHAIRMAN BARTON. But certainly we don't want to put anything
in that hadn't been cleared. Mr. Chairman, they have every right to
object if they haven't seen it.
MR. WHITFIELD. Well, while they are discussing it,
Mr. Inslee, why don't you proceed with your questions.
MR. INSLEE. Thank you. Dr. Wegman, can you cite to us the
first three laws of thermodynamics?
DR. WEGMAN. Probably not.
MR. INSLEE. And you shouldn't be ashamed of that because you
are a statistician, not a physicist.
DR. WEGMAN. That is correct.
MR. INSLEE. But it is important for us to talk about that
in the context of some things I want to ask you. Because I believe
reviewing the literature, and I spent some time doing this, it is
beyond any reasonable doubt that there is a strong worldwide
scientific consensus that human activities are putting carbon
dioxide and other global warming pollutants in the air in a way
that is changing our climate in fundamental ways. I want to ask
you some questions about your testimony here today. I want to
refer you to a chart that is up on the screen to your left, and it
shows concentrations of carbon dioxide in the Earth's atmosphere
going back 160,000 years and basically what it shows is that the
concentrations now which are in the lower right-hand circle are
higher than they have been in any time in the last 160,000 years.
They also show that those concentrations of carbon dioxide will go
up approximately doubling in the next century by the year 2100
unless this Congress pulls its head out of the sand and does
something about it. Now, the question I want to ask you, these
carbon dioxide samples are beyond dispute because of direct
physical measurement of old air trapped in glaciers and that they
are not subject to any scientific doubt whatsoever. Neither as far
as I know is there any question but that the carbon dioxide levels
will significantly increase in the order of doubling of pre-
industrial times in the next century if we do not act. So the
question I ask you, is anything in your criticism of the Mann
report in any way suggests that those conclusions I just stated to
you that are reflected on this graph regarding carbon dioxide levels
are faulty?
DR. WEGMAN. No, I don't believe they are.
MR. INSLEE. So if you accept the first three laws of
thermodynamics and basic chemistry and our ability to judge CO2
levels and if you accept the premise that carbon dioxide in the
atmosphere has the capacity of essentially trapping heat in the
energy system of the Earth--by the way, do you accept that
proposition?
DR. WEGMAN. I don't know about the second proposition. I do
not know the mechanisms for trapping heat.
MR. INSLEE. Well, I will just tell you, the mechanisms of
carbon dioxide essentially traps heat in infrared range of a
frequency. Light comes in an ultraviolet range, it bounces back in
an--not really bounces back but emitted in an infrared range and
carbon dioxide traps it. It traps it like a blanket, as a crude
metaphor. Now, what we know beyond a shadow of a doubt is that
carbon dioxide in the next century is going to be at levels double
any time in the last 160,000 years and double what it was in pre-
industrial times. Now, does your criticism of Dr. Mann's research
in any way suggest that it would not be a good idea to reduce our
carbon dioxide loading into the atmosphere?
DR. WEGMAN. My expertise does not extend to global warming
and I have no position on this.
MR. INSLEE. Well, I think that is important for you to say
that because what we are finding here is that there is this enormous
worldwide consensus. I look at the joint academy statement--this is
a joint academy statement of every science academy in the
industrialized world and every single one of them state that it is
a consensus that human activity is causing changes to the climate.
I will just read directly. "It is likely that most of the warming
in recent decades can be attributed to human activities. This
warming has already led to changes in the Earth's climate." It is
signed by Canada, Germany, France, Italy, Japan, United Kingdom,
Russia, China, Brazil, and the National Academy of Sciences under
the administration of George Bush. Now, I guess the question to
you is, do you have any reason to believe all those academies should
change their conclusion because of your criticism of one report?
DR. WEGMAN. Of course not.
MR. INSLEE. Why not?
DR. WEGMAN. Because my report was very specific on a very
specific issue that was asked of me and we answered that very
specific question.
MR. INSLEE. Well, let me suggest another reason. The
reason you don't suggest these academies are wrong is because they
have a mountain of evidence from ice core data, through glacier
data, to ocean acidification, to radar data, to surface and deep
ocean temperature data that indicate that this world is changing
because we are putting too much carbon dioxide in it. Isn't that
right? That is why you are not suggesting they change their report.
DR. WEGMAN. Well, there is the old statistical process that
says association does not mean causation.
MR. INSLEE. Well, there is another statistical by Mark
Twain is that there are three kinds of lies: lies, damn lies, and
statistics, but I won't bring that one up. I want to ask--
DR. WEGMAN. Of course, he is not a statistician either.
MR. INSLEE. Dr. North, I want to quote--in your testimony
you said, "However, our reservations with some aspects of the
original papers by Mann et al. should not be construed as evidence
that our committee does not believe that the climate is warming and
will continue to warm as a result of human activities." You go on
to say, "The scientific consensus regarding human-induced global
warming would not be substantively altered if for example the
global mean surface temperature 1,000 years ago was found to be was
warm as it is today." Now, in listening to your testimony, what I
take from this is that even if we were to conclude that Dr. Mann
had never been born, the study had never been done, conclude even
if there was a medieval warming period that approximated
temperatures today, even if we were to accept that as a verity,
even if we knew that today, what I am hearing your testimony tell
us is that there is enough evidence of other methods and other
dynamics at work in the climate today that we can with a reasonable
degree of assurance conclude that humans are responsible for at
least a portion of the changes in temperatures. Is that a fair
statement?
DR. NORTH. Well, let me separate myself from the report
now. I believe that is true but we didn't address that issue in
the report.
MR. INSLEE. And could you at least in summary fashion tell
us about the other evidence that leads to your conclusion other than
Dr. Mann's?
DR. NORTH. Well, let me mention a few things that my
colleague on the committee, Kurt Cuffey from the University of
California-Berkeley sent. So this is a little about the medieval
warm period. It takes a couple minutes so I apologize for that.
So Greenland shows a clear signal of both medieval warmth and 20th
Century warming. These are recorded unambiguously in isotopes and
boreholes, nothing to do with this extrapolation method. The
medieval was warmer than the 20th Century up to about 1990, but you
know it has warmed quite a bit in the last 15 years, so another
piece of evidence is Ellesmere Island. This is in the Canadian
Arctic and there is an icecap there. It also shows evidence of a
medieval warm period and 20th Century warming and the isotopes and
melt records. The melt in particular shows summertime warmth in
the 20th Century was greater than the medieval warm period, so
there is that one. The composite of all available low latitude--
this is Tibet and the Andes and there is things in Africa,
Kilimanjaro. Ice core, isotope records show the 20th Century
climate is truly anomalous on the time scale of 2,000 years. This
is an objective quantitative measure of climate arising from
physical processes. We cannot, however, separate a pure
temperature signal from it because these glaciers are influenced
by both moisture availability and temperature because hydrology is
important too. All we can say is that the sum of the climate
processes determining the isotope records have reached an anomalous
state. One more--two more. Melt at the summit of Quelccaya--this
is a big icecap in the Andes, the largest Andean icecap--was strong
enough in the late 20th Century to destroy annual layering of
isotopes which did not happen during the medieval period. Now, the
tropics are a very interesting place to look at climate. They are
probably a little more representative of the global average, not
as much natural variability in the tropics. So we had melting
recently in the Quelccaya glacier but it didn't happen in the
medieval warm period.
MR. INSLEE. Doctor, I want to ask one quick question. My
time is almost up.
DR. NORTH. I am sorry.
MR. INSLEE. Put the slide up on the acidification, Tracy,
that one right there if I can. Doctor, I made reference to
acidification that is taking place in our oceans as a result of
carbon dioxide going into the atmosphere, then going into solution
in the oceans. Could you briefly summarize that dynamic and what
the state of our knowledge is about that?
DR. NORTH. I am not an expert on this. I have seen the
report and the essence is that as we increase carbon dioxide in the
atmosphere, the carbon dioxide of course dissolves in seawater
just as it does in Pepsi-Cola, so the greater the partial pressure
of carbon dioxide in the atmosphere, the more that will be
dissolved in the ocean and then you wind up with--by combining with
other things, you wind up with a more acidic ocean so the pH of the
ocean goes down, becomes more acidic. This attacks the corals and
other things. So there could be something going on with aquatic
life. Again, we are really pretty far away from--
MR. INSLEE. And is that independent of temperature issues?
DR. NORTH. That is independent of temperature.
MR. INSLEE. So even if temperature doesn't go up, this
dynamic can acidify the ocean?
DR. NORTH. That has been happening and I presume will
continue to happen.
MR. INSLEE. Thank you. Well, we would like to change that
actually. Some of us have ideas about that.
DR. NORTH. That is not my job.
MR. WHITFIELD. Mrs. Blackburn, you are recognized for
10 minutes.
MRS. BLACKBURN. Thank you, Mr. Chairman, and thank you all
for your patience as we work through our votes today. Dr. Wegman,
I have got three quick questions for you and Dr. North, I have got,
I think one probably for you and I am going to try to finish so
everyone gets their questions in before the next vote. But
Dr. Wegman, you said in your testimony that Dr. Mann's data is very
obscure, incomplete, and disorganized, and I wanted you to expand
on that and give us an example of how that data should have been
presented, if you have something tangible.
DR. WEGMAN. Well, I had two things in mind. First of all,
when I read the paper originally, it took me probably 10 times to
read it to really understand what he was trying to say. He uses
phrases that are not standard in the literature I am familiar
with. He uses, for example, the phrase "statistical skill" and I
floated that phrase by a lot of my statistical colleagues and
nobody had ever heard of that phrase, statistical skill. He uses
measures of quality of fit that are not focused on the kind of
things typically we do. We went to his website to try and figure
out where his data was. He has a website at the University of
Virginia. We basically downloaded everything that was in his
FTP website to try and gather together--try and understand what
was going on. The materials tended to be very cryptic. When we
looked at the Fortran code that he wrote, it was very difficult
to understand how you could, in the Fortran code you read in the
data, but it was unclear where the data was and how you could
actually read it in and the coding of the data, so all those
things tended to make it very difficult to try and replicate anything
that he did. Ultimately, I believe it was in 2004, he published a
corrigendum and it showed that some of the data that he used in
the 1998 paper was not referenced in the 1998 paper and other
material that he did reference in the 1998 paper was not actually
used. So there was a lack of clarity in both the archived data as
well as the writing of the appear itself that I found difficult to
decipher.
CHAIRMAN BARTON. Will the gentlelady yield just for--
MRS. BLACKBURN. I will yield.
CHAIRMAN BARTON. When you said his data was in Fortran
code, what is Fortran code?
DR. WEGMAN. Fortran is a computer programming language that
was invented in 1957.
CHAIRMAN BARTON. And when was the last time anybody else
than Dr. Mann used that code?
DR. WEGMAN. Well, I suspect--
CHAIRMAN BARTON. I knew it at Texas A&M in the 1960s and I
had not heard the term and I wanted to make sure we were
talking the same--
DR. WEGMAN. Well, certainly programming languages have
evolved dramatically over the years. Most of my colleagues
use a software package called RS Plus. Many people use Mat
Lab these days.
CHAIRMAN BARTON. The Fortran code is not something that
would be normally used today by too many people?
DR. WEGMAN. I would think in certain circles it might be
but it is reflective of the notion that there aren't--
DR. NORTH. Most climate models do use Fortran code.
CHAIRMAN BARTON. Oh, they do?
DR. NORTH. Yes.
CHAIRMAN BARTON. So that is standard?
DR. NORTH. It is standard in mathematical solution of these
kinds of problems, not statistics. He is right about that.
So Mat Lab is coming on but Fortran is very commonly used
in large climate model work.
CHAIRMAN BARTON. Well, then I should be able to do some of
this because I can code in Fortran. I yield back.
MRS. BLACKBURN. Dr. Wegman, I still want to come to you.
So what you are saying is that he--I want to go back to one
thing on the data that he chose to input on the website, he
was selective in the nature of what he chose to put in there
and I guess that is much like what we saw with the
calibration issue over the years that he used in that--
DR. WEGMAN. There were a large number of proxies that were
used in the 1998 and 1999 papers. As a matter of fact, it
probably wasn't very selective. He essentially threw
everything including the kitchen sink into this data set.
MRS. BLACKBURN. I want to ask you a question that Dr. Crowley
makes a statement in his testimony that was submitted to us,
that the data is reused, Dr. Mann's data is reused because
it is the best data. But you say that other papers cannot
claim to be independent verification if they reuse the same
data. So I would like for you to speak to that and kind of
reconcile the differing views.
DR. WEGMAN. Well, in one of our plots we had a plot that
showed the data that was being used as the proxies versus
the 11 or 12 papers that had been published since 1998 and
the striking thing is, I think, that essentially there are
two methodologies that we talked about, the CPS methodology
and the CFR methodology, and my contention is that if you
use the same data and the same basic methodology, you can--
MRS. BLACKBURN. Then following on with that, if you
were to structure an external statistical review for
climate papers that would guarantee to be an
independent verification of methods used, how would
you structure this?
DR. WEGMAN. Well, I think there are a couple of approaches.
One of the analogies I kind of liked was that the folks that
do the hockey stick kind of thing call themselves--I think
they call themselves the hockey team and when games are
being played, you also need referees, so I think it would
be a good idea to have referees for the hockey games. My
own feeling is that it would be useful as we said in one of
our recommendations that there be an external review and
that it be funded as part of this kind of activity. If you
have significant statistical methodology being used in a
scientific study, then you really ought to have statistical
review as well as the peer paleoclimate review. I think
this extends beyond just paleoclimate stuff. It is true,
for example, in biostatistics, biological science, medical
science, that there is typically a heavy involvement with
statistical review. I think in terms of things like
sociology, psychology, there is heavy involvement with
statisticians in this kind of framework. It appears to me
that in the physical sciences, the same mental set is not
typically done.
MRS. BLACKBURN. Thank you. Dr. North, I have got a couple
of quick questions on surface records and satellite
measurements that I want to give to you but I have only got
a minute and a half left and I think I will submit these to
you and then ask for your response, and Mr. Chairman, I
will yield back so somebody else can get their questions on
the record before we go for another vote.
MR. WHITFIELD. Thank you, Mrs. Blackburn. At this time I
recognize Mr. Stupak.
MR. STUPAK. Thank you, Mr. Chairman. Dr. Wegman, in your
report you criticized Dr. Mann for not obtaining any
feedback or review from mainstream statisticians. In
compiling your report, did you obtain any feedback or
review from paleoclimatologists?
DR. WEGMAN. No, of course not, but we weren't addressing
paleoclimate issues. We were addressing--
MR. STUPAK. But you said you had difficulty understanding
some of the terms of art that Dr. Mann used and you had to
call your social network to figure it out so wouldn't it
have been helpful to have paleoclimatologists?
DR. WEGMAN. To say that I didn't contact any climate
people is not entirely accurate. We have--
MR. STUPAK. But they weren't used in compiling your
report--that was the question--correct?
DR. WEGMAN. Well, I am not sure how to answer that. I
certainly--
MR. STUPAK. Well, yes or no is probably the best way.
Did you have any paleoclimatologists when you compiled
your report?
DR. WEGMAN. Not on our team, but that doesn't mean I
didn't talk to any.
MR. STUPAK. Did anyone outside your social network peer
review your report?
DR. WEGMAN. Yes.
MR. STUPAK. Who was that?
DR. WEGMAN. Well, Enders Robinson.
MR. STUPAK. Is that the e-mail we were talking about
earlier?
DR. WEGMAN. Pardon?
MR. STUPAK. Is that the e-mail that was--
DR. WEGMAN. Yes. So--
MR. STUPAK. When you do peer review--
DR. WEGMAN. Let me answer the question. Enders Robinson,
Grace Waba, who is a member of the National Academy, Noel
Cressy, who is at the Ohio State University, Bill Wasorik,
who is at Buffalo State SUNY, David Banks, who is at Duke
University, Rich Schareen is the immediate past president
of the American Statistical--
MR. STUPAK. Let me ask you this question. If you had a
peer review, when are peer reviews usually done? Before
a report is finalized or after?
DR. WEGMAN. We had submitted this and had feedback from-
-
MR. STUPAK. No, no, I am talking about general peer
review. If you are going to have a peer review, don't
you usually do it before you finalize your report?
DR. WEGMAN. Yes.
MR. STUPAK. Well, your peer review was after you
finalized it?
DR. WEGMAN. No, it was before. We submitted this long
before.
MR. STUPAK. Well, when was your report finalized?
DR. WEGMAN. I think we dated the final copy about
4 days ago.
MR. STUPAK. Four days ago, so that would be about
July 15. This e-mail sort of indicates it is July 17
that you asked for this peer review.
DR. WEGMAN. I had feedback from Enders much earlier
han that. We had asked him to send material to us for
purposes of coming here.
MR. STUPAK. Well, the e-mail read into the record is
Tuesday, July 18, so that would be 3 days after you
finalized your report.
DR. WEGMAN. I am sorry. We--
MR. STUPAK. Have you seen this e-mail, the one that--
DR. WEGMAN. Yes, of course I have. Dr. Robinson saw
our material before the 18th, before the 17th, before
the 16th. He gave us feedback. We incorporated that.
He gave us feedback verbally. We incorporated that
because there was some interest in getting this report
to the committee.
CHAIRMAN BARTON. Would my friend from Michigan yield
for one simple question on this same point?
MR. STUPAK. Sure.
CHAIRMAN BARTON. Dr. Wegman, do you object to
Mr. Stupak or anybody in the Minority submitting your
report for a peer review as long as the peers are
qualified in statistical analysis?
DR. WEGMAN. Not at all.
CHAIRMAN BARTON. Thank you.
MR. STUPAK. In doing peer reviews, do scientists who
do the report, do they usually submit to people they
want to do the peer review? Isn't that sort of an
independent review?
DR. WEGMAN. This is basically the same mechanism that
was used at the National Academy. The national--you
know, this is not a--
MR. STUPAK. Did you ask these people to do your peer
review?
DR. WEGMAN. Yes.
MR. STUPAK. So would they be part of your social
network?
DR. WEGMAN. No. When I talk about social network, I am
talking about people with whom I have actively
collaborated in writing research papers.
MR. STUPAK. It sounds--
DR. WEGMAN. None of these people have actively
collaborated with me in writing research papers.
MR. STUPAK. Isn't the same kind of social network you
criticized Dr. Mann on because the people that reviewed
his were paleoclimatologists?
DR. WEGMAN. Were the people that had actually worked with
and published papers with.
MR. STUPAK. And you have published papers with some of these
people that peer reviewed your report?
DR. WEGMAN. No. I just told you no, I haven't.
MR. STUPAK. Let me ask you this. Page 34 of your report, I
think you have it in front of you, your 52-page summary there,
you have a figure that you say is a digitized version of the
temperature profile in the IPCC assessment report of 1990. I
take it you read the 1990 IPCC report?
DR. WEGMAN. I am sorry. What page was it?
MR. STUPAK. Page 34 of your report. It is figure 4-5. It
is this one right here. We have had some--it has been
referred to as figure 2 on the screen a couple times today.
DR. WEGMAN. No, I have not been able to obtain a copy of the
1990 report.
MR. STUPAK. Well, then you must have at least discussed this
temperature profile.
DR. WEGMAN. The temperature profile that was published in
1990 I believe was related to the European temperatures and
was a cartoon--essentially a cartoon. The point of our
discussion here was not that we were trying to say that this
was what happened in 1990. The point of our discussion was
that you could reproduce this shape from the CPF, CFP and the
climate plus--whatever--CPS methodology so we are not
endorsing that this was the temperature that was thought of
in 1990. We are simply using this as an example.
MR. STUPAK. Were you endorsing 1300 as being a real high
temperature time? Were you endorsing it in your report?
DR. WEGMAN. No, we have not said that.
MR. STUPAK. What was the 1990 IPCC temperature profile based
on? Basically what was this based on? You are a statistician.
DR. WEGMAN. This--
MR. STUPAK. Was this based on data?
DR. WEGMAN. As I just said moments ago, this was a cartoon I
believe that was supposed to be representing a consensus
opinion of what global temperature was like in 1990 as
published by the IPCC.
MR. STUPAK. Well, is this cartoon then--again, I am on page
34, I am reading now from your report, discussion you have
underneath this cartoon. Last line: "The 1990 report was
not predicated on global warming scenario. It is clear at
least in 1990 the medieval warm period was thought to have
temperatures considerably warmer than the present era." Is
that your discussion?
DR. WEGMAN. Yes.
MR. STUPAK. So we should not believe that statement then?
DR. WEGMAN. No, I said--I didn't say I believed it was. I
said they believed it was. The IPCC gave that report in 1990.
MR. STUPAK. All right. This chart--
DR. WEGMAN. I didn't--
MR. STUPAK. This is in your executive summary, right, page 34,
and what I read was correct?
DR. WEGMAN. Yes.
MR. STUPAK. Okay. Let me ask you this question. Have you
reviewed any of Mr. Mann's later refinements of his 1999
report?
DR. WEGMAN. I have reviewed some level of detail, not in
intense level of detail, the continuing papers, most of which
are referenced--in fact, the ones that are referenced--
MR. STUPAK. Did he refine his data and his methodology?
DR. WEGMAN. My take on the situation is that rather than accept
the criticism that was leveled, he rallied the wagons around
and tried to defend this incorrect methodology.
MR. STUPAK. But did he refine his methods in later studies
that he conducted, not whether he rallied the troops? Did
he refine his methods? Was his job more accurate as he went
on with later reports?
DR. WEGMAN. I believe that he does not acknowledge his
fundamental mistake and that he has developed additional
papers with himself and his colleagues that try and defend
the original hockey stick shape.
MR. STUPAK. Do you know that or are you just guessing?
DR. WEGMAN. I am guessing that.
MR. STUPAK. Okay. Statisticians, should they guess or
should they have facts to--
DR. WEGMAN. That is called statistical estimation, yes.
MR. STUPAK. I see. Or a cartoon.
DR. WEGMAN. The cartoon is IPCC's cartoon, not mine.
MR. STUPAK. You relied upon it though in your executive
summary. So I am looking at the cartoon. There is no
data, is there, to say that around 1300 it warmer than it
is in the latter half of--
DR. WEGMAN. I think that is an inaccurate statement. I think
there is data. I think the data--
MR. STUPAK. Do you have any of it? Can you show us where any
of that is?
DR. WEGMAN. No, I don't have it. I take no responsibility for
what IPCC did in 1990. There is no way I could do that. Their
data is not available to me. In fact, the reason it was
digitized was that I had to go back and construct it from their
picture. That doesn't mean no data exist. And in fact, as far
as I know, it was based on European and Asian temperature
profiles that were available in the 1990s.
MR. STUPAK. Sure, and in that, it was thought--it was still not
clear that all the fluctuations indicated were truly global.
In fact, I think some of the testimony earlier said that parts
of western Europe, China, Japan, and eastern U.S.A. were a few
degrees warmer in July than other parts of the world. Parts of
Australia, Chile, and I think Greenland were actually cooler,
they said, and China was actually colder than at any other time.
DR. WEGMAN. Yes, I don't dispute that.
MR. WHITFIELD. The gentleman's time has expired. I recognize
Mr. Bass.
MR. BASS. And I thank the gentleman for recognizing me. Before
I start my questions, I just want to mention that there is a
considerable amount of climate change work going underway in
New Hampshire, my home state of New Hampshire, the Cold Research
Laboratory which is run by the Army Corps of Engineers. They
are studying ice core samples from both the Arctic and the
Antarctic icecaps and also at the University of New Hampshire.
NOAA, National Oceanographic and Atmospheric Administration is
conducting ongoing longitudinal studies on the North Atlantic,
air, water temperatures. And thirdly, at Hubbard Brook which
is another research lab, they are studying climate change
effect on trees and plants and other organic matter.
CHAIRMAN BARTON. Could the gentleman yield while--
MR. BASS. Yes. Sure.
CHAIRMAN BARTON. Dr. North, Mr. Stupak just went to some
lengths discussing this chart on page 34 of Dr. Wegman's report
that is from the IPCC assessment report of 1990. Can you tell
us what the IPCC assessment report of 1990 was?
DR. NORTH. The IPCC is the Intergovernmental Panel on Climate
Change. It is under the auspices of the United Nations and I
don't know the network all the way down to this group but this
is a group that meets and is tasked to come up with a report
every 5 years approximately.
CHAIRMAN BARTON. But in layman's terms, could we say that
the IPPC--
DR. NORTH. No, IPCC.
CHAIRMAN BARTON. IPCC is the technical working group for
the United Nations council of parties that ultimately
drafted the Kyoto Accords?
DR. NORTH. I don't know if there is a connection. I just
don't know that. I am sorry.
CHAIRMAN BARTON. It is my understanding that the IPCC is
the group that prepared all the analytical materials and
forwarded them on--
DR. NORTH. They may have used their information. The
IPCC, their job is to provide assessments, so Congress,
political bodies go to them and ask for an assessment of
the state of the art or the state of the science at the
particular time as it is seen at that time. Of course, it
changes so they came out again in 1995 and again in 2000
and there will soon be another one issued.
CHAIRMAN BARTON. But in 1990 when these scientists produced
that report, this was their assessment of temperatures between
the year 1000 and the mid-1950s?
DR. NORTH. That is what they thought at that time.
CHAIRMAN BARTON. It doesn't mean they were right, it doesn't
mean that they haven't changed their mind.
DR. NORTH. That is why--
CHAIRMAN BARTON. But in 1990 the state of the art was,
that is what--
DR. NORTH. That is what they thought.
CHAIRMAN BARTON. That is what it was. I yield back.
MR. BASS. Thank you, Mr. Chairman. Dr. Karl is going to
follow you in the second panel and I will read a sentence out
of his testimony and ask you a question about it, the last
page. "At the present time there is no formal process whereby
federally funded scientists must submit their data to a
long-term data archive facility for use by others. The
submission of data to institutions like NOAA's, national
climatic data center, the world's paleoclimatic data center,
requires significant investment of time by the principal
investigators who collected the data to provide the useful
information about the proxy data to the receiving data center.
In addition, if such data are submitted, a significant
investment by the data center would need to be made to ensure
that the data is usable by others in perpetuity and safeguards
for future generations," and then he goes on about
discussions. Dr. North, do you think this is an appropriate
priority, and if so, do you think it would require any
legislative action? What are your observations about Dr.
Karl? And I think Dr. Wegman made the same contention. How
do you feel about it, Dr. North?
DR. NORTH. Before I say anything, I should say that I know
Dr. Karl and I have actually collaborated with him on some
things, so that is a fact. I visited his laboratory, his
center in Asheville, which is a very nice operation there.
So I do think it is a good idea. I think it is something
that the Government through a national laboratory like his
should take on. I think this is too much for the little
principal investigator out at your university or mine to
deal with. So this is a way that data like this can be
archived in a nice, clean environment. At Texas A&M, for
example, we have the ocean drilling program and so we store
these cores there that have been dug and they are carefully
archived and protected and so I think that different
laboratories should be charged with that kind of duty instead
of having every little PI's home base, so I do think it is a
good idea.
CHAIRMAN BARTON. Would the gentleman yield on that?
MR. BASS. Certainly.
CHAIRMAN BARTON. I just think the record should show that
when I was Congressman for Texas A&M, I helped get the money
to establish that program and I am responsible for some of
those core samples.
DR. NORTH. And I work with some of those people--
CHAIRMAN BARTON. I want the record to show that.
MR. BASS. Reclaiming my time. I might suggest that this
concept might be a starting point for some bipartisan
cooperation legislatively if necessary to achieve this
objective which would move the issue forward. Dr. Wegman,
there has been some discussion about the network issues
associated with paleoclimatologists. Is it substantially
different than--you know, the incestuous nature of the
relationships between the paleoclimatologists. Do you think
that it is the same or is different from other academic
subjects?
DR. WEGMAN. I don't know all of the academic subjects. What
is true, I believe, is that in less focused activities,
there are probably more competing social networks which
even the playing field a little bit more than it appears
to be in the paleoclimatology area. As mentioned earlier,
I think for one person to have 43 coauthors is an unusually
large number of coauthors. I personally believe that I
probably have maybe 15 people that I have worked with over
the years.
MR. BASS. Fair enough. Would you take--is it appropriate
to take into account in that analysis the size of the
entire climatic science community or is paleoclimatology
so specialized that you couldn't?
DR. WEGMAN. Yes. I think one of the interesting things
that we will probably hear later on is the notion that
this paleoclimatology is really an interdisciplinary area
so it involves dendrology, it involves people that work
with trees, with ice cores and so on and so forth. So it
is not totally insular in the sense that it doesn't
involve people from other parts of this arena. What is
insular though I think is that it doesn't really involve
people from the areas that I call the enabling sciences
such as mathematics, computer science, and so on. But I
think if you sort of followed the second order, third
order, fourth order links, you would probably get a more
interesting social network as well.
MR. BASS. One last question, Dr. Wegman. The National
Academy of Science report that was released last month
states the following: "It can be said with a high level
of confidence that the global mean surface temperature
was higher during the last few decades of the 20th Century
than during any comparable"--during, I don't know, there
must be a typo here-"during the preceding four centuries."
Now, I understand from your testimony on the first page
that you want to distance yourself from the issue of
global warming, its causes, and its solutions, but would
you agree with that statement?
DR. WEGMAN. Yes. I think that is a reasonably cautious
verifiable statement that in terms of--and I speak now not
as a professional statistician but as a citizen of this
country. It seems to me that it is entirely reasonable to
say that Dr. North and his panel made an accurate
assessment, but it must be understood in the context which
is that we have relatively speaking a Little Ice Age,
which everybody seems to acknowledge, and so it is not so
surprising that it is warming if we are coming out of a
Little Ice Age.
MR. BASS. I want to thank both of you gentlemen for your
testimony today and I yield back.
MR. WALDEN. [Presiding] The gentleman yields back his
time. The gentlelady from Illinois, Ms. Schakowsky, is
recognized for 10 minutes.
MS. SCHAKOWSKY. Thank you, Mr. Chairman. I have so
many things I want to ask here. Let me start again.
Dr. North, I want to confirm what I think you already said.
Is Dr. Mann's hockey stick study considered to be the
foundation on which all climate change science is based?
DR. NORTH. No.
MS. SCHAKOWSKY. It isn't. And again I want to say, if
it never were, if the study simply--the hockey stick, the
original and there was a revised in 2003-2004, right, my
understanding is, which I guess you disagree, Dr. Wegman,
acknowledged some of the mistakes and made some changes
but if it never did, would most scientists essentially
arrive at the same conclusion as we are seeing, that we
are engaged--that this is a time of global warming
attributable in large part to human activity?
DR. NORTH. Yes, I think that is true.
DR. WEGMAN. By the way, for what it is worth, I think it
is true although I would caution you to not say most
scientists. Most climate scientists would probably--
DR. NORTH. That is better. Thank you. I appreciate
that.
MS. SCHAKOWSKY. Okay, most climate scientists. Should we
not rely on climate scientists for our information about
the climate?
DR. WEGMAN. The point I was making was that you are saying
most scientists, so the testimony--
MS. SCHAKOWSKY. Well, let me ask--
DR. WEGMAN. --of a chemist is irrelevant to--
MS. SCHAKOWSKY. Exactly. So would you agree then that
climate scientists are those that we should primarily refer
to when we are asking questions about climate?
DR. WEGMAN. Certainly.
MS. SCHAKOWSKY. So you would agree that human activities
are not only increasing atmosphere greenhouse gases but that
it is attribute would you say in large part mostly in terms
of your understanding as not a climate scientist to human
activity?
DR. WEGMAN. I am in no position to say--
MS. SCHAKOWSKY. Well, what did you say you did agree with
earlier?
DR. WEGMAN. I said I agree that it is warming. That is what
I agreed to. I mean, I said it several times now that the
temperature record from 1850 onwards indicate that it is
warming.
MS. SCHAKOWSKY. I also had said earlier that in my question
to Dr. North and that most scientists agree that in large
part or for your purposes I will say in some part
attributable to human activity. Would you agree with that?
DR. WEGMAN. I don't know that for a fact.
MS. SCHAKOWSKY. Okay. You don't know that.
DR. WEGMAN. Again, it is the connection between carbon
dioxide and temperature increase. Now, Mr. Inslee pointed
out that he thinks there is a physical explanation based
on a blanket of carbon dioxide in the reflection. Carbon
dioxide is heavier than air. Where it sits in the
atmospheric profile, I don't know. I am not an atmospheric
scientist to know that but presumably if the atmospheric--
if the carbon dioxide is close to the surface of the Earth,
it is not reflecting a lot of infrared back.
MS. SCHAKOWSKY. Okay. But are you not really qualified
to--
DR. WEGMAN. No, of course not.
MS. SCHAKOWSKY. --comment on that. I think since we are
talking about scientific data, statistics, let us be clear,
and you are challenging a report which form what I
understand as Dr. North in some part at least you agree
with the critique of the Mann data, so--and I am certainly--
I am neither, but we are policymakers here so what I--do you
believe that your report disproves that climate change is
manmade in any way?
DR. WEGMAN. No.
MS. SCHAKOWSKY. And since you think that you are not in a
position to make a decision on global warming, are you
uncomfortable at all, Dr. Wegman, that the consequences of
what you are saying today to policymakers, I think most of
whom, if not all of them, are neither statisticians or climate
scientists, could have the impact of saying we don't need to
do anything. Does that make you uncomfortable at all?
DR. WEGMAN. I would hope that our legislators are smarter
than that to know that when somebody says that they are using
wrong methodology, that does not imply that some fact is not
true. I would hope that you would take my testimony with the
idea that if something is wrong with this piece of work, it
ought to be discarded as a policy tool, and that is precisely
what I am saying.
MS. SCHAKOWSKY. Well, let me ask you this. Dr. Mann has
published dozens of study since the original hockey stick
study and as I said earlier, beginning in 2003 he reformulated
the statistical methods. Do you take into account these later
studies in your report?
DR. WEGMAN. I have read his later studies. I was not asked
about his later studies. I think as science iterates, things
do get better, but as I indicated before, one of the
unfortunate aspects of this overall situation with Dr. Mann
and his colleagues, my attack is not an attack at all. It
is simply trying to lay out what I perceive to be a true
statement. I think it is unfortunate that rather than moving
on and saying gosh, I made a mistake and here is the better
situation, here is a better approach, there continues to be
a defense which is captured in his web log called
realclimate.org.
MS. SCHAKOWSKY. And I understand that there are these
battles and sort of the academic politics and scientific
politics, et cetera, but do you disagree with Dr. North that
even without Dr. Mann altogether or are you using these
social--what do you call it--to say that everything now has
to be discredited?
DR. WEGMAN. No, I don't think everything at all has to be
discredited, and I think the things that do not use the
techniques, the flawed methodology with respect to principal
components, anything that doesn't use those, I have no
position on.
MS. SCHAKOWSKY. And you talked about the cartoon that was
in the Wall Street Journal article and then my understanding
that the graph or whatever you call this, this drawing that
it in your report, is it not true that it ends in 1975?
DR. WEGMAN. I think that is approximately accurate. But
again, I--this also appears in the National Academy report
as well as the Wall Street Journal. I did not have the
original data for that cartoon, for that graph, and so I had
no way of knowing what the full range of the time frame was
for that.
MS. SCHAKOWSKY. And would you confirm that, Dr. North, that
it goes approximately or maybe exactly to 1975?
DR. NORTH. It is 1975. That is correct.
MS. SCHAKOWSKY. I am trying very hard to understand the
point of this hearing and this conflict because if we are
through many studies come to the conclusion that there is
such a thing is global warming, which is hard to deny on a
day like today and yesterday, et cetera, although I am not
the scientist, and that it at least in some part is caused
by human activity, then why we are doing this really does
escape me. I can understand why in academia you may have
an interest in discrediting Mann and back and forth, but I
am very concerned that this is being used in a way to
discredit the whole notion that our country and the rest of
the industrialized and developing ought to do anything
about global warming, and that is why I asked you that
question, Dr. Wegman, if this does not make you somewhat
uncomfortable. Can you see in any way how this is being
used and does it bother you?
DR. WEGMAN. Well, I can understand that it is your job to
sort out the political ramifications of what I have said.
In some sense it is not fair for you to say well, gee, you
have reported on some fact and that is going to be used in
a bad way. The other side of the coin is that, you have
tried to get me to say that manmade carbon dioxide emissions
are associated with the global warming.
MS. SCHAKOWSKY. Which you can't, right, because you are not
a climate scientist.
DR. WEGMAN. I cannot say that, but what I can say is that
from 1850 to the present time, the global temperature rise
is about 1.2 degrees Centigrade according to the Mann chart.
One point two degrees Centigrade translates to about two
degrees Fahrenheit. I challenge anybody to go out and tell
the difference between 72 and 74 degrees Fahrenheit. What
I do say and what I have said repeatedly is that you need
to focus on the basic science. You need to understand what
the transfer of heat from the ocean to the atmosphere, how
that dynamic works, how the climate is going to change
based on the physical mechanisms, a fundamental understanding
of the physical mechanisms, not on some statistical
estimation of those signals.
MR. WALDEN. The gentlelady's time has expired. The gentleman
from Florida, Mr. Stearns, for 10.
MR. STEARNS. I thank you, Mr. Chairman. Let me thank both of
you for your patience here and how long you have been sitting.
We have been changing chairmen here. They get to go but you
don't so we are very appreciative of what you are doing here.
I think you aptly replied to Ms. Schakowsky's comment that
basically we are trying to look at the science of this.
Mr. Chairman, I think it would be appropriate to put by
unanimous consent this Wall Street Journal article, if you
don't mind to put this in. It is--
MR. WALDEN. Without objection.
[The information follows:]
MR. STEARNS. Thank you. It talked about the hockey stick
hokum and it goes on to talk a little bit about Mr. Mann and
we all talked about it all morning but it says in 2001 the
IPCC replaced the first graph with a second in its third
report on climate change and since then this graph has cropped
up all over the place. In fact, I think it is in Vice
President Gore's movie and I believe it is in his book,
"Inconvenient Truth." On page 65 he has got the source as
the IPCC and then a little bit above it he talks about the
hockey stick, a graphic image representing the research of
climate scientist Michael Mann and his colleagues. So I
would just say to my colleagues and Ms. Schakowsky to that it
is important that if a graph suddenly becomes a significant
graph in all these publications and shows up everywhere and
is used in debate to make argument, I think it is important
for all of us to look at this graph and I think that is all
Dr. Wegman is doing is to say we are looking at this graph
and as it turns out in this book, "An Inconvenient Truth" by
Vice President Gore that he is using a graph as I understand
it that has been established this morning that the
methodology and the statistical analysis of it is incorrect
and--
MS. SCHAKOWSKY. No, that is not--will the gentleman yield
for a second?
MR. STEARNS. Well, let me ask--
MS. SCHAKOWSKY. Just for one second.
MR. WALDEN. Just regular order.
MR. STEARNS. I will be glad to do that. Let me just ask
Dr. Wegman, if I have in his book the reference to the
hockey stick and I have reference to the IPCC, then we have
here a graph that you in fact are disputing because of its
methodology and the statistics. Would that be a fair
statement?
DR. WEGMAN. Well, I would like to be careful in that
regard.
MR. STEARNS. Sure. I know. Do you want me to bring the
book down and have the staff bring the book to you?
DR. WEGMAN. I have one.
MR. STEARNS. Oh, you have it.
MS. SCHAKOWSKY. Would the gentleman yield--
MR. STUPAK. Would the gentleman yield on that point
then?
MR. STEARNS. Well, let me just finish with my question
here because what I am trying to understand is, you have
a graph that suddenly goes everywhere and we have
established today that the methodology for Dr. Mann's graph
is questionable, so the question is, if it shows up
everywhere, shouldn't the American people understand that
some of the reference here in the book, the methodology is
in question? That is all I am asking.
MR. STUPAK. Would the gentleman yield on that point?
MR. STEARNS. Well, let me ask--
MR. STUPAK. Because if you are going to ask the
question--
MR. WALDEN. Regular order, please. It is the gentleman's
time--
MR. STEARNS. I am not asking the question to you. I am
asking it to Dr. Wegman, so I think, Mr. Chairman, I would
like to have the question asked to him and not to my fellow
colleagues.
DR. WEGMAN. Let me be precise on the statement. There is
some ambiguity in this book because it talks about ice
cores and as I understand it, this particular--
MR. STEARNS. This is on page 65.
DR. WEGMAN. This particular picture--
MR. STEARNS. Yeah, that is right, the same one.
DR. WEGMAN. --was based on ice core studies--
MR. STEARNS. But it says below, it says source, IPCC, at
the very little, small little note there.
DR. WEGMAN. Right.
MR. STEARNS. Okay.
DR. WEGMAN. Higher on the same page in the text it talks
about Mann but I believe if one is going to be precise,
this is a piece of study based on ice cores, not on the
temperature reconstruction.
MR. STEARNS. So we just don't know, and I think that is
accurate. I am glad you pointed that out so that the reader
or anybody looking at this would not necessarily say that the
source of the IPCC is indeed Dr. Mann's hockey stick--
MS. SCHAKOWSKY. Would the gentleman yield for just a minute?
MR. STEARNS. No, I am just asking Dr. Wegman--
MS. SCHAKOWSKY. Please, I can read from--I am looking at the
same--
MR. STEARNS. You folks had your time. I am just--
MR. WALDEN. Regular order.
MR. STEARNS. When I complete my thing. So the question is,
he says IPCC here and he has got this graph that looks like a
hockey stick, you are saying that you cannot correlate that to
mean that it is Dr. Mann's graph? That is what you are saying?
DR. WEGMAN. I believe that is true.
MR. STEARNS. Okay. All right. Yes, I will be glad to yield
to Ms. Schakowsky.
MS. SCHAKOWSKY. Thank you. I just want to read to you from
that same--it says "But as Dr. Thompson's thermometer show,"
and so it is not based on Dr. Mann. This is a different source
which our staff had confirmed with Al Gore. I just want to
make--
MR. STEARNS. I respect that.
MS. SCHAKOWSKY. --that point. I know, but your question wanted
to reinforce the notion that this was based on this false or
inaccurate Dr. Mann study--
MR. STEARNS. Well, I think--
MS. SCHAKOWSKY. --and it is not.
MR. STEARNS. Okay.
DR. WEGMAN. And I responded that it was not.
MS. SCHAKOWSKY. No, I--
MR. STEARNS. Go ahead. You respond to that.
DR. WEGMAN. I responded exactly the same way you just did.
MR. STEARNS. And I think that is important to realize because
it is showing up not just here but it is showing everywhere
and so it is not precise that that is Dr. Mann's graph here,
and that is what you have confirmed. Now, I think the other
real big question that we sometimes forget is, what effect does
this have? I mean, what is--you mentioned here that it could
be two degrees Fahrenheit from 1850 to 2006 and you say how
many people could know the difference between 72 degrees and
74. That was your words. The Competitive Enterprise Institute
put out a report and let me just read from that. Dr. James
Hanson of NASA, the father of the greenhouse theory, and
Richard Linzen of MIT, both of them are renowned climatologists
in the world, agree that if nothing is done to restrict
greenhouse gases, the world will see a global temperature
increase of about one degree Centigrade in the next 50 to 100
years. Hanson and his colleagues predict additional warming
in the next 50 years of .5 degrees Centigrade. A warming rate
of .1, tenth of a percent Centigrade per decade, does that
seem like an accurate statistic to you? Would you generally
agree with that or disagree? I know it is difficult but--
DR. WEGMAN. I have no way of truly knowing.
MR. STEARNS. But I mean, if you say in the last 156 years we
have only had two degrees Fahrenheit, I mean, this would
confirm that this is not something that is out of control.
Wouldn't you say that basically--my point I am trying to
establish is, that the estimates of this future warming should
not get us into a hysterical mode. I know--
DR. WEGMAN. I would tend to concur but what I would also say
is that the global average temperature is probably not a very
good measure of global warming in the sense that, as I said
before, ocean circulation, salinity, how the Gulf current
subducts when it gives up its heat in the Northern Hemisphere,
understanding the coupling of that to the atmosphere seems to
me to be the scientific issue at hand that really ought to be
investigated more thoroughly.
MR. STEARNS. Also in this Competitive Enterprise Institute,
the question came up, and Mr. Waxman mentioned a whole group
of scientists, renowned scientists, that said that we are into
a global warming and in this report it says, "What do
scientists agree on and they agree that global average
temperature is about .6 degrees Celsius or just over one degree
Fahrenheit higher than it was a century ago. Atmospheric
levels of carbon dioxide have risen by about 30 percent over
the 200 years and carbon dioxide like water vapor is a
greenhouse gas whose increase is likely to warm the Earth's
atmosphere." Is that generally you think accurate?
DR. WEGMAN. As far I know, yes.
MR. STEARNS. But is there in your opinion a scientific
consensus that global warming is real and bad for us? Could
you say categorically, both you and Dr. North today, that
there is a scientific consensus and evidence that global warming
is bad and we should be very concerned about it? That is a
tough question, I know.
DR. WEGMAN. I believe there is a consensus that global
warming is real. My friends in Finland think it is a great
thing.
MR. STEARNS. And your friends here in the United States
don't. Would that be fair to say?
DR. WEGMAN. Well--
MR. STEARNS. I mean, that it is occurring but it is not as
significant the people that are out there saying we have
got to do something tomorrow, we have got to do something,
do something.
DR. WEGMAN. I think it is probably less urgent than some
would have it be.
MR. STEARNS. Dr. North, I am going to give you a few
moments, unless you want to--you don't have to say anything.
DR. NORTH. Well, my feeling is that it is happening but I
don't do good or bad.
MR. STEARNS. Let me just conclude, Mr. Chairman, just by
saying that Dr. Wegman said that in the last 156 years it
has gone up just about two degrees Fahrenheit and so I don't
really think we are into a very, very serious concern that
we all should be worried about getting overly hot tomorrow.
MR. WALDEN. The gentleman's time has expired. The
gentlelady from Wisconsin, Ms. Baldwin, for 10 minutes.
MS. BALDWIN. Thank you, Mr. Chairman. Dr. Wegman, your
report includes a social networking analysis of the
authorship in temperature reconstruction, and to your
knowledge, has this type of social network analysis ever
been done before to look at an academic field?
DR. WEGMAN. No, and in fact, based on reactions to this, I
think it is probably a good idea that we do this more
broadly.
MS. BALDWIN. And am I correct in understanding that your
analysis did not include talking to the paleoclimatologists
to get their perspective on how they interact nor did it
include substantively analyzing their interactions?
DR. WEGMAN. No. We simply looked at their connection in
terms of, based on engineering compendics, based on their
coauthorship.
MS. BALDWIN. In your report, you state that, and I quote,
"Our findings from this analysis suggest authors in the
area of paleoclimate studies are closely connected and thus
independent studies may not be as independent as they might
appear on the surface." Are you saying that based on your
social network analysis, that you are concluding that
independent studies may not be independent or are you saying
that your network analysis suggests a lack of independence
as a hypothesis that one would need to investigate further
before one could draw a conclusion?
DR. WEGMAN. I think one should take our social network
analysis with a grain of salt to understand that this is an
unusual configuration of people with a highly central person
involved in this. It is no surprise to any working scientist
that there are groups of statisticians, groups of
mathematicians, groups of paleoclimate scientists, groups of
physicists that work together closely and that there are
competing social networks. I would hasten to add that social
networks doesn't mean I go out and drink a beer with somebody.
It doesn't mean I am a buddy of theirs. It means that I work
with them, that I think like they do, that we have similar
approaches. Now, if the group of people operating in this
area is relatively small, as I believe it is in the
paleoclimate area, then I think there is some evidence that
probably should be investigated more clearly, that these
people are refereeing their own papers. After all, Michael
Mann was an editor of the Journal of Climate and he
publishes a lot of his papers in the Journal of Climate. It
is pretty hard to say well, I am going to take this guy who
is well known and I am going to start rejecting his papers.
That is a pretty hard thing to do.
MS. BALDWIN. Well, Dr. Wegman, my question was, is this a
hypothesis or is it a conclusion that you have drawn? If
it is a hypothesis that would need to be investigated
further and of course earlier we heard Dr. North's response
to a question about what this--how fiercely competitive
people early in their scientific careers, late in their
scientific careers are. I am a granddaughter and a niece of
two researchers and I feel like I have had a lifelong sense
of how competitive these things, even if you have a very
narrow perspective. But are you reaching a conclusion or
a hypothesis?
DR. WEGMAN. No, this is a hypothesis.
MS. BALDWIN. Okay. Then if I understand you correctly,
there are at least two problems with the Wall Street
Journal's statement in an editorial last week that your
"conclusion is that the coterie of the most frequently
published climatologists is so insular and so close-knit
that no effective independent review of the work of
Mr. Mann is likely," because first your social network
analysis wasn't of climatologists but a much narrower
group of temperature reconstructionists, and second,
your social network analysis did not allow you to reach
a conclusion about the independence of review of
Dr. Mann's work.
DR. WEGMAN. I think that there is--you know, in some
sense you are putting words in my mouth but I think
there is evidence--
MS. BALDWIN. Well, the Wall Street Journal--
DR. WEGMAN. Let me finish. I think there is evidence
based on this social network analysis, based on the real
climate.org web log, based on the general reaction of
Dr. Mann and, for that matter, Dr. Bradley and Dr. Hughes
to the initial inquiries to the committee that there is a
tight-knit group of people who are interacting with each
other and who frankly don't seem to like to be criticized.
MS. BALDWIN. Dr. Wegman, I have an additional question.
I think it has been touched on before but I just want to
get some real clarity on this. I understand that the data
that you used is based on Mann's 1998 and 1999 studies.
In the recent years Dr. Mann has altered his
reconstructions using different methods and proxies. Each
time he has been able to reach virtually the same
conclusions. Did you analyze any data from Mann's later
studies or those from other reputable climate scientists
who have reached similar conclusions?
DR. WEGMAN. We did not attempt to reproduce any of the
later material. However, what we did do was look at the
proxies that were used and we looked at the series of
papers beginning actually with Jones and Bradley, I think
it was, in 1993 and compared the proxies that they were
using and the methodologies that they were using.
Basically Mann articulates I believe in his 2005 paper
the set of papers that used the climate field
reconstruction, the CFR methodology, and also uses the
CPS methodology. Those are articulated by Mann, not by
me.
MS. BALDWIN. But you used the 1998 and 1999 studies?
DR. WEGMAN. We were asked to address the issues in 1998
and 1999, yes.
MS. BALDWIN. I would now yield my remaining time to
Mr. Inslee, who requested that.
MR. INSLEE. Thank you. Doctor, I have been trying to figure
out how to characterize the situation, and the best I can do
is to say that we don't debate gravity anymore and we should
not debate whether there is a human contribution to global
warming anymore, and the way I look at this is sort of like
if you had reviewed Newton's Principia where he laid out the
basic laws of physics that we have now based, until quantum
mechanics came around, most of our science, if you found a
statistical flaw, which I will bet you could if you looked
at the whole Principia that didn't meet sort of regular
statistical proofs right now, you might come into Congress,
if the Republicans controlled Congress in 1695, anyway, and
say, you know, I found this statistical flaw in this one
little piece of Newton's theory, even after we have a
mountain of evidence that gravity is a fact, not a theory,
upon which we base our science, and that is the reason that
you are not urging, as I understand it, us to reject
Dr. Mann and his group's conclusion, that humans are a
causative factor for global warming. The reason you are
not asking us to reject that conclusion is that you
recognize that you have found what you believe is a
statistical flaw in one study but it does not contravene
the mountain of evidence that says global warming is
caused a not insignificant part by human activity. Is
that a pretty fair metaphor for this?
DR. WEGMAN. Well, I--you know, the issue is, I was asked
a very specific question. I came here to testify on a
very specific question. And you are asking me to testify
off of my level expertise and I--
MR. INSLEE. Well, let me just ask you--
DR. WEGMAN. --am not going to do that.
MR. INSLEE. Let me ask you a quick question. If you
found a statistical flaw in the Principia published by
Sir Isaac Newton in 16 whenever it was, would you suggest
that we reject the theory of gravity?
DR. WEGMAN. I would not suggest anything because that was
not the question I was asked and that is not the reason I
am here.
MR. INSLEE. Well, unfortunately, this is the reason--
DR. WEGMAN. I mean, if you are asking me as an ordinary
citizen--
MR. INSLEE. No, I want you to make sure you understand
the reality of the situation. I am giving you all the
sincerity that I can give to you. But the reason you are
here is not why you think you are here, okay. The reason
you are here is to try to win a debate with some industries
in this country who are afraid to look forward to a new
energy future for this Nation, and the reason you are here
is to try to create doubt about whether this country should
move forward with a new technological clean energy future
or whether we should remain addicted to fossil fuels. That
is the reason you are here. Now, that is not the reason
individually why you came but that is the reason you are
here. Thank you very much.
MR. WALDEN. The gentleman's time has expired, which is
the reason I am here to keep control of this.
DR. WEGMAN. But I didn't get to answer.
MR. WALDEN. Well, I will just give Dr. North a question.
Does anybody still study gravitational theory in the
scientific community?
DR. NORTH. Yes, they do.
MR. WALDEN. If you find--
DR. NORTH. It is a very active field in physics.
MR. WALDEN. Do you ever learn anything new?
Dr. North. Absolutely. Things are being learned all
the time.
MR. WALDEN. And are you allowed then to publish new
findings that might contradict old findings?
DR. NORTH. Absolutely.
MR. WALDEN. Okay. Good. Science moves forward. Now,
I have to apologize. I was in another markup earlier
and so I missed some of the questions and some of the
opening statements although I am familiar with both of
your gentlemen's testimony. But I just want to make
sure I understand one sort of underlying piece, and
that is, did you both indicate that Dr. Mann's
underlying statistical analysis was incorrect?
Dr. Wegman?
DR. WEGMAN. Yes.
MR. WALDEN. Dr. North?
DR. NORTH. Well, we found that it is not--there were
many choices to make. They probably didn't make the best
choice when they did the analysis the way they did.
MR. WALDEN. What do you when--
DR. NORTH. When their claims are wrong, it just means they
are not very convincing because of the way they did it.
MR. WALDEN. Okay. Now, I am not a scientist so tell me--
DR. NORTH. That was nuanced. I apologize.
MR. WALDEN. No, no. Tell me what that means as a
layperson, as a lawmaker, when you say they made choices
in their--
DR. NORTH. Well, when you approach a problem like this,
there are many choices when you try to do a statistical
analysis and so there are many choices as to should you
deter in the data in the 20th Century or should you not.
Should you use this kind of validation procedure or a
different one.
MR. WALDEN. Right.
DR. NORTH. And in fact, one series of papers by Burger
and Cubasch actually looked at the situation and decided
there were 64 different ways you could have done it, and
had you chosen--and so they actually showed us a family of
extrapolations you would have gotten using all of those
different--
MR. WALDEN. And did they all look like a hockey stick?
DR. NORTH. They all--well, I mean, to me they do. But,
it is a bit curved. It is not exactly like the hockey
stick but within the error bars, and by the way, in the
Wall Street Journal article, there is really a mistake
made in that graphic, and that has to do with the error
bars. It does show--these two graphics are in our
reports, the same ones that are in the Wall Street
Journal report, and if you look at the Wall Street Journal
article, they don't put the margin of error in there, which
is really important.
MR. WALDEN. What is the margin--
DR. NORTH. I mean, it is totally irresponsible to do this
without the margin of error.
MR. WALDEN. Okay. Can I ask you, what should that be so
we clarify the record, the margin of error?
DR. NORTH. The margin of error is the plus-minus 95 percent
confidence interval.
MR. WALDEN. And that is what it should have been here?
DR. NORTH. That is right.
MR. WALDEN. The plus or minus--
DR. NORTH. And so when you look at the family of curves,
they all fall pretty close to that gray area in this graphic
but in the Wall Street Journal article, the gray is removed.
MR. WALDEN. Now, in the Wall Street Journal article too,
they make a reference to a McIntyre and McKitrick critique,
and I guess, have you reviewed that one, Dr. North
DR. NORTH. Oh, I am familiar with their work and, in fact,
Mr. McIntyre is here. He will be testifying later.
MR. WALDEN. Did he present to your panel?
DR. NORTH. Yes, he did. And in fact--
MR. WALDEN. Can their data be replicated or the results
be replicated?
DR. NORTH. Well, what they did was a critical study,
somewhat like the Wegman report, and I think they did an
honest job. It was a nice piece of work.
MR. WALDEN. Dr. Wegman--
DR. NORTH. I have no complaint about what they did.
MR. WALDEN. In terms of replicating data or replicating
studies, my understanding is, it is difficult to replicate
the Mann study but it was possible to replicate the
McIntyre and McKitrick study.
DR. WEGMAN. Yes, that is correct, and we did so.
MR. WALDEN. I want to move on to a little different topic
and that is related to data sharing because I have run into
this in another committee where I am a subcommittee chair
on science and that was, there was a dispute--imagine that--
over a report that was run out and published and somebody
else tried to get the data to see if they could replicate it
and there was a long delay and it was a real problem, and I
know Dr. North, in your report, you say--page 112 of the
surface temperature reconstructions the past 2,000 years,
you make a comment that says, "Our view is that all research
benefits from full and open access to published data sets
and the clear explanation of analytical methods is mandatory.
Peers should have access to the information needed to
reproduce published results so that increased confidence in
the outcome of the study can be generated inside and outside
the scientific community," and you make that comment. Then
I note--
DR. NORTH. I was about to read it to you.
MR. WALDEN. What is that?
Dr. North. I was about to read it to you.
MR. WALDEN. Well, we can do it in the key of C next time
together. Then Dr. Wegman, on page 4 of your testimony,
you say, "Additionally, we judge that sharing research
materials, data, and results was haphazardly and grudgingly
done," and further I believe it on page 66, there is a
reference--there is a question, "Has the information needed
to replicate their work been available, and the answer is,
in our opinion, no. As mentioned earlier, there were gaps
in MBH98." Do we have a situation here where it was very
difficult to get the data to do replication, and if so,
why, do you think?
DR. WEGMAN. As I mentioned earlier, we did download the
data. We have seen the letter that Dr. Mann replied to the
committee which basically took the position that this is my
intellectual property and I don't have to share it and the
National Science Foundation tells me so.
MR. WALDEN. Is that the case, Dr. North? Do you speak for
the National Academy of Science?
Dr. North. No, no.
DR. WEGMAN. But the issue is that if there is free and open
access to the data and the materials that are associated
with the data, it makes the policing of this kind of
activity, the referees for the hockey game as I said earlier,
it makes it so much easier to be able to do that, and we
think that that is an important aspect of the scientific
enterprise.
MR. WALDEN. How do statisticians do these sorts of
evaluations? Do you share data among yourselves?
DR. WEGMAN. Typically in terms of computer code, there are
two places that people typically go to. There is an
electronic journal called the Journal of Statistical
Software which is a refereed journal. People submit their
code to that journal. There is also a website that people
submit both data and code to.
MR. WALDEN. I don't know if you have had a chance to see
Mr. Crowley's testimony whom we will hear from later today
but he has some rather unflattering statements about your
report. I know it is shocking that different scientists
have different views of different scientists and their
reports. He says that there are a number of flaws in your
report and goes on to list some. Do you have any comment
on the testimony we are going to hear later since you
won't be back at--
DR. WEGMAN. Well, I probably will be here but not sworn
in or at least--
MR. WALDEN. Right. You will still be under oath, they
inform me.
DR. WEGMAN. I understand where Dr. Crowley is coming
from. He is in a relatively awkward position of having
to defend the position that Dr. Mann had taken.
MR. WALDEN. Why? Why is that an awkward position?
DR. WEGMAN. Well, because you have heard from both of
us this morning that there are fundamental flaws in the
Mann work and to come and have to defend that is an
awkward situation, I think. Frankly, I would not have wanted
to get the letter that Dr. Mann got and the other coauthors
because that is kind of not on the radar screen of typical
scientists. You know, you write a paper and you have a
file somewhere and right now my dean is telling me that we
should throw everything that is more than 3 years old, we
shouldn't keep it in the file drawers because we have space
considerations, we have to keep space, but I--you know, I
think I jotted down the phrases he used about me which is
that I am naive and--I think it was naive and uninformed.
I don't think those are accurate statements because he has
never talked to me either. He has only read what we wrote
and he has read it without the interaction with us as
statisticians so we will see what happens this afternoon.
MR. WALDEN. Is he a statistician, do you know?
DR. WEGMAN. Not that I know of.
MR. WALDEN. You made a comment about the potential
conflict with Dr. Mann being an editor of a journal and
also submitting work to that journal.
DR. WEGMAN. Yes.
MR. WALDEN. Do you know if he proofs his own work or does
he hold himself--
DR. WEGMAN. Generally the process is that an editor of a
journal will submit it, pass on the material to an associate
editor who will in turn select some referees. That process
is typically what happens in a journal. When I was editor
of a journal, I refrained from submitting anything to the
same journal that I was editor of simply because it puts
pressure on the associate editors and referees to approve.
MR. WALDEN. Gentlemen, we appreciate your testimony and I
will go to the full committee Chairman, Mr. Barton.
CHAIRMAN BARTON. Well, I don't want to do a second round
because we have subjected these two gentlemen to close to--
what is it--four hours of dialog. I would want to--I want
to ask unanimous consent to ask Dr. North to comment on the
recommendations that Dr. Wegman gave and I also want to
renew my request that the Enders Robinson e-mail be put
into the official record.
MR. STUPAK. Mr. Chairman, as to the e-mail of Robinson, I
have no problem with that being entered in the record, but
if you are going to ask further follow-up questions, I know
there is one two further follow-up questions on this side
we would like to ask.
[The information follows:]
CHAIRMAN BARTON. I am sorry. I got the first part. I
didn't get your second part.
MR. STUPAK. I said there are one or two follow-up
questions--
CHAIRMAN BARTON. Oh, you all have some follow-up? Okay.
Could I be recognized then for 5 minutes? Could we do the
second--
MR. STUPAK. No objection.
CHAIRMAN BARTON. Five minutes so that we can let this
panel go.
MR. WALDEN. The Chairman is recognized for 5 minutes.
CHAIRMAN BARTON. Thank you. Dr. North, Dr. Wegman makes
four recommendations on page 6 of his testimony. Do you
have that in front of you?
DR. NORTH. I think I have copied them out of there so I
think I have them here, yes.
CHAIRMAN BARTON. Could you comment on each recommendation,
whether you think his recommendations have merit?
DR. NORTH. Let--I will try to do that. So recommendation
one was when massive amounts of public monies and so forth
are at stake, academic work should have more intense level
of scrutiny and review. Well, nobody would argue with
that, of course. It is especially the--we always want to
do things better. It is especially the case that authors
of policy-related documents like IPCC and so forth should
be--
CHAIRMAN BARTON. He says the review should not be the same
people that constructed the academic paper.
DR. NORTH. So that is a really very interesting question and
subject. You know, when you ask for an expert scientific
review of the state of art or the science and you go to the
world experts, and that is what the IPCC tries to, you will
find authors of the chapters who have also coauthored some of
the papers involved and indeed I think sometimes they do
promote their own work. That is human nature. We all know
how that works. So that process isn't exactly perfect, but
I cannot imagine a better, more efficient way to pull
several thousand scientists together and they have to meet
repeatedly several times over the course of a year, over
the course of a couple of years. One time we actually had
one of the meetings in College Station some years ago and
so people get tired of this. It is really hard to work.
I mean, it sounds like it is fun but--
CHAIRMAN BARTON. To the largest extent possible, if you
can--
DR. NORTH. So it is very, very hard to--
CHAIRMAN BARTON. Sometimes there is not but two experts
in the world and so, you know--
Dr. North. That is right.
CHAIRMAN BARTON. But if it possible--
Dr. North. So, you know, you could go another way and
ask a situation like the academy did. We had a small
committee of 12 people who were picked on the basis that
they were not connected with any of the--I mean, as
little as we could possibly do, connected with any of
the principals and the problem, so--
CHAIRMAN BARTON. But what about his recommendation
number two that there should be a more comprehensive and
concise policy on disclosure and that data collected under
Federal support should be made publicly available?
DR. NORTH. This is not a bad idea, and in fact, I think
Tom Karl is going to address that.
CHAIRMAN BARTON. And then his recommendation number three
is that if you are doing review and doing studies that
include some sort of a statistical approach on which your
conclusions are based, that there should be statistical
evaluation of the statistical practices. He says it
should be a mandatory part of all grant applications.
DR. NORTH. I think that is a little over the top. I
think--
CHAIRMAN BARTON. A little over--
DR. NORTH. I think carrying this to the Federal drug
approval process is--
CHAIRMAN BARTON. So you would--
DR. NORTH. It is not a good analogy.
CHAIRMAN BARTON. Well, what about his last one, that
emphasis should be placed on the Federal funding of
research related to fundamental understanding of the
mechanisms of climate change. I think you would accept
that. And that the funding should focus on
interdisciplinary teams and avoid narrowly focused
discipline research, and he is trying to broaden the
field so that it is not the same group of people talking
to the same group of people.
DR. NORTH. Well, it seems to me the two statements are
contradictory. The first one says you should narrow the
field and the second one says you should broaden the
field, so, I mean--
CHAIRMAN BARTON. You are not real fired up about--
DR. NORTH. I want to see more money come into the field.
I think we all would like to see that. That is great.
But I am not sure that one was very well formed out.
CHAIRMAN BARTON. Well, let me before I yield back my 52
seconds say why we are doing this hearing, because I have
been here almost the entire time for every question and
every statement. I missed a little bit but not much. I
don't disagree fundamentally with some of what my friends
on the minority side have stated. There is no question
that the temperature is warmer today than it was in 1850.
I think there still is a question about the cause of that,
and some of these reports and studies that purport not
only to state the fact of the warming but the consequences
of it, I think should be open to honest public debate
without challenging the merits. Where I disagree with
some of my friends on the minority side is that before
we make massive public policy changes that affect every
American citizen in this country, we need to have with
the highest degree of certainty that the facts really are
the facts. Now, I have right here a magazine article from
Newsweek April 28, 1975, that is talking about the
cataclysmic consequences of global cooling. Now, that is
30 years ago and the science has changed. Now we are
talking about the cataclysmic consequences of global
warming. If the United States has ratified Kyoto and if
the United States Congress working with the Administration
had begun to implement Kyoto, it requires a reduction in
CO2, I believe about 30 to 40 percent, and that means you
are not going to have coal-fired power plant combustion
in many parts of this country. It means that you are
going to have to reduce the automobile emissions of the
vehicles that are made in Michigan. And before we go
down that trail, I think it is imperative that we do the
oversight and do the science and talk--I am not opposed
to talking to the climatologists but I agree with
Dr. Wegman that we need to make sure that it is an
interdisciplinary approach so that we really get everything
on the table. If that shows that the human correlation is
beyond dispute, then I believe we do have an obligation to
take what steps we can to remedy that but I don't believe
that science yet shows that. With that I yield back,
Mr. Chairman.
MR. WHITFIELD. Thank you, Mr. Chairman. At this time I
recognize Mr. Stupak for--
MR. STUPAK. Thank you, Mr. Chairman. Chairman Barton,
and I take it, that means we are going to have a lot more
hearings on global warming because there are a lot more
reports than just Dr. Mann's 1998-1999 report, so if we
are going to come to those policy decisions, I would hope
we would have more than just one hearing about one report
and look at the whole spectrum of reports on global
warming. Dr. North, if I may, the IPCC process, is that
based upon sound science, sound methodology?
DR. NORTH. In my opinion, when you go out and ask the
active scientists in the field to give you an assessment,
they select themselves and it has been my experience in
the three that have been produced that they do just that.
I had very little to do with the last one. I served a
referee on--
MR. STUPAK. Sure.
DR. NORTH. But the one before, I had a little bit more
to do with it, but I think the process is pretty good.
You know, it is human. It has some flaws in it but I
think I--it is probably the most massive assessment of
this kind that has ever been made. It is remarkable
that you get people to do that. And I will tell you this,
people are tired of participating. It is a lot of work.
Traveling to these countries and having these workshops
and meetings, it is a lot of work and so to actually ask
people who are not experts to come in and read all of
those papers that they weren't involved in, that is asking
a lot of people and you won't get anybody to do it because
there is no money for this. There is no pay for this.
MR. STUPAK. Okay.
DR. NORTH. Incidentally, the academy report people didn't
get paid anything either.
MR. STUPAK. Dr. North, you also mentioned the hockey stick
hokum that was in the Wall Street Journal last Friday in
which they claimed that the graph from 1990 that we have
talked a lot about today showing the warming period in the
Middle Ages, the Wall Street Journal goes on to say that in
1990 the consensus "held that the medieval warm period was
considerably warmer than the present day." It has been a
long hearing here today but is there any scientific
evidence from anyone that supports the claim that
temperatures in the Middle Ages were higher than they are
today?
DR. NORTH. There may be some locations on the Earth but so
why do we care about the global average? You know, that
has come up a couple of times. Because if CO2 is the
reason, it is a global forcing so you expect the response
to be at the global scale. This is really important.
That is why--I mean, nobody takes a picnic at the global
scale but the scientists are very interested in what
happens to the global average because that is what is being
forced by the CO2. So that is why we are so fixated on the
global average and getting large-scale averages. It is
easier to measure it because when make measurements at a lot
of locations, a lot of the random errors cancel out. That
is good. The same thing happens with our models. They do
that better than anything else.
MR. STUPAK. Dr. Wegman, I thought I heard you say, and
correct me if I am wrong, when you are making comparisons
you are saying that you used--I think it was figure 4 on
your chart--that you used North American factors in your
analysis with Dr. Mann's?
DR. WEGMAN. Dr. Mann himself used North American--what he
called the North American PC1 proxy which was a composite
based on the principal of component methodology of North
American tree rings.
MR. STUPAK. Sure.
DR. WEGMAN. And that is what--we replicated that, yes.
MR. STUPAK. So in your analysis, you used just North
American, right?
DR. WEGMAN. We used the North America proxy.
MR. STUPAK. The P1, the P2--
DR. WEGMAN. The PC1--
MR. STUPAK. --and the P3?
DR. WEGMAN. Yes.
MR. STUPAK. PC. I am sorry. PC1, PC2. But didn't really
Dr. Mann use 12 proxy indicators from all over the world?
DR. WEGMAN. We were not trying to do paleoclimate
reconstruction. We were trying to illustrate what happened
if you did--
MR. STUPAK. Sure.
DR. WEGMAN. --the principal component--
MR. STUPAK. Dr. Mann used 12 proxies to come up with his
analysis. You took three from North America. Is it fair
to say then that using from throughout the world would have
a different result than if you just looked at the three in
North America?
DR. WEGMAN. Let us be clear. He was doing Northern
Hemisphere, NH, reconstruction. He wasn't doing global
reconstruction in--
MR. STUPAK. But if you take a look at his report, and I
know you did, they talk about Tasmania, taking tree rings
from there, Morocco, tree rings from there, France, the
Greenland stack core which we talked about, the ice core,
polar Urals, again, the tree ring density. It seemed to
me he took them from all over the world where your focus
is only on North America. So how could you make the
comparison then when you use global statistics as opposed
to just one part of the world in doing your measurements?
DR. WEGMAN. Well, I am not sure I understand what you
are getting at. The--
MR. STUPAK. From a layperson who is not a statistician,
I would think if you are going to compare Dr. Mann's
statistics, if you will, you would use all of them as
opposed to--
DR. WEGMAN. Our discussion--
MR. STUPAK. --just three of them.
DR. WEGMAN. Our discussion is on Dr. Mann's methodology,
not his conclusions in terms of paleoclimate--
MR. STUPAK. But you charted, did you not? Didn't you
use X axis, Y axis and chart it all out and that is why
you got different than the hockey stick? You only used
three where he used 12.
DR. WEGMAN. No, no, no. We used the same data to get the
hockey stick in that one figure--
MR. STUPAK. From North America?
DR. WEGMAN. From North America.
MR. STUPAK. And he took his from the worldwide.
DR. WEGMAN. No, no, no.
MR. STUPAK. That is not what table one says.
DR. WEGMAN. What we said was that we used that comparison
chart that we had that showed the hockey stick. The
comparison was meant to show that if--
MR. STUPAK. Right here, yes?
DR. WEGMAN. That is it. If you go to the top chart by
using his methodology on the same set of data and the
bottom chart is what you would get if you did the centered
data, if you did it properly mathematically. So the point--
MR. STUPAK. But yours is only on PC1, PC2--
DR. WEGMAN. So is his--
MR. STUPAK. --and PC3.
DR. WEGMAN. --in that picture.
MR. STUPAK. So you are saying that picture was only PC1,
PC2--
DR. WEGMAN. That is--
MR. STUPAK. --PC3 from Mann.
DR. WEGMAN. We are using exactly the same data in the top
picture and the bottom picture.
MR. STUPAK. Okay. Thank you.
MR. WHITFIELD. The gentleman's time has expired. Dr. North,
in the testimony today, there seems to be universal agreement
that the temperature is going up and in the last century it
went up about one degree Fahrenheit, I believe is what most
people have agreed to, and there has also been a lot of
testimony that for a period of time between 1500 to 1800,
whatever, that there was a period in which there was a
cooling off. So I just want to zero in on this. You have
said and others have said and I think there is universal
agreement that we are going through a warming trend, and it
has been said by some people that that might not be
surprising coming from a cooling off period that you would
normally get warmer going through a warming trend. So the
question that I would ask, as you look into the future, how
much warmer can it become before it is something that we
should really be alarmed about from your viewpoint, from
experiences?
Dr. North. Well, I will say this--well, two things. One
is about the Little Ice Age and is it simply a recovery.
In other words, is the Earth's temperature a kind of
oscillating thing and that the slope upward now is just
recovery from a Little Ice Age which was apparently maybe
some natural phenomenon. Well, I am not sure that that is
actually the right picture. We don't know exactly the true
origins of the Little Ice Age but some studies, in fact, a
very good one by Tom Crowley, who will be speaking later,
suggests that this is due to a series of volcanoes during
that period which caused a cooling. It was not a great
cooling but some cooling. So now it is--you know, now
that we are going through a period when they are not as
frequent as they were at that time, the Earth is simply
warming back toward equilibrium from that. But now we
are also forcing the warming with the CO2 and other
greenhouse gases that are being emitted into the
atmosphere. So while if we look at the future, what we
might think is that by the end of this century the
warming, if it continues and we do nothing about it, will
probably be somewhere between about three degrees
Fahrenheit and about eight degrees Fahrenheit. Well,
three may not be so bad. Eight would be pretty bad,
pretty bad. And so in fact, even three is not as benign
as you might think. You know, you can look at--for us in
our everyday life, three degrees Fahrenheit doesn't seem
to mean anything. People after all live in Minneapolis
and they live in Houston. But it really does affect
conditions. Tree lines move. There is a tree line that
runs right up the center of the United States along I-35
between Austin and Minneapolis.
MR. WHITFIELD. Right.
DR. NORTH. That tree line can move hundreds of miles
depending on just a couple of degrees or changes in
moisture. So what looks like to us in our everyday life
not very much, if these things persist for a long time,
there are broader ecological responses at these kind of
low frequencies that are important. So, I don't know all
of the bad or good things that might happen. I mean,
there would probably be some winners and losers in a
situation like this. And I have to confess to you, I don't
know enough about it.
MR. WHITFIELD. But you know as we grapple with this, we
have like a 250-year reserve of coal in America. We all
want to be less dependent on foreign oil. There are some
people that don't want to use fossil fuel at all, it would
be better to come up with new innovation, new technology
and move on to something cleaner and that can be a goal of
ours. In representing a coal area of the country, I have
a lot of constituents who come up to me and they will say
well, sure, there is some carbon dioxide caused by human
beings but there is more carbon dioxide emissions caused
by natural processes. Now, I would just like to get your
views on that comment. Is there any basis for that or is
that just somebody--
DR. NORTH. There is a lot of carbon dioxide emitted into
the atmosphere every year and a lot of absorbed back into
the system every year, in fact, many times what humans put
in. The problem is this. There was an equilibrium
established between what is going out and what is drawn
back down every year by the system. The oceans and the
biosphere, there is this exchange that goes on all the
time. The problem with this is that the time scale, the
time constant, as we say, is quite long. It takes a
couple of hundred years for these adjustments to
re-establish themselves, so if you dump in the carbon
dioxide much more rapidly than the system can accommodate,
it builds up in the atmosphere. If we were to wait several
hundred years, then things may come back down, but we
don't have that luxury. So the fact is, we are pouring it
in there faster than the system can dispose of it. That
is the way--
MR. WHITFIELD. Thank you very much. Who is next over
here? Mr. Inslee.
MR. INSLEE. Thank you. Just on that note, Dr. North, I
have heard the CO2 that we put in today in the atmosphere
could be there as long as 100 years?
DR. NORTH. A couple of hundred years.
MR. INSLEE. I want to use Dr. Wegman's expertise to try to
understand an interesting phenomenon. You talked about
social networking. I thought you could give us some insights
about that. Dr. Naomi Oresky of the University of California
at San Diego published a study in Science magazine some time
ago. She and her team selected a large random sampling of
928 articles about global warming that have been published
in peer-reviewed scientific journals and she wanted to look
at what they said, these 928 randomly selected peer-reviewed
articles about whether they accept or reject or question the
idea that humans are contributing to global warming. Of 928
studies, what do you think percentage questioned the
proposition or rejected or even cast doubt on the proposition
that humans were causing global warming? What do you think,
Dr. Wegman? What percentage? Zero. Zero percentage of the
scientifically peer-reviewed articles drew the same conclusion
that my good friend Joe Barton drew, that there is doubt about
this. Zero. Now, my question is, another study looked at 636
randomly selected articles about global warming chosen from
the New York Times, the Washington Post, the L.A. Times, and
the Wall Street Journal. Of those randomly selected
publications and those well-respected publications, what
percent cast doubt as to the cause of global warming? What
do you think?
DR. WEGMAN. Probably about 50 percent.
MR. INSLEE. Fifty-three percent. You win the prize for the
day of closest guess, or as you say, estimation. Over half
of the popular articles suggested there is a significant
question as to whether or not humans are contributing to
global warming but zero percentage of the peer-reviewed
science. Now, I believe that is one of the reasons that
Congress has not acted on this because frankly, the press is
creating doubt where there isn't any. So the question of a
social scientist, the social networks, do we have a problem
with the press that are hanging out in the bars all together
too much too like the climatologists or what is your
explanation for this huge anomaly?
DR. WEGMAN. Well, there is no doubt in my mind that there
are two camps in the publication literature as well in the
popular press and, they are competing just like I suggested
that academics compete in social science that there is two
networks that are trying to promote different agendas.
MR. INSLEE. Well, my point is, I hope the press starts to
get off the story of doubt and get on the story of a
scientific consensus which exists in those 900 articles, and
no one should report this hearing unless they say that
because both you and Dr. North and every single person who
is going to testify today is going to say that there is a
scientific consensus that humans are responsible for at least
a portion of the global warming that is taking place. Now, I
want to ask Dr. North if we can put this slide up here about
the CO2 and go back to the one he had there just a moment
ago. Dr. North, I gave some of a very inarticulate
description of how carbon dioxide works to trap energy in the
planetary system. Could you give a little better
explanation? We will see that all the scientists, everybody
has projected levels of approximating double of pre-industrial
times if we don't change our course. Could you explain in a
little better way how carbon dioxide affects the energy
balance of the Earth?
DR. NORTH. I will try. First of all, carbon dioxide is well
mixed in the atmosphere so it isn't just lying down on the
surface. It is very well mixed. This process takes a few
months but--and in fact, if you emit it in one hemisphere of
the Earth, it takes about a year or two before it homogenizes
throughout the world. So whether you emit your gas, your CO2
in Texas or anywhere else, it doesn't make any difference.
It winds up homogeneous throughout the world. So what
happens now? So the sunlight comes in, passes right through
the CO2 and warms the ground. The ground in contact with
the atmosphere through latent heat release, that is,
evaporation from the surface and just sensible heat convection
to the surface warms the atmosphere. So and then we establish
an equilibrium because the radiation going out to space
matches exactly what comes in over a long-term average. So
that is the energy balance of the Earth. Now, suppose you
turn up the carbon dioxide a little bit in the atmosphere.
Well, one thing that happens is, since the gas homogenizes
all through the planet, all around the planet. The level up
in the atmosphere where the CO2 emits to space goes up a
little bit and higher in the atmosphere, 50 meters or
something like that if you double it. That means it emits
from a cooler place in the atmosphere once you have doubled
it. That means the amount going out isn't as much as it was
before. So what happens is, you have to warm the surface in
order to regain the equilibrium. That is a complicated
explanation. But in the process right in the middle of this,
you warm the planet a little bit, more water comes into the
atmosphere from the oceans and other wet surfaces. Water
vapor is also a greenhouse gas so this process gets amplified
maybe a factor of two. So basically, I mean, what you said
about the blanket is more or less right. A slightly more
technical discussion is well, when you put in more of this
stuff, it now emits from a higher place from a cooler surface
rather than a warm surface so the radiation out to space is
less, you have got to warm up the planet to match again.
Sorry for such a long-winded answer.
MR. WHITFIELD. Thank you. The gentleman's time has expired.
Mr. Walden.
MR. WALDEN. Thank you very much, Mr. Chairman. Dr. North,
what are some of the biggest natural emitters of CO2?
DR. NORTH. Well, there are many. Decaying biological matter
is one, so rotting, decaying at the floor of the great forests
and all over the planet, respiring animals and so forth. So
there are many--
MR. WALDEN. What about forest fires?
DR. NORTH. Forest fires contribute but not nearly as
significant as these other natural products, and also volcanoes
of course emit CO2 but on our scale, I mean, that is sporadic.
It does happen from time to time and of course it is the
historical origin of CO2 in our atmosphere but--
MR. WALDEN. And what consumes--
DR. NORTH. --it is not important.
MR. WALDEN. What consumes CO2?
DR. NORTH. So what consumes CO2 is the biological matter, the
photosynthesis process, so sunlight is combined with--
MR. WALDEN. Plant matter--
DR. NORTH. --chlorophyll in the plant leaves and that is
converted to--so it removes CO2.
MR. WALDEN. So younger, healthier plants and trees consume
more CO2 than older, dying--
DR. NORTH. As they grow, they consume. Right. You are
making wood with the carbon.
MR. WALDEN. Because I also in my other part in the Congress
chair the Subcommittee on Forests and Forest Health and we
see--
DR. NORTH. That is very important.
MR. WALDEN. --these overgrown, decaying and dying forests.
We see fires occur that emit far more than CO2. They emit a
lot of other noxious gases. They have--
DR. NORTH. Sure.
MR. WALDEN. You know, the smoke will settle on the valleys.
I mean, it causes all kinds of problems and then the decaying
matter sits there for 3 or 4 years rather than being processed
and a new forest planted sooner. Are you aware of any research
that would indicate that by planting sooner, getting a healthy
forest a start faster, you might begin consuming carbon quicker
than just leaving it to regenerate naturally?
DR. NORTH. Well, you are getting way off from my field but,
intuitively, yes.
MR. WALDEN. All right. Dr. Wegman, in your report, it is
page 27, you say a common phrase among statisticians is
correlation does not imply causation, and you go on to say the
variables affecting Earth's climate and atmosphere are most
likely to be numerous and confounding, making conclusive
statements without specific findings with regard to atmospheric
forcings suggests a lack of scientific rigor and possibly an
agenda. What do you mean by that?
DR. WEGMAN. Well, as we--when we were talking about tree ring
growth, for example--
MR. WALDEN. Right.
DR. WEGMAN. --there are many, many factors. Moisture as
well as--
MR. WALDEN. Carbohydrates. Right.
DR. WEGMAN. And nitrates, for example, that are emitted into
the atmosphere. All of those affect tree ring growth.
MR. WALDEN. Can you pinpoint temperature in a tree ring?
DR. WEGMAN. Well, presumably there is some element of that.
I am not an expert on tree ring dendrology but presumably all
other factors being equal, if things are warmer, there is
more sunlight, there is a longer growing season, presumably
the trees are going to have wider tree rings. So the issue
though is the confounding factors. If you simply say that
this tree ring growth, what is called the late wood density,
is higher, that means the temperature is higher and ignore
all the confounding factors, you are certainly not teasing
out what really is the temperature.
MR. WALDEN. Now, we have seen the slide a couple of times
from my colleague from Washington, Mr. Inslee, that shows
CO2 levels back 160,000 years. Can either of you tell me,
how do we know with precision what happened 160,000 years
ago?
DR. NORTH. Would you like me to--
MR. WALDEN. Sure. Maybe from you, Dr. Wegman,
statistically, what does that mean and how do you evaluate
it, and Dr. North, from you maybe, the science behind--
DR. WEGMAN. Well, we have read actually Bradley's work on
this material so essentially when snow gets deposited, it
gets compressed, ultimately it becomes a second layer
called a firn, f-i-r-n, and then ultimately ice and when
the snow gets compressed it has ice, so it has bubbles of
air in there and presumably what is happening is that as
they drill ice cores down and go further into the past,
presumably 160,000 years of ice, they can look at these
microscopic bubbles of air and get the greenhouse gas
composition associated with that. So that is again a
statistical estimation process--
MR. WALDEN. Are you comfortable with that process as a
statistician, not as a--
DR. WEGMAN. Well, presumably that curve that we have
seen a couple of times from Congressman Inslee should
have error bars as well associated with it.
MR. WALDEN. Should have what?
DR. WEGMAN. Error bars associated with it, imprecision,
how much variability there is.
MR. WALDEN. And do we know what that would be? I guess
he has left. So we are--it is much like the criticism
Dr. North had of the Wall Street Journal report where
it lacked the 95 percent--
DR. NORTH. Yes, we would like to see those error bars.
That is very--
MR. WALDEN. Yes, we would like to see it as politicians
in our polls too to know, what plus or minus are we
dealing with here. Thank you, Mr. Chairman. Thank you,
gentlemen.
MR. WHITFIELD. Ms. Schakowsky.
DR. NORTH. I would like to point out that we now
actually can go back 650,000 years. Six hundred and
fifty thousand years in Antarctica in the past year.
MR. WALDEN. With precision?
DR. NORTH. Just not 150 but 650,000 years, still no
CO2 at this level.
MR. WALDEN. There is still no what?
DR. NORTH. No CO2 at this same concentration.
MR. WALDEN. I see. Thank you.
MS. SCHAKOWSKY. I wanted to explore a little bit the
statement that Chairman Barton made. He was referring to,
I think it was 1975 or sometime in the 1970s when
apparently there was a prediction of cooling, that actually
the planet was getting cooler, and here is my question,
and maybe I am not asking the right one and you could fill
me in on that. But could not--and he used it, I thought,
as making the point that science is not conclusive. But I
am wondering if one could not also see it as a confirmation
that human activity is in fact causing fairly dramatic
change in the climate, something that may not have been
factored in in 1975 but the science based on sort of older
predictors. So I just wanted to ask how to interpret--and
first of all, is that the case that it was predicted to be
a cooling period? Let me ask Dr. North, the climate
scientist, first.
DR. NORTH. Yes, there was a prediction made in the 1970s by
Reed Bryson, a professor at Madison. He probably gave us all
a hard time about this because I have heard this a thousand
times in the last year or so, few years. So but, there are
two competing factors. There is the dust in the atmosphere,
the tiny aerosols, tiny droplets of water and they come from
air pollution and volcanoes and other things but mainly air
pollution in our urban areas, manufacturing processes and so
on. So out come these tiny droplets. Well, they scatter
the sunlight back to space and therefore tend to cool the
planet a little bit. The other competing factor is the
greenhouse gases. They have been rising, and especially
during the war when there was a lot of energy produced and
not very much regulation on what was allowed to go into the
atmosphere. At that time there was actually--the aerosols
were kind of winning the war, winning the war of balancing
the heat in the atmosphere, so there was a cooling that did
occur and probably Reed Bryson was right and that that was
probably the dominant effect. But it didn't take very long
the way we are putting the greenhouse gases in exponentially.
The greenhouse gas is increasing roughly a percent per year
all together, so this is an enormous rise in the other
competing factor which causes the warming. So the thinking
is that the warming has now become much greater than the
cooling due to the aerosols.
MS. SCHAKOWSKY. And haven't we--because of the hole in the
ozone layer, haven't we reduced aerosols or--
DR. NORTH. Well, the ozone layer, I would give--that is a
completely different story, so I would rather we not get off
to that.
MS. SCHAKOWSKY. Okay. There was another scientific question
I wanted to ask you and again I am not sure how to phrase
it. There was something about variability, and isn't there
a conclusion that could be made that if there is a great
variability, that that might be something that we really need
to worry about in fact that the effects of carbon dioxide in
the atmosphere in fact may be worse than we thought if we
are--
DR. NORTH. Yes. There are natural fluctuations in the
system just as weather tickles the whole system and the whole
thing rumbles. I mean, we have a climate system that sort of
rattles around, so this is the part that we call natural
variability. It is a kind of noise in the system. But then
when we apply these nudges that are continuous, then we get
a secular trend and the noise on top of it. And by the way,
that does tend to be a linear process. There have been many,
many studies with climate models, and while of course they
are not perfect, they do imitate the atmospheric climate
system quite well, and for small nudges like the ones we are
talking about, I mean, they seem to us to be quite big but
in fact, in that system, they are tiny. We are changing the
temperature a degree or two Kelvin compared to 300, so they
are tiny. So this is actually a fairly linear process. The
signals that we see in the system from warming and cooling
and other things, pretty linear, not that nonlinear. So
natural variability is there and we worry that we don't
understand every bit of it. For example, it could be that
there are slow processes in the climate system such as the
deep oceans, the overturning and so on of the deep oceans,
and it could be that that is the underlying reason for
whatever this medieval warm period was. We are not sure
about that. It could be that some warm water surfaced.
What we know now though is that that is not the cause of
the warming in the last 50 years. The warming in the last
50 years could not have been because of--we now have data.
We know that is not the reason. In fact, if we look at the
map of warming, we see that it is warming more over the
continents than it is over the oceans. They are being
pulled along because they are not as heavy, they are not
as inertial. So the fingerprints of the warming are
exactly what we would expect if carbon dioxide were the
reason.
Now, as we go back 1,000 years, we don't have all that
information to put in there to check it out so we don't
know exactly why that might have happened then but we
have a very good idea of what has been going on the last
100 years.
MS. SCHAKOWSKY. Thank you.
MR. WHITFIELD. The gentlelady's time has expired, and
Ms. Baldwin, you are recognized.
MS. BALDWIN. Thank you, Mr. Chairman. As has been
referenced earlier in several opening statements and some
questions, we know how the tobacco industry wanting to keep
doubt in the public mind and in fact in 1993 the Wall Street
Journal published a front-page expos� on how the tobacco
industry had kept the public doubt alive about whether
smoking caused cancer. For four decades the big tobacco
companies funded a sham research organization to feed the
public doubt about the health effects of smoking, and
despite smoking being responsible for over 400,000 deaths
a year, that strategy worked tremendously well for decades.
The Wall Street Journal quoted one big tobacco employee who
said, and I quote, "The scientists can come from Mars but no
matter how obscure or misbegotten, as long as they are
willing to tell the scientific lie that it is not proven,
the tobacco industry is off the hook." In May of this year,
we learned that some of the same people who worked on tobacco
also worked to confuse the consensus on global warming.
Mark Hurtsgard reported in Vanity Fair that for 20 years
Dr. Frederick Siete directed $45 million in medical research
for R.J. Reynolds to maintain a hint of doubt about the
hazards of smoking. In the 1990s Sietes turned his attention
to global warming. Dr. Sietes assaulted the integrity of the
Intergovernmental Panel on Climate Change on the op-ed page
of the Wall Street Journal. He accused the Clinton
Administration of misrepresenting the science and authored a
paper which said that global warming was an exaggerated
threat.
These people have a plan. They want this hearing to stand
for the proposition that there is not a consensus on global
warming and they have stalled action for a decade or two and
they think they can drag it out even longer. So Dr. North,
I am wondering if you can help put this in context.
Dr. Mann had concluded that the late 20th Century warmth in
the Northern Hemisphere was unprecedented during the last
1,000 years. You said very clearly in your testimony that
Dr. Mann's conclusion has been subsequently supported by an
array of evidence. We have a high level of confidence that
late 20th Century is the warmest period the planet has seen
in the last 400 years and you found it was plausible that
the planet is warmer than it has been in 1,000 years. Is
that a fair summary?
DR. NORTH. Yes.
MS. BALDWIN. You said it was plausible that the planet is
warmer now than it has been any time in the last 1,000 years.
Has anyone provided affirmative evidence that there has been
a warmer period in the last 1,000 years?
DR. NORTH. No, we have not. That is what we mean by
plausible, that there just doesn't seem to be any counter
information, so it is a reasonable thing to--
MS. BALDWIN. Is it plausible that human beings have caused
greenhouse gas emissions that are contributing--I am sorry.
Let me put it in the negative. Is it plausible that
human-caused greenhouse gas emissions are not contributing
to global warming?
DR. NORTH. It is not plausible.
MS. BALDWIN. How confident is the scientific community that
human emissions are contributing to global warming?
Seventy-five percent, 80 percent?
DR. NORTH. In the scientific--in the climate science
community, I think that Mr. Inslee's quote about the number
of papers and who says yes and who says no tells the story.
MS. BALDWIN. Okay.
DR. NORTH. It is hard to find anyone who works in this
field who is opposed. I mean, if somebody can come up with
a really good physical explanation for why this is false,
they will win the Nobel Prize. So there are a lot of people
who might be attracted to the idea but we can't find any.
MS. BALDWIN. Well, finally, I just want to ask you about
the IPCC report since we have been hearing a lot about it.
Does the NRC report in any way discredit the IPCC's 2001
third assessment report?
DR. NORTH. Well, we have some differences with the details
of the hockey stick curve and we said that. We are a
little less confident. I mean, our error bars as we have
been saying, our margin of error is a little larger than
what was stated in that report and that is natural. As we
go on and learn more, we adjust and adapt. So, no, we
don't believe individual years--Dr. Wegman said this, and
we agree. We don't trust individual years, the 1998 or
2006 or something as being the warmest of any time period
because we can't state things to that degree.
MS. BALDWIN. Just to clarify, my question was, did your
report in any way discredit the IPCC's 2001 third assessment
report? Would you view--
DR. NORTH. No, we wouldn't--
MS. BALDWIN. --what you are describing as discrediting
that report?
DR. NORTH. No, it doesn't discredit it.
MS. BALDWIN. Okay. Thank you.
MR. WHITFIELD. Thank you, and after almost 5 hours, that
concludes the first panel, so we should be through with
the second panel in about 10 hours. Dr. Wegman, I want to
thank you very much and Dr. North for your testimony and
obviously this is a subject matter of great interest and
importance and we thank you for your testimony, and now I
look forward to the second panel and so I will release you
all. And on the second panel we have another distinguished
group of individuals. Mr. Thomas Karl is director of the
National Climatic Data Center from Asheville, North Carolina.
Dr. Thomas Crowley is the Nicholas Professor of Earth System
Science at Duke University. Mr. Stephen McIntyre of Playter
Boulevard in Toronto Canada, and then Dr. Hans von Storch,
who is the director of the Institute for Coastal Research
who flew to this meeting from Germany exclusively for this
meeting, and Dr. Storch, how do I pronounce the name of
your town in Germany where you are from? On here it says
G-e-e-s-t-h-a-c-h-t.
DR. VON STORCH. Geesthacht.
MR. WHITFIELD. Geesthacht. Okay. Anyway, we welcome all
of you, and as you know, this is an Oversight and
Investigations hearing and it is our customary manner to
take this testimony under oath and I would ask you, do any
of you have objection to testifying under oath? And I am
assuming you do not need legal counsel. So if you would
please raise your right hand.
[Witnesses sworn.]
MR. WHITFIELD. Thank you very much. You all are now under
oath, and Mr. Karl, we will start with you and we will
recognize you for your 5-minute opening statement.
STATEMENTS OF DR. THOMAS R. KARL, DIRECTOR, NATIONAL CLIMATIC DATA
CENTER; DR. THOMAS J. CROWLEY, NICHOLAS PROFESSOR OF EARTH SYSTEM
SCIENCE; DR. HANS VON STORCH, DIRECTOR OF INSTITUTE FOR COASTAL
RESEARCH; AND MR. STEPHEN MCINTYRE, TORONTO, ONTARIO
DR. KARL. Mr. Chairman, members of the committee, I am
pleased to have the opportunity to testify before you
today. I am the Director of NOAA's National Climatic Data
Center. The National Climatic Data Center houses the World
Data Center for Paleoclimatology, which includes the data
sets that have been used to reconstruct temperatures for
the past 1,000 years or more.
I was one of the two coordinating lead authors for chapter
2 of the Intergovernmental Panel on Climate Change, the
IPCC 2001 assessment. The primary intent of the IPCC
periodic assessments is to provide government policymakers
with the latest and most comprehensive scientific
information possible about the human influences on our
global climate in a language that has meaning and relevance
to government policymakers. Our responsibility as
coordinating lead author was to act as co-chair during the
lead author chapter meetings. Each chapter has multiple
lead authors and chapter 2 had 10 lead authors. Chapter 2
was to assess the data for changes and variations in
climate. Coordinating lead authors are ultimately
responsible for ensuring that the final version of the
chapter is delivered to the IPCC bureau on schedule. Each
chapter is agreed to by all lead authors and discussed and
reviewed with other chapter lead authors. There is a very
lengthy review process which includes review editors to
oversee the review process. In 2001 the IPCC report
concluded, and I quote, "New analyses indicate that the
magnitude of the warming over the 20th Century is likely to
have been the largest of any century in the last 1,000
years," and I emphasize warming here, the magnitude of the
warming. Those are my words. "The 1990s are likely to have
been the warmest decade of the millennium in the Northern
Hemisphere and 1998 is likely to have been the warmest year."
These findings were developed after careful consideration of
the published literature on this topic in 2001.
The IPCC lead authors considered uncertainties related to
two types of temperature reconstruction errors. Such errors
can be thought of as having two fundamentally different
sources. I will use some technical terms. Parametric and
structural, but I will define these. Parametric uncertainty,
which results from finite sample sizes to estimate
coefficients of a statistical model, is much less important
than structural uncertainty. Human decisions that underlie
the development of the reconstructed time series may be
thought of as forming a structure depicting both real and
artificial behavior in paleoclimatic data. Assumptions
that guide the decisions made by the experts may not be
correct. More important factors may have been ignored.
These possibilities lead to structural uncertainty.
Structural uncertainty can only be estimated by comparing
the differences of equally plausible reconstruction
methods. The IPCC 2001 lead authors were able to estimate
structural uncertainty associated with the IPCC findings
because of the availability of several reconstructed time
series.
It is important to note the language used by IPCC in the
2001 assessment included an expert assessment of the
certainty of various findings. The IPCC reported findings
when the probability of being true reflected certainty
between 66 and 90 percent, or in odds terms, better than
two to one. Lead authors were asked to develop findings
based on at least three levels of certainty, likely,
better than two to one odds of being correct, very likely,
better than nine to one odds, and virtually certain,
better than 99 to one. These odds of probability were
based on the lead author's assessment of the published
literature and in consideration of thousands of expert
review comments. I note that such expert assessments in
related fields such as the probability of precipitation
forecasting have proven to be quite reliable.
Several research teams have challenged the reconstructed
temperatures featured in IPCC. These challenges are not
without validity. But now each of the challenges have
been assessed in a variety of new analyses. For the
past several years there have been at least half a dozen
new analyses using many of the same paleoclimatic data
featured in IPCC 2001 as well as new data covering longer
time periods or slightly expanded geographic coverage.
Of all these analyses, none show temperatures during the
past 1,000 years higher than the last few decades of the
20th Century and into the 21st Century. These analyses
used different statistical methods, various types of
paleoclimatic data and different temperature calibration
approaches.
In June, the National Research Council reassessed the
1,000-year reconstructed time series. The NRC not only
assessed the paleoclimatic data but considered how well
the data stands up to our ability to simulate the temperature
record of the past 1,000 years. The NRC found that for the
most part, climate model simulations are consistent with
reconstructed paleoclimatic data of the Northern
Hemisphere. The NRC report indicates it is plausible, as
we heard, that the last few decades of the 20th Century
were warmer than any other time during the past 1,000
years. I note the NRC does not define the odds of
probability associated with the term "plausible." In
contrast to IPCC 2001, the recent NRC report did not
highlight the rate of temperature increase during the
20th Century compared to the previous 10 centuries. I
note the rate of temperature increase is also relevant
to our ability to adapt to changes in both our society
as well as the planet's ecosystems.
In order to improve our estimates of reconstructed
temperature, more proxy records await our extraction.
Setting out to extract and calibrate proxy paleoclimatic
data is necessary but not sufficient to reduce further
uncertainty. The data from proxies must also be accessible
by the broader science community for analysis. At the
present time there is no formal process whereby federally
funded scientists must submit their data to a long-term
data archive facility for use by the general community.
In conclusion, considering the additional evidence since
the IPCC 2001 assessment, I would extend the IPCC 2001
statement about the Northern Hemisphere temperatures in
the 1990s being higher than any other decade during the
past 1,000 years with probability of better than two to
one to include the most recent two decades.
Thank you, Mr. Chairman and committee members, for
allowing me the opportunity to discuss and inform the
committee.
[The prepared statement of Dr. Thomas R. Karl follows:]
PREPARED STATEMENT OF DR. THOMAS R. KARL, DIRECTOR, NATIONAL
CLIMATIC DATA CENTER, NATIONAL OCEANIC AND ATMOSPHERIC
ADMINISTRATION, U.S. DEPARTMENT OF COMMERCE
MR. WHITFIELD. Thank you, Mr. Karl, and Dr. Crowley, you
are recognized for your 5-minute opening statement.
DR. CROWLEY. Thank you very much for the opportunity to present
my testimony. I will briefly state my credentials and give a
short history of the Mann et al. paper with respect to the
Intergovernmental Panel for Climate Change report.
As background, I received a Ph.D. in marine geology from
Brown University and I specialized in study of the
Earth's past climates. Over the last few years I have
spent part of my time working on climate change over the
last 1,000 to 2,000 years. You have gone over some
aspects of the Mann et al. paper ad nauseum so I am going
to skip over some elements of what I am going to say and
then discuss aspects of how I perceived the Mann et al.
report was included in the IPCC, okay. I was not part of
IPCC but I am familiar enough with some of the science
that was going on that I thought it might be useful. But
it is my perception of it, okay.
So with respect to the inclusion of the Mann et al. report,
especially into the summary for policymakers, at that time
there were three reconstructions that went back 1,000
years, okay, at the time of the IPCC 3, so back to the
Middle Ages. Now, one of the reconstructions--Mann et al.
was the second to come along. One of the reconstructions
uses completely different methodology from Mann et al.,
and if I could have the second figure there, okay, and I
can't read that very well. Really focus on, if you can
even read, the right axis, okay. That is temperature
variations. Forget the left axis there, and that is time
over the last 1,000 years, and the Mann et al.
reconstruction is in green. That is decadally smooth Mann
et al., reconstruction, okay. And this other
reconstruction which I was involved in really stemmed from
a discussion I had at a meeting where people say well, I
don't believe Mann, and there was nothing written about
it. They just say they don't believe Mann. And so out
of this grew, I said okay, I got so exasperated. We
just--I will go analyze some data myself and just see
what it looks like, and we deliberately took a very
different approach rather than using what they call the
sealed method for reconstructing a temperature. We took
this other methodology which has the scientific term
"bonehead" associated with it in which we just added up
all the individual curves and took the average, okay.
And the reason we do that in part is so we can see
exactly in the terms of the curve here, you can
understand exactly how your composite curve originates
from the nature of the raw data, okay, and that is real
easy. If there is a bump, you can go back to the raw
data and see where it came from, okay. And the other
reason for doing that is geological data is by
definition dirty data and sometimes it is very helpful
sometimes to be somewhat conservative in the statistical
methodologies you employ. So what we did is, the bonehead
approach using some of the data from Mann et al. but
other records also, some of which have been cited as
indicative of a medieval warm period, and even though some
of these records locally clearly show temperatures locally
warmer than 20th Century during the Middle Ages, when we
summed up all the different records, we got a pattern that
was surprisingly similar to what Mann had gotten as you
can see from the red curve there. Yes, there are some
differences there but the similarities look a lot more--
you know, a lot--there are more similarities than there
are differences there. We stopped our analysis in 1960,
okay, so that is why we don't get this big tail at the
end. But over most of it is pretty similar. So this was
in some way was a very--it was a surprise. I had no idea
what it would look like, but it suggested that the Mann
et al. result might be robust in terms of its pattern
about the relative magnitude of warmth in the Middle Ages
and what was happening there, when you go back to the raw
data which you can easily do with this type of
reconstruction, the reason we didn't get a very warm
medieval warm period was that whereas some places were
warm, others were cold at the same time so when you
averaged them, it came out to some value in between. So
we understood then why that happened, why we were getting
that result.
Now, there is a follow-up to that. Our reconstruction,
we weren't trying to say it was better than Mann or
anything. We were just trying to do what is called a
sensitivity test on the Mann et al. result, okay. Now, the
Mann et al. result was the only paper that actually
estimated the sensitivities, the uncertainties of your
conclusion which Dr. North has emphasized is very
important, and for that reason, I believe it was legitimate
to include that, to select that as the paper that would go
in to highlight the millennial perspective for IPCC
because it was the one that had the objectively determined
uncertainties in the reconstruction, okay. So that is
how it wound up in IPCC and they had some additional
information that it might be okay.
Now, science progresses and sometimes past conclusions
have to be modified. A notable example with respect to
IPCC involves this significance of satellite upper air
data that previously had not agreed with model
predictions. Now they seem to, okay. That is just the
way science goes. Similarly, some papers have been
published since the IPCC suggesting greater variability
than Mann et al., and contrary to claims of the Wegman
report, and again, I should point out here, I apologize
for the sometimes poor use of terms that I have used to
describe Dr. Wegman and I apologize to Dr. Wegman for
that. But contrary to the claims in that report, one of
these reconstructions used a completely independent data
set for verification.
Can we have the next figure, please? And I was hoping
to have a pointer, but the main point here is what you
see here is--I just want to spend a little bit of time
on this because you are seeing basically the same net
conclusion as you see from Mann et al. even though we
had greater variability that Mann et al. in this
reconstruction, and again, this is sort of a slightly
sophisticated update of the bonehead methodology, okay.
So it is bonehead squared or something. But what you
see here is we have reconstructions here in blue and red
and yellow, different length of time series, but it goes
back to about 500 A.D., and we have uncertainties
assigned to these reconstructions based on the uncertainty
in the overlap interval with the instrumental record here.
But the difference we get is that we have a completely
independent validation based on the methodology data from
borehole measurements of heat flow in the Earth's interior,
okay. That is completely independent from the data we
use. And statistically, we actually have two borehole
scientists on our team for that paper plus two sets of
statistical climatologists, I might add, that the
relationship between this low resolution borehole record
and this higher resolution surface reconstruction are
indistinguishable and yet the variations you see here are
much greater than what you see in Mann et al., okay, the
variability. We have a slightly warmer medieval warm
period than Mann et al. but even there if you take decadal
smoothing there, that peak value here in the medieval
warm period really at best approximates what happens in
the mid-20th Century, all right? And again, because of
the nature of the way we combine the data, we understand
exactly why it doesn't get really warm, okay. And so
this is a paper that is coming out--well, it has actually
been accepted by the Journal of Climate and will be out
sometime later this year. So this is one of the things
we don't agree with Mann in terms of variability. Others,
Mann has updated his reconstruction and he still believes
that it is the same. So there are still differences in
the field but a number of other studies show higher
variability at that time.
The interesting point about the higher variability and you
have to be really aware of this is that it is not--some
people may--it almost seems sometimes in reading papers
that people enjoy disproving Mann, okay, but one of the
things you have to be aware of, you have a reconstruction
that has higher variability and greater warming in the
Middle Ages. What it means is, your climate system has
higher sensitivity, okay, than the Mann et al.
reconstruction which has only small wiggles, okay, and
high climate sensitivity carries over to what the
implications are for carbon dioxide forcing because the
only--sensitivity means that if you have a certain amount
of forcing, you either get a small response or a big
response, okay. You have a system with low sensitivity,
then it doesn't wiggle much. If that was true for
carbon dioxide, you wouldn't have to worry about it.
You just close the door and throw away the key and keep
burning oil until you want. If it has a high
sensitivity though, you have to start worrying, and the
implication of this result is that climate sensitivity
is much higher than before, okay.
So now, I may be almost out of time here, okay, because
I have spent a lot of time on this. I have a few
comments--
MR. WHITFIELD. Dr. Crowley, you are about 4 minutes
over your time, but if you want to summarize, then there
will be plenty of questions for you as well.
DR. CROWLEY. Okay. I just wanted to highlight a couple
points on the Wegman report. I am not going to talk
about their assessment of the Mann et al. thing. That is
really--I disagree with them with respect to their
recommendations and I will just summarize these
disagreements, one being that the interactions with the
statistics community have really increased very
significantly and I think that Dr. Wegman and his
colleagues may have been working with--had a small sample
problem just looking at some of the paleoclimate papers
because in fact it is a rather substantial improvement
in the interactions between real statisticians and the
climate--and percolating down into the paleoclimate
community, and that is true even for the IPCC. The key
chapter in the new IPCC report actually has a
statistician and a statistical climatologist as co-lead
authors of this chapter, okay. So they are being well
integrated into the process.
And finally, with respect to authors should not assess
their own work, this sounds fine in theory but in
practice it seems almost unworkable because who else
but experts can produce an expert report. And with
respect to the IPCC, I think it is a marvelous document.
It involves hundreds of scientists, reviews of thousands
of papers, and received on the order of 10,000 comments
for each of the earlier drafts.
MR. WHITFIELD. Are you about ready to conclude,
Dr. Crowley?
DR. CROWLEY. So my feeling is that it is a very, very
thoroughly reviewed and vetted manuscript and I think
it is just about the best thing we have.
[The prepared statement of Dr. Thomas J. Crowley
follows:]
PREPARED STATEMENT OF DR. THOMAS J. CROWLEY, NICHOLAS
PROFESSOR OF EARTH SCIENCE SYSTEM, DUKE UNIVERSITY
I thank the committee for the opportunity to submit my response
to the findings of the NRC and Wegman Reports. As background
to my testimony, I will briefly state my credentials. I
received a Ph.D. in marine geology from Brown University and
have a long interest in the history of the Earth's past
climates, both from a modeling and observational viewpoint. I
have published about 100 peer-reviewed papers and have
co-authored a book on the subject. I have worked in academia,
the private sector, and at two government agencies - at NSF as
a program director in climate and at NASA/Goddard Space Flight
Center as a National Research Council senior fellow. I am
presently the Nicholas Professor of Earth Systems Science in
the Nicholas School of the Environment at Duke University.
Because this hearing has been called to better understand the
influence of the much-discussed 1998 and 1999 papers by
Michael Mann, Raymond Bradley, and Malcolm Hughes, I think it
would be useful to provide a brief scientific background to
the subject. Prior to 1998 there had been only one attempt
to summarize the various types of data from past climate to
get a broader picture as to how it has changed over the last
few centuries. In 1998 Mann et al. introduced a new
technique to develop more quantitative estimates of the
nature of climate change since AD 1400 for the northern
hemisphere, and in 1999 the group extended that record back
to AD 1000 and concluded that the late 20th century warming
was the largest in the last 1000 years. This report was
among a number of scientific studies highlighted in the IPCC
Third Assessment Report (TAR) to conclude that "there is new
and stronger evidence that most of the observed warming over
the last fifty years is attributable to human activities".
With respect to the committee's interests in whether the
objectivity of the IPCC with respect to the Mann et al.
studies I elaborate on several points below. At the time of
IPCC TAR it represented the best estimate of past millennial
temperatures and their uncertainties, and that the most
important conclusion from IPCC (stated above) does not depend
on the Mann et al. papers for its credibility, and are even
more robust today than they were in 2001.
The final part of my presentation involves a number of
objections, both major and minor, to the Wegman Report.
I have five main points to make concerning the following
subjects:
(1) The relation between the Mann et al paper and the IPCC
Third Report in 2001. The Mann et al paper was certainly
influential in the IPCC Third Assessment Report (TAR), but
so were many other papers. But the papers that made the
biggest difference were the ones focusing on the instrumental
record in which it was shown that models and data could not
be reconciled unless an anthropogenic greenhouse influence
was invoked. The most compelling driver of all was the fact
that global temperatures kept going up and up since the
1996 report, and meltback of glaciers increased in many
parts of the world. I might add that this trend has only
accelerated since 2001, with melting in the Arctic and on
Greenland reaching alarming levels.
(2) The Mann et al paper in and of itself. At the time of
IPCC TAR there were two other reconstructions going back
to the Middle Ages, with decadally smoothed data showing,
at best, past millennial temperatures comparable to the
mid-20th century warm interval. One reconstruction
(Crowley and Lowery, attached) using a completely different
methodology agreed with Mann et al. quite well (Fig. 2).
However, Mann et al. was the only paper of the three that
estimated uncertainties, and it is no surprise that this
paper was the one chosen to highlight the millennial
perspective for IPCC. The significant criticisms of the
Mann et al. paper that have been published since 2001 are
by definition after the fact with respect to IPCC TAR.
(3) The present state of our knowledge on millennial
changes Science always progresses and sometimes past
conclusons have to be modified. A notable example with
respect to IPCC involves the significant reassessment of
satellite upper air data that previously had not agreed
with model predictions of increasing air temperatures in
that region; new assessments indicated that the models and
data were now in approximate agreement. Similarly, some
papers have been published in the last five years suggesting
greater variability than Mann et al. Contrary to the
claims of the Wegman Report, one of these reconstructions
(Hegerl et al., attachment 2) uses a completely independent
data set from borehole measurements (fig. 3) of the
effects of air temperature change on heat flow in the upper
part of the Earth's crust.
Because Mann et al. have more recently obtained
results similar to their earlier work, but now using
a different methodology, it continues to be necessary
to understand the causes of differences among the
different reconstructions before the estimates of
higher temperature variability can be accepted.
Even if the latter estimates ultimately prove to be
more accurate, there is no room for gloating (as
sometimes seems evident in discussion of the newer
results), for the higher variability inevitably
implies a higher climate sensitivity, which is a
cause of much more serious concern for either the
committee, or society at large. By this I mean
that for any given level of climate forcing from
carbon dioxide, the expected temperature response
would be larger than it would if the Mann et al.
reconstruction was ultimately deemed to be the
"final word" on the magnitude of past climate
change (see Hegerl et al., third attachment).
(4) The claim of unusual level of warmth for the late
20th century is still valid for all but one of the new
reconstructions. Contrary to the conclusions of the
the Wegman report, there is reason to believe in the
unique nature of late 20th century warmth (this is the
only major point in which I differ from the NRC report).
Although the early millennium records are small in
number, the composite reconstruction agrees in the
overlap interval (A.D. 1500-1960) with reconstructions
using more extensive data sets. Furthermore,
examination of the raw data indicates that even in the
high latitude northern hemisphere they show regional
variations in the timing of warmth that is much greater
than in the late 20th century. In other words, some
regions are warm and some cold - a very different
pattern from the late 20th century, where almost every
region has warmed over the last 100 years. It is
therefore no surprise that, when these records are
composited, the sum value is smaller than for the late
20th century.
(5) The conclusions and recommendations of the Wegman
Report have some serious flaws. In addition to a
number of technical errors, large and small, the
following comments can be made in the bullets on page
two of the committee's summary of findings (fact sheet):
(a) bullet one (concerning specifics of Mann et al.) -
responses discussed above
(b) bullet two - "many of the proxies are reused in
most of the papers....it is not surprising that would
obtain similar results..." This almost sounds as if
it is wrong for everyone to use the best existing data!
The more important point, and one not stated, is that
different methodologies are employed by each of the
investigators. Furthermore, there is nothing wrong
with talking to or even collaborating with someone else
in a field that you respect, and has expertise that you
don't have. The Wegman Report almost seems to imply
that collaboration is equivalent to collusion, a result
that would apply to the Wegman Report itself if that
were always true.
The inference in the same bullet concerning the failure
of the peer review statement is an oversimplification.
The anonymity of peer review still allows papers to be
rejected, as almost any scientist can testify. As a
former NSF program director, I have had significant
opportunity to evaluate the peer-review system. It is
not perfect but in general the best work gets funded. For
publications, editors usually select a variety of reviewers
who cover the different expertises in the study. But it is
just not practical to expand the number of peer reviews for
many publications - the work load is just too onerous for
the reviewing pool, and most people will simply decline the
request to review the papers. Finally, I would like to
comment that the Wegman Report now before the committee has
not undergone any extensive peer review from anyone in the
climate community prior to its submission to the committee
for inclusion into the record and, most problematically,
possible use as a guide to further recommendations by the
committee.
(c) Bullet three - the researchers do not seem to be interacting
with the statistical community. This statement is based on a
small subsample of paleoclimate papers. Overall, there is
increasingly strong incorporation of statistical methodologies
in the climate sciences, including increased interactions with
statisticians. For example, the National Center for
Atmospheric Research has had a postdoctoral program for
statisticians for thirteen years. A key project jointly funded
by DOE and NOAA for detection and attribution of climate change
involves not only several statistical climatologists but also
explicitly seeks out input from statisticians. The present
(and key) IPCC Fourth assessment chapter on detection and
attribution of climate change has a statistician and statistical
climatologist (with a training in applied mathematics) as
co-lead authors. Statisticians are welcome to respond to any of
the chapters in the review process. From these statements it is
clear that the Wegman Report is somewhat uninformed with respect
to the effort to include statisticians in the IPCC review process.
I might add that interactions between geoscientists and
statisticians have long been hampered by what can only be described
by some as a condescending attitude from some statisticians that
geoscientists were not employing the most recent, state of the art
statistical methods. Such attitudes almost guarantee subsequent
poor communication and fail to recognize the unusual nature of
"field laboratory" geoscience data, which are very different than
"closed laboratories" where the conditions of an experiment are
well controlled. The latter types of data require an intimate
understanding of the raw data and simpler, more robust statistical
methodologies that recognize the limitations of such data.
(d) Bullet four - authors of policy assessment should not assess
their own work. This statement may sound fine but in practice but
seems almost totally workable. Who else but experts should
produce an expert report? The third and fourth IPCC reports
involved hundreds of scientists around the world, a review of
thousands of papers, and received on the order of 10,000 comments
in the early stages of drafts. The final summary for policymakers
requires a vote - by government representatives of the signatory
nations -- on every single sentence before it is accepted! I can
attest from personal experience that the resultant high quality of
the IPCC documents make them ideal choices for teaching graduate
and professional courses because they are by definition our best
statement on the present state of knowledge of the climate system.
It is inconceivable to me that a report of this quality could be
produced by a group of nonspecialists.
(e) Bullet five - paleoclimate data does not provide insight into
physical processes The statement on physical processes is
completely wrong. In fact, paleoclimate modeling results indicate
that about half of the decadally scaled variance between 1270 and
1850 can be explained by natural variations in solar and
(primarily) volcanic forcing. When these forcings are carried
over into the 20th century, they cannot explain the 20th
temperature rise. Only greenhouse gases can explain the rise,
not only for the late 20th century, but also in part for the
mid-20th century.
In this same bullet the Wegman Report recommends that federal
research should emphasize fundamental understanding of the
mechanisms of climate change and should focus on interdisciplinary
teams to avoid narrowly focused discipline research. I find this
to be an extremely na�ve statement. Climate studies are among the
most interdisciplinary field that one can imagine - as just one
example I submit a copy of a paper (attachment four) on causes of
climate change over the last millennium that discusses changes in
solar output, volcanism, trace gas variations in climate, tree
rings, ice cores, climate models, impact of vegetation, etc etc.
There are many other examples of interdisciplinary activities.
As a former program director at the National Science Foundation,
I think I can also speak for many present program managers in
federal agencies concerning the lack of interdisciplinary
activities on different projects. This interdisciplinary is
the core concept of terms such as "Global Change" and "Earth
Systems Science" and as such the agencies have made a great
effort at supporting interdisciplinary research. Furthermore,
every major modeling group in IPCC addresses a host of
interdisciplinary science.
But it would be a big mistake to forget the lone investigator.
Sometimes the most fundamental findings in a field come from
these lone investigators (who may nevertheless have much
contact with many others). There must be room for individual
creative science in climate science.
Summary and Concluding Remarks In my view the debate over
the Mann et al paper is a tempest in a teapot. It is
legitimate material for scientific discussion but the
implications with respect to the operations of the IPCC are
unproven and seemingly based, in my opinion, much more on
repetition of innuendo than on any real facts. Although
there is always a need for enhanced interaction with the
statistics community, the lack of communication is seriously
misrepresented in the Wegman Reprot. I believe that this
report should not be used as either a legitimate assessment
of the science or as a guide to policy modification.
Finally, I believe it is time to stop using Michael Mann as
a whipping post and to start directing attention to the more
important matters of whether anything should be done about
global warming, and if so, what?
Attachments:
1. Crowley, T.J., and Lowery, T.S., 2000. How warm was the
Medieval Warm Period? Ambio (publication of the Royal
Swedish Academy of Sciences), v. 29, no. 1, pp 51-54.
2. Hegerl, G.C., Crowley, T.J., Allen, M., Hyde, W.T.,
Pollack, H.N., Smerdon, J., and Zorita, E., 2006. Detection
of human influence on a new, validated, 1500 year temperature
reconstruction, Journal of Climate (accepted).
3. Hegerl, G.C., Crowley, T.J., Hyde, W.T., and Frame, D.J.,
2006. Climate sensitivity constrained by temperature
reconstructions of the past seven centuries. Nature, v.
440, 1029-1032.
4. Crowley, T.J., Causes of climate change over the last
1000 years. Science, v. 289, 270-277.
MR. WHITFIELD. Thank you. Dr. von Storch, you are
recognized for 5 minutes.
DR. VON STORCH. Thank you very much for inviting me here.
I just wanted to mention that I am joined here by my
colleague, Eduardo Zorito, from the same laboratory sitting
there in the back.
Next transparency, please. So I am just summarizing
my paper here. So first scientific aspects. So the
progression-type methods of the so-called hockey
stick studies of Mann, Bradley, and Hughes suffer from
a number of problems which should have been addressed
before the hockey stick was elevated to an
authoritative description of the temperature history
of the past 1,000 years. It says 1,000 to 2,000 years
but that is an error.
Second, the claim by the IPCC third assessment report,
that is the 2001, that there is reliable evidence that
climate is beginning to change due to human action was
based on a number of different lines of argument which
are insensitive to the validity of the MBH studies, that
is, the present debate about the validity of the hockey
stick is of marginal relevance for the detection of
present anthropogenic climate change. I claim the
major problems are not of a statistical nature but are
related to the social practice of climate change studies.
Next transparency, please. In the Wegman report, let me
say a few words about the Wegman report. We have in our
working group examined how serious the error of biased
centering would be on the overall results given a
temperature history reminiscent of the IPCC 1990 version.
The paper has been published and the effect is very minor.
It does not mean that it is not a glitch but it really
doesn't matter here, at least to the extent we could test
it.
There are other aspects which are much more relevant I
would have hoped that Dr. Wegman would have taken this up,
that is, the usage of the trend as a key element for
training the progression model. It is a bit funny to use
the trend to train something and I will show you in a
second what that means.
And second, the method of something, what is called scaling,
that is, that you artificially make sure that the variance
of the predictor, that is, the temperature, equals the
variance of the predicted temperature, the derived
temperature. So you multiply it by a number so that it
just comes out as if you could explain the total variance
by the proxy. You cannot. You know that you cannot do it
and therefore you introduce an error which you cannot avoid.
Third, we welcome the suggestion by Wegman and his
colleagues to invest much more effort to examine the error
structure in deriving temperature data from proxies.
There are two main issues. First is the homogeneity of
proxies. If in the year 1960 the tree ring means something
for temperature--no, I mean--yes, it does not mean that this
is the same information in the year 1200. It could be that
the process to get out the information from a 1200 tree ring
is different from the 1960. Second, the instationarities of
the late proxy and temperature. We know that there are some
problems at least that has been explained at the Academy
hearing that nowadays the link between temperature and CO2
seems to be damaged. When Hughes was asked what the reason
could be, he gave three different hypotheses, and when he was
asked, do you think it could have happened in the past, the
answer was yes. So it could be that the link which we see
now these days in the past 100 years or so would be different
than previous times. We cannot know that and we have to think
about how to model this effect.
The next transparency, please. That shows the danger of
relying on trends. So you see here, a times series throughout
the instrumental period, that is, the period when we think we
have enough data to derive Northern Hemisphere mean annual
temperature from instrumental data, and you see in yellow, that
is the area when the method has been trained and then we see
it has been trained from 1910--well, it has been trained for
a longer time showing a 21-year running means. And the red
curve is what the MBH method was indicating the temperature
variation should have been in this period and the black is a
new analysis of the climate research unit. It was produced
after that was done, and now what you see here is that the
green and the black curve are very nicely coincident during
the trend but nothing else. Nothing else is reproduced and
so it is just what this method is fixing up is the trend and
nothing else, or it may be so. One should check that out.
And so this is a bit dubious.
Next transparency, please. Understand that you are concerned
about the quality control process of climate change science,
and I would claim that parts of climate change science, in
particular paleoclimatic reconstructions have suffered from
gatekeeping and insistence usage of reviewers. I myself can
say that they were always the same type of reviews we got,
the same style and I am sure that it was the same person and
I am sure it was the person we have spoken about here quite
a bit.
And I also claim that editors in science magazines have
failed to ensure the reproducibility of key results. The
methods have not been described properly and their data one
could not access. Part of the mess here is due to the
practice of Nature and Science that they have a bias towards
interesting results. I mean, they have--their way of
operating is not only that the results are innovative and
valid but they must also be interesting. Then what I think
is really not good that in the IPCC process experts assess
their own work.
That is, to conclude this, climate change science has
suffered from limiting action of gatekeepers and the public
preference for interesting results. Climate change science
should provide stakeholders with a broad range of options
and not narrow this range to reduce numbers of options
preferred for certain world use.
I was a bit disappointed about the comment from the lady
from Illinois who said aren't you afraid if you say this
that this would have negative implications for the policy
process. I mean, is that really--I mean, I was kind of
shocked. I mean, should we really adopt what we say if
that is useful for the policy process? Is that what you
expect from science? If we give advice, that we first think
is it useful for something. I think that is not the way we
should operate, or if we do that, you should not listen to
us.
Next transparency. This is not to please the people on the
right-hand side. The acceptance of the IPCC in the community,
this is actually--it is very well accepted and it is very hard
to see this but it is the result of a survey which was asking
to what extent do you agree or disagree that the IPCC report
is of great use of the advancement of science. That is on
the left-hand side. And then you see a statistical
description of the responses. At the bottom they would say
strongly agree. At the top they would say strongly
disagree. And then there are--on the left-hand side there
are results from 1996 and on the right-hand side 2003, one
block for U.S., the other for E.U., and you see in 1996
there was a median of three. That means people, most said
well, it is useful. In 2003 the median was two, so they
are much more convinced that this is done well. And the
same result is with a question to what extent do you agree
or disagree that the IPCC reports accurately reflect the
consensus of thought within the scientific community. So
there is broader agreement that the community is doing
right even though I don't think that the Oreskes study was
done well and there have been numerous responses on that
which have not been accepted by science for whatever
reasons.
The last transparency, please. We have to keep in mind
that climate change science takes place in a cultural
context. It has something to do with what we think we have
been trained at and a possibly remarkable result is that
the concept of anthropogenic climate change is not new in
Western culture. This is not a new invention in the
history of this. We have documented very many cases and
the first scientific publication we have on that is from
1781 by a physician named Williamson from Philadelphia
who was speaking about the changing climate due to human
action. At that time the weather in this part of the
world was greatly improved because of taking away forests.
Second, climate change science is something what we call
post-mormal, that means it goes along with high
uncertainties and high relevance. In that case, it is
quite normal that the boundaries between value-driven
agendas and curiosity-driven science get blurred and we
should admit that there is a considerable influence of
extrascientific agendas on the scientific process of
climate change studies. I think we have seen that today
also. The processes of climate change studies need to be
analyzed and accompanied by social and policy scientists.
So this process we are seeing here, how we argue, we
should be something like--yes, always an analysis by
social scientists and I think what Dr. Wegman and his
colleagues started to do was quite useful in this respect,
that we understand to what extent we are driven by
non-scientific motives, and this ends my presentation
here.
[The prepared statement of Dr. Hans von Storch follows:]
PREPARED STATEMENT OF DR. HANS VON STORCH, DIRECTOR OF INSTITUTE
FOR COAST RESEARCH, GKSS-RESEARCH CENTER, GERMANY
Introduction of person
I, Hans von Storch, have been actively involved in climate
science since the early 1980s. I have held positions with the
Meteorological Institute of the University of Hamburg and at
the Max-Planck Institute for Meteorology in Hamburg. At the
present time, I am a director of the Institute for Coastal
Research of the GKSS Research Center in Germany. I have
co-authored more than 120 peer-reviewed articles on various
issues of climate dynamics, climate statistics, climate change
and climate impact as well as the textbook "Statistical
Analysis in Climate Research" (together with Francis Zwiers)
published by Cambridge University Press. I was a lead author
of Chapter 10 of the Third Assessment Report of the IPCC, but
I am not involved in the Fourth Assessment Report of the
IPCC.
Based on the scientific evidence, I am convinced that we are
facing anthropogenic climate change brought about by the
emission of greenhouse gases into the atmosphere.
For further personal details please refer to my web-page:
http://w3g.gkss.de/staff/storch.
Hans von Storch
Director of Institute for Coastal Research, GKSS Research
Center, Geesthacht, Germany
Professor at Meteorological Institute, University of Hamburg,
Hamburg, Germany
e-mail: [email protected], mobile +49 171 212 2046
Outline
I briefly address three aspects of the hockey-stick issue,
namely
1. Scientific aspects:
- How valid are the regression-type methodologies for
reconstruction historical climates?
- How relevant are these reconstructions for claims that we
presently experience a climate change outside the range of
what we consider as "normal" (no human interference).
2. The process of achieving success of a scientific knowledg
e claims in the climate science community:
- Independence of the review process or presence of
gatekeepers.
- Reproducibility
- Selection process by Nature & Science.
- Acceptance by IPCC assessment process.
3. The social conditioning of climate science:
- The history of perceived anthropogenic climate changes.
- Post-normal science.
On the basis of my analysis I draw a couple of conclusions,
chief being that the process of climate science must be
organized in a sustainable manner. This means that climate
science should be conducted with a low sense of subjective
passion; that climate science provides "if-then" answers to
questions society poses; that it presents to the society a
broad range of possible policy responses and does not restrict
the range of policy options to a small corridor that appeals
to certain value-driven agendas.
The conditioning of science by the culture of its actors and
society is unavoidable. However, the scientists can attempt
to make such influences explicit by acknowledging and explicitly
reflecting on such influences, especially by engaging social
scientists in the process of critical self-reflection. The
Wegman-report claims that a major problem in studies such as
MBH would be an insufficient engagement by mainstream
statisticians. I think a major problem with this study and its
transformation into a policy-relevant issue is an insufficient
comprehension of the social dynamics of the post-normal
process of (not only) climate science.
There are three appendices to this document:
1. My responses to the "Boehlert"-questions given at the NRC
hearing on March 2, 2006 in Washington.
2. A contribution to the debate about the "Barton-letters" on
the "Prometheus"-weblog http://sciencepolicy.colorado.edu/prometheus/
dated July 8, 2005
(http://sciencepolicy.colorado.edu/prometheus/archives/climate_
change/000486hans_von_storch_on_b.html)
3. An English translation of an article published in the German
weekly "DER SPIEGEL" (4/2005): von Storch and Stehr: A climate of
staged angst.
(http://sciencepolicy.colorado.edu/prometheus/archives/climate_
change/000343a_climate_of_staged_.html)
Scientific aspects
How valid are the regression-type methodologies for reconstruction
historical climates?
The key statistical assumption of any of such methods is the
uniformity of informational content in the proxies which are
regressed on the climate variables (mostly temperature). In other
words, are these data influenced by non-climatic variable factors
(inhomogeneity), is the transfer function linking proxies and
temperature constant in time (stationarity)? Likely, most if not
all proxy data (tree rings, coral rings, vine harvests) suffer from
some inhomogeneities and instationarities. This is unavoidable and
has to be dealt with by using additional insight into the system,
e.g. by data assimilation approaches combining limited theoretical
(models) and empirical knowledge (uncertain data).
Regression-type models are designed so that they return only part
of the full variability of the variable of interest, namely that
part which can be traced back to the proxies. Not all of the
variability can be accounted for in this way. The difference in
variability of temperature and of proxy-derived temperature is
dealt with by "scaling", i.e., by applying a suitable normalization.
If "scaling" is used, then the basic principle of regression is
violated, as the part of variability in the predictand (temperature),
which can not statistically traced back to the predictor (proxy), is
nevertheless related to predictor-variability. Scaling is useful,
when the transfer function is not regression (screening of
co-variability of two variables) but based on physical arguments.
Nevertheless, attempts like those by MBH are useful and should be
explored. They may provide useful estimates. The problem with MBH
was that the result was presented by the IPCC and others in a manner
so that one could believe a realistic description of historical
temperature variations had successfully been achieved. The NRC report
published in June 2006 has made clear that such a belief was incorrect.
How relevant are these reconstructions for claims that we presently
experience a climate change outside the range of what we consider as
"normal"
Whether the present climate is influenced by non-natural factors is
answered through "detection" studies. Such studies are based on the
insight that the predicted signal of human-caused climate change
should emerge in most recent times from the natural variability.
Second, one would expect it to manifest itself with a higher "than
normal" rate of change. Thus, the signal is expected to be a rapid
warming in the most recent past. The method to test this hypothesis
is to find out if we have a "steeper-than-normal" recent upward
temperature trend. The hypothesis is not "we have a period which is
warmer than ever in historical times". In that sense the claim
whether the last decade is the warmest of the past millennium is not
relevant to detection; the question is whether the recent rate of
warming is markedly stronger than what has happened in the past.
The hypothesis is tested by framing the problem as a statistical
test of a null hypothesis. The null hypothesis reads "the present
trend is of natural origin". Then, one determines the range of
trends consistent with natural variability - and rejects the null
hypothesis (and accepts the hypothesis that the trends is not of
natural origins) if the present trend is larger than, say, 97.5%
of trends originating entirely from natural variability.
The crux of this approach is of course the determination of the
range of trends which are observable under natural conditions. To
do so, one may rely only on the instrumental period, which is
contaminated by the expected signal and rather short, on
multi-century reconstructions as MBH and on extended model
simulations of undisturbed conditions. Obviously the determination
of the range of "normal" trends is uncertain and absolute certainty
can not be attained within a reasonable time.
We1 have examined which range the different historical
reconstructions suggest. To do so, the time series of reconstructions
have been "modelled" as a long-memory process, and standard
deviations of trends are derived. Here, the trend is defined as the
difference of two 30 years means 100 years apart. Then these trends
are determined from the instrumental record as given as multiples
of the standard deviations derived from the different reconstructions.
The result is given in the diagram; the curves are all the same, but
they differ in scale because of the unit of different standard
deviations derived from the reconstructions given at the figure
caption. The horizontal dashed lines mark 2, 2.5 and 3 standard
deviations. Two standard deviations correspond to a risk of false
rejection of the null hypothesis of 2.5%.
Obviously, in all cases, the critical 2-standard deviation mark is
passed sometimes in the past decades; in case of MBH this happens
very early, while in Moberg's more variable reconstruction at about
1980.
I conclude that the claim of "detection of anthropogenic climate
change" is valid independently of which historical temperature
reconstruction one chooses to believe in.
It should also been taken notice that the claims of successful
detection on non-natural warming trends and its attribution to
chiefly elevated greenhouse gas concentrations in the atmosphere
in the Third Assessment report were not based on the historical
reconstructions but on the analysis of the instrumental temperature
record as well as on numerical experiments with climate models.
The process of achieving success of a scientific knowledge claim
in the climate science community
A normal condition in the progress of science is that knowledge
claims are accepted only after a "peer-review" process. The
peer-review process attempts to assure that knowledge claims are
consistent with the empirical evidence, and properly related to
contemporary accepted knowledge claims, and that the methods are
sound and are reproducibly described. The "peer-review" process
does not eliminate the possibility that new ideas are rejected
since they may contradict contemporary, powerful but possibly
false knowledge claims (see Ludwik Fleck's seminal book on
"Generation of a Scientific Fact"). In order to minimize such a
danger, the verdict of peer-reviewers should, to first order
approximation, be independent of the persons involved in the
review process. Nonetheless, the danger is that a few scholars
may become powerful gatekeepers, for example as reviewers who
are regularly called upon or as editors of scientific journals.
The primary goal of such gatekeepers is to fend off publications
which may contradict their own thinking, and not to ensure that
only internally consistent and plausible publications reach the
market of knowledge claims (i.e. scientific journals).
Unfortunately this seems to have happened in the field of
historical global climate reconstructions, where a small group of
scientists has exerted an undue control of the entire field.
Usually, a further mechanism more closely tied to the substance
of research is used to quality-control scientific knowledge
claims, namely reproducibility. This mechanism has ceased to
operate in some quarters of paleo-climate science, since some
scientists consider "their" data as their personal property and
not that of the scientific community, so that others are unable
to challenge conclusions drawn from these data by analysing the
raw data in their own manner. Although such secrecy is a very
human trait it violates the norms of science. Even hostile
competitors should have an opportunity to independently re-examine
the empirical evidence for conclusions drawn by others, in
particular when they become relevant for the policy domain. Data
must be become public; the methods employed must be described in
algorithmic detail.
Another relevant aspect is the functioning of the two prestigious
journals "Science" and "Nature". The journals enjoy high esteem
within and outside of the scientific community as having the
highest scientific standards, which is not always the case. The
contents of Nature and Science also receive exceptional attention
in the media world-wide. However, different from "normal"
scientific journals, the editorial decision to accept a
scientist's contribution to Science or Nature is also based on
the newsworthiness of the research contribution. The presented
results must not only be valid and innovative but must also be
of interest for a wider community of readers. Such a criterion
is reasonable from a economic point-of-view, but it clearly
introduces a filter in what is reaching the public is not solely
based on the scientific merit of research. Research results with
stronger media appeal fare better in this competition of
scientific findings; results biased towards higher sensitivity
to human interference are more interesting to a broad audience
than findings that report low sensitivities. In addition, there
may also be a bias towards certain authors, who are well known,
because they enjoy public visibility, or command appealing
writing skills, "sell" well. Sometimes such contributions are
invited.
Another problem with the same journals is that their articles
must be relatively short so that technical aspects cannot be
described in any detail; indeed, the MBH publication was cursory
on the methodical side - thus the statistical method, the
validation and the reproducibility, have not been seriously
subject to the review process. Ironically, after publication in
"Nature" the method was considered "peer-reviewed" and thus
valid. However, this was not the case, as the method had not
been properly described.
The IPCC has different levels of operation - the generation of
the technical chapters, which is done by a group of "lead
authors", headed by "convening lead authors", and the process
of arriving at a SPM (Summary for policymakers) and other
overall assessment documents, which is done by the convening
lead authors and representatives of the countries.
How the selection process of lead and convening lead authors
is done, I do not know - but it is clear that the "lead
authors" are supposed to be experts in the field. This leads
to the situation that the IPCC chapters are dominated by the
authors of the most influential articles in their respective
fields of research. Participation as a lead or convening lead
author has the advantage that one can make sure that one's own
work is positively covered in the IPCC report. However, most
lead and convening lead author excel as honest brokers, but
some level of gatekeeping may prevail. Indeed, the reputation
of the IPCC among scientist has increased to very high levels
in the past years.
The IPCC procedure differs markedly from the procedure adopted
by the National Research Council assessment. In that case, a
group of eminent scientists was chosen, who have contributed
to the issue only little or not at all, but have a god
understanding of the field as a whole. These scientists then
invited a group of experts to present the different angles
and knowledge claims. I consider the NRC procedure better in
assessing the field of knowledge than the IPCC approach. It
may be, however, that the NRC approach can not be used for
such a complex and large field, which the IPCC is covering.
In case of the MBH temperature reconstruction one should note
that in the technical chapter of the TAR different
reconstructions had been presented; it was the SPM and the
synthesis report, where the range of reconstructions was
reduced to just one, the MBH. It would be interesting to learn
how this could have happened.
The social conditioning of climate science
Science is a social process, which, as all social processes, is
conditioned by the culture of the actors. This does not mean
that scientists would do their analysis irrationally or in a
biased manner, but it means that our questioning may by guided
by culturally constructed concerns and interests. Also, we may
be convinced of the validity of some findings more easily if
these findings are consistent with our prior lay-knowledge.
The history of perceived anthropogenic climate changes
It has often been claimed that anthropogenic climate change is
a recent concept. This is incorrect. In the history of ideas of
the past 1000 years, we2 have found a number of occasions when
(western) people have used the concept to explain observed
changes:
"During the last 20 years the concept of anthropogenic climate
change has left academic circles and become a major public
concern. Some people consider 'global warming' as the major
environmental threat to the planet. Even though mostly
considered a novel threat, a look into history tells us that
claims of humans deliberately or unintentionally changing
climate is a frequent phenomenon in Western culture. Climate
change, due to natural and anthropogenic causes, has often
been discussed since classical times. Environmental change
including climate change was seen by some as a biblical mandate,
to 'complete the Creation'. In line with this view, the prospect
of climate change was considered as a promising challenge in
more modern times. Only since the middle of the 20th century,
has anthropogenic climate change become a menacing prospect.
The concept of anthropogenic climate change seems to be deeply
embedded in popular thinking, at least in Europe, which
resurfaces every now and then after scientific discoveries.
Also, extreme weather phenomena have in the past often been
explained by adverse human interference."3
This finding is insofar relevant as it points out that we, as
members of the western culture, are somehow prepared to accept
"anthropogenic influence" as an explanation for otherwise
unexplainable events, such as a cluster of extreme events. Our
common understanding is that such a human influence would be
associated with negative impacts. This pre-conditioning may
influence our process of drawing conclusions, in particular
when we (scientists) deal with the problem of transferring
scientific findings into the political arena.
Post-normal science.
Most of environmental science is what sociologists call
"post-normal", i.e., loaded with high uncertainty on an
issue of great practical importance. Climate change science
is an example of such post-normal science.4
A characteristic of post-normal science is that the
boundaries between science and value-driven agendas get
blurred; that representatives of NGOs are considered to
know better about the functioning and dynamics of systems
than scientists; that parliamentarian committees delve
into the technicalities of science; that amateurs engage
in the technical debate: and that some scientist try to
force "solutions" upon policymakers and the public. In
such a situation it becomes entirely possible that
individual scientists emphasize those insights which are
assumed to influence certain policy decisions more
forcefully, while downplaying others.
Typical for such a post-normal situation is the flooding
of the media with books and movies which dramatize the
issue. Recent examples include: The Day After Tomorrow,
State of Fear, Satanic Gases, The Revenge of Gaia, and An
Inconvenient Truth.
In this situation we need a discussion, not only among
scientists about the role of science for the public,
which must be the provisions of options for policy, not
the narrowing of the range of options to satisfy different
worldviews. To limit the influence of non- or pre-scientific
knowledge claims, social and policy scientists need to
analyse the different processes in climate science, and the
interdependence of culture, policy, politics, media and
climate science. Even if science can never be fully
"objective", it may nevertheless be possible to make climate
science a considerably more objective practice than what we
have in these days.
Appendices
(a) My answers to Chairman Boehlerts questions, given at the
NRC hearing
What is the current scientific consensus on the temperature
record of the last 1,000 or 2,000 years? What are the main
areas of uncertainty and how significant are they?
There is consensus on the "blade", but the claimed
smoothness of the shaft is likely false.
The main problem is the loss of information encoded in
the proxy data and the shortness of the instrumental record
for training the statistical models.
What is the current scientific consensus on the conclusions
reached by Drs. Mann, Bradley and Hughes? What are principal
scientific criticism of their work and how significant are
they?
Has the information needed to replicate their work been
available? Have other scientists been able to replicate their
work?
There is no consensus on the claims (which?) made by MBH. The
main critique is that the method is suffering from a too large
loss of variability on long time scales.
No, the information required for replication was not made
available in a suitable manner. The original publication in
"nature" did not provide this information and was obviously
published without careful review of the methodology.
Yes, the details of the method were finally determined, among
others by B�rger et al., who checked a wide range of
combinations of details - which all gave widely different
results.
How central is the debate over the paleoclimate temperature
record to the overall consensus on global climate change? How
central is the work of Drs. Mann, Bradley and Hughes to the
consensus on the temperature record?
The main conclusions about "detection and attribution" are
drawn from the instrumental record and models; the different
reconstructions do not contradict "detection".
The MBH work is widely accepted as truth outside of people
directly engaged in the issue, because of a less than
satisfactory marketing by the IPCC.
(b) My posting on weblog "Prometheus" July 08, 2005 on the
"Barton letters"
My reaction to Rep. Barton's requests is split. In his five
letters, he is asking for information from two different groups,
namely institutions with reviewing responsibilities (IPCC, NSF)
and individuals with scientific responsibilities (M, B and H).
I find his inquiry of the performance of the institutions IPCC
and NSF valid, but the interrogative questioning of the
individual scientists is inadequate.
a) Scientists. The scientists have the task to be innovative,
creative, to try new avenues of analysis and the like. They
have the right to err, the right to suggest explanations and
interpretations which may need to be revised at a later time.
They should document what they have done, so that others can
replicate.
However, this documentation often can not take the form of
keeping runnable old codes of the applied algorithms, simply
because the software is no longer consistent with quickly
replaced hardware. For instance, most of the state-of-the-art
coupled AOGCMs used in the mid 1990s are simply no longer
available and running at, for instance, the German Climate
Computer Center. After replacing a high performance computer
with a new system, the standard model codes, including community
models, need to be adapted to the requirements and possibilities
of the new system, and the old code will often no longer run.
This has nothing to do with the norms of the community but simply
with technological progress. Also specific commercial libraries of
specialized algorithms may no longer be accessible. Data and codes
written on old magnetic tapes or even floppies are usually no
longer readable.
Therefore the documentation must take the form of a mathematical
description of the algorithms used. This is in many if not most
cases sufficient for replication. Also, the intention of
replicability is not to exactly redo somebody's simulation and
analysis, but to find the same result with a similar code and
different but statistical equivalent samples. The problem is usually
not that the codes contain errors (even if many of the more complex
ones likely contain minor, mostly insignificant errors), but that
specific elements of implementation and specific aspects of the
considered sample of evidence will lead to conclusions, which do not
hold if another sample is considered or a different but equally good
algorithm is employed. The reason is that we want to learn about the
dynamics of the real world, and these insights should not depend on
random choices in sampling and implementation. We generally do not
expect scientists to manufacture results, or that unintended but
significant errors will affect the eventually published conclusions.
Having this situation in mind, I consider Rep. Barton's requests to
the three scientists as inadequate and out-of-scale. However, the
language used by Rep. Barton makes me perceiving this request as
aggressive and on the verge of threatening.
The situation is different with the second groups of recipients,
the:
b) "Reviewers". Reviewers have a different role, namely they shall
make sure that the standards of scientific reporting are held up.
They have to ensure that the proposed explanations are considered
by independent experts as to whether the presented analysis seems
valid and in principle reproducible. "Independent" means that the
reviewers have no vested interests for or against the case
presented. In the conventional set-up these interests usually
refer to academic schools of thought, but in the unfortunate,
post-normal case of climate science independence from the
political utility of the case should be established.
In this case, I find the inquiry of Rep. Barton to be valid. The
IPCC has failed to ensure that the assessment reports, which
shall review the existing published knowledge and knowledge
claims, should have been prepared by scientists not significantly
involved in the research themselves. Instead, the IPCC has chosen
to invite scientists, who dominate the debate about the considered
issues, to participate in the assessment. This was already in the
Second Assessment Report a contested problem, and the IPCC would
have done better in inviting other, considerably more independent
scientists for this task. Instead, the IPCC has asked scientists
like Professor Mann to review his own work. This does not represent
an "independent" review.
The NSF seems to have failed to ensure that sufficient information
is provided about work done under its auspices.
Rep. Barton should also have asked the editors of "Nature", why
the original manuscript was accepted for publication even though
the key aspect of replicability was obviously not met by the MBH
manuscript. Actually, MBH could not meet this condition because
of the strict length limitation of that journal (nowadays one
would ask for extensive Supplementary Online Material). One
should ask why the manuscript was accepted nevertheless - and
not, as in many other cases, the manuscript was recommended to
be published in a "normal" journal without the severe length
limitations. I believe the reasons for Nature were the journalistic
reasons - namely the expected broad interest in the subject. One
should also ask why after the critique von McIntyre and McKitrik
only MBH got the opportunity for a correction of his paper, whereas
the short manuscript of their opponents was rejected.
To conclude - the requests to M, B and H are not fair but may
unfortunately lead to a repressive atmosphere within climate
science; the requests to NSF and the IPCC, however, are
appropriate, as these institutions may have failed in a primary
task, namely to guarantee an open scientific discourse. And,
Rep. Barton should have included the editors of Nature in his
analysis.
A Climate of Staged Angst
By Hans von Storch and Nico Stehr
The days are gone when climate researchers sat in their ivory
towers packed to the rafters with supercomputers. Nowadays
their field has become the stuff of thrillers, and they
themselves have risen to take on the leading roles. The topic is
so hotly contested, the prognoses so spectacular, that they are
no longer merely the subject of media reports; now the
specialists in staged apocalypse have moved in. Last year Roland
Emmerich depicted a climatic collapse provoked by humankind in
his film "The Day After Tomorrow." Since last week the
belletristic counterpart has been available in German bookstores:
the novel "State of Fear," by the best-selling author Michael
Crichton.
The thriller is about the violent conflict between sober
environmental realists and radical environmental idealists. For
the idealists, the organized fear of abrupt climate change serves
as a handy weapon. They interpret every somehow unusual weather
event as proof of anthropogenic global warming. "You have to
structure your information so that it's always confirmed, no
matter what kind of weather we have," the P.R. consultant for
the environmentalist organization advises. The realists, who
protest that the evidence that human activity has increased
meteorological extremes is thin, are fighting a losing battle.
Their dry scientific arguments are unable to gain any ground
against the colorful, horrific visions of the climate idealists.
Film and novel have certain aspects in common. Where Emmerich
holds out the prospect of a threatening climate catastrophe, the
book prophesies an economic collapse. In both cases, greenhouse
gases produced by humankind are the culprit - in the film,
because the emissions themselves are too much; in the book,
because the fear of them is. The idealists are so obsessed with
their mission that ultimately, in order to rouse the public, they
themselves bring about the foretold catastrophes.
Despite a good deal of factually untrue - and thus all the more
striking - compression, Crichton has quite correctly observed the
dynamic of the paths of communication among scientists,
environmentalist organizations, the state and the civilian
population. For there is indeed a serious problem for the natural
sciences: namely, the public depiction and perception of climate
change. Research has landed in a crisis because its public actors
assert themselves on the saturated market of discussion by
overselling the topic.
Climate change of man-made origin is an important subject. But
is it truly the "most important problem on the planet," as an
American senator claims? Are world peace, or the conquest of
poverty, not similarly daunting challenges? And what about
population growth, demographic change or quite normal natural
disasters?
In the U.S., only a very few remain interested in the greenhouse
effect. At the end of the 1980s, the situation was still different.
That was the era of the great drought of 1988, the Mississippi
flood of 1993, and the climate capers ought by rights to have taken
off in earnest from that point. But that never happened in the U.S.,
and interest petered out. According to a survey by the CBS television
network in May 2003, environmental problems were no longer ranked
among the six most important subjects; and even within environmental
problems, the topic of climate came in only in seventh place. In
Germany, so far, things are still seen differently. But for how much
longer?
In order to keep the topic of "climate catastrophe" - a concept
nonexistent outside the German-speaking world, by the way -
continually in the public eye, the media feel obligated, exactly
like the protagonists in Crichton's thriller, to keep framing the
topic "a bit more attractively." At the beginning of the 1990s -
severe storms had just swept through the country - one could read and
hear in the German media that storms were due to become ever more
severe. Since then, storms have become rarer in northern Europe. But
no notice is taken of this. The fact that barometric fluctuations in
Stockholm have shown no systematic change in the frequency and
severity of storms since Napoleon's time is passed over in silence.
Instead, there is now talk of heat waves and floods. Very much in
the style of Crichton's instigators of fear, the story is now that
all manner of extreme events are on the increase. Thus even drought
in Brandenburg and deluge on the Oder fit the picture without
apparent contradiction.
Add to this - besides normal floods and storms - other, more
dramatically threatening, scenarios: the reversal of the Gulf
Stream and the resultant cooling of large areas of Europe, for
instance, or even the rapid melting of the Greenland ice pack.
The question has already been publicly raised whether perhaps even
the Asian tsunami can be attributed to the disastrous effects of
human activity.
This will not be able to hold the public's attention for long. Soon
people will have become accustomed to these warnings, and will
return to the topics of the day: unemployment and Hartz IV, Turkey's
entry to the E.U. or whether Borussia Dortmund can avert disaster on
the soccer field and in the boardroom. Thus we will see firsthand
how the prophets of doom will draw the climatic dangers in even more
garish colours. The terrifying visions to haunt the future can
already be guessed at: the breakup of the west Antarctic shelf ice,
which will cause the water level to rise much more rapidly, and after
a few decades of uncontrolled carbon dioxide emissions, an abrupt rise
in temperatures, giving us a deadly atmosphere like that of Venus.
Prospects such as these have long been in the public eye; can they not
compete effortlessly with Emmerich's Hollywood images?
The costs of stirring up fear are high. It sacrifices the otherwise
so highly valued principle of sustainability. A scarce resource -
public attention and trust in the reliability of science - is used up
without being renewed by the practice of positive examples.
But what do climate researchers themselves think, how do they deal
with the media and the population?
Public statements by noted German climate researchers give the
impression that the scientific bases of the climate problem have
essentially been solved. Thus science has provided the prerequisites
for us now to react appropriately to the goal; meaning, in this case,
to reduce greenhouse gas emissions as much as possible.
This does not at all reflect the situation in the scientific
community. A considerable number of climatologists are still by no
means convinced that the fundamental questions have been adequately
dealt with. Thus, in the last year a survey among climate
researchers throughout the world found that a quarter of the
respondents still harbor doubts about the human origin of the most
recent climatic changes.
The majority of researchers are indeed of the opinion that global
climate change caused by human activity is occurring, that it
will accelerate in the future, and that it will thus become more
readily apparent. This change will be accompanied by warmer
temperatures and a higher water level. In the more distant future,
that is, in about 100 years, a considerable increase of atmospheric
greenhouse gases is foreseen, together with an increase in heavy
precipitation in our latitudes; in some regions there could be
more powerful storms, in others weaker ones.
But again and again, there are scientists to whom, true to the
alarmists' maxim in Crichton's book, this does not sound dramatic
enough. Thus, more and more often they connect current extreme
weather events with anthropogenic climate change. To be sure, this
is usually carefully formulated; interviews sound something like
this: "Is the flooding of the Elbe, the hurricane in Florida, this
year's mild winter evidence for the climate catastrophe?" Answer:
"That's scientifically unproven. But many people see it that way."
Neither of these statements is false. In combination, however,
they suggest the conclusion: Of course these weather events are
evidence. Only no one dares to say this explicitly either.
The pattern is always the same: the significance of individual
events is processed to suit the media and cleverly dramatized;
when prognoses for the future are cited, among all the possible
scenarios it is regularly the one with the highest rates of
increase in greenhouse gas emissions - and thus with the most
drastic climatic consequences - that is chosen; equally plausible
variations with significantly lower emission increases go unmentioned.
Whom does this serve? It is assumed that fear can motivate listeners,
but it is forgotten that it mobilizes them only in the short term.
Climatic changes, however, demand long-term reactions. The effect on
public opinion in the short view may indeed be "better," and thus may
also have a positive effect on reputation and research funding. But
in order for this to function in the long run, each most recent claim
about the future of the climate and of the planet must be ever more
dramatic than the previous one. Once apocalyptic heat waves have been
predicted, the climate-based extinction of animal species no longer
attracts attention. Time to move on to the reversal of the Gulf
Stream. Thus there arises a spiral of exaggeration. Each individual
step may appear to be harmless; in total, however, the knowledge
about climate, climate fluctuations, climate change and climatic
effects that is transferred to the public becomes dramatically
distorted.
Sadly, the mechanisms for correction within science itself have
failed. Within the sciences, openly expressed doubts about the
current evidence for climatic catastrophe are often seen as
inconvenient, because they damage the "good cause," particularly
since they could be "misused by skeptics." The incremental
dramatization comes to be accepted, while any correction of the
exaggeration is regarded as dangerous, because it is politically
inopportune. Doubts are not made public; rather, people are led
to believe in a solid edifice of knowledge that needs only to be
completed at the outer edges.
The result of this self-censorship in scientists' minds is a deaf
ear for new and surprising ideas that compete with or even
contradict conventional patterns of explanation; science
degenerates into being a repair shop for popular, politically
opportune claims to knowledge. Thus it not only becomes sterile;
it also loses its ability to advise the public objectively.
One example of this is the discussion of the so-called "hockey
stick," a temperature curve that allegedly depicts the development
over the last 1000 years, and whose shape resembles that of a
hockey stick. In 2001 the Intergovernmental Panel on Climate
Change, the committee of climate researchers appointed by UNO,
rashly institutionalized this curve as the iconic symbol for
anthropogenic climate change: At the end of a centuries-long
period of stable temperatures, the upward-bent blade of the
hockey stick represents the human influence.
In October 2004, we were able to demonstrate in the scientific
journal "Science" that the methodological bases that led to this
hockey-stick curve are mistaken. We wanted to reverse the spiral
of exaggeration somewhat, without also relativizing the central
message - that climate change caused by human activity does indeed
exist. Prominent representatives of climate research, however, did
not respond by taking issue with the facts. Instead, they worried
that the noble cause of protecting the climate might have been
done harm.
Other scientists lapse into a zeal reminiscent of nothing so much
as the McCarthy era. For them, methodological criticism is the
spawn of "conservative think tanks and propagandists for the oil
and coal lobby," which they believe they must expose; dramatizing
climate change, on the other hand, is defended as a sensible means
of educating society.
What is true for other sciences should also hold for climate
research: Dissent is the motor of further development, Differences
of opinion are not an unpleasant family affair. The concealment of
dissent and uncertainty in favor of a politically good cause takes
its toll on credibility, for the public is more intelligent than
is usually assumed. In the long term, these allegedly so helpful
dramatizations achieve the opposite of that which they wish to
achieve.
By doing so, however, both science and society will have wasted
an opportunity.
Hans von Storch, 55, heads the Coastal Research Institute of the
GKSS Research Centre in Geesthacht, Germany; he is considered
leading experts statistical analysis of climatological data and
simulations. Together with Nico Stehr, 62, sociologist at the
Zeppelin University in Friedrichshafen, Germany he has conducted
ongoing research into the public perception of climate change.
Translated by Paul Malone
First published in Der Spiegel No. 4, 2005.
MR. WHITFIELD. Thank you, Dr. von Storch, and
Mr. McIntyre, you are recognized for 5 minutes.
MR. MCINTYRE. Good afternoon, Mr. Chairman and members of the
committee. My name is Steve McIntyre. I appreciate the
invitation to appear today to discuss my research coauthored with
Ross McKitrick of the University of Guelph which in part led to
today's meeting.
I have three main messages. First, little reliance can
be placed not only the original Mann reconstruction,
various efforts to salvage it, or similar multi-proxy
studies even ones which did not use Mann's methodology.
Second, peer review as practiced by academic journals is
not an audit but something much more limited. In turn,
scientific overviews such as the ones produced by IPCC or
even by the NAS panel are based almost entirely on
literature review rather than independent testing. Third,
there is already an existing data archive which is
excellent, but in order to make it work scientists actually
have to archive their data and code. This is not done
consistently in the paleoclimate community and it makes
replication virtually impossible in many cases. Much of
this work is funded by the U.S. Federal government and
some very simple administrative measures under existing
policies could alleviate many of the problems.
In the two reports, only one topic was specifically
audited in the sense of independent testing as opposed to
literature review, and that was simply whether Mann's
method was biased towards producing hockey stick-shaped
series. Both reports verified this hotly contested result.
Both panels agreed with varying emphasis that no confidence
could be placed on reconstructions prior to 1600 and that
Mann's statistical methods were unsatisfactory. The Wegman
report considered how such an error could have remained
undetected. In addition to their comments, an important
reason that the IPCC does not carry out independent tests.
Some comments of Dr. Bloomfield's at the NAS press conference
may lead people to believe that a hockey stick could be
obtained from a simple average of all MBH proxies. This is
simply not the case as you see by the graph on both screens.
The NAS panel illustrated several other reconstructions but
their consideration was merely a literature review. They
did not attempt to replicate or audit these other studies as
I have tried to do. Each one has replication problems. One
of the criticisms of the Mann study recognized by the NAS
panel was its use of bristle cones and closely related
foxtails, a flawed proxy which the panel said should be
avoided. However, they did not assess this. The impact of
not using bristle cones can be substantial. Removal of merely
two bristle cone series changes relative medieval modern levels
in the Crowley and Lowery reconstruction that was shown to you
earlier. The panel noted the so-called divergence problem in
which temperatures in the last half of the 20th Century
increase while tree ring widths and densities decrease. They
offered no solution other than reduced confidence, but the
problem is worse. How can we even trust the shape of the
curve in previous warm periods if they miss the present one?
Bias sampling can arise not simply from Mann's principal
component methods, but by non-random and biased selection of
small samples. In this graph shown here, even the selection
of a single site, of a different version from a single site
can have a dramatic impact on a worldwide reconstruction.
Here different versions impact the Briffa 2000 reconstruction
and all but one subsequent reconstruction shown in the
various spaghetti graphs. The issue of the polar Urals is
substantive. Naurzbaev et al., which included Mann's coauthor
Hughes, whose methods were cited by the NAS panel with a
approval, concluded that medieval summer temperatures in this
area were over 2.3 degrees Centigrade warmer than at present.
The Wegman reported noted pervasive problems in paleoclimate
research practices. A simple policy shown here already in
existence at the American Economic Review and other journals
and in fact a policy introduced by Dr. Bernanke, presently
Chairman of the Federal Reserve System, would alleviate many
of these problems. There is no reason for journals not to
adopt similar rules for paleoclimatology where data sets are
similar in size and scale to many econometric studies. In
fact, the 1991 policy statement of the U.S. global change
research program already requires data archiving and many
agencies such as NASA have complied with these policies.
However, the National Science Foundation does not and a senior
NSF official wrote to me saying that dissemination of data was
merely up to the professional judgment of the researchers.
Ironically, even the NAS panel relied heavily on unarchived
data. The Department of Energy itself does not comply. It
funded the development of the well-known CRU temperature series
used by IPCC but their agreements failed to ensure that even
DOE has access to the supporting data.
Nothing that I say here should be construed as diminishing the
seriousness of climate change as public issue. It is precisely
because it is a serious issue that policymakers are entitled to
the best possible information. You should not receive incorrect
confidence assessments as happened with the hockey stick. You
should discourage practices that interfere with efforts to
verify results.
Finally, at the NAS press conference, when asked about
overselling of the hockey stick, panelist Cuffy said that the
IPCC sent a very misleading message through its prominent use.
Yet IPCC procedures which permitted this remain unchanged for
the upcoming fourth assessment report.
Thank you very much.
[The prepared statement of Mr. Stephen McIntyre follows:]
PREPARED STATEMENT OF STEPHEN MCINTYRE, TORONTO, ONTARIO, CANADA
SUMMARY
1. little reliance can be placed on the original MBH reconstruction,
various efforts to salvage it or similar multiproxy studies, even
ones which do not use Mann's principal components methodology;
2. peer review as practiced by academic journals is not an audit,
but something much more limited. Scientific overviews, such as
ones produced by IPCC or the NAS panel, are nearly entirely based
on literature review rather than independent due diligence.
3. much work in dispute is funded by the U.S. federal government.
Some very simple administrative measures under existing policies
could alleviate many of the replication problems that plague
paleoclimate.
TESTIMONY
Good morning, Mr Chairman and members of the Committee.
My name is Stephen McIntyre. I appreciate the invitation to appear
today to discuss my research, coauthored with Ross McKitrick of the
University of Guelph. Our publications led in part to the reports of
the NAS panel and the Wegman committee.
A year ago, the University Corporation of Atmospheric Research (UCAR)
issued a national news release stating that our "highly publicized
criticisms of the MBH graph are unfounded." Sir John Houghton,
co-chair of IPCC, gave evidence to a Senate committee, stating that
our results had been shown to be "largely false". The situation today
is different as both the NAS and Wegman reports have recognized our
major findings while drawing different conclusions on their impact.
I would like to convey three main messages today:
1. little reliance can be placed on the original MBH reconstruction,
various efforts to salvage it or similar multiproxy studies, even ones
which do not use Mann's principal components methodology;
2. peer review as practiced by academic journals is not an audit, but
something much more limited. Scientific overviews, such as ones
produced by IPCC or the NAS panel, are nearly entirely based on
literature review rather than independent due diligence.
3. much work in dispute is funded by the U.S. federal government. Some
very simple administrative measures under existing policies could
alleviate many of the replication problems that plague paleoclimate.
In the NAS and Wegman reports, only one topic has been specifically
"audited" - in the sense of carrying out independent simulations as
opposed to review of previous literature:
* Mann's principal component method is biased towards producing
hockey stick shaped series.
Both audits verified this result, first published by us, but hotly
contested for the past two years. Both panels agreed (with varying
emphasis) that MBH confidence claims were incorrectly calculated,
indeed that no confidence intervals prior to 1600 could be calculated
and that MBH statistical methods were unsatisfactory.
The Wegman report considered why such an error could have remained
undetected in such a prominent study, an issue not considered by
the NAS panel. In addition to their comments, I note that IPCC does
not verify information from the scientific literature.
The NAS panel also endorsed our important criticism of MBH dependence
on proxies known not to be temperature proxies, agreeing that
bristlecones should be avoided.
The NAS panel cited several other reconstructions, but their
consideration was merely a literature review. They did not attempt to
replicate or audit these other studies and cannot vouch for them.
Having examined most of them closely, I do not believe that any of
them provide robust or reliable information on relative medieval-
modern levels.
For example, some comments of Dr Bloomfield's at the NAS press
conference may lead people to believe that a hockey stick could be
obtained from a simple average of all 415 MBH proxies. This is not
the case, as shown in Figure 1 below.
Figure 1. Top - Average of all 415 MBH proxies; bottom - MBH
reconstruction.
The NAS panel illustrated four other multiproxy studies, as shown in
Figure 2 below. However, all four use bristlecones or closely-related
foxtails. The panel did not analyse the impact on each study of
avoiding bristlecones, as they elsewhere recommended.
Figure 2. Excerpt from figure S-1 of NAS panel report
The impact of avoiding bristlecones in accordance with the NAS
recommendation can be substantial - as shown in Figure 3 for Crowley
and Lowery 2000, where the removal of two bristlecone series changes
relative medieval-modern levels.
Figure 3. Left - Excerpt from Crowley (2000); right - replication
with red showing effect without bristlecones and without instrumental
splicing.
The NAS panel noted the so-called "Divergence Problem", in which
temperatures in the last half of the 20th century increase, while
tree ring widths and densities decrease, demonstrated here for a
rare large-sample (387) study of "temperature-sensitive" sites
[Briffa et al 1998]. NAS offered no solution other than reduced
confidence. But the problem is worse: how can we even trust the
shape of the curve in previous warm intervals, if they miss the
present one?
Figure 4. Ring widths and density from Briffa et al 1988.
Biased sampling can arise not simply from Mann's principal
component methods, but from non-random and biased selection of
small samples. If you "mine" or "snoop" a network of red noise
looking for what appear to be "temperature-sensitive" trends,
an average of the picks will also yield a hockey stick shaped
series. The Wegman report shows evidence of non-random picking.
While the NAS panel noted the potential impact of inclusion/
exclusion of even individual series, they did not investigate it.
Here is an important example that affects multiple studies. The
first Briffa version of the Polar Urals series said that the
early 11th century was among the coldest of the millennium;
updated sampling in 1998 showed the opposite, but Briffa did not
report it. Instead he substituted another series from a site 70
miles away with a hockey stick shape. This substitution had a
dramatic impact on the medieval-modern relationship in the Briffa
(2000) reconstruction and nearly all other subsequent studies.
Figure 5. Left - three different versions of Polar Urals series.
Top - from Briffa et al 1995; middle - from Esper et al 2002 (the
only use of this version); bottom - the version in Briffa (2000)
and subsequent studies other than Esper et al 2002. Right: the
impact on the reconstruction in Briffa (2000). Black - Briffa
(2000) version; red - using Polar Urals update. . All series in
standard deviation units and 21-year gaussian smooth.
In our NAS presentation, we cited Naurzbaev et al 2004 (including
MBH co-author Hughes) as offering a promising new line of handling
tree ring data. NAS cited this with approval, but did not report
their conclusion that medieval summer temperatures were over 2.3
deg C warmer or that medieval treelines in the Polar Urals (and
elsewhere) were higher than modern treelines.
Figure 6. Treelines at Polar Urals site (Shiyatov 1995).
While the NAS panel did not address the issue of archiving, other
than in generalities, the Wegman report noted pervasive problems
in paleoclimate research practices. A simple policy - already in
existence at the American Economic Review and other journals -
would alleviate many of these problems. There is no reason not
to require similar rules for paleoclimatology, where data sets and
code are similar in size and scale.
Submitters should be aware that the Editors now routinely require,
as a condition of publication, that authors of papers including
empirical results (including simulations) provide to this office,
in electronic form, data and code sufficient to permit replication.
To the extent that senior policy-makers have previously turned
their attention to the matter, the 1991 Policy Statement of the
U.S Global Change Research Program already requires data archiving
after a limited period of exclusive use and, in 1997, provided
recommended language for agencies to implement in grant agreements.
Many agencies (e.g. NASA) have complied with these policies.
The overall purpose of these policy statements is to facilitate
full and open access to quality data for global change research.
They ...represent the U.S. Government's position on the access to
global change research data....
For those programs in which selected principal investigators have
initial periods of exclusive data use, data should be made openly
available as soon as they become widely useful. In each case the
funding agency should explicitly define the duration of any
exclusive use period.
Yet when I copied NSF on a request for data necessary to replicate
key MBH results, a program officer not only refused to support the
request, but intervened to counsel Mann against supplying the data.
Dr. Mann and his other US colleagues are under no obligation to
provide you with any additional data ... His research is published
in the peer-reviewed literature which has passed muster with the
editors of those journals and other scientists who have reviewed
his manuscripts. You are free to your analysis of climate data
and he is free to his.
Subsequently, a senior NSF official said that dissemination of
data was merely up to the "professional judgement" of the
researchers. Ironically, the NAS panel relied heavily on
unarchived data.
In general, we allow researchers the freedom to convey their
scientific results in a manner consistent with their professional
judgement...
The Department of Energy funded the development of the well-known
CRU instrumental temperature series, used by IPCC and others. In
response to a request for supporting data, Philip Jones, a prominent
researcher said:
We have 25 or so years invested in the work. Why should I make the
data available to you, when your aim is to try and find something
wrong with it?
Although DOE had funded the collection, their past and present grant
agreements had not ensured that even DOE had access to the supporting
data and they said that they were unable to assist.
Phil [is] not obligated under the conditions of past or present DOE
proposal awards to provide these items to CDIAC. I regret we cannot
furnish the materials you seek
In conclusion, I re-iterate that you can place little reliance on any
existing multiproxy study; that you need to distinguish between the
limited due diligence of journal peer review and the substantive due
diligence of an audit; and that simple administrative measures can
substantially improve paleoclimate research practices.
Both the NAS report and Wegman reports are valuable studies by
accomplished authors. Nothing that I say here should be construed as
diminishing the seriousness of climate change as a public issue. It
is precisely because it is a serious issue that policy-makers are
entitled to the best possible information and should ensure that data,
code and methods be accurately and completely archived and discourage
practices that interfere with scientific reproducibility.
References:
See NAS Panel report.
MR. WHITFIELD. Thank you, Mr. McIntyre, and at this time I
am going to recognize the full committee Chairman, Mr. Barton,
for 10 minutes.
CHAIRMAN BARTON. Thank you. I want--let me thank Ms. Baldwin
before she leaves. She and Mr. Inslee and Mr. Stupak have been
here the entire time and I think they need to be given
accolades. Mr. Whitfield and I almost have to be here but
they don't, so we appreciate you all's attendance. I want to
thank these witnesses for waiting 5 hours to testify. That
shows a little bit of fortitude on your part.
My first question goes to you, Dr. Karl. Talking about the
peer review and the acceptance, if I were to ask Mr. Inslee and
Mr. Stupak and Ms. Baldwin to review the work of this committee
in this Congress and then turn around and ask Mr. Whitfield and
Mr. Walden and Mr. Shimkus, I would probably get two radically
different assessments. Same body of work but my friends on the
Democrat side would view the accomplishments in all probability
substantially different than my colleagues on the Republican
side because both are biased in an open and honest way and have
a different worldview on some issues, not on all issues. So it
shouldn't be surprising if the same people that Dr. Wegman calls
a social network and are interacting all the time that they view
positively the output, should it?
DR. KARL. Are you asking about whether or not the review
process is skewed?
CHAIRMAN BARTON. No, I am just asking you to comment because I
will stipulate that everybody in the climatology community, the
environmental community, have got good faith and are trying to
do what they think is right for the world. I am not--but there
are biases on both sides, and one of Dr. Wegman's criticisms,
and Dr. McIntyre reinforces it, is that you are not really
getting independent review, and there are cases, as Dr. Crowley
pointed out, there may not be anybody that can be independent
because they don't understand it. If I want somebody to
interview Albert Einstein's work in the 1930s, there probably
weren't two or three people in the world that even knew what
he was talking about, so you do get that, but what happened
with Dr. Mann's study in 1998 was that it was accepted very
quickly as kind of the gold standard and it was given a
literary review, but it really wasn't given an independent
scientific statistical review. It was just accepted. And
unless Dr. McIntyre is not being true, some of these other
studies that have come out that Dr. Crowley referred to, he
used the same data sets and the same modeling or something
that is very close to it. So how can us poor mortals that
have to make the policy decisions know what to believe when
the so-called scientific community could be portrayed as
scratching each other's back? I mean, I am not trying to be
mean about it. You know, I just am kind of puzzled.
DR. KARL. I mean, I can tell you the process that we use in
IPCC. It may shed some light on it. In the IPCC report,
each of the lead authors are asked to assess the published
literature up until a certain time after which no more new
material can be considered and what lead authors do is take a
look at that material and try to write up their consistencies
among what has been published, inconsistencies, what is
available today compared to what was available during either
the previous IPCC report or previous to that. Having done
that, those writings then are subjected to international
review. Anyone and everybody is open to review to report and
the process takes place over several years. So there is ample
time, ample review time--
CHAIRMAN BARTON. But do they really review it? Again, I am
not saying that your folks don't make a good-faith effort, but
it is just like my analogy. If I asked Mr. Whitfield, who is
a subcommittee Chairman because I appointed him subcommittee
Chairman as Chairman, if I say Ed, could you review my
performance as chairman of the full committee, I bet he is
going to give me a pretty high performance rating. Now, on
the other hand, if I asked Mr. Inslee to review my performance
as full committee Chairman, and I have consistently opposed
his amendments and I have consistently made life difficult for
him, which is not true but let us assume that it is true, he
is not going to rate me the same. In all probability, Jay
Inslee is going to be more independent and objective than
Ed Whitfield, and they are both good people. But one of them
is more dependent on me, interacts more, benefits more with
that interaction than the other and it appears to me that what
Dr. Wegman and Mr. McIntyre are saying is, it may be because
there are just not enough experts, it may be for any number of
reasons, but a very small set of people review each other's
work and lo and behold, they all come to the same conclusions.
Now, we didn't put it into the record, but in 1975 we have the
Newsweek story about the meteorologists all being unanimously
in agreement that the world is in a world-cooling period and
it has catastrophic consequences and there was unanimous
agreement. It was la di la di da. Those were meteorologists.
Now, that is 31 years ago. The world has changed. We are
now worried about global warming but it the same thing. You
know, I am not qualified to say whether the conclusions are
right or wrong. I agree with what Dr. Wegman said and
Dr. North said, that--I can't conclusively say what is causing
it. I can admit that the statistical record in the last 150
years that the temperature is going up, but I would like to
see the scientific community self-regulate itself a little bit
better so that when you have these statements like Dr. Mann
made that the 1990s were the warmest period in 1,000 years and
1998 is the warmest year in 1,000 years, that you can replicate
that with statistically valid modeling technique that is open
to the public and everybody takes their shot at. I think we
have pretty conclusively proven today that that is not the
case, at least in that study. That is not the case. So that
is my question to you, what can the scientific community do
to give us more certainty or more reliability that the
conclusions of these studies are really based on fact and not
on opinion.
DR. KARL. I suspect, and I don't know for sure, but if you
request the records from the IPCC Bureau, for example, you
could--because it is public--you could get available the
disciplines of the individuals who commented on that report
and I note there is an IPCC report going on now, and that may
be a way for this committee to try and see the breadth and
scope of--
CHAIRMAN BARTON. Well, are you willing to recommend that--one
of the recommendations of Dr. Wegman is that the data be
publicly available? Is that something that you would
support? Because we have apparently had a real problem with
Dr. Mann, getting his data and, it has been federally
funded. I think it should be available, that anybody who
has the scientific ability and the mathematical ability to
study it, study it. Do you agree with that?
DR. KARL. Yes. Our Center actually houses the Paleoclimate
World Data Center and we actually encourage researchers to
archive their data, not the actual proxy itself like the
tree ring or the ice core but the data from which they are
derived. We are fairly successful in many instances, but I
am sure there is a number of instances where we don't have
data simply because of its significant investment on both
the PI's time and--
CHAIRMAN BARTON. And either Dr. North--I think Dr. North's
report, or it may have been Dr. Wegman's, says there are
only 30 of these data sets in existence right now, that
there are a fairly limited number of data sets. So we are
basing a lot of decisions on a fairly narrow band.
Let me ask you something, Mr. McIntyre. Since you had the
gumption to criticize Dr. Mann, how have you been received
in this community. Are people patting you on the back and
inviting you to their Christmas party and saying right on,
way to go, we really appreciate it, or are they kind of
giving you the cold shoulder and ask why the hell you did
what you did?
MR. MCINTYRE. I would say cold shoulder would be
overstating the friendliness of it. I would say that I
have been reviled and--
CHAIRMAN BARTON. And so your skepticism for scientific
truth has not been welcomed with open warms. Is that a
fair statement?
MR. MCINTYRE. I would say it has been an uphill fight.
Having said that one finds certain allies and certain
moments of comfort. I mean, quite frankly I could
understand why there would be some reluctance to take the
claims seriously at the beginning. That is one of the
reasons why I archived the source code and calculations
so that people could replicate it. Aside from the fact
that I think it is something that should be done anyway,
but my position was if anybody thinks that my results are
wrong, then I would like to know. I would like to be the
first person to know rather than the last person to know,
and--but I--for example, the University Corporation of
Atmospheric Research put out a national press release
saying that all our claims are unfounded. Sir John
Houghton, co-chair of IPCC, testified to a Senate
committee that our claims were false. So while I would
say not all of our claims have been acknowledged, some of
them have. Both of these reports have certainly endorsed
a finding on methodology that surprised people and so, I
feel a little more comfortable now. Also, some people have
been very generous and welcoming. Dr. von Storch has
encouraged me both publicly and privately.
CHAIRMAN BARTON. Dr. Crowley, this might be my last
question. You mentioned in your oral statement--I didn't
see it in your written statement but it may have been
there--that there have been problems in the past with
correlation of current temperature readings and their
consequences with satellite readings and that those
correlations are much better today. Is that true? Did I--
DR. CROWLEY. Yes, that is true.
CHAIRMAN BARTON. Now, my understanding is that what
changed is that we have gone back and reprogrammed the
software on the satellites so that they will conform with
the model predictions. Do you agree or disagree with that?
DR. CROWLEY. I completely disagree with that.
CHAIRMAN BARTON. Can you push your--I don't know that your
microphone is on. You said--I think you said--
DR. CROWLEY. I disagree with you. It is not the case of
trying to get it to conform to model predictions. In fact,
it stuck out like sore thumb for 10 years. The climate
community took it very seriously as a disagreement and
pondered over it and there was eventually a comparison
between two different groups of satellite analysts in
which they found a programming error in one of the
algorithms for reducing the data that gave the differences
in the trends because this other group actually had gotten
a bigger trend in the satellite data than the one that
John Christy at University--
CHAIRMAN BARTON. Do you think that that disagreement is
worthy of being pursued by this subcommittee?
DR. CROWLEY. Well, what has happened is that the
disagreement has diminished to the point where I am not
sure it is worth the subcommittee's effort to inquire.
It has been found to be a programming error, and an
innocent one but that happens when you are working with
satellite or any other thing. It just took a long time--
CHAIRMAN BARTON. Do you consider Dr. Mann's methodology
a programming error? If you were Dr. Mann and--
DR. CROWLEY. No, because I don't think he actually
wrote--I don't think his programs--when it is a programming
error, it is like a coding error or something. I think
that there is a methodological error, okay. There is a
difference between, as you know, since you took programming,
between the--you can program a methodology that could be
wrong, okay. So I don't think it was programming. I
think it was a methodological error.
CHAIRMAN BARTON. Well, my time--
DR. CROWLEY. Not a--yeah, a methodological.
CHAIRMAN BARTON. Thank you, Mr. Chairman.
MR. WHITFIELD. Mr. Inslee, you are recognized for
10 minutes.
MR. INSLEE. Thank you. I wanted to ask Mr. Karl about the
conclusions, if I can find them here. In your testimony you
talked about reviewing a variety of papers and you said of
all the analysis, only one shows temperatures during medieval
times higher than those of the early 20th Century and none of
the analyses show temperatures higher than the last few
decades of the 20th Century and into the 21st Century. So I
take it that means that none of the analyses that have been
done have shown temperatures at any point higher than the
last few decades and into this century. Is that an exhaustive
review of the analyses or is there something you might have
missed or is that pretty much a total review of the
literature on this?
DR. KARL. There is always a danger one could have missed a
report but none of the reports I looked at, which probably
seven or eight reports using the approaches from as been
discussed here. I think "bonehead" is a term and RPG and
various terms have been given to these things, but I don't
think any of them show temperatures, except for one, that
were as warm as what we saw in the mid part of the 20th
Century, none of them as warm as the late part of the 20th
Century and the early part of the 21st century, and in
addition, I might add the error bars are frequently being
discussed. If you look at the error bars, the wide error
bars, the 95 percent confidence error bars, it is even hard
to find in those error bars in those reports to come up to
the levels as high as we see in the last couple decades.
MR. INSLEE. So is it a fair synopsis here that today we
have heard some criticism of one report that suggested that
these are higher temperatures we are experiencing now than
we have at any time in the last 1,000 years and multiple
reports that have reached the conclusion that it is likely
we are having higher temperatures right now than we did at
any time in the last 1,000 years. Is that sort of a fair
statement of what we are hearing?
DR. KARL. I think so, and again, the word "likely" you
know, I point out, we use the word "likely" with better
than two to one odds and so with that kind of a caveat, I
feel quite comfortable in saying that.
MR. INSLEE. Well, the way I look at this, just so you
know, is that you have got about six studies showing that
gravity exists and you have got one study questioning the
statistical mechanisms used in one of those six studies,
and I sort of conclude that both gravity and global
warming due to human activity exist, and that is just how
I look at it. I want to refer--you also concluded,
"These analyses indicated that the later half of the 20th
Century is certainly warmer than any time during the past
several hundred years, parentheses, based on the length of
the borehole and glacial length proxies, paren, and the
past 1,200 years based on isotopic ice core records." So
you indicated that these are warmer during the past
several years and you say based on the length of the
borehole and glacial length proxies. What are those two
proxies?
DR. KARL. Those are proxies that are completely independent
of the tree ring analysis which is heavily used in some of
these multi-proxy reconstructions. But the borehole
measurements are--there is probably about--I think the
academy actually gave a number of about 679 different
boreholes where the conduction of heat from the atmosphere
is constantly conducting into the Earth's surface and you
can go back in time to try and deduce what the actual
temperatures were in the lower parts of the atmosphere. Now,
you have to be careful which boreholes you look at but
nonetheless, with current methods, you can go back to about
400 or more years. That was an important piece of evidence
that when we did the IPCC in 2001 we intercompared those
borehole measurements with the Mann record, for example.
MR. INSLEE. So as I take it then, we have got totally
independent results independent from the Mann analysis that
is consistent with the conclusion that it is likely that we
are in warmer temperatures now than we have been in the
last several hundred years. Now, you made reference to
glacial length proxies. What are those?
DR. KARL. Now, the glacial length proxies, this is where a
model was used to try and look at the ablation of glaciers
across primarily the Northern Hemisphere and a model has
been shown to be able to reproduce approximately the
temperatures that would be needed to cause those glaciers to
melt. Again, you have to be careful about what glaciers you
select. Some of them are more sensitive to precipitation but
nonetheless another independent method, and again, it shows
that the later part of the 20th Century is warmer than
anything we have seen in the last several hundred years.
MR. INSLEE. Now, you also reported that these analyses
indicated that these temperatures we are now experiencing are
warmer than in the past 1,200 years based on isotopic core
records. Are the isotopic core records independent of the
Mann research and could you describe what they are?
DR. KARL. Yes. They are independent as well. The difference
is, they are far fewer in terms of geographic coverage. So
what you are actually looking at here is the isotopic decay
within these records, the same kind of records that are looked
at for the air bubbles that are trapped in the ice. Now you
try to relate through isotopic decay to temperatures and there
are some relationships that have been developed and again you
see some significant warming in the latter part of the 20th
Century compared to what we saw earlier.
MR. INSLEE. So we have multiple independent scientifically
sound measures to conclude these are the likeliest warmest
temperatures we have had in 1,000 years independent of the
Mann report. Is that correct?
DR. KARL. That is correct.
MR. INSLEE. Dr. Crowley, you talked about something that I
had heard and I appreciate you talking about it, about
amplitude, about the effect of how much amplitude there is in
the system, how sensitive the system it is to CO2 forcing, and
I think this is interesting because basically the Wall Street
Journal editorial staff has done everything they can to suggest
this is not a problem and they have attacked the Mann research
effectively saying that, but is it fair to say that actually if
one would want to debunk the idea of global warming, if one
would want to say we shouldn't worry about global warming, if
one would want to say that we should really just continue on
our path of putting megatons of CO2 in the air without change,
if one really wanted to argue that, one would really want to
argue that Mann was right because Mann had a conclusion that
there was less effect on temperature by CO2 changes than some
of the other studies. Is that right?
DR. CROWLEY. That is true. Another way of putting it is that
those who love to hate Mann should learn to hate to love him.
MR. INSLEE. Well, that will take us about 8 minutes to figure
out up here on this panel. But could you explain why that is?
I just heard this yesterday for the first time. It is an
intriguing thought, that this could be a reversal of approaches
here, but why is it important to know how much CO2 can affect
temperature and what does the Mann research indicate versus
other research?
DR. CROWLEY. Well, it is like pushing on a string. Jerry
North explained this to me years ago. Suppose you have two
strings, one that is very thick, coiled spring, and then
another one that is very thin and weak. You push on the thick
coiled spring, it is not going to move very much whereas one
that is very flexible is going to move a lot, and that is
really like pushing is like the climate forcing the responses
to climate system, so if you have a system that has a very
low sensitivity, it is not going to respond much, like the
thickly coiled spring. You have one that is less thickly
coiled, it is going to respond more and you are going to get
bigger temperature changes and that is the thing we worry
about, is whether the temperature change is being large, and
the study came out recently in Nature where we tried to
quantify that and that at least with respect to the
paleoclimate records and showed objectively what I was saying--
MR. INSLEE. So if Mann was wrong, this problem that we are
going to be at in 2100 when CO2 levels are twice the rate of
pre-industrial times--
DR. CROWLEY. We are going to have larger temperature
variability.
MR. INSLEE. So if Mann is wrong, that means we are going to
have greater increases in temperature once this CO2 levels
skyrocket like this and even some of the other researchers
have predicted. Is that the situation?
DR. CROWLEY. Right.
MR. INSLEE. That will news to the Wall Street Journal
editorial board.
DR. CROWLEY. Sure.
MR. INSLEE. Thank you.
MR. WHITFIELD. Thank you, Mr. Inslee. Dr. von Storch, in your
presentation you made the comment that parts of climate change
science, in particular paleoclimatic reconstructions have
suffered from gatekeeping and incestuous usage of reviewers and
then you talked about they have a bias toward interesting
results, and we have a lot of testimony today about the Wall
Street Journal and the oil industry and the coal industry love
to debunk all of this science about global warming, which may
be true, but I was interestingly reading an article the other
day about a gentleman named Chris Landsea, who was on the IPCC
panel and was an expert in hurricanes. And we heard testimony
today in some of the opening statements that global warming is
causing more hurricanes, stronger hurricanes and it is a
serious problem. Henry Waxman is the one that made that comment
and there was another person that made that comment. And
Chris Landsea was asked by a gentleman named Dr. Kevin Trenberth
to provide the write-up for the AR4 assessment, the fourth
assessment report of the IPCC. He was asked to do the write-up
for the Atlantic Hurricanes, and soon after he was asked,
Dr. Trinberth went to Harvard University and participated in a
program entitled on the topic: "experts to warn global warming
likely to continue spurring more outbreaks and intense hurricane
activity." And there was big press about it and there were all
sorts of articles written about it. And Landsea was so upset
about this as they were just getting ready to do this assessment
that he submitted his resignation. And he said, "It is beyond
me why my colleagues would utilize the media to push an
unsupported agenda that recenty hurricane activity has been
due to global warming. Given Dr. Trenberth's role as the
IPCC's lead author responsible for preparing the text on
hurricanes, his public statements are so far outside of any
scientific understanding led me to concern that it would be
very difficult for the IPCC process to proceed objectively
with regards to the assessment on hurricane activity." Now,
we are all human beings, we make a lot of mistakes. We are
biased. We do this, we do that. But is that something that
happens in the IPCC frequently or infrequently or do you have
any comment about it?
DR. VON STORCH. Only through the media, and I had the
impression that this was not very helpful, what has happened
there, but I don't know the details, and this would be an
example where I would ask some social scientists to really go
after this, what really has happened here. I think it would
be worth doing it. But when we speak about this storm
business, I would like to tell a little story, namely in the
early 1990s we had the press in northern Europe full of
messages that we would have more storms, and these storms
would be proof or would be a result of global warming going
on. And you have to know that when people think about
climate change, anthropogenic climate change in the past, it
always is associated with more storms. So if you read about
the cooling in the 1970s, what the response would be, it was
cooler and more stormy, so it seems that it is part of our
cultural heritage that whenever we think we change climate
to the worse, then we have more storms. Later on it turned
out that we actually have less storms now in northern
Europe. And if we believe our climate change models, and I
do believe them and I am sincerely convinced that we see
global warming happening. If we believe these models then
we should have an intensification of storms in our part of
the world with stronger wind speeds of the order of 10 percent
of the end of the century, that would be a signal which cannot
be detected. While if you go into the details, then you find
out that several aspects are rather similar to the ongoing
hurricane debate, namely that good data exists only for a
short time. Satellites are flying only since the 1970s or
so, and observing this, and you have decades with strong
activity and decades with less strong activity. It is the
same with the storms in our part of the world. And so I
would say in this case one should be very careful in making
definite conclusions about that. And if we believe our
models, and I am not sure if we should believe in this
respect our models, then we also should have a signal which
is much weaker now, hardly detectable at this time. So in
this case with the hurricanes, I would advise to wait a
little bit before definite conclusions are drawn. And this
would be an example that somehow this preconception that
storms are getting worse when climate is changing is somehow
controlling what we think.
MR. WHITFIELD. Mr. McIntyre, I know that you and
Mr. McKitrick were the ones that first started looking at
the Mann study or report. How did that come about? Was
this just an area of interest that you have had, or what?
MR. MCINTYRE. Well, that is actually a fairly long story
but I was just--at that time I was just a private citizen.
The study was being--we were told in Canada that 1998 was
the warmest year of the millennium. I have worked in the
mineral exploration business for many years. I deal with
geologists who were unimpressed by that statement and I
just wondered one day how they knew that. When I looked
at the IPCC report as somebody that is in the mineral
exploration business, which is a very promotional business,
I was struck at how promotional many of the statements
were and particular how promotional the hockey stick graph
was. I thought actually sort of in a professional way,
I thought it was well designed, well presented. It was
there to convey a message but I certainly felt like I was
being sold when I saw that. Some months later, business
was slow. I thought I would be interested in looking at
the data. I assumed there was some kind of due diligence
package like you would see in a business thing that they
had prepared for the IPCC auditors. At that time I had no
idea that such things didn't typically exist in the
academic community so I e-mailed Dr. Mann out of the blue
and asked him where the data was and just for the location
of the data of this which I assumed to be part of the due
diligence package and he said he had forgotten where the
data was. So I was astonished as there had been so much
publicity. He said he would have an associate locate it
for me. The associate said that it wasn't in any one
place, but he would get it together for me so I thought that
was nice of him but just, it seemed an odd situation and I
just thought well, nobody has ever looked at this and if
nobody has ever looked at it, well, I will do it, so I didn't
expect to be the center of an academic debate or any furor,
but when I looked at it, I started finding problems and here
we are today.
MR. WHITFIELD. And I would ask Dr. Crowley and Mr. McIntyre
or anybody else that wants to comment: the Wall Street
Journal that has been referred to many times today says that
Dr. Mann's methodology could produce hockey sticks from
random trendless data. Is that a correct statement or is
that incorrect statement?
MR. MCINTYRE. Well, let me answer that. That is true, and
that is the one specific item that was verified by both
panels, and both the NAS panel and the Wegman report
specifically confirm that his methodology would produce a
hockey stick from random data.
MR. WHITFIELD. Okay. Dr. Crowley, did you want to comment
on that?
DR. CROWLEY. I am not an expert in statistics so I just
have to defer from that answer. All I can say is that when
we took a completely different approach with the very simple
averaging, we got an answer that was pretty similar.
MR. WHITFIELD. Dr. von Storch?
DR. VON STORCH. I think I have a bit of reputation in
studies of climatology as I am the coauthor of I would say
the leading statistics book in that field. So first of all,
what Mr. McIntyre is saying is correct. You can get that.
But this requires that you have no other significant signals
in the field, in particular no correlation in space, and
this is not the case in climatological variables and so I
would say even if it is entirely true what he said and I
would include it in the next version of this book we have
written. I would say in very many practical situations it
would not show up.
MR. WHITFIELD. Thank you. My time has expired.
CHAIRMAN BARTON. Has Mr. Stupak not gone yet?
MR. STUPAK. No.
CHAIRMAN BARTON. Well, then let us get Mr. Stupak. He has
waited patiently all afternoon.
MR. STUPAK. Dr. Karl, if I may, Dr. von Storch says that
the reputation of the IPCC has increased to very high levels
in the past years, that most lead authors are honest brokers
of the work they review and that perhaps in such a complex
and large field as the IPCC is addressing, it may not be
possible to have lead authors who have not contributed to
the field. But then Dr. von Storch concludes that an
independent review by the IPCC is not possible under the
current system. How would you respond to that?
DR. KARL. Again, no human-conceived system is perfect. I
don't know how you might improve it in terms of the way it
operates today. The peer review process really is driven by
others' availability to comment and the IPCC documents are
open for everyone from every discipline to comment on
including the governments of the world. I think one of the
issues that has been discussed in the hearing today is one
that is typical of science where you can publish something
but sometimes it takes a period of years to try and come up
with a different analysis, technique, or to explore the
decisions that are made in a particular analysis technique.
The IPCC process right now is over a period of 2 years. I
don't see how you could actually open up a process more
and I don't see how you could actually have a process
whereby every piece of information is going to be evaluated
in terms of a new analysis, and that is the reason it is
done every 5 or 6 years to update, see if there are
differences. So, for example, I am sure all the work being
done since the 2001 IPCC assessment and the next one that is
coming out next year will be included and assessed.
MR. STUPAK. Well, the 2001 IPCC report really referenced
other studies other than the 1998 and 1999 Mann hockey stick
study, right?
DR. KARL. Yes. In fact, as I said, it would have been--I
hate to use the words "very unlikely" because those are
like the words that are used in the IPCC but I don't think
IPCC would have actually made a statement about the 1990s
had it only been based on one article. If it was just the
Mann work, I just don't think we would have had the
confidence to say anything.
MR. STUPAK. I am looking at your 2001 report here, and I
am on page--and in there it says new analysis of proxy
data for the Northern Hemisphere indicate that the increase
in temperature in the 20th Century is likely to have been
the largest of any century during the past 1,000 years. It
is also likely that in the Northern Hemisphere the 1990s
was the warmest decade and 1998 was the warmest year. That
was the conclusion of 2001 and that is based upon more than
just the Mann study. Isn't that correct?
DR. KARL. That is correct.
MR. STUPAK. Okay. You used the word "likely." I know
today especially when the Chairman asked questions it was
like absolute based upon the Mann study and that is not the
case, it based upon--your 2001 report takes some other
things other than the Mann hockey stick study, right?
DR. KARL. That is correct.
MR. STUPAK. What is the significance of the word "likely"?
Not working in your field, I may have a different view of
"likely" but you use it twice. Can you give any further
explanation of that?
DR. KARL. What we tried to do is clarify what we meant by
the word "likely" because it can be taken all different
ways because it is used frequently in the literature. We
define "likely" as a probability of the statement being
true between 66 and 90 percent of the time. That means
slightly better than two to one odds at the low end, and
at the high end close to nine to one odds.
MR. STUPAK. You have been here all day. Is there anything
you have heard today which would make you change your mind
about the conclusions of the 2001 IPCC report?
DR. KARL. No. If you ask me to give qualifications about
the findings in the 2001 report with the same caveat in
terms of defining likelihood, I personally would not
change anything.
MR. STUPAK. And going further in this, your 2001 report,
the IPCC report, they talk about the Jones et al., about
having the warmest year of the past millennium in the
Northern Hemisphere, Jones et al. in 1998 came to a
similar conclusion from largely independent data and
entirely independent methodology. Crowley and Lowery in
2000 reach a similar conclusion. Borehole data, Pollick,
et cetera, in 1998 independently support this conclusion
for the past 500 years. So there is plenty of other
things to base that conclusion upon and not just the
Mann--
DR. KARL. That is correct.
MR. STUPAK. And somewhere today someone said something
like there is over 900 reports or studies on global
warming. Is that correct?
DR. KARL. I am sure there is even more than that. I
think that was a random sample, so there is probably in
the tens of thousands.
MR. STUPAK. Okay. Thank you. Dr. Crowley, if I may,
when I was asking Dr. Wegman about this chart here,
which was showing the warm age there in around 1300 or
so, I think he called it the cartoon graph, was his word.
Is that based on any set of data or anything or--
DR. CROWLEY. That is pretty much a cartoon graph
ctually. This is really in the first round of IPCC.
Nobody ever felt there was a need to--had thought of
whether there should be a need to have a quantitative
estimate of climate for the last 1,000 years. They
wanted to try to provide a perspective and they didn't
realize they didn't have one and they basically talked
to some people and there was a lot of anecdotal
evidence for medieval warm period, that people said it
was warmer than the present roughly during these years,
you know, so it was really pretty much of a guesstimate,
and it was only when we started looking at a number of
sites that had a very good chronology so we knew where
they were in time and that we realized that the timing of
the warmth was not the same in different regions, that
that peak collapsed.
MR. STUPAK. So it is not fair to compare this cartoon
graph with Dr. Mann's hockey stick?
DR. CROWLEY. No, I don't think that was intention of
Dr. Wegman. I think he was just--
MR. STUPAK. No, I guess the Wall Street Journal used
it more as one of those. You said the Wegman report
should not be a legitimate assessment of the science of
global warming or as a guide to policy modification.
Can you elaborate a little bit on that?
DR. CROWLEY. Well, I felt that--again, I have to--I
can't remember exactly where--do you have it listed where
I said that so I can--
MR. STUPAK. Let me find it here.
DR. CROWLEY. Last page. So what I said is I disagree
with many in the fact sheet and also in the report itself.
It is not like I disagreed with what he was saying about
his analysis of the Mann et al. record there but some of
the recommendations that he was making I think that I
felt there was a need---I just disagreed with him and so
I was concerned that in terms of recommending any changes.
I am not saying that interaction with statisticians is bad.
I strongly favor very enhanced interaction but a lot of
that is already happening.
MR. STUPAK. Mr. McIntyre, you are not a
paleoclimatologist, right?
MR. MCINTYRE. No.
MR. STUPAK. And you are not a statistician?
MR. MCINTYRE. I studied mathematics and statistics at
university.
MR. STUPAK. So are you a statistician then?
MR. MCINTYRE. I have not practiced as a statistician, but
this is what I have been doing for the last few years. I
think that--
MR. STUPAK. You have been doing statistics the last
2 years then?
MR. MCINTYRE. I have been working at statistical analysis
of multi-proxy studies for the last 3 years.
MR. STUPAK. Three years. Okay.
MR. MCINTYRE. I note that my findings have been endorsed
by both the NAS panel and the Wegman report.
MR. STUPAK. In this--again, reading the Wall Street Journal
editorial. I am not sure how accurate this is but it say
you and Mr. McKitrick published an article in a peer review
journal. What discipline did the peer review?
MR. MCINTYRE. We have published articles in two journals,
Geophysical Research Letters, which is the same journal
that published the original Mann article, and Energy and
Environment.
MR. STUPAK. Let me ask Dr. Crowley if I can. Both you
and Dr. Karl and the National Research Council have stated
that the Mann study was not the most influential work in
the IPCC 2001 report. You testified that the papers that
made the biggest differences were ones that said the
influence of greenhouse gases had to be used to reconcile
the data and the models and the most compelling driver was
the fact that global temperatures kept going up and glacier
melt was increasing. Why then is there so much emphasis on
the Mann report?
DR. CROWLEY. Well, there has been this discussion before
about it being used as an icon, okay, and people say well,
if it is not right, then is IPCC wrong, so there has then
been that connection drawn. So I think for rightly or
wrongly, I am not sure if IPCC is the only one responsible
for broad--for using that as an icon but it has effectively
become one and I think that is really the--what the--I
guess the argument settles down to.
MR. STUPAK. Thank you. I guess my time is up. We have
got 3 minutes to go vote.
MR. WHITFIELD. I want to thank all of you on the panel,
one, for being here, two, for being so patient, and three,
for what you do and the contributions that all of you are
making. We may or may not have some more hearings on this.
I know we do have an invitation out to Dr. Mann and we
will see if he is going to come or not. But I want to
ask unanimous consent that the document binder be submitted
into the record of this hearing, unanimous consent that the
document in Newsweek that Chairman Barton referred to about
the cooling world be entered into the record and then I
would like to keep the record open for 30 days for any
follow-up questions we may have. So without objection, so
ordered and this hearing is concluded, and thank you all
again for being with us. We genuinely appreciate it.
[The information follows:]
[Whereupon, at 4:12 p.m., the subcommittee was adjourned.]
RESPONSE FOR THE RECORD OF DR. GERALD R. NORTH, DEPARTMENT OF
ATMOSPHERIC SCIENCES, TEXAS A&M UNIVERSITY
The Honorable Ed Whitfield
1. As you chaired the National Research Council panel that
recently issued the report on millennial temperature
reconstructions:
a. Where in the report did the panel describe "plausible" as
suggesting roughly a 2/3rds probability of being correct?
In the report we shunned the use of numerical probability
assessments in favor of descriptive statements (e.g., "high
confidence") and statements that describe our relative confidence
in different conclusions (e.g. "less confidence"). I may have
mistakenly mentioned the "two to one odds" figure in the oral
press release of the report, and it may also have appeared in
some press accounts, but it does not appear in the report, and
I avoided using it in my sworn testimony.
b. In the report, did the panel attach probability estimates to
the term "plausible"?
No. The committee avoided numerical probability estimates because
many of the uncertainties associated with reconstructing surface
temperatures are not purely statistical in nature, but rather
arise from physical factors associated with each proxy that
are simply unquantifiable at this time. In our view it is not
possible to quantify all of the inherent uncertainties
associated with reconstructing surface temperatures from proxy
data, which in turn precludes assigning numerical probabilities
to statements regarding the unique nature of recent warmth.
c. Why did the panel choose to use the term "plausible," as
opposed for example to terms such as "likely," to describe
confidence in millennial temperature reconstructions?
In the IPCC reports, the term "likely" is used to indicate an
estimated probability of between 66% and 90%, i.e. greater
than two-thirds odds but less than nine-in-ten chances. We
avoided numerical estimates such as these because we did not
want to imply that we had performed a rigorous probability
assessment. Instead, we tried to express our collective
confidence in different conclusions using descriptive
language.
2. When considering the panel's findings that it is "plausible"
that recent decades were the warmest in a millennium, is that
correct to interpret that to mean the panel's consensus view
was that plausible means roughly a 2/3rds probability of being
correct, as was suggested in news reports following the press
conference releasing the report?
Our working definition of "plausible" was that the assertion
is reasonable, or in other words there is not a convincing
argument to refute the assertion. We used this term to describe
our assessment of the statement that "the last few decades of
the 20th century were warmer than any comparable period over
the last millennium" because none of the available evidence to
date contradicts this assertion. In our view it is not
currently possible to perform a quantitative evaluation of
recent warmth relative to the past 1,000 years that includes
all of the inherent uncertainties associated with reconstructing
surface temperatures from proxy data. This precludes stronger
statements of confidence, but it does not mean that the
assertion is false. In fact, all of the large-scale surface
temperature reconstructions that we examined support the
assertion that global-mean temperatures during the last few
decades of the 20th century were unprecedented over at least
the past 1,000 years, and a larger fraction of geographically
diverse proxy records experienced exceptional warmth during
the late 20th century than during any other extended period
from 900 A.D. onward.
3. Did the panel perform its own, in-depth technical analysis
of the methods and procedures-- such as checking the underlying
data sets or attempting to replicate the findings - used in the
various temperature reconstruction articles and presentations
it considered in formulating its report?
Our committee relied on the published, refereed scientific
literature to reach its conclusions. We did not attempt to
replicate the work of any previous author, with the lone
exception of a simple computer program (reproduced in Appendix B
of our report) that was used to illustrate an interesting
artifact of the principal components methodology first noted by
McIntyre and McKitrick. When evaluating the results of different
studies, we placed higher confidence in those results that were
reproduced in several different studies--for instance a number
of independent lines of evidence indicate that the late 20th
century warmth was unprecedented in at least the last 400 years,
giving us high confidence in this conclusion. Less confidence
can be placed in conclusions regarding large-scale surface
temperatures prior to about 1600 A.D. because there are simply
fewer independent lines of evidence to consider, although the
evidence that does exist indicates that the late 20th century
warmth is unprecedented for at least the last 1,000 years.
4. The NRC panel made specific reference to ice borehole studies
in Greenland by Dahl-Jensen, which suggest warmer temperatures
in that region during the Medieval Warm Period than today. Please
explain the value of regional temperature measurements such as
this for understanding the potential effects of recent warming
trends?
There are two main reasons for using large-scale averages rather
than individual regional measurements to evaluate global
environmental changes: 1) Random measurement errors and climate
fluctuations tend to cancel out when spatial averages are
performed, allowing researchers to obtain a more reliable
estimate than is possible for a local or a regional average;
2) The greenhouse effect operates at the global scale, hence
large-scale averages are the best way to evaluate the response
of the climate to increasing greenhouse gas concentrations.
Current climate models also are better at computing large-scale
averages than regional-scale values.
Of course in order to detect large-scale climate anomalies,
either in the modern temperature record or in proxy-based
temperature reconstructions, it helps to have a large network of
high quality measurements for geographically-diverse regions.
The main reason that we have high confidence in the temperature
increase over the past 100 years and in the statement that
temperatures are warmer now than at any other time over the last
400 years is because we have a sufficiently large number of
well-characterized local measurements to calculate a reliable
large-scale average. Several proxies (including historical and
archeological evidence as well as quantitative temperature
estimates from ice cores and boreholes) indicate that the area
around Greenland was warmer between about 1000 and 1200 A.D.
than it is today. There is also evidence for warm temperatures
during medieval times from other regions of the world. However,
studies suggest that these warm anomalies appear to have occurred
at different times at different places rather than being globally
synchronous, and also appear to have been offset by cold
anomalies in other regions. The few large-scale surface
temperature reconstructions that extend back far enough to
rigorously compare large-scale medieval temperatures to modern
warmth suggest that the medieval period was, at most, comparable
in warmth to the first half of the 20th century. However, as
noted above in response to question (4), it is difficult to
quantify the full uncertainty associated with estimates of
surface temperature prior to about 1600 A.D.
The Honorable Bart Stupak
1. In the study performed by a special committee of the National
Academy of Sciences (NAS) on surface temperature reconstructions
over the past 2,000 years, it was stated that, for the time prior
to 1600 A.D., scientists are less certain about the actual
average northern hemispheric surface temperatures. The Medieval
Warm Period (MWP) occurred prior to 1600. How certain are
climatologists that there was a globally or even hemispherically
MWP that was warmer than the past several decades?
Indeed, the paucity of proxy data for periods prior to about
1600 A.D., especially in the tropics and the Southern Hemisphere,
limits our confidence in statements regarding the global mean
temperature of the past few decades compared to medieval times.
Several proxies indicate that the area around Greenland was
warmer between about 1000 and 1200 A.D. than it is today. There
is also evidence for warm temperatures during medieval times
from other regions of the world. However, studies suggest that
these warm anomalies appear to have occurred at different times
at different places rather than being hemispherically or globally
synchronous, and also appear to have been offset by cold anomalies
in other regions. Although it is difficult to quantify the full
uncertainty associated with estimates of surface temperature prior
to about 1600 A.D., all of the large-scale surface temperature
reconstructions that we examined support the assertion that
global-mean temperatures during the last few decades of the
20th century were unprecedented over at least the past 1,000
years, and a larger fraction of geographically diverse proxy
records experienced exceptional warmth during the late 20th
century than during any other extended period from 900 A.D.
onward. Hence we find it plausible (or in other words, no
evidence exists to refute the claim) that "the last few decades
of the 20th century were warmer than any comparable period over
the last millennium." This statement can be more strongly
applied to the Northern Hemisphere than to the globe because
there is very little proxy data from the Southern Hemisphere
before about 1600 A.D.
2. The 1990 Intergovernmental Panel on Climate Change (IPCC)
Report contains a "schematic diagram" that shows temperature
changes for 900 A.D. through 1975, but does not give specific
temperatures. The text of the report notes, "it is still not
clear whether all the fluctuations indicated were truly global."
Am I correct in my understanding that this schematic diagram is
not a graph of specific data points consisting of global
temperature for particular years or time periods? Am I also
correct that the scientific consensus at the time was that
there was significant uncertainty about whether the diagram
accurately portrayed the global temperature profile over the
last 1,000 years?
Yes, the schematic diagram that appeared in the 1990 IPCC
Report was simply a qualitative depiction of how scientists
thought that large-scale temperatures may have evolved from
900 A.D. to about 1975. There was very little proxy data
available at that time, and the data that did exist tended to
be concentrated in just a few geographical regions, such as
Greenland. The lack of a temperature scale and supporting
documentation strongly suggests that the diagram was not
based on a quantitative analysis, and also implies that
there was considerable uncertainty about the magnitude and
timing of the indicated fluctuations. As stated in our
report, there is still considerable uncertainty about the
exact timing and magnitude of past temperature fluctuations,
especially prior to about 1600 A.D., but our knowledge has
advanced considerably since 1990. Figure S-1 from our
report illustrates the current state of the science in
large-scale surface temperature reconstructions for the
last 1,000 years.
3. What level of certainty is there that the temperature ranges
for the period of 900 through 1975 A.D. schematically displayed
in the 1990 IPCC report are accurate? Prior to Dr. Mann's work,
had anyone attempted to attach a level of certainty to the data
relating to surface temperature reconstruction?
There were no uncertainty assessments attached to the 1990 IPCC
diagram. As discussed in response to question (2) above, this
diagram was simply a qualitative depiction of how scientists
thought that large-scale temperatures may have evolved from
900 A.D. to about 1975. The papers by Dr. Mann and his
colleagues in 1998 and 1999 were, to my knowledge, the first
attempts to assign statistical error bars to a large-scale
surface temperature reconstruction. As noted in our report,
these error bars provide an indication of how well the
reconstructed temperatures match observations during the
"calibration period," but they do not represent all of
uncertainties inherent in reconstructing surface temperature
from proxy data. The actual uncertainties in the
reconstruction would be somewhat larger, and difficult to
quantify.
4. Mr. McIntyre has testified that the NAS report stated that
the bristlecone pine proxy used by Dr. Mann in his original
work should not have been used. Was that the conclusion of the
panel? Please describe the conclusion and provide citations.
Let me quote directly from page 50 of the prepublication
version of our report:
The possibility that increasing tree ring widths in modern
times might be driven by increasing atmospheric carbon
dioxide (CO2) concentrations, rather than increasing
temperatures, was first proposed by LaMarche et al. (1984) for
bristlecone pines (Pinus longaeva) in the White Mountains of
California. In old age, these trees can assume a "stripbark"
form, characterized by a band of trunk that remains alive and
continues to grow after the rest of the stem has died. Such
trees are sensitive to higher atmospheric CO2 concentrations
(Graybill and Idso 1993), possibly because of greater water-use
efficiency (Knapp et al. 2001, Bunn et al. 2003) or different
carbon partitioning among tree parts (Tang et al. 1999). Support
for a direct CO2 influence on tree ring records extracted from
"full-bark" trees is less conclusive. Increasing mean ring width
was reported for Pinus cembra from the central Alps growing well
below treeline (Nicolussi et al. 1995). Free-Air CO2 Enrichment
(FACE) data for conifer plantations in the Duke Forest (Hamilton
et al. 2002) and at the alpine treeline (H�ttenschwiler et al.
2002) also showed increased tree growth after exposure to
atmospheric CO2 concentrations about 50 percent greater than
present. On the other hand, no convincing evidence for such
effect was found in conifer tree ring records from the Sierra
Nevada in California (Graumlich 1991) or the Rocky Mountains in
Colorado (Kienast and Luxmoore 1988). Further evidence comes
from a recent review of data for mature trees in four climatic
zones, which concluded that pine growth at treeline is limited
by factors other than carbon (K�rner 2003). While 'strip-bark'
samples should be avoided for temperature reconstructions,
attention should also be paid to the confounding effects of
nthropogenic nitrogen deposition (Vitousek et al. 1997), since
the nutrient conditions of the soil determine wood growth
response to increased atmospheric CO2 (Kostiainen et al. 2004).
However, in forest areas below treeline where modern nitrogen
input could be expected to influence dendroclimatic records,
such as Scotland (Hughes et al. 1984) and Maine (Conkey 1986),
the relationship between temperature and tree ring parameters
was stable over time.
In summary, it appears that there is a carbon dioxide
fertilization effect in some trees, but not in all the places
where the samples used in the Mann et al studies were taken.
Also note that this section of the report discusses the
calibration of tree-ring records since atmospheric carbon dioxide
levels started to increase around 150 years ago. Hence, in
context, what the clause "strip-bark samples should be avoided
for temperature reconstructions" was intended to convey is that
strip-bark samples from the mid-19th century to the present are
very difficult to calibrate against instrumental records of
temperature, and the easiest solution is therefore not to use
them. However, strip-bark data are considered suspect only after
the modern increase in atmospheric carbon dioxide concentrations.
This is why other studies that rely on strip-bark pine records
only use them to infer past temperatures prior to 1850 (e.g.,
Biondi et al. 1999). This reference, and all of those cited in
the above quote, can be found in the reference section of our
report.
5. The recent work by Wahl & Amman redid Dr. Mann's original
work, but recentered it as Mr. Mcintyre suggested. Wahl and
Amman's work, however, resulted in the same "hockey stick"
distribution. Please explain why this work was not fully
considered and evaluated in the NAS study.
We did consider the Wahl and Ammann paper that was accepted for
publication in the journal Climatic Change on February 28th of
this year, in which they found that decentering has only a
relatively minor influence on the shape of the final
reconstruction. This paper was one of many that influenced our
evaluation of the Mann et al. (1998, 1999) papers and the
robustness of surface temperature reconstructions in general.
The effects of decentering are described explicitly in Chapter
9 of our report, and our conclusions regarding how decentering
influences surface temperature reconstructions can be found in
the following excerpt from page 106 of the prepublication
version of the report:
As part of their statistical methods, Mann et al. used a type
of principal component analysis that tends to bias the shape of
the reconstructions. A description of this effect is given in
Chapter 9. In practice, this method, though not recommended,
does not appear to unduly influence reconstructions of
hemispheric mean temperature; reconstructions performed without
using principal component analysis are qualitatively similar
to the original curves presented by Mann et al. (Crowley and
Lowry 2000, Huybers 2005, D'Arrigo et al. 2006, Hegerl et al.
2006, Wahl and Ammann in press).
Drs. Wahl and Ammann (along with Dr. Ritson) also authored a
paper that appeared in Science magazine on April 28th of this
year alongside a response written by Drs. von Storch and
Zorita. These papers were under embargo during our
deliberations, and thus we were not able to consider them
during our deliberations, although we did note (on page 105)
that "the...debate in the scientific literature continues even
as this report goes to press (von Storch et al. 2006, Wahl et
al. 2006)." These papers address a separate statistical issue
than the one discussed above, in particular the issue of
detrending the data prior to performing principal components
analysis. My personal impression of these two papers is that
the quote cited above still applies, that is, none of the
statistical criticisms that have been raised by various authors
unduly influence the shape of the final reconstruction. This is
attested to by the fact that reconstructions performed without
using principal components yield similar results.
6. In the hearing, Dr. Wegman challenged "anybody" to tell him
the difference between 72 and 74 degrees Fahrenheit. Please
describe the climatic and other changes that can result from a
global increase in temperature of 2 degrees Fahrenheit.
As context, let me first point out that the difference in
global-mean temperature between today and the height of the
last Ice Age, when New York and Seattle were covered with over
a kilometer of ice, is estimated to be only about 10 degrees
Fahrenheit. Hence, a change in global-mean temperature of two
degrees would represent a considerable perturbation to the
global climate system. Small changes in local temperatures
can also be associated with large impacts. For example, for
every degree Fahrenheit increase in mean annual temperature
near Greenland, the rate of sea level rise is projected to
increase by 10%. Snowpacks on mountains in the western U.S.,
which millions of people depend on for drinking water and
other uses, is likewise extremely sensitive to small
temperature changes. Natural ecosystems are also vulnerable
to changes in temperature--in the Midwest, a one degree
change in annual mean temperature might translate into
several hundred miles in the ecological distribution of
certain plants and grasses, and a warming of just a few
degrees could have devastating impacts on New England's maple
syrup industry and California's vineyards. Many parts of
the climate system are already feeling the impacts of the
one degree rise in global-mean temperature observed during
the 20th century. As we noted on page 27 of the prepublication
version of our report: "glaciers are retreating, permafrost
is melting, snowcover is decreasing, Arctic sea ice is
thinning, rivers and lakes are melting earlier and freezing
later, bird migration and nesting dates are changing, flowers
are blooming earlier, and the ranges of many insect and plant
species are spreading to higher latitudes and higher elevations
(e.g., ACIA 2001, Parmesan and Yohe 2003, Root et al. 2003,
Bertaux et al. 2004, Bradshaw and Holzapfel 2006)."
7. Dr. Von Storch testified that the effect of the "decentering"
error in the Mann study, which was the basis of the McIntyre and
Wegman criticisms, was "very minor." The NAS study did not refer
to "decentering." How significant was the analysis of "decentering"
to the NAS conclusions?
I believe Dr. von Storch was referring to the same phenomenon that
I described in my response to your question #5. Our committee
did consider the effects of decentering, along with other
criticisms of the Mann et al methodology, and found that it
"does not appear to unduly influence reconstructions of
hemispheric mean temperature."
8. At the hearing you were asked if you disputed the conclusions
or the methodology of Dr. Wegman's report, and you stated that
you did not. Were you referring solely to Dr. Wegman's criticism
of the statistical approach of Dr. Mann, or were you also
referring to Dr. Wegman's social network analysis and conclusions?
Dr. Wegman's criticisms of the statistical methodology in the
papers by Mann et al were consistent with our findings. Our
committee did not consider any social network analyses and we
did not have access to Dr. Wegman's report during our
deliberations so we did not have an opportunity to discuss his
conclusions. Personally, I was not impressed by the social
network analysis in the Wegman report, nor did I agree with most
of the report's conclusions on this subject. As I stated in my
testimony, one might erroneously conclude, based on a social
network analysis analogous to the one performed on Dr. Mann, that
a very active and charismatic scientist is somehow guilty of
conspiring or being inside a closed community or 'mutual
admiration society'. I would expect that a social network
analysis of Enrico Fermi or any of the other scientists
involved with the development of modern physics would yield a
similar pattern of connections, yet there is no reason to
believe that theoretical physics has suffered from being a
tight-knit community. Moreover, as far as I can tell the only
data that went into Dr. Wegman's analysis was a list of
individuals that Dr. Mann has co-authored papers with. It is
difficult to see how this data has any bearing on the
peer-review process, the need to include statisticians on every
team that engages in climate research (which in my view is a
particularly unrealistic and unnecessary recommendation), or
any of the other findings and recommendations in Dr. Wegman's
report. I was also somewhat taken aback by the tone of the
Wegman Report, which seems overly accusatory towards Dr. Mann
and his colleagues, rather than being a neutral, impartial
assessment of the techniques used in his research. In my
opinion, while the techniques used in the original Mann et al
papers may have been slightly flawed, the work was the first
of its kind and deserves considerable credit for moving the
field of paleoclimate research forward. It is also important
to note that the main conclusions of the Mann et al studies
have been supported by subsequent research. Finally, while our
committee would agree with Dr. Wegman that access to research
data could and should be improved, as discussed on page 23 of
the prepublication version of our report, we also acknowledge
the complicated nature of such mandates, especially in areas
such as computer code where intellectual property rights need
to be considered.
The Honorable Marsha Blackburn
1. Dr. Mann used many temperature measurements from different
sources to produce his graph. In your opinion, how much
emphasis or reliance did he place on surface records and
satellite measurements?
To perform their surface temperature reconstruction, Dr. Mann
and his colleagues made use of proxy data derived primarily
from tree rings, ice cores, and documentary sources. Tree
rings and ice cores, like other natural proxies, do not record
temperature directly, but are correlated with local temperatures
through physical and physiological mechanisms. They also
made use of surface thermometer records from the last 150
years, which were used to calibrate the reconstruction (i.e.
translate the proxy data into a record of temperature) and to
validate their results (i.e. test whether the reconstructed
temperatures match a portion of the observations reserved for
this purpose). All paleoclimate reconstructions use a similar
methodology, with the exception of reconstructions based on
borehole temperature measurements and glacier length records,
which are translated directly into temperature time series
using models based on the laws of physics. Satellite measurements
are not used in any paleoclimate reconstructions because they
only go back about 30 years, which is much too short for this
application.
a. How much weight do you think should be given to these
measurements?
Dr. Mann and his colleagues used all of the quality-controlled
proxy data that they had at their disposal at the time. As we
indicated in our report, the available proxy data are plentiful
and geographically diverse for the last 400 years, but decrease
in number and become subject to increasing uncertainties going
back further into the past. Hence, we have high confidence in
the surface temperature reconstructions based on these data for
the last 400 years, but less confidence in reconstructions for
the period from 900 to 1600 A.D. This increasing uncertainty
moving back in time is reflected, in part, by the increasing
size of the error bars prior to 1600 A.D. in the original
'hockey stick' curve, although these error bars do not accoun
t for all of the uncertainties inherent in the reconstruction.
2. The surface record and the satellite measurements indicate
that if maybe natural warming and not human-induced warming.
Yet, in your testimony, you say that increasing concentrations
of greenhouse gases caused the warming. How do we reconcile
your statement with the historical record?
The temperature record alone cannot tell us the difference
between 'natural' and 'human-induced' temperature changes. One
has to try to explain the observed warming using the laws of
physics. During the last 100 years, the global-mean temperature
first increased strongly, then remained constant or decreased
slightly, then increased strongly again. Simple radiative
transfer calculations and sophistical climate models both show
that the total amount of warming observed over the 20th
century is consistent with the observed increases in greenhouse
gas concentrations in the atmosphere, which are undeniably the
result of human activities. Changes in solar output can also
influence the climate system. However, satellite measurements
show that the sun has not increased in luminosity over the
last 30 years, and estimates based on terrestrial measurements
show only a modest increase in solar output during the first
half of the 20th century. A third factor that may have had a
significant influence on global-mean climate during the 20th
century is atmospheric aerosols. These are the tiny particles
that, like greenhouse gases, are emitted from volcanoes and
other natural sources as well as from anthropogenic sources,
but have been increasing in concentration in the atmosphere over
the past century mainly due to the burning of fossil fuels and
other human activities. Aerosols influence climate in a variety
of ways, some of which are well known and others of which are
active areas of research, but in general they have a cooling
influence on climate. There is some evidence that suggests that
aerosols may be primarily responsible for the slight decrease in
global-mean temperature observed during the middle of the 20th
century, and they might also be offsetting some of the warming
due to greenhouse gases.
a. Also, the historical record indicates that in the past 100
years, the Earth's global temperature warmed and cooled
significantly while the concentrations of carbon dioxide
increased. Would this not also indicate that the level of carbon
dioxide in the atmosphere has had little effect on the warming
of the atmosphere?
No. The Earth's temperature over the past 100 years was
influenced by increases in carbon dioxide and other greenhouse
gases, which have a warming effect, by changes in aerosols, which
generally cool the climate, and by other climate forcings.
Thus, the observed temperature variations reflect the net effect
of these different forcings.
We have a very good understanding of the direct impact of carbon
dioxide and other greenhouse gases on global temperature.
Straightforward radiative transfer calculations tell us that
carbon dioxide has a significant influence on global climate.
Sophisticated climate models also show that the observed
temperature changes during the 20th century cannot be reproduced
unless greenhouse gases increases are included. There are also
other lines of evidence indicating that carbon dioxide and other
greenhouse gases have a strong influence on global climate. For
example, models cannot reproduce the global-mean cooling that
occurred during the last Ice Age without incorporating the reduced
levels of greenhouse gases that prevailed during that time.
3. You also state in your testimony that even if it was as warm
or warmer 1000 years ago than today that it would not effect
today's consensus on global warming. That seems to not be logical
because if the Earth goes through natural cycles of warming and
cooling, then would not the warming and cooling cycles over the
past 60 and 500 years be a similar indication of phenomenon?
It is true that the Earth has experienced natural cycles of
warming and cooling over its history, however natural climate
forcings (solar activity, changes in natural aerosols) observed
over the last century are not large enough to produce the
observed warming, especially for the last 30 years. There is a
large and compelling body of evidence indicating that human-
induced greenhouse gas increases are responsible for at least
part of the total warming over the 20th century, and most of
the warming over the last 30 years. Over the last 100 years
and especially the last 30 years, we have very good data for
both temperature and all of the major climate forcings
(greenhouse gases, solar activity, and aerosols). Analyses of
these data indicate that human-induced greenhouse gases appear
to be responsible for much of the warming over the last 30
years and at least part of the total warming over the last
century. Reconstructions of surface temperature over the past
1,000 years are one piece of the scientific evidence, but
these reconstructions are sufficiently uncertain, especially
prior to 1600 A.D., that they are not usually considered to be
among the primary evidence for human-induced global warming.
In addition, temperature data alone do not tell us anything
about cause and effect.
In contrast, we know that greenhouse gases did not vary much
during the 1,000 years prior to the industrial revolution,
but we have very little data about how solar output and
aerosols varied over this period. Moreover, what little
evidence we do have shows only small variations in climate
forcing due to natural causes. Hence, if we were to find
out that the global-mean temperature 1,000 years ago was
warmer than today, this would mean that the Earth's climate
is even more sensitive to small forcings than we thought,
which would mean that projections of future warming may be
overly conservative.
RESPONSE FOR THE RECORD OF DR. THOMAS J. CROWLEY, NICHOLAS
PROFESSOR OF EARTH SCIENCE SYSTEM, DUKE UNIVERSITY
Response by T. Crowley to Followup Questions on July 19
Testimony
The Honorable Marsha Blackburn:
1. Do you agree or disagree with the surface record and
satellite data which indicate that global temperatures did not
start to rise significantly until the 1998 El Nino?
I emphatically disagree with this statement. The surface
temperature record clearly shows very substantial warming
before 1998. Recent work furthermore indicates that the
satellite observations are close to being reconciled with these
surface observations - and that the prior differences between
the two was to a coding error in the analysis of the satellite
data, not a problem with the surface data. Congresswoman
Blackburn, anyone who tries to tell you that the warming did
not occur until 1998 is seriously misleading you.
2. Do you believe the available data shows a global Little
Ice Age and/or Medieval Warm Period?
It is not easy to give an unequivocal answer to this, because
southern hemisphere data are considerably more spotty than
northern hemisphere data. The available data suggest that
the southern hemisphere did indeed have a cold period about
the same time as the northern hemisphere. There are some
indications of warmth in the southern hemisphere prior to
that time, but it is not clear whether the timing of that
warmth was the same as in the northern hemisphere. Although
some northern hemisphere places during the Middle Ages were
locally warmer than they are today, in the best-dated records
the timing of Medieval warmth varied in different places.
This is why composite reconstructions almost always show that
the mean warmth for the Middle Ages is usually comparable to
the mid-20th century but not the late 20th century.
3. Do you agree or disagree with the statement that warming
from 1900 to 1940 was caused by increase of solar activity
or the warming of the Sun?
I disagree with the statement because it is too categorical.
There are some indications that changes in solar behavior may
have contributed to the mid-20th century warming. But when
this "solar connection"is tested by going farther back in time
the conclusions become much more equivocal. The most methodical
analysis (see Attachment #1 - Hegerl et al. 2003) provides at
best weak support for the long-term role of solar variability.
Furthermore, the magnitude of past solar variations is very
uncertain - even optimistic estimates indicate it is only a
fraction of present greenhouse gas forcing. The present
thinking is that the mid-20th century warming was due to a
combination of weakened volcanic cooling, greenhouse warming,
"natural variability", and perhaps a modest contribution from
solar output changes.
4. What is your opinion on the effect of the 1998 El Nino on
the recent rise in temperatures?
The 1998 El Nino certainly contributed to the (at that time)
record global temperatures but I don't think anyone seriously
thinks it has a long term effect on global temperature - the
heat just dissipates too quickly in the atmosphere to have
such an effect. I might add that it has taken less than a
decade for the continually rising temperatures to approach or
equal the 1998 temperatures. This increase is very
disconcerting in terms of how fast the planet is warming.
End of reply to the Honorable Marsha Blackburn
The Honorable Bart Stupak:
1. In the hearing, Dr. Wegman testified that your 2000 published
work, which used a simple averaging proxy methodology, obtained
the same "hockey stick" configuration as Dr. Mann's original
work did. Dr. Wegman blames this conclusion on "proxies
appropriately selected" apparently because of use of the
bristlecone pine proxy.
Please explain if and why your work also used the bristlecone
pine proxy and respond to Dr. Wegman's criticisms of its use.
I do not recall Dr. Wegman making this testimony but will a
ccept your claim. Actually the purpose of the Crowley-Lowery
2000 study (ms. submitted as hard copy during testimony) was
not to reproduce Mann et al. with a different methodology but
just to determine what would happen if we took a broad swath
of data and just summed them up. I was as surprised as anyone
that the result was as close to Mann et al. as it was - bristlecone
pine or no bristlecone pine (the one we used was different than
Mann et al's). The principal significance of our finding was that
the Mann et al. result appeared to be robust because it could be
reproduced with a different methodology - a standard approach in
science.
The bristlecone pine business is a red herring. If the bristlecone
pine record is removed from the composite of a dozen or so records,
it will show slightly greater warming in the Middle Ages. But one
record can only make so much a difference when it is averaged among
a dozen, especially since the general shape of the bristlecone pine
record is comparable to the other records.
A more important objection to the bristlecone pine argument is that
it should not be included. Why not? In statistics anyone can use
something as a predictor or something else. The question is how
could a predictor is it? Some have claimed that it should not be
included because it is more affected by some other process (for
example, precipitation). But a principal assumption of regression
based prediction approaches is that the variables used for making
predictions are linearly correlated with the variable they are
predicting (in this theoretical case, precipitation with temperature).
The degree of skill in the predictor can be tested by its correlation
with temperature. If it has a poor correlation, it has little skill.
This is an approach we have adopted in later papers, but the purpose
of the original study was to just take as simple as an approach as
possible.
2. There were numerous references in the hearing to a schematic
drawing of what scientists supposed surface temperatures might have
been from 1000 A.D. to 1975 in the 1990 report of the
Intergovernmental Panel for Climate Change (IPCC) . You stated in
your testimony that Dr. Mann's study represented the first attempt
to estimate the uncertainties for surface temperature reconstructions
prior to the instrumental period. Can you describe what level of
uncertainty would have been placed on the 1990 schematic drawing,
and what level of uncertainty Dr. Mann established for the period
prior to 1600 A.D.
This is a good question! But before answering it I have to explain
what happened during the formulation of the 1990 figure. At that
time we really did not have any hemispheric estimates of temperature.
What IPCC did in 1990 was informally poll various experts for a
"guesstimate" of what the temperatures were like (I vaguely recall
being asked by someone around that time, but I do not know if it was
related to the IPCC figure). Many scientists had heard of the
"Medieval Warm Period" and stories of warmth greater than the
present. Despite warnings from a prominent Chinese scientist, and
a prominent English scientist, that the timing of warmth in the
Middle Ages was not the same in all places, many people (including
some still now) assumed that the Medieval Warmth was globally
synchronous. Thus the 1990 figure - entirely schematic and left
standing until it could be replaced by an alternate quantitative
estimate, with meaningful uncertainty estimates (i.e., the Mann
et al. paper, and others that have followed).
Now for the uncertainty estimates. One would have to be very wary
to apply uncertainty estimates to a qualitative figure, but if one
were to do so, then maybe a "ball park" 0.5 �C (about 1.0 �F)
uncertainty might be applied. If so, then one would have to
conclude that is not possible to make a robust statement that the
Middle Ages were warmer than the present, because the original
estimate likely did not exceed 0.5�C above "present" (which at
the time of writing of the report was about seventeen years ago).
[Note that I cannot find my copy of the original figure, so I
would have to doublecheck the 0.5*C peak, but because the
uncertainty estimate is also uncertain, I still stand by my
conclusion about "inability to make a robust statement"
With respect to the uncertainty estimates prior to 1600 in the
Mann et al. paper, the most that can be stated is the estimates
are substantially larger than for the later period just because
there are much fewer records. The uncertainties for estimates
of annual temperature are about 0.5�C in Mann et al. (1999).
However, the degree of uncertainty would decrease as records
are smoothed. For example, forty year smoothing of the Mann
et al. record yields uncertainties of about 0.4�C. Smoothing
comparable to the very smoothed 1990 IPCC figure has not, to my
knowledge, been computed, but a reasonable guess would be that
it would be in the range of 0.2-0.3�C.
3. Please describe the peer review process for your most
recent publications.
The peer review process has been pretty similar for my entire
scientific career. The paper goes out to 2-3 reviewers, who
almost always provide anonymous peer reviews (i.e., they can
say anything they want about it!). If the reviewers like the
paper but have questions, the editor will request that a
revised manuscript be prepared that takes into account reviewer
concerns, and that a separate accounting be made to the editor
and reviewer about how specifically we addressed those concerned.
Depending on the seriousness of the concerns, the editors will
then either review the response themselves, or send it back to
the reviewers (if the concerns are minor he or she would
probably not sent it back to the reviewers). In some cases the
reviewer may still be dissatisfied, in which case the authors
would have to reiterate, but in many cases the reviewers will be
satisfied. In some cases an editor might decide that if a
reviewer is still dissatisfied, then the editor may choose to
reject the paper. Only after the editor is fully satisfied that
reviewers and reconciled will the editor accept the paper. In
some cases the editor may accept a paper even if there are
disagreements with reviewers, because a subject matter may be
controversial and an editor may feel that all sides of an issue
deserve a public airing. In that case an editor may still
accept a paper that has been opposed by a reviewer.
End of reply to the Honorable Bart Stupak
The Honorable Henry A. Waxman:
1. You were added to the witness list for this hearing on short
notice, and therefore had very little time to prepare your
testimony. In reviewing your previously submitted testimony, is
there anything you would like to clarify or supplement for the
record.
Thank you for the opportunity to respond to this. I am satisfied
with most of the document but there are a few typos and
grammatical mishaps I would like to correct. I am also chagrined
by the choice of words I sometimes used to describe some of
Dr. Wegman's report, and would like to change those. I will
therefore send you a slightly revised version of the original
document that makes such changes. If it is not possible to
replace the original with the revision, then my statement
herein is all I would like to add as a supplement.
End of Reply to the Honorable Henry A. Waxman
QUESTIONS SURROUNDING THE 'HOCKEY STICK' TEMPERATURE STUDIES:
IMPLICATIONS FOR CLIMATE CHANGE ASSESSMENTS
THURSDAY, JULY 27, 2006
HOUSE OF REPRESENTATIVES,
COMMITTEE ON ENERGY AND COMMERCE,
SUBCOMMITTEE ON OVERSIGHT AND INVESTIGATIONS,
Washington, DC.
The subcommittee met, pursuant to call, at 2:00 p.m.,
in Room 2322 of the Rayburn House Office Building,
Hon. Ed Whitfield (Chairman) presiding.
Members present: Representatives Stearns, Pickering, Bass,
Blackburn, Barton (ex officio), Stupak, Schakowsky, Inslee,
Baldwin, Waxman, and Whitfield.
Staff present: Mark Paoletta, Chief Counsel for Oversight
and Investigations; Peter Spencer, Professional Staff Member;
Tom Feddo, Counsel; Matt Johnson, Legislative Clerk;
John Halliwell, Policy Coordinator; Clayton Matheson,
Analyst; Mike Abraham, Legislative Clerk; Edith Holleman,
Minority Counsel; David Vogel, Minority Research Assistant;
Chris Knauer, Minority Investigator; and Lorie Schmidt,
Minority Counsel.
MR. WHITFIELD. This hearing will come to order, and I
want to certainly welcome everyone to today's hearing.
This is the second day of our hearing regarding questions
about what we popularly call the hockey stick temperature
studies and the implications for climate change assessments.
We have reconvened this hearing to accommodate a key person
in the matters before us, and that is Dr. Michael Mann of
Penn State University. Dr. Mann was unable to attend the
session on the subject last week, and we are looking
forward to his testimony.
As you know, he was one of the leaders in the methodology
of developing the methodology that developed the hockey
stick graph, and we hope we can continue to explore some
of the broader questions surrounding temperature
reconstruction findings, their use in the IPCC assessment,
and other issues that prompted our inquiry into this
matter last year. Now the hockey stick graphic and the
underlying studies were influential in a prominent set of
findings by the IPCC, and really the hockey stick graphic
has become an icon for all those concerned about global
warming.
In point of fact, from the very first set of findings on
the very first page of discussion in its 2001 summary for
policy makers the IPCC states that 20th Century temperature
increases were likely the largest in 1000 years, and it was
likely that in the Northern Hemisphere the 1990s was the
warmest decade and 1998 the warmest year, a phrase that is
almost verbatim what Dr. Mann and his colleagues wrote in
their 1999 paper. Next to these findings the IPCC summary
then displays Dr. Mann and his colleagues' hockey stick
shaped temperature graph which helped this work prominently
and moved it into the public eye.
Now let me just take a moment and make a few observations
about last week's hearing. First, through our discussion
of both the National Research Council report and the Wegman
report the original studies by Mann and his co-authors
appeared to be flawed, and cannot support the related
findings of the 2001 IPCC assessment. Dr. Wegman's
independent committee found and reported that Dr. Mann and
his co-authors incorrectly applied a statistical methodology
that would preferentially create hockey stick shapes.
Dr. Wegman also found that more recent methodologies used in
temperature reconstruction studies may also generate
problematic biases when determining temperature histories.
Now the National Research Council based on the Mann analysis
and newer supporting evidence finds that it is plausible that
the Northern Hemisphere was warmer during the last few
decades of the 20th Century than during any period comparable
in the preceding millennium. Even less confidence, and I am
quoting from their report, even less confidence can be placed
in the original conclusion by Mann that the 1990s are likely
the warmest decade, and 1998 the warmest year.
The NRC's panel review determined that Dr. Mann made in the
words of the NRC witnesses inappropriate choices and that
the panel had much the same misgivings about Dr. Mann's work,
That was documented at much greater length by Dr. Wegman.
Moreover, both the NRC and Wegman reports essentially
corroborated the main criticisms raised by the McIntyre-McKitrick
studies about Dr. Mann's initial hockey stick studies. Now
while much attention was given to Dr. Wegman's social network
analysis, I think it is only fair to observe the limits of what
he was trying to illustrate as he himself explained.
Dr. Wegman was not seeking to impugn the integrity of any of
the scientists who work in the area, but it is clear that peer
review somehow failed to pick up the flaws in the hockey stick
studies. Dr. Wegman simply raises the possibilities that given
the evident publishing relationship among the authors of many of
the relevant works combined with the failure to involve
statisticians that Dr. Manns' peers may have been too close to
the topic to scrutinize the studies as rigorously as they might
have.
Whatever the case, Dr. Manns' peers failed to catch the errors
that Wegman, the NRC and McIntyre identified. Now this failure
as Dr. von Storch suggested last week may be less an issue with
the community of paleoclimatologists than with the journal
editors themselves. Now finally I think it is important to
note that virtually everyone at the hearing last week, both
members and witnesses, took the view that criticisms of the
hockey stick studies or of the peer review and assessment
process should not be considered as a judgment about the
changes in global temperature, but rather the issues at
hand concern legitimate questions about the rigor of
scientific analysis, the results of which ultimately reach
policy makers and that is what we base our decision-making
decisions on.
So the hockey stick story provides a clear case study into
what may be the lack of proper scrutiny, and the questions
last week about the independence of peer review or the gate
keeping issues in my mind are legitimate. And I think that
everyone would agree that we must be very careful and make
sure that when we do these analyses and they receive the
publicity that they do that they be scientifically based and
as close to accurate as possible.
Now in addition to Dr. Mann, both Dr. Wegman and
Dr. McIntyre are returning to recap their testimony and to
answer any questions related to their work, and certainly
Dr. Mann may want to raise some issues regarding what you
all said. We have a few additional panelists as well. As
we were preparing this panel, some have been suggested by
the minority side, and I am not sure which ones, but I want
to welcome Dr. John Christy, the Director of the Earth
System Science Center, and an Alabama State climatologist at
the University of Alabama, Huntsville, and Dr. Gulledge of
the Pew Center for Climate Change. And then finally I would
like to recognize Dr. Ralph Cicerone, who is the President
of the National Academy of Sciences, and happened to be in
the same fraternity that I was, so, Dr. Cicerone, welcome.
And he has been instrumental in the National Academy's focus
on climate change research in recent years. Indeed, he
chaired the National Research Council's 2001 report for
President Bush that helped pave the way for the United States
to conduct its own climate change assessment. I want to
welcome all of you. Thank you for your time. We look
forward to your testimony. And I yield and recognize the
distinguished ranking member, Mr. Stupak.
[The prepared statement of Hon. Ed Whitfield follows:]
PREPARED STATEMENT OF THE HON. ED WHITFIELD, CHAIRMAN, SUBCOMMITTEE
ON OVERSIGHT AND INVESTIGATIONS
Good afternoon and welcome to a second day of our hearing regarding
questions about what we popularly call the "hockey stick" temperature
studies and the implications for climate change assessments.
We've reconvened this hearing to accommodate a key person in the
matters before us, Dr. Michael Mann, of Penn State University.
Dr. Mann was unable to attend the informative session on this subject
last week. Although Dr. Thomas Crowley - Dr. Mann's personally
recommended replacement - did testify, we are providing Dr. Mann the
opportunity to discuss his work and respond to some of the views
expressed about his work.
Welcome Dr. Mann, I'm looking forward to your testimony and
participation. I hope we can continue to explore some of the broader
questions surrounding temperature reconstruction findings, their use
in the IPCC assessment, and other issues that prompted our inquiry
into this matter last year.
The hockey stick graphic and the underlying studies were
influential in a prominent set of findings by the IPCC. In
point of fact, from the very first set of findings on the
very first page of discussion in its 2001 Summary for
Policymakers, the IPCC states that 20th Century temperature
increases were likely the largest in 1,000 years and it was
[quote] "likely that, in the Northern Hemisphere, the 1990s
was the warmest decade and 1998 the warmest year," a phrase
that is almost verbatim what Dr. Mann and his colleagues
wrote in their 1999 paper. Next to these findings, the IPCC
Summary then displays Dr. Mann and his colleagues' hockey
stick-shaped temperature graph, which helped this work
prominently into the public eye.
Let me take a moment and make few observations about last week's
hearing.
First, through our discussion of both the National Research Council
report and the Wegman report, we established that the original
studies by Mann and his coauthors were flawed, and could not support
the related findings of the 2001 IPCC assessment. Dr. Wegman's
independent committee found and reported that Dr. Mann and his
coauthors incorrectly applied a statistical methodology that would
preferentially create hockey stick shapes. Dr. Wegman also found
that more recent methodologies used in temperature reconstruction
studies may also generate problematic biases when determining
temperature histories.
The National Research Council, upon its review of the current state
of science on this subject, likewise found that the hockey stick
studies could not support the 2001 IPCC finding drawn from them.
The NRC panel's review determined that Dr. Mann made, in the words
of the NRC witnesses, "inappropriate" choices, and that the panel
had "much the same misgivings about [Dr. Mann's] work that was
documented at much greater length by Dr. Wegman."
Moreover, both the NRC and Wegman reports essentially corroborated
the main criticisms raised by the McIntyre-McKitrick studies about
Dr. Mann's initial hockey stick studies.
While much attention was given to Dr. Wegman's social network
analysis, I think it is only fair to observe the limits of what he
was trying to illustrate, as he himself tried to explain.
Dr. Wegman was not seeking to impugn the integrity of any of the
scientists who work in this area, but it is clear that peer review
somehow failed to pick up the flaws in the hockey stick studies.
Dr. Wegman simply raises the possibility that, given the evident
publishing relationship among the authors of many of the relevant
works, combined with the failure to involve statisticians,
Dr. Mann's peers may have been too close to the topic to
scrutinize the studies as rigorously as they might have. Whatever
the case, Dr. Mann's peers failed to catch the errors Wegman, the
NRC, and McIntyre identified.
This failure, as Dr. von Storch suggested last week, may be less
an issue with the community of paleoclimatologists, than with the
journal editors themselves. The Committee can remain cautious
about Dr. Wegman's social network analysis, as he is, and still
legitimately raise the broader question about the rigor of review
and breadth of reviewers in this field.
Finally, I think it is important to note that virtually everyone
at the hearing last week - both members and witnesses - took the
view that criticisms of the hockey stick studies or of the
peer-review and assessment process should not be construed as a
judgment about the changes in global temperatures.
Rather, the issues at hand concern legitimate questions about the
rigor of scientific analysis, the results of which ultimately reach
policy makers. The hockey stick story provides a clear case study
into the lack of proper scrutiny, and the questions last week about
the independence of peer-review, or the "gate keeping" issues, were
entirely legitimate. I hope that as we proceed today, we keep this
in mind. And I hope that we can all reach agreement on ways to
improve the process.
Let me note that we have, in addition to Dr. Mann, both Dr. Wegman
and Mr. McIntyre returning to recap their testimony and to answer
questions related to their work, if necessary. Both of them
graciously agreed to adjust their busy schedules, including family
and work obligations, to return today at our request so that
Dr. Mann could confront his critics. Thank you very much for
coming back.
We have a few additional panelists as well. As we were preparing
this panel, our minority counterparts requested an additional
witness. In the event, we accommodated their requests so that we
could have as informative and balanced a panel as possible.
So let me welcome Dr. John Christy, the Director of the Earth System
Science Center and Alabama State Climatologist at the University of
Alabama, Huntsville and Dr. Jay Gulledge, of the Pew Center for
Climate Change.
Finally, I'd like to recognize a most-distinguished witness,
Dr. Ralph Cicerone [sisserone], President of the National Academy
of Sciences. Dr. Cicerone has been instrumental in the National
Academies' focus on climate change research in recent years. Indeed,
he chaired the National Research Council's 2001 report for President
Bush that helped pave the way for the United States to conduct its
own climate change assessments.
Welcome Dr. Cicerone, and welcome all the witnesses, I look forward
to another informative panel.
I now yield to my distinguished Ranking Member, Mr. Stupak.
MR. STUPAK. Thank you, Mr. Chairman. Today we are holding
a very strange hearing. Originally scheduled to give
Dr. Michael Mann a chance to respond to critics who provided
testimony to this committee last week, this hearing has now
expanded to allow these critics to attack the very science
of global warming. Witnesses reappearing in the committee
today, once commissioned by the Majority to do a very limited
and biased review, had attempted to discredit Dr. Mann's
8-year old study on reconstruction of surface temperatures
over the last thousand years, and his conclusion that the
earth is warming at an unprecedented rate.
However, as Dr. North testified last week, a comprehensive
review of temperature reconstruction research by the National
Academy of Science at the request of the Science Committee
found that there were numerous other studies concluding that
the Earth is warming at an unprecedented rate. Now instead
of allowing Dr. Mann to respond to last week's allegations,
two of our witnesses, apparently unhappy with the outcome of
last week's hearing have decided to rewrite and expand their
testimony to raise new issues, new complaints, and new
questions.
This re-written testimony is no longer limited to Dr. Mann's
statistical methods and their own work, but also includes
areas of climatology totally outside their expertise. As a
result, it appears that these critics have lost interest in
simply attacking Dr. Mann's work. Now the purpose of today's
hearing is to cast doubt on all scientific evidence of global
warming. Mr. Chairman, if we are going to discuss the larger
issue of global warming, which many of us on this side would
be happy to do, we need to put more time and effort into
putting together a series of well thought out hearings with
adequate time for witnesses and staff to prepare.
If the Majority were truly interested only in temperature
reconstruction over the past thousand years we could have heard
from all of the scientists who have worked on this topic both
before and after Dr. Mann's original 1998 and 1999 publications.
Instead, the Majority asked Dr. Wegman, a statistician with no
expertise in paleoclimatology, to verify only Mr. McIntyre's
critique of Dr. Mann's initial work. Dr. Wegman was not even
asked if Dr. Mann's conclusions would change if the criticisms
were incorporated and the analysis were re-created, nor did he
volunteer to do that.
Other climatologists have recreated Dr. Mann's work and have
come to the same conclusions using both similar and different
data sets and methodologies. Dr. Wegman, who has not reviewed
this work and did not discuss any of the studies in his
testimony last week, will try to discredit all of these
studies with an unsupported hypothesis questioning the
independence of a large group of scientists work.
Another witness we will hear from today, Dr. Christy, has
supported the science behind global warming but will argue
that by acting to curb global warming we may deny the poor
in other countries the advantages that we have here in America.
This is also the argument of a new group, the Interfaith
Stewardship Alliance, but we have not heard from the alliance
when trying to provide low-income emergency assistance for
people in my district.
However, the threat of rising temperatures and the negative
results of them, including diminished agricultural production,
and quite possibly the flooding of vast heavily populated
coastal areas due to the melting of the polar ice caps, can
be far more of a threat to developing countries than efforts
to limit harmful industrial emissions. The National Climatic
Data Center has recently confirmed that the first half of
2006 was the warmest first half of any year in the United
States since 1895. This warming trend is continuing.
Today's headline in the Washington Post, I should say
Tuesday's headline in the Washington Post, "Deadly Heat
Continues in California." The morgue in Fresno, California
has many bodies of elderly people overcome by heat.
Unprecedented temperatures have been recorded recently in
Oregon and South Dakota, among other places. Forty-five
percent of the United States is in moderate to extreme
drought conditions. These conditions have spawned more than
50,000 wildfires burning approximately 4 million acres.
Congress is not particularly capable to judge science that
deals with linear regressions, Pearson's R square, centering
and de-centering, or regulized expectation maximization. As
Dr. Cicerone will remind us, that is why Congress created the
National Academy of Science. We are, however, able to
understand the strategy of Exxon Mobil, outlined in their
1998 action plan. This plan argued, and I quote, "victory
will be achieved when average citizens understand, recognize
uncertainties in climate science." This appears to be the
focus of today's hearing, to confuse and complicate the
findings of climate scientists, and Dr. Mann is unfortunately
in the crosshairs. I yield back the balance of my time.
[Additional information submitted for the record follows:]
MR. WHITFIELD. The chair recognizes the chairman of the Energy
and Commerce Committee, Mr. Barton of Texas.
CHAIRMAN BARTON. Thank you, Mr. Chairman, and thank you for
this hearing. I want to thank our witnesses for being here,
some of them for the second time. We are obviously glad to
have Dr. Mann here. We appreciate you being able to join
us. It is clear from last week's hearing on global climate
temperature studies that we face issues involving more than
the particulars of Dr. Mann's specific hockey stick study.
However, it is the particulars of these studies and how
the existing climate assessment process has dealt with
them that got us here today.
I appreciate the participation of this panel. I am glad
that Dr. Ralph Cicerone is here. He is the President of
the National Academy of Sciences. I think he is going to
add significant weight and gravitus to the hearing today.
As you noted in your statement, Chairman Whitfield, last
week's hearing demonstrated why we as policymakers need to
understand the quality and the reliability of the science
on which we are urged to base public policy that is both
sweeping and costly. Some very respected and authoritative
sources testified last week that Dr. Mann's studies were
flawed. They couldn't support the findings for which they
were used in the United Nations Climate Change Assessment,
the IPCC. Today I hope that we are going to examine some of
these issues in more detail.
I recognize that additional work has been published that
supports the broad outline of some of those conclusions in
Dr. Mann's initial hockey stick study, but according to the
National Research Council even that subsequent work cannot
provide the level of confidence that IPCC placed upon the
original hockey stick analysis. Nothing about the process
of turning observations into accepted theory is smooth. It
has been said that the politics of small towns and big
universities are brutal. They make us look amateurs by
comparison. Looking at what is happening in this issue, I
think that might well be true. Unfortunately, that is the
way this science progresses.
I not only accept it, bumps included, but, believe it or not,
I support it. What I can't accept is the improbable notion
that this committee may not ask science or research-related
questions that bear on policy making when the answers could
improve the information we use to reach the policy decisions
that we are elected to make. It is just wrong to say that
questions are not permitted, free debate is improper or
that anyone who wonders if the scientific establishment
really has it right should be dismissed as anti-science or
oblivious to the real risk of man-made climate change.
This committee holds a very key role in any policy-making
decision related to climate change. As its Chairman, I
have an obligation to be cognizant of that and to do
everything possible to get a fair record but also get into
the details of some of the theories that the policies, the
recommended policies, are supposedly based upon. We are
interested in Dr. Mann's work, not because of Dr. Mann, as
nice a fellow as he may or may not be; we are interested
in Dr. Mann's work because it was the original. It was
seminal. It is referred to.
I haven't seen Vice President Gore's movie, but I am told
in that movie Dr. Mann's hockey stick diagram is shown
repeatedly. It is only fair to take a look at the original
seminal work to see if it really lives up to what it claims
to be. During our last hearing, we were shrugged at for
asking about that particular study saying it was too early,
too distant, but the fact is that that particular study is
the study that much of the latter conclusions have been
based upon. It is only common sense to take a look at
it. We are going to work on the issue, and if it turns
out that that study is not the right study and if there
are more current studies that are more correct, we will
take a look at those too and we will find out what the
truth is. The truth is the truth. The truth may be
inconvenient. It may be politically incorrect, but the
truth is the truth.
A couple of months ago Chairman Whitfield and I asked
the U.S. Government Accountability Office to help us
examine Federal data sharing policies especially as they
related to climate change research. This work will help
our efforts to improve the exchange of scientific data
and other essential information, which as we have seen
has been a particular problem in the climate change
arena. When the dust settles on these hearings, I am
going to prepare a request to the National Research
Council, which Dr. Cicerone who is with us today
chairs, to take some of the issues that Dr. Wegman and
others have raised and take a look at it.
I am going to ask for a study to assess how to include
a wider spectrum of scientific disciplines in climate
change research so that we can be enlightened by the
very best work across the field of scientific
research. I am going to ask that this study be
coordinated and run though the NRC's Division on
Engineering and Physical Sciences so that we can
ensure that the disciplines like mathematics and
physics and statistics participate up front. I would
be happy to hear any of Dr. Cicerone's comments on
that today as we go forward.
Letting a wider scientific community address questions
about climate change assessments can only help the
process and improve the results. We have an obligation
on this committee on behalf of the American people to
ensure that the decision makers have the best
information possible, not just the politically correct
information. I want to thank again our panel for
coming. I want to especially thank Dr. Mann for
changing his schedule to be here. I look forward to a
very productive exchange of views as we go forward
today. Thank you, Mr. Chairman.
[The prepared statement of Hon. Joe Barton follows:]
PREPARED STATEMENT OF THE HON. JOE BARTON, CHAIRMAN, COMMITTEE
ON ENERGY AND COMMERCE
Thank you, Chairman Whitfield. It is clear from last week's
hearing on global climate temperature studies that we face
issues involving much more than the particulars of Dr. Mann's
"hockey stick" studies. However, it is the particulars of
these studies - and how the existing climate assessment process
dealt with them - that got us here today. And so I appreciate
that Dr. Mann accepted our invitation to lay out his important
work on global temperature reconstruction, as well as to answer
our broader questions concerning climate change assessments.
I also appreciate the participation and perspective of our
distinguished panelists today, including Dr. Ralph Cicerone,
the President of the National Academy of Sciences. Let me also
welcome back Dr. Wegman and Mr. McIntyre, who testified last
week.
As you noted, Chairman Whitfield, last week's hearing
demonstrated why we as policymakers need to understand
the quality and reliability of the science on which
we are urged to base policy that is both sweeping
and costly. Some very respected and authoritative
sources testified last week that Dr. Mann's studies
were flawed, and that they couldn't support the
findings for which they were used by the United
Nation's climate change assessment, the IPCC.
Today I hope we can examine some of these issues a
bit more.
I do recognize that additional work has been published that
supports in broad outline some of the conclusions of
Dr. Mann's initial "hockey stick" studies. But according to
the National Research Council, even that subsequent work
cannot provide the level of confidence that IPCC placed upon
the hockey stick studies.
Nothing about the process of turning observations into
accepted theories is smooth. It has been said that the
politics of small towns and big universities are brutal
enough to make our kind look amateurish by comparison, and I
think that might be true. In any case, that's the way
science progresses. I not only accept it -- bumps
included -- but I support it.
What I can't accept is the improbable notion that this
committee may not ask science- or research-related questions
that bear on policymaking when the answers could improve the
information we use to reach those policy decisions. It is
just wrong to say that questions are not permitted, or that
free debate is improper, or that anyone who wonders if the
scientific establishment really has it right should be
dismissed as anti-science or oblivious to the real risks of
manmade climate change. Because this Committee holds a key
role in any policymaking relating to climate change, as its
Chairman I will do everything I can to ensure that the very
best information on these issues is available to us.
We're interested in Dr. Mann's work because it is seminal.
During our last hearing, some shrugged at it as distant and
early, but the fact is that Dr. Mann's conclusions influence
both current research and global policy. As we try to close
the loop on our concerns, I also want to emphasize that this
Committee will continue to work on the issues raised here,
to help ensure the reliability of future scientific assessments.
A couple of months ago, Chairman Whitfield and I asked the
U.S. Government Accountability Office to help us examine
federal data sharing policies, especially as they related to
climate change research. This work will help our efforts to
improve the exchange of scientific data and other essential
information - which as we have seen has been a particular
problem in this climate change arena.
Also, when the dust settles on these hearings, I'm going to
prepare a request to the National Research Council, which
Dr. Cicerone chairs, to take on some of the issues that
Dr. Wegman and others have raised for us. I will ask for a
study that assesses how to include a wider spectrum of
scientific disciplines in climate change research so that we
can be enlightened by the very best work that our scientists
conduct, all of them. I'll ask that this study be coordinated
and run though the NRC's Division on Engineering and Physical
Sciences, so that we can ensure that disciplines like
mathematics, physics, and statistics participate up front.
I'll welcome Dr. Cicerone's perspective on this today, so that
we can formulate an effective request.
Letting a wider scientific community address questions about
climate change assessments can only help the process and
improve the results. We have an obligation on this Committee
to ensure that America's decision-makers have the best
information possible.
Thank you all for coming to testify today. I yield back the
remainder of my time.
MR. WHITFIELD. Mr. Waxman of California is recognized.
MR. WAXMAN. Thank you very much, Mr. Chairman. The
magnitude of global warming and the crisis that we are
facing on this planet demands a serious response from
this body. We should be holding hearings to understand
the ramifications of recent studies detailing the
harmful effects of global warming that we are seeing
all around us from increased wildfires in the west to
more intense hurricanes, more acidic oceans. We should
examine practical steps this Congress and the
Administration must take to reduce global warming
pollution. We should explore how best to re-engage
with the international community on addressing this
problem because this is going to require all countries
to do their part.
We should investigate the well-funded effort by certain
oil companies to manufacture controversy and cast doubt
on the reality of global warming and the human
contribution to it. This hearing today is the third
that this committee has held on the issue of global
warming. We are the committee that would move
legislation forward on this subject, and this is really
a continuation of the second one, which was last week.
In that hearing, the Republican majority attempted to
discredit a respected climate scientist and a study
he published 8 years ago. Well, not only is this use of
the subcommittee ridiculous and unfair, it is also a
waste. Yet, despite its intended focus, today's hearing
does give us the opportunity to learn more about the
current state of climate science, and I am looking
forward to hearing the views of Dr. Ralph Cicerone, who
is the President of the National Academy of Sciences,
and the Chairman of the National Research Council and a
fraternity brother of the Chairman of this subcommittee,
and he is an eminent climate scientist.
I am also very pleased we are going to hear from
Dr. Mann, who is one of the world's most distinguished
paleoclimatologists. Eight years ago, Dr. Mann and his
colleagues published a groundbreaking study that
reconstructed the temperature of the Earth over the past
600 years using proxy data such as tree rings. Since
2002, Dr. Mann has published another half dozen papers
revising and building on his work. These latter studies,
as well as many independent paleoclimate reconstructions
by other scientists continue to find the same thing. The
warmer temperatures in the last few decades are
unprecedented compared to anything we have experienced in
the last thousand years.
Now the Majority, the Republicans, won't use this hearing
to examine Dr. Mann's recent studies or the independent
confirmation of its work. Instead, they want to focus
exclusively on his original work in 1998 and 1999 because
they think they can find a statistical flaw. So what?
The strategy is not a subtle one. Because they think they
found a flaw in one study out of thousands the Majority
wants to build the one study into the pillar of the
scientific case for global warming. The Chairman seems
to think that if he can discredit one climate scientist,
Dr. Mann, he can cast doubt on all the climate change
research. In effect, it is back to the tactics of the
tobacco industry.
I remember well when they would send their scientists to
come in and just cast a little doubt about whether
smoking cigarettes really do cause cancer, whether there
is really a medical problem. I think intimidation is
part of the strategy we are seeing. This subcommittee
launched this campaign against Dr. Mann and several of
his colleagues last year by demanding to know the source
of funding for every study they had ever conducted and
demanding that they turn over all the data for all their
research. These are bullying tactics and they drew highly
unusual protests from the American Association for the
Advancement of Science, the National Academy of Sciences,
and the Republican Chairman of the House Science Committee,
among others.
Well, we are having Dr. Mann here today. It is important
that he be here. Last week we held a hearing where he was
criticized. Now he has got his accusers back again. They
couldn't wait to have the hearing where all of them were
together. But this subcommittee will hear about Dr. Mann's
work from him and those who criticize him. The subcommittee
will hear the many other completely independent lines of
evidence that support the reality of global warming and the
role of humans in causing it.
The scientific evidence of human contribution to global
warming is clear and compelling. The only open question is
how long members of this subcommittee will keep pretending
that it doesn't exist. I don't know how many hearings we
are going to have on the subject of Dr. Mann's one study in
1998, but it seems to me that as we look around this country
and in in fact all around the world just today we are seeing
a continuation of some of the highest temperatures on
record. We ought to get serious about this matter of
global warming and climate change. We ought to be holding
hearings about the important issues that relate to it and
not this one issue over and over again. I yield back the
balance of my time.
MR. WHITFIELD. I would point out that even though
Dr. Mann was not here last week, he did suggest that
Dr. Crowley come on his behalf, and Dr. Crowley did
testify. I recognize the gentleman from Mississippi for
an opening statement.
MR. PICKERING. Mr. Chairman, I thank you for this hearing,
and I yield back my time. I want to get to the panel as
quickly as possible.
MR. WHITFIELD. Mrs. Blackburn, you are recognized.
MRS. BLACKBURN. Thank you, Mr. Chairman. I do want to
thank you for the hearing, and I want to welcome all of our
witnesses. I want to thank you for being patient with us
and allowing us some more time to visit with you. At last
week's hearing we did hear testimony regarding errors in
Dr. Mann's 1998 and 1999 hockey stick report, and today we
are going to be able to hear Dr. Mann's response to that.
We are pleased to have him join us and are looking forward
to that response.
I do still have some questions, and I find some of the
circumstances involving Dr. Mann's paper a little bit
disconcerting. It seems that it could only be corroborated
by a social network and that seems to be a problem. It is
difficult for me to see how scientists and policy makers
could agree with and legislate anything based on research
which by all appearances cannot be corroborated by
independent review. Second, it is apparent that until now
no independent experts have examined Dr. Mann's data and
statistical procedures.
Again, it is difficult to rely on data that has not been
rigorously examined for consistency and validity. I am
looking forward to some answers on that, and I would not
say that it is intimidation that has brought questions
forward. I would say it really is curiosity and a desire
to know answers. Finally, I have noticed a trend, and this
trend raises questions, and it is that trend by where a close
group of scientists who support climate change theory tend to
be serving as the primary peer reviewers and the lack of that
independent review, and those reviewers are checking one
another's work. And it may be strictly coincidence but again
it does not lead me to believe these papers are being as
thoroughly examined as they might by those that are
independent, and the public is not being as well served as
they should of what they are told is scientific proof.
It is critical that even if we should discount the 1990 IPCC
report, recent analysis of over 250 climate studies and
historical records showed that the medieval warm period was
global and higher than present day temperature, and they both
concurred that the little Ice Age occurred worldwide and
produced a substantial drop in the average temperature. Also,
satellite data and the U.S. surface record indicate that the
Earth's temperature in the past 100 years has undergone both
warming and cooling trends.
Last week I mentioned in 1960 when I was in high school there
was a commonly held premise that we were returning to the Ice
Age and by the time I reached my current age and a new
millennium dawned we would be in a perpetual winter with food
shortages, et cetera. So we had that, that we were dealing
with in a cooling trend and that we were being taught as
high schoolers in the '60s, but recent trends seemed to be
caused by solar activity in the 1990 El Nino, not necessarily
by the increase of green house gas emissions.
Mr. Chairman, policy makers depend on the integrity of data.
The public depends on the integrity of data. Educational
institutions depend on the integrity of data and results,
and I believe it is necessary and proper for us to set
quality standards for data release and verification for any
research that receives Federal funds. Thank you, and I yield
back.
MR. WHITFIELD. Thank you. I recognize Ms. Baldwin of
Wisconsin for her opening statement.
MS. BALDWIN. Thank you, Mr. Chairman. Again, we are here
discussing global warming, and again I think our focus is off
target. Rather than addressing action steps to address global
warming in a bipartisan coordinated and effective manner, we
are covering up the real issues with irrelevant chatter about
the basis of a study that was released almost a decade ago, a
study that has been updated, revised, reviewed, and validated
time and time again in recent years. Unfortunately, the goal
of these hearings is not to show that there is an abundance
of science demonstrating that the Earth is warming at an
unprecedented rate, that carbon dioxide levels are rising,
and that human activities are largely the cause. Rather it
is an attempt to poke holes in an old study and divert
attention away from the decisions that we as policy makers
often have to make.
Decisions like should we let big business profits override
human interests or should our policy time horizon be a few
short years or should we be thinking about protecting
generations yet to come. For if this hearing and even
Dr. Wegman's analysis were not commissioned for political
reasons but rather out of a concern that study after study
shows the Earth is warming, sea levels rising and snow caps
melting, then we would be focusing on current information.
The committee would have asked Dr. Wegman to review
Dr. Mann's and other reputable scientists' work that has
been published in recent years. But this is not what the
committee requested nor what Dr. Wegman studied.
Instead, the focus is on Dr. Mann's 1998 and 1999 study that
contains acknowledged flaws. The argument made over the
last week against Dr. Mann's early work are old and tired
and really I believe their desperate attempts to divert
attention away from what countless experts agree, that
climate change is happening, the global warming is
happening, and that our actions, things we as humans do
each and every day, contribute to this crisis. It is
troubling that the United States appears to be alone on this
island of skeptics. More troubling is that we are virtually
alone and are inaction.
Despite being the largest consumer of electricity, oil, and
natural gas, we refuse to take bold steps that will allow us
to lead the world on environmental issues, yet countries with
significantly smaller footprints on the world are making
incredible advances that improve the quality of the air they
breathe, the food and water they consume, and the lifestyles
they lead. Let me just give a couple of examples. China's
fuel economy standards are more stringent than those in
Australia, Canada, California, and the United States.
Meanwhile, we haven't increased our fuel economy standards in
over 20 years.
Brazil's ethanol program, the largest in the world, has
created rural jobs, reduced air pollution, and reduced
Brazil's green house gas emissions while reducing its
dependence on imported oil, yet we refuse to take necessary
steps to reduce our dependence on foreign energy. Denmark
has the highest utilization rate of wind energy in the world
with wind producing approximately 20 percent of Danish
electrical consumption. Meanwhile, our government has issued
notices of presumed hazard to wind developers in the Midwest
halting and threatening to permanently derail wind production.
And just yesterday Northern Ireland announced that all new
homes built starting in 2008 must have solar roof panels. In
this country, I look forward to the day when we take this bold
step. Mr. Chairman, we could spend the next few hours
discussing the fine points of Dr. Mann's 1998 and 1999 study,
and Dr. Wegman's analysis of it, or we could focus on what is
really going on. The Earth's temperature is rising and has
reached levels higher than ever recorded. It is true
regardless of whether you center, de-center, or average the
data each and every way you read it the conclusion is the
same.
False logic will not bring us closer to an understanding of
the scientific truth, so let's stop politicizing science.
Rather, let's show our commitment to our environment which
we have a moral and ethical obligation to protect. I hope
that today we will take steps in that right direction but I
fear we will not. I yield back, Mr. Chairman.
MR. WHITFIELD. Thank you, Ms. Baldwin. I recognize
Mr. Stearns of Florida.
MR. STEARNS. Thank you, Mr. Chairman, and I thank you for
having this hearing. Listening to the folks on the other
side, I would say to my colleague from California asking why
aren't we spending our time developing legislation, I would
say it is probably incumbent upon us as Chairman Barton
pointed out to find out if the facts are correct. We have
from the last hearing some inquiry that shows there
potentially exists some dubious research particularly embodied
on the hockey stick effect that shows a huge global warning
in our period.
Now if you look at the data and you go to the recent release
from the National Research Council, Thursday, June 22, 2006,
it shows that from the period 1400 A.D. to 1900 A.D. were in
a little Ice Age, but when you go back further back to 1000
A.D. to 1400 A.D. we were in a warm period, so is it possible
that what we are seeing here is sinusoidal and that perhaps
we should inquire if this hockey stick graph is the basis for
this alarm that we should start developing legislation
immediately. Obviously, it is the centerpiece of movies.
It is the centerpiece of documents that have been popular,
but what it shows is that the temperatures were stable in
other parts of our period and were much higher in the
medieval and obviously there was not the human population,
there was not the gasoline that supposedly is driving this
warming period now.
So I think we owe it to our constituents. We owe it to
all the Americans to find out if the policy decision for
this hockey stick is accurate so I think what we are doing
today, Mr. Chairman, is just simply trying to develop an
accurate understanding of what is out there. Now we had the
hearing last week and we heard from Dr. Wegman. This report
provided an independent critique of the statistical method
of Dr. Mann, which shows that his information basically
produced the hockey stick. Dr. Mann asserted that the
increase in the temperatures in the Northern Hemisphere in
the 20th Century is likely to have been the largest of any
century during the past 1,000 years.
The report also found that 1990 was the warmest decade and
1998 the warmest year of the millennium. Dr. Mann's claims
are repeated so often they are now considered facts, but as
often the case with statistics, a deeper look at some of
these claims show that perhaps there is more than meets the
eye. Dr. Wegman's final report found that Dr. Mann misused
certain statistical methods in his studies which
inappropriately selected hockey stick shapes in the
temperature history. Dr. Wegman concludes that Dr. Mann's
work cannot support the claim that the 1990s were the warmest
decade of the millennium.
Specifically, Dr. Wegman found that the temperature proxies
used by Dr. Mann are incorrectly centered on the mean of the
period 1902 to 1995 rather than on the whole time period.
Because the hockey stick proxies are centered too low, they
will exhibit a larger affected variance allowing the graph
to exhibit a much more dramatic jump in average temperature.
The net effect of de-centering in Dr. Mann's study is to
produce this hockey stick shape. Centering on the overall
mean is a critical factor in using the principal component
of methodology properly according to Dr. Wegman.
So that is sort of in a nutshell what we have here so by
golly, I think it is worthwhile to have a second hearing on
this, Mr. Chairman, and to try to understand what is
happening here, and at the same time not be overly critical
of anybody because in the end all we want is the truth, and
to understand if we are in an emergency situation or
basically we are in a period where there are highs and lows
in this earth temperature. And, in fact, in the report that
has come out with the working group of the Intergovernmental
Panel on Climate Change, which was used in many reports, it
shows the last 140 years the temperature of the Earth has
gone up 1.5 degrees Fahrenheit, so that is 140 years. Now
that could be coming off a cold cycle which means 1.5
degrees Fahrenheit is even more negligible.
So the question of global warming is something we should
look at, and I think before we pass legislation or as
Ms. Baldwin talked about this chattering irrelevance, we
should find out what is relevant to the studies and if they
make sense before we pass legislation. I yield back,
Mr. Chairman.
MR. WHITFIELD. Thank you. The chair recognizes
s. Schakowsky of Illinois.
MS. SCHAKOWSKY. Thank you, Mr. Chairman. I find this
hearing really depressing among other things. There is a
sense that somehow there is a pretense that what we are
engaged in here is some sort of scientific-like inquiry
but the fact of the matter is that the scientific
community has reached consensus. You can say anything
you want at this hearing but that is simply the truth.
I want to read something from Al Gore's book but lest you
think it is Al Gore's words it is a statement of 48 Nobel
Prize winning scientists. It says, "By ignoring scientific
consensus on critical issues such as global climate change
President Bush and his Administration are threatening the
Earth's future."
I am not so upset about a waste of time. We do plenty of
that around here. But I am depressed about it because that
is what is at stake here, the time that we are spending
here. I also just want to say since we are getting into
this petty he said, you said, back and forth, the charts that
Al Gore said--he talked about this teacher of his,
Dr. Roger Ravelle. It was his chart that he first
presented. When he showed a chart that looks very similar
to our hockey stick it was Dr. Lonnie Thompson's study that
he was talking about. These have been repeated over and
over again. How many times, 928 peer reviewed articles
dealing with climate change published in scientific journals
during the previous 10 years, percentage in doubt as to the
cause of global warming, 0 percent.
The answer is in. And so it seems to me unless somewhere
there, and Dr. Wegman already has told us over and over
again, he is nearly a paleoclimatologist, he is not a
climate scientist of any sort, unless someone can tell us
that the planet is not warming and that it is not that the
warming, I am sure no one would do that, that the warming
is not at least in part attributable to human activity then
what we should be talking about is what we are going to do
to address the problem. What do we know? We know Greenland
is melting. We know that some of our districts could be
under water. We know that human life as we know it could be
unsustainable in many ways on this planet. Drought, more
severe storms, flooding, all the things, not to mention for
my littler grandchildren that polar bears are drowning and
different species of trees aren't going to be there.
Look in magazines, the old National Geographics, to look at
the changing of the trees in the north. This is happening.
So why we would be spending our time in what may be--fight
about it. Fine. Let the scientific community do whatever it
wants, Dr. Mann and his old study, and let Dr. Mann defend
himself, but what we should be sitting down and doing, what
are those strategies that we can employ to decrease the
effects of global warming so that life as we know--so what
if it is normal? So what if--but if human activity is
contributing to a greater than normal warming or even an
upswing right now and the life that we have established on
this planet is in danger then we ought to be thinking about
the ways that we address this problem.
And Mr. Waxman talked about the tobacco companies. Well,
we have now here on July 27, 2006, ABC News--ever wonder
why so many people still seem confused about global
warming? This is a quote from the--the answer appears to
be that confusion leads to profit especially if you are in
some parts of the energy business. One Colorado electric
cooperative has openly admitted that it has paid $100,000
to a university academic who prides himself on being a
global warming skeptic. Intermountain Rural Electric
Association is heavily invested in power plants that burn
coal, one of the chief sources of greenhouse gases that
scientists agree is quickly pushing Earth's average
temperature to dangerous levels.
Scientists and consumer advocates say the co-op is trying
to confuse its clients about the virtually total
scientific consensus on the causes of global warming. Now
virtually totally scientific consensus. Well, maybe we
can find one or two more. Maybe we could have a dozen
more hearings of individuals who want to come in and
challenge what is the scientific consensus. But I am
depressed about it and I am worried about it because time
is wasting for us to do something constructive about this.
I thank you, Mr. Chairman.
MR. WHITFIELD. Thank you. Mr. Bass of New Hampshire.
MR. BASS. Thank you, Mr. Chairman. I wasn't planning to
give an opening statement but I am kind of warming up to
it here. I have been somewhat amused listening to these
opening statements going back and forth like a ping pong
ball across the table, and I just have to observe that
we could sort of divide this debate into four different
categories. We have the don't worry, be happy crowd.
We have the crowd that believes that the world is warming
but because we can't agree on what to do, we might as well
let the good times roll while we can. Then there is the
for want of a better word the political crowd that
maintains that this whole issue is the fault of George
Bush, Halliburton, the tobacco companies, tax cuts, and
failure to raise the minimum wage.
Frankly, Mr. Chairman, I think these hearings have been
constructive. I think they have been logical. I think
Dr. Wegman's testimony's last week was dispassionate,
scientific, interesting. I think it is great that we have
Dr. Mann here today to present another point of view. I
happen to believe personally that there is a problem of
global warming in the world and there is a pretty good
possibility that that may have been caused by the excessive
growth of the use of hydrocarbons over the last century. I
don't blame Republicans or Democrats or tobacco companies
or any other entity for it. I think it is an issue that
we need to address, and we need to address it in a logical
fashion, and this is the beginning of that process.
Now I think if I were a member of the general public I
would want to have a few questions answered ultimately as
a result of this debate. Number one, is there a warming
trend going on? Number two, is it caused by natural
sources or by man? Are the oceans getting warmer? Are
hurricanes getting stronger? Is global warming the reason
why hurricanes might be getting stronger? The oceans are
a CO2 sink. Is global warming affecting the ability of
the oceans to absorb CO2 and so forth? I think that is
the logical progression that a hearing such as the one
that we had last week and what we have today leads to--we
don't need to have a hearing that deals with the
conclusions before we build the evidence.
So I want to thank you, Mr. Chairman, for this hearing and
as one who supports the concept that we need to address
this problem I think we are moving in the right direction.
I yield back.
MR. WHITFIELD. Thank you. At this time I recognize
Mr. Inslee of Washington.
MR. INSLEE. This really is pathetically unworthy of
America, the most technologically oriented society in human
history, and we are here debating the equivalent of
gravity. Literally while America literally burns we
fiddle. This hearing makes Nero look like a responsible
Roman citizen. And we have got to pull our heads out of
the sand in that regard. Now the reason is--and I am not
depressed like Ms. Schakowsky. I am enraged. Since the
last hearing if anybody bothers to read the newspapers an
article comes out showing that 80 percent of the mass of
the glaciers in my state in North Cascades National Park,
one of the jewels in the crown, melted. A study comes
out yesterday. Highest heat loss, 50 deaths in
California, and we are sitting here fiddling around.
Article comes out yesterday. We have a dead zone in the
North Pacific where fish are dying because of change in
the circulation patterns in our oceans. And we sit here
and fiddle around. This would be the equivalent after
the Titanic of the oversight committee having a hearing
on how they arranged the deck chairs back in that good
old day. Now why is this so ridiculous? It is
ridiculous because there is total scientific consensus
not only in American but in the world that we are
responsible in part for the change in the climatic
systems of the globe. I would refer to a science article
that studied 928 peer reviewed articles and not a single
one of those peer review articles said anything that most
of the folks on the Majority side want them to say.
They all said that every single association in the world
that has studied this have concluded the climate is
changing and humans are partially responsible. That
includes the American Meteorological Society, the
American Geo-Physical Unit, the Advancement of Science
Association, the American Academy of Sciences, and the
International Panel of Climate Change. And you know what
they got here? They got nothing. They got nothing to
say that those things are not true. We are sitting here
trying to poke holes in an 8-year old study. You know
what it is like to me? It is like at the soccer final
championship, and you saw the head butt by Zidane. He
head butted, and everybody says he butted him. And they
would argue but there was a guy up there in section 23B
and it didn't look like a head butt to him, and maybe
his eyesight was a little bad.
The world knows what is going on here, and it is a sham.
I want to refer to some of the science of this. They
know it is a sham if you look at this graph up here.
Atmospheric concentrations of carbon dioxide are going
up unassailable.
Next slide, please.
Our contributions are going up from fossil fuel burning.
No question about that. Next slide, please.
We see the contributions, the CO2 levels globally over
the last 400,000 years on the top and the temperature at
the bottom. What you see is that they are very, very
closely related. It is an amazing relationship. And
what you will see at the top if I can get a laser pointer
to show right up here were 370 PPM. That is higher than
any time in the last 400,000 years, and what is scary is
it is going through the roof. It will be double
preindustrial times in my lifetime and my children's
lifetime.
None of this is arguable. All of this is known. And we
are going to hear discussion today that we have ice core
data that I will talk about that is independent of
Dr. Mann's research. We have physical evidence of changes
of oxygen isotopes that prove what is going on, which is
we are changing the climate of the United States and the
world. Next slide, please.
I just want to show you, this is Antarctic ice core data. The
blue showing, if I can get my facts straight here, the blue
showing temperature, the red showing CO2 variations. The
relationship is incredibly similar.
And again if you look where we are going to be during my
lifetime and my children's lifetime, we will be right
here. We will be almost off the charts, and we will be
double what we were in preindustrial times. I challenge
anyone here at this table, and I got an outstanding
question for all of you in this hearing, you tell me if
you double CO2 levels for preindustrial levels if you
think that is a good idea for America. I want all of
you tell me if you think that is a good idea. I think it
is a really bad idea. We ought to start being more the
American eagle and less the ostrich and we ought to fly
with new technology instead of putting our head under
the sand on this issue and then this commerce committee
will start helping America.
Next slide, please, if I can just show you one more
thing.
This is a picture of ice core. We are sitting here talking about
some paleoclimatic proxy data, and we are going to spend hours
talking about it, but the fingerprints, the DNA evidence, is in
the air in that core picture I am showing you because it is
400,000 year old air. We can directly measure the oxygen isotopes
that is a direct measurement of the temperature. We know what is
going on and it is not a pretty picture. And I look forward to
the day that we start doing something about this instead of just
having these ridiculous examples and arguing gravity. Thank you,
Mr. Chairman.
One more comment too before I leave just briefly. I
noted Mr. Barton, my good friend, I congratulate him on
the baseball game this year, they whooped us again, and I
notice he hadn't seen this movie about climate change. I
am going to invite Mr. Barton to go see this movie with
me. I am going to buy him as much popcorn as he wants,
and I am going to agree to go to any movie he wants to go
to from Zorba the Greek to Lawrence of Arabia, anything
he wants me to see. I think it would be good for both of
us. Thanks very much.
MR. WHITFIELD. Thank you very much. You can see we are a
very social group.
CHAIRMAN BARTON. If I go he is going to have to pay.
MR. WHITFIELD. Obviously this is a subject that people
feel very strongly about, and we are delighted with our
witnesses on the first panel today. Now it is your turn
to talk, and we appreciate you being so patient while we
talked. Our first witness, and I will introduce all of
you, Dr. Michael Mann who is the Associate Professor and
Director of the Earth System Science Center at Penn State
University, University Park, Pennsylvania; Dr. John Christy,
Professor and Director of Earth System Science Center,
University of Alabama in Huntsville; Dr. Ralph Cicerone,
President of the National Academy of Sciences; Mr. Stephen
McIntyre of Toronto, Ontario, Canada; Dr. Jay Gulledge,
Senior Research Fellow, Pew Center on Global Climate
Change; and Dr. Edward Wegman, Director, Center for
Computational Statistics at George Mason University.
We welcome all of you. As you know, this is an Oversight
and Investigations hearing, and we do take our testimony
under oath, and I would ask any of you do you have any
objection to testifying under oath? Under the rules of the
House and rules of the committee you also are entitled to
legal counsel. I am assuming that none of you have legal
counsel with you today, but do any of you have legal counsel
today? Okay. Then if you would stand and raise your right
hand, I would like to swear you in.
[Witnesses sworn.]
MR. WHITFIELD. Thank you very much. All of you are now
under oath. And, Dr. Mann, we will recognize you for
5 minutes for your opening statement.
TESTIMONY OF DR. MICHAEL E. MANN, ASSOCIATE PROFESSOR AND DIRECTOR,
EARTH SYSTEM SCIENCE CENTER, THE PENNSYLVANIA STATE UNIVERSITY;
DR. JOHN R. CHRISTY, PROFESSOR AND DIRECTOR, EARTH SYSTEM SCIENCE
CENTER, NSSTC, UNIVERSITY OF ALABAMA IN HUNTSVILLE; DR. RALPH J.
CICERONE, PRESIDENT, NATIONAL ACADEMY OF SCIENCES; MR. STEPHEN
MCINTYRE, TORONTO, ONTARIO, CANADA; DR. JAY GULLEDGE, SENIOR
RESEARCH FELLOW, PEW CENTER ON GLOBAL CLIMATE CHANGE; AND DR.
EDWARD J. WEGMAN, DIRECTOR, CENTER FOR COMPUTATIONAL STATISTICS,
GEORGE MASON UNIVERSITY
DR. MANN. Mr. Chairman, members of the committee, thank you for
inviting me here to appear before you today. I became a climate
scientist because the Earth's climate is a fascinating and complex
system and understanding how it works is so important. Part of my
research has involved examining preindustrial climate history in
order to learn about the natural variations in the Earth's climate.
My research in this field, not just the initial work that my
colleagues and I published in the late 1990s, but my recent research
as well suggests late 20th Century Northern Hemisphere average
temperatures are unprecedented over at least the past 1,000 years.
Of course, we have accurate thermometer measurements only
back about 100 years, and so we estimate climate prior to
that period from indirect sources called climate proxies
such as tree rings, corals, and ice cores. This work
involves many uncertainties and there are numerous judgment
calls that must be made. For that reason we are rarely
categorical in the conclusions that we reach. What is
important, however, is that the scientific community has
reached consensus that recent northern hemispheric average
warmth appears to be unprecedented over at least the past
1,000 years, and that this warmth can only be explained by
anthropogenic or human influences on the climate.
This conclusion is not based on single studies or isolated
research but is confirmed by many studies using different
sets of data and independent statistical methods and indeed
this conclusion was just echoed weeks ago by a report of
the National Academy of Sciences, the most prestigious
nonpartisan scientific body in the Nation. So where does
my research fit into this? Taken as a whole my own
research is in accord with the scientific mainstream
reflected in the National Academy report and elsewhere that
there has been unprecedented warming in the Northern
Hemisphere over the past 100 years.
Exhibit A, if you can take a look at Exhibit A there, that
shows that this conclusion is common to a number of similar
studies including two I was involved with. This committee
is not looking at my work on the whole or on the larger
body of science on this issue. It is instead focusing on
the first study of this type my colleagues and I published
and undertook in 1996 while I was still a graduate student.
While there were previous reconstructions based on proxy
data our study was the first to estimate global patterns
of past temperature change and the first to estimate
uncertainties. Our initial study published in the journal,
Nature, in 1998 was followed by an additional study in the
journal, Geophysical Research Letters, in 1999. The main
conclusion of the 1998 study was that there had been
unprecedented warming in the Northern Hemisphere in recent
decades. The 1999 study reinforced this conclusion but
also reassessed and expanded the uncertainties and added
he tentative conclusion that it was likely that the 1990s
were the warmest decade over that thousand year time period
and that 1998 was the warmest year.
The 1999 study included a graphic depiction of the
temperature history over the last millennium, which
demonstrated an unprecedented rise during the 20th Century.
Some have dubbed this graphic the hockey stick. If the
question this committee seeks to answer is whether knowing
what I know today, a decade after starting the original
study, my colleagues and I would conduct it in exactly the
same way, the answer is plainly no. The field of
paleoclimate reconstruction has evolved tremendously over
the past decade.
Important new proxy data have been developed.
Reconstructions have been compared with independent
estimates from climate model simulations and confirmed by
those simulations. Statistical methods for reconstructing
climate from proxy data have been refined and rigorously
tested, and I have been actively working in each of these
areas. This is important because all the focus of criticism
on our work in the late 1990s has been on the statistical
conventions we used. My co-authors and I have not used those
conventions in our later work.
The critique goes only to our first reconstruction effort. It
does not apply to our more recent studies all of which
indicate the same basic hockey stick result. Exhibit B
demonstrates this point. The green reconstruction does not
use principal component analysis at all so the statistical
conventions being discussed here have no relevance, and it is
the same basic reconstruction, if you will, essentially the
same "hockey stick." Now our critics do not confront the
fact that our basic conclusion is not an isolated or
aberrational finding reached only in one study. Every
climate scientist who has performed a detailed reconstruction
of the climate of the past 1,000 years using different proxy
data and different statistical methods has come up with the
same basic hockey stick pattern, that is to say a
reconstruction that agrees with our original reconstruction
within its estimates uncertainties.
My critics also fail to recognize that even if their
criticisms are accepted it has no bearing on the outcome.
Dr. Wegman's report argues that the hockey stick pattern
derives from the statistical conventions used in our 1998
and 1999 studies. However, using alternative statistical
conventions yields the same hockey stick pattern. The
hockey stick pattern is intrinsic to the data. That was
the conclusion of the National Academy. Page 116 of the
National Academy report says the statistical convention my
colleagues and I used "does not appear to unduly influence
reconstructions of hemispheric mean temperature;
reconstructions performed without using principal component
analysis are qualitatively similar to the original curves
presented by Mann et al."
This was also the conclusion reached by Dr. Hans von Storch
who testified here last week, and by four independent teams
of scientists who published peer reviewed articles
considering and rejecting the conclusion that the statistical
methods used in our early studies were responsible for the
hockey stick result. Finally, my critics ignore the fact
that other scientists have repeated original results using
the centered PCA analysis that Dr. Wegman favors and have
concluded that the result is basically the same as we
originally reported. This is summarized in Exhibit C.
So even if one accepts as valid the criticisms about the
statistical conventions used in our early work our results are
essentially unaffected. As you can see, the two curves are
barely distinguishable within the width of the lines that are
shown. And as I have said before our key conclusion that
recent hemispheric warmth appears unprecedented over at least
the past millennium has been confirmed by every study that
has examined the same question.
Finally, it is worth expressing again that paleoclimate
reconstructions represent just one of many independent lines
of evidence that support the conclusion that human activity
is already having a substantial impact on global climate.
I appreciate this opportunity to answer the committee's
questions. I am sorry I could not be here last week but
as I had explained to committee staff, I had to take care
of my infant daughter while my wife was attending a
conference.
[The prepared statement of Dr. Michael E. Mann follows:]
PREPARED STATEMENT OF DR. MICHAEL E. MANN, ASSOCIATE PROFESSOR AND
DIRECTOR, EARTH SYSTEM SCIENCE CENTER, THE PENNSYLVANIA STATE
UNIVERSITY
MR. WHITFIELD. Dr. Mann, thank you. You have heard all
the bells going off. We do have a series of four votes on
the floor but before we go, Dr. Christy, I am going to ask
you to give your opening statement. Then we will recess for
probably about 30 minutes and we will come back and take the
rest of the testimony.
DR. CHRISTY. Thank you. Chairman Whitfield, Ranking Member Stupak,
and committee members, I am John Christy, Director of the Earth System
Science Center at the University of Alabama in Huntsville, and the
Alabama state climatologist. I served as a lead author of IPCC 2002
chapter on observations with Dr. Mann, and as panelist on the NAS
report on temperature reconstructions. As the lead author of the
IPCC, I helped craft the now infamous statement about the 1990s and
1998 being the warmest decade and year.
Our confidence was described as likely rather than very
likely or virtually certain. In other words, we chose a
relatively low level of confidence because of the following
concerns known at that time. First, that the hockey stick
was new and had not had time for independent analysis for
confirmation or revision. Two, a key factor or a key anchor
for that early part of the record was a western tree ring
series that explained only about 5 percent of the overall
variability. And, three, that the unavoidable constraints
on the length of the calibration and validation periods
really prevented confident knowledge of the relative warmth
of different centuries.
A more disappointing aspect of the IPCC regarding temperatures
over the last millennium was that some important work was not
included, specifically the work of Dahl-Jensen et al., 1998,
which I recommended for inclusion many times, was completely
missing from this section. These borehole temperatures from
Greenland represented probably the most reliable regional
temperatures over the last millennium. Thus, in at least
one location we had high confidence that it was warmer 1,000
years ago, and though Greenland's temperature may not be
tightly connected to hemispheric averages, Greenland is
important for sea level averages. If Greenland were warmer
in the relatively recent past were its edges also melting
as they appear to be now under cooler conditions? I believe
the IPCC missed an opportunity to demonstrate climate
complexity by excluding this information in 2001.
Dr. Roy Spencer and I created the first satellite-based data set
temperature back in 1990. We are now working on improvements to the
8th revision brought about by the divergence of the two most recent
satellites.
When asked by others, we provided sections of our code and
relevant data files. By sharing this information, we opened
ourselves up to exposure or a possible problem which we had
somehow missed, and frankly this was not personally easy. On
the other hand, if there was a mistake we wanted it fixed.
Not knowing the outcome of the work done by scientists at
Remote Sensing Systems they asked if they could publish what
we had sent them. In my formal scientific response, I wrote,
"Oh, what the heck. I think it would be fine to use and
critique, that is sort of what science is all about."
And so it was that in August 2005 RSS published a clear
example of an artifact which created errors in the tropics in
our data. In Science magazine the following November we
published the information about our now-corrected
temperatures and expressed our gratitude to RSS for
discovering our error. While a bit painful, this process as
recommended in the National Academy's report, resulted in
progress and better scientific information.
Finally, greenhouse gas concentrations are increasing, and
therefore the radiation budget of the atmosphere will be
altered. In response, the surface temperatures will or
should rise. Our observational work, however, has not been
able to show clear support for the manner or magnitude of
this response as depicted by current climate models. For
policy makers this is important. For example, we cannot
reliably reproduce or predict the climate for large regions
within the United States. It would be a far more difficult
task to reliably predict the effects of a policy that reduce
greenhouse gas emissions.
Simply put, we cannot say with any confidence to you or to
the American taxpayer that by adopting policy X we will cause
an impact Y on the weather of the climate system.
What I really find disturbing today is the demonization of energy and
its most common byproduct, carbon dioxide, CO2. I cannot call CO2 a
pollutant when it is a source of life on the planet. CO2 is plant
food. But, as importantly, the extra CO2 we have put in the air
represents astounding improvements in the health, longevity, and
quality of human life. I suspect half of us in this hearing room
would not be here but for the benefits wrought by affordable energy.
Energy use is not evil.
I believe my experience in Africa is important in this whole
discussion of energy and climate. In the 1970s I taught
science and math as a missionary teacher, and I saw the
energy system there. The energy source was wood chopped
from the forest. The energy transmission system was the
backs of women and girls hauling wood an average of three
miles each day. The energy use system was burning the
wood in an open fire indoors for heat and light. The
consequence of that energy system was deforestation and
habitat loss while for people it was poor respiratory
and eye health. The U.N. estimates 1.6 million women
and children die each year from the effects of this
indoor smoke.
Energy demand will grow, as it should, to allow these
people to experience the advances in health and quality
of life that we enjoy. They are far more vulnerable to
the impacts of poverty, water pollution, and political
strife than whatever the climate does. I simply close
with a plea, please remember the needs and aspirations
of the poorest among us when energy policy is made.
Thank you very much.
[The prepared statement of Dr. John R. Christy follows:]
PREPARED STATEMENT OF DR. JOHN R. CHRISTY, PROFESSOR AND DIRECTOR,
EARTH SYSTEM SCIENCE CENTER, NSSTC, UNIVERSITY OF ALABAMA IN
HUNTSVILLE
MR. WHITFIELD. Dr. Christy, thank you. We are going to
go vote. It is now 15 after 3:00 so we will reconvene
about 15 till 4:00. Down in the basement there is a
little snack center and if you go out the main first floor
of the Rayburn Building and walk over to Longworth there
is a wonderful ice cream shop so whatever you decide to do.
[Recess.]
MR. WHITFIELD. The hearing will reconvene, and we apologize
for the delay. We are about 35 minutes later than we said.
But, Dr. Cicerone, you are recognized for your 5-minute
opening statement.
DR. CICERONE. Thank you, Chairman Whitfield and members of the
committee. My name is Ralph Cicerone. I am President of the National
Academy of Sciences and Chairman of the National Research Council.
Prior to this year, I was Chancellor of the University of California at
Irvine where I was Aldrich professor in Earth System Science and also
professor of chemistry. This afternoon I will summarize the state of
scientific understanding on climate change very briefly, based on
findings and recommendations in NAS and NRC reports and in some recent
refereed publications. Our reports, quite often written with the
National Academy of Engineering and the Institute of Medicine, go
through a peer review process and although we are not part of the
Government, we were chartered by Congress and President Lincoln to
provide advice on matters of science and technology.
I would like to first start with how is it that humans can
influence the climate of an entire planet. The strongest
answer is the greenhouse effect which is a natural
phenomenon. Without the natural greenhouse effect, the
Earth would be much colder than it is right now. We can
test that prediction by looking at Mars and Venus, for
example. Now humans are amplifying the natural greenhouse
effect. Just to give you one major, the extra energy
trapped near the earth's surface by a variety of greenhouse
gases is about 2-1/2 watts per square meter now, which is
about 100 times larger than all the energy usage by humans
worldwide on the entire planet from all sources, fossil
fuels, nuclear wind, hypothermal, you name it. It is a big
number. This is what gives humans leverage to influence an
entire planetary climate.
There is no doubt that the Earth is warming. Weather station
records and ship-based observations show that the global
average surface temperature in the air has increased by about
1.2 degrees Fahrenheit since the beginning of the last
century, more than half of the increase since 1975. Scientists
have also measured upward temperature trends in the lower
atmosphere and in the upper oceans, and this continuing warming
has been accompanied by worldwide changes and many other
indicators, such as decreases in Arctic sea ice thickness and
extent, and shifts in ecosystems.
What is the primary evidence for this widely accepted view
that global warming is occurring, that human beings are
responsible at least in part for the warming and that the
Earth's climate will continue to change during this current
century. There are many lines of evidence. Let me summarize
them briefly. First, measurements show large increases in
carbon dioxide and other greenhouse gases, such as methane and
nitrous oxide, beginning in the middle of the 19th Century.
These increases in greenhouse gases are due to human
activities such as burning fossil fuel for energy,
agricultural and industrial processes, and so forth. The
concentration of carbon dioxide is now at its highest level
shown by actual measurements in the last 650,000 years. The
record has been extended back that far now.
Second, we understand how carbon dioxide and other greenhouse
gases physically affect global temperature. Rigorous
radioactive transfer calculations of the temperature changes
due to increasing greenhouse gas concentrations, together
with reasonable assumptions about climate feedbacks provide a
physically based mathematically sound explanation for the
observed warming.
Third, state-of-the-art mathematical climate models are able
to reproduce the warming of the past century, but only if
human-caused greenhouse gases are included. Fourth, and I
did not have this in my written testimony, but simulations
of the stratospheric penetrating volcano, Mount Penatubo, in
mid-June 1991 were able to show the exact timing of the cooling
that took place afterwards based on the sulphate particles and
got the magnitude of the cooling almost right. And these were
primitive models at the time. Models have improved a great
deal since.
Fifth, analysis of high-quality, precise measurements of the
sun's total brightness over the past 25 years show little, if
any, change in the long-term average of solar output over this
time period. Thus, changes in the sun, the best explanation
for a natural explanation cannot explain the warming over the
past 25 years.
Six, the oceans have warmed in recent decades and the stratosphere
has cooled. Land masses north of the tropical region in the Northern
Hemisphere have warmed even more than the oceans. All of these large
scale changes, their sizes and patterns are consistent with the
predicted geographical and temporal pattern of greenhouse surface
warming.
Seventh, ice covered regions of the Earth have experienced
significant melting. For example, the average annual sea
ice extent of the Artic has decreased by about 8 percent
or nearly a million square kilometers over the past 30
years. Sea ice thickness measured, for example, by the
United States Navy has decreased over the period.
Measurements from Earth orbiting satellites from synthetic
aperture radars and from Earth's gravity sensors over the
last few years have shown that both Greenland and West
Antarctic ice sheets are losing ice.
Eighth, several publications in the last 2 years show that
hurricane intensities have increased in some parts of the
world in lock step with sea surface temperatures.
While we are quite certain that the Earth's surface has heated up
during the last 30 years, and that it is hotter now than at any
time during the last 400 years, predicting what will happen to
important climate variables besides temperature is more difficult.
As we stated in our 2001 report climate change simulations
yield a globally averaged surface temperature increase by
the end of this century of maybe 2-1/2 to 10 degrees
Fahrenheit. As I said, temperature is easier to predict
than other changes such as rainfall, storm patterns, and
ecosystems, and the prediction of extreme events, which is
what probably humans and other biological creatures respond
to the most are very difficult.
While these future climate changes and their impacts are
inherently uncertain, they are far from unknown. We can
paint useful broad brush pictures now of how global warming
may affect certain regions of the world. For example, these
mathematical models generally project more warming in
continental regions than over the oceans and in polar regions
rather than near the equator. Precipitation is expected to
increase in the tropics, decrease in the subtropics, and
increase in the midlatitudes. Rainfall is expected to
increase in monsoon regimes. We can give a lot of broad brush
predictions like that that are difficult to prove, but that is
the state of the science now.
Even if no further increases in the atmospheric concentrations
of greenhouse gases occur, which would be a difficult to
achieve scenario, we are very likely to experience additional
warming of about 7/10ths of a degree Fahrenheit in the coming
decades. In colder climates such warming could bring less
severe winters and longer growing seasons if soil moisture is
adequate. Several studies, quite credible, have projected
that summertime ice in the Arctic could disappear in this
century, the end of the century.
The combined effects of ice melting and sea water expansion
from ocean warming will likely cause the global average sea
level to rise by anywhere between 1/10th and 9/10ths of a
meter in this century. So coastal communities will experience
increased flooding due to seal level rise and are likely to
experience more severe storms and storm surges. And of
course increased acidification of the surface ocean due to
the added carbon dioxide from the atmosphere is occurring.
It will continue and it will harm marine organisms such as
corals and some plankton species.
In summary, there are multiple lines of evidence supporting
the reality of and human roles in global climate change. I
think I will stop there to be as brief as possible. With
your permission, Mr. Chairman, I have submitted two
appendices.
[The prepared statement of Dr. Ralph J. Cicerone
follows:]
PREPARED STATEMENT OF DR. RALPH J. CICERONE, PRESIDENT, NATIONAL
ACADEMY OF SCIENCES
MR. WHITFIELD. Well, thank you so much, and your entire
statement is part of the record, and we appreciate your
being here. Mr. McIntyre, you are recognized for
5 minutes.
MR. MCINTYRE. Thank you. Good afternoon, Mr. Chairman, and
members of the committee. My name is Stephen McIntyre. I
appreciate the invitation to appear before you once again. I will
recap my testimony from last week, referring to the NAS and Wegman
reports. The Wegman report drew attention to a remarkable lack of
independence in data used in supposedly independent studies. Some
proxies are used in nearly every such study. This raises the
spectre that problems in one proxy can spill over to multiple
reconstructions.
One such problem has already been identified. The NAS panel
agreed that strip bark bristlecones should be avoided in
temperature reconstructions but they did not assess the
potential impact of this conclusion. Last week I showed that
this recommendation reversed the estimates of medieval modern
levels in the Crowley and Lowery reconstruction. Here we
show the impact of this on the Mann study, where the
conclusion of 20th Century uniqueness does not withstand
removing the bristlecones. Every reconstruction using
bristlecones will have to be reconsidered in the light of
thee NAS recommendation.
By coincidence the key bristlecone sites are located in an
area recently studied by Dr. Christy where he recompiled
high altitude temperature data. There is actually a slight
negative correlation between Christy's temperature data and
Mann's key principal component series. You can readily see
why the NAS panel said that bristlecones should be avoided
as a temperature proxy. Further grounds for concern about
the use of this data comes from fossil trees located well
above modern tree lines in this area, dated to the Medieval
Warm Period. Recent ecological niche studies have concluded
that the annual minimum temperatures in this area were 3.2
degrees Centigrade warmer, that is 6 degrees Fahrenheit
warmer, than at present.
Dr. Mann likes to say that any problems do not arise
simply, and I emphasize simply, from the flawed PC method.
If the proxies were ideal, such as the synthetic data
studied by von Storch and Zorita, the bad method may not
make a difference. But in such circumstances a simple
average would also have a hockey stick shape which were not
observed in the simple average of the Mann proxies. The
real problem, and the one observed by Wegman, is that the
PC method as applied to low quality data caused a minor
pattern, in this case bristlecones, to be exaggerated as
a dominant pattern in worldwide climate.
Notably, Dr. Mann's testimony does not mention
bristlecones but in his data, the hockey stick shape is
dependent on them. The graph here shows in red the
contribution to his reconstruction for bristlecones. The
other colors show the contribution from other classes of
proxies. As you can see, there is very little information
from the other proxies.
Dr. Mann has also said that he can get a hockey stick
shape in another way. There are many ways of processing
Mann'a data set. Some result in hockey stick shape
series, some do not. Burger and Cubasch in 2005 showed a
bewildering variety of outcomes based on a slight
variation in methodology. Sometimes you are told that
scientists have moved on, and that the criticized methods
are no longer used. This is not the case. All of
Dr. Mann's more recent work used his disputed PC1. Mann's
PC1 was used in the prominent article, Osborne and Briffa
2006, and even occurs illustrated as a temperature proxy
in one of the NAS illustrations.
An important control on any statistical study is reporting
of adverse results. The verification r2 statistic is
commonly used in paleoclimate studies and was said in the
original article to have been considered. However, early
periods of the reconstruction failed the significance test,
a fact which was never reported. At the NAS press
conference, Dr. Bloomfield said that he found nothing
unusual about MBH reporting. If paleoclimate research
practices do not require scientists to disclose results
adverse to their claims, then this reduces the ability of
policy makers to rely on these studies.
Last week I pointed out many problems with data and code
access. Much relevant Mann data did not become available
until 2004, 6 years after the original study, and then
only after a formal complaint to Nature. Mann's archiving
practices are by no means the worse in the community.
Much of Lonnie Thompson's data remains unarchived 20 years
after it was collected. The efforts of your committee led
to Dr. Mann disclosing a considerable amount of source
code. Unfortunately, the source code does not operate
with the data as archived and it does not include code for
important steps such as the calculation of confidence
intervals or PC retention rules.
Wahl and Ammann have been described as independent studies
but they are co-authors and collaborators with Dr. Mann
and their efforts, whatever their merit, can hardly be
described as independent. To the credit of Wahl and
Ammann, they have archived their code for their study
following a practice that we followed. Their code
reconciles to ours and any differences between the studies
do not arise from differing arithmetic.
The interest of this committee in reconstruction seems to
have been prompted in part when Dr. Mann was quoted by
the Wall Street Journal as saying that he would "not be
intimidated into disclosing his algorithm." Such
attitudes are inconsistent with the requirement of policy
makers if they are to rely on such studies. If you are
to rely on paleoclimate studies you should be concerned
about disclosure, data access, and replication because,
first, peer review at journals is very limited and does
not constitute sufficient due diligence for policy
reliance.
Second, IPCC does not carry out independent testing or
verification. Third, to enable and facilitate independent
testing, paleoclimate research needs to achieve
dramatically improved standards for archiving data and
code. Fourth, because much of the work is funded by the
U.S. Federal government, improved administrative practices
by NSF and DOE could make a direct and immediate impact
and improvement. Thank you.
[The prepared statement of Stephen McIntyre follows:]
PREPARED STATEMENT OF STEPHEN MCINTYRE, TORONTO, ONTARIO, CANADA
SUMMARY
1. little reliance can be placed on the original MBH reconstruction,
various efforts to salvage it or similar multiproxy studies, even
ones which do not use Mann's principal components methodology;
2. peer review as practiced by academic journals is insufficient
due diligence for policy reliance. IPCC reports are only a literature
review rather than independent due diligence.
3. to enable and facilitate independent testing, paleoclimate research
practices need to achieve dramatically improved standards for
archiving data and code.
4. administrative policies governing work directly funded by the
U.S. government can make a direct and immediate difference.
Good morning, Mr Chairman and members of the Committee.
My name is Stephen McIntyre. I appreciate the invitation to appear
before you once again. I will recapitulate my testimony from last
week, making further reference to the NAS and Wegman reports.
The Wegman report drew attention to a remarkable lack of
independence in the proxies used in supposedly "independent"
studies. Some sites are used in nearly every study. This
raises the spectre that problems with one proxy can spill over
to multiple studies. One such situation has already been
identified. The NAS panel agreed that strip-bark bristlecones
should be "avoided in temperature reconstructions". Last week,
we showed that this reversed medieval-modern levels in the
Crowley and Lowery 2000 reconstruction. Figure 1 below shows
the impact on MBH, where conclusions of 20th century uniqueness
do not withstand removing the bristlecones. Wegman showed that
bristlecones were used in multiple studies and each one will
have to be reconsidered in light of the NAS recommendation.
Figure 1. MBH99 reconstruction and estimate of MBH99-type
reconstruction without bristlecones. 20-year gaussian smooth.
By coincidence, the key bristlecone and foxtail proxies that
establish the pattern in Mann's critical PC series are located
in almost the exact area studied by Christy, as shown in the
location map on the left. As you see, there is little correlation
on either a smoothed or unsmoothed basis - actually a slight
negative correlation - between temperature and Mann's PC1. You
can readily see why the NAS panel said that this data should be
avoided as a temperature proxy.
Figure 2. Left - location of foxtail and bristlecone sites in
the Sierra Nevada and White Mountains. Right - Black - annual
mean of maximum and minimum temperatures (data, Christy, pers.
comm.); red - MBH98 NOAMER PC1.
Further grounds for concern about using Mann's PC1 as a
temperature proxy comes from the evidence of fossil trees well
above modern tree lines, dated to the Medieval Warm Period.
Millar et al. 2006 concluded that annual minimum temperatures in
this area were then significantly warmer (+3.2 �C) than at
present.
Figure 3. A dead trunk above current treeline from a foxtail pine
that lived about 1000 years ago near Bighorn Plateau in Sequoia
National Park.
Dr Mann likes to say that any problems do not arise simply from
the flawed PC method. However, it's not true that the flawed PC
method has nothing to do with the problems. A simple average of
Mann's proxies does not yield a hockey stick shaped series, as
shown in Figure 4 below. If you have proxies of ideal quality,
even a bad PC method can yield meaningful results - which is
what von Storch and Zorita observed, using idealized data
generated in a climate model. However, the problem is that
Mann's PC method was applied to low-quality data, where the
flawed method caused a minor pattern in bristlecones to be
exaggerated as a "dominant pattern" in worldwide climate.
Figure 4. Left: Top - Average of all 415 MBH proxies; bottom -
MBH reconstruction. Both in standard deviation units.
In the MBH data set, the hockey stick shape is dependent on the
bristlecones. All the statistical salvage jobs Dr. Mann cites
are variations on schemes to load the final weight on the very
data the NAS panel said should not be used.
Figure 5. Top - Contribution (deg C) of proxy groups (proxy
type x continent e.g. Asian tree rings; South American ice
cores) to the MBH reconstruction, with bristlecones and foxtails
in red. Bottom - Same series in standard deviation units. The
bristlecone contribution closely matches the final MBH
reconstruction.
There are many ways of processing the MBH data - some result in
hockey-stick shaped series; some do not. B�rger and Cubasch 2005
showed a bewildering variety of outcomes based on slight
variations in MBH methodology.
Figure 6: Different MBH-type results from slight methodological
differences from Burger and Cubasch [2005] SI Figure 1.
Sometimes you're told that scientists have "moved on" and that
the methods criticized by Wegman and the NAS panel are no
longer used. However, this is not the case. Rutherford et al.,
coauthored by Dr Mann and published in late 2005, used the
identical PC method as the 1998 paper.
Although 415 individual proxy series were used, data reduction
by using leading PCs of tree-ring networks results in a
smaller set of 112 indicators in the multiproxy-PC network
available back to 1820 (Fig. 1a), with a decreasing number of
indicators available progressively further back in time.
Twenty-two of the indicators (representing 95 individual proxy
series) extend back to at least A.D. 1400.
Mann's PC1 was also used in Osborn and Briffa 2006. And
despite criticisms of the PC methodology by the NAS panel,
they themselves used it, perhaps inadvertently, in one of
their illustrations as a temperature proxy - see the top panel
of Figure 6 of the NAS report.
An important control on any statistical study is reporting of
adverse results. The verification r2 statistic is commonly used
in paleoclimate studies and was said to have been considered in
MBH98. However, its early periods had insignificant values of
this statistic, a fact that was never reported. At the NAS
press conference, Dr Bloomfield said that he found nothing
unusual about reporting of results in MBH. If paleoclimate
research practices do not require scientists to disclose
results adverse to their claims, then this reduces the ability
of policy-makers to rely on these studies.
Source: Wahl and Ammann 2006.
Last week, we pointed out many problems with data and code
access in paleoclimate. In the MBH case, much relevant data
did not become available until the 2004 corrigendum, 6 years
after the original study, and only then after a formal
complaint to Nature. The efforts of your committee led to
Dr Mann disclosing a considerable amount of source code.
Unfortunately, as Dr Wegman reported to you, the source code
does not work with any data sets presently archived and is
inoperable. It also does not include code for some important
steps, such as MBH99 confidence intervals or PC retention
rules, which neither ourselves nor Wahl and Ammann have been
able to replicate. Since Wahl and Ammann are recent coauthors
and collaborators with Mann, their efforts hardly can be
described as "independent" replication.
Dr Mann and his associates are by no means the worst in the
paleoclimate field in archiving data. It is undoubtedly
frustrating for Dr Mann to be the center of attention when
many of his colleagues are much worse. For example, despite
over 2 years of effort, I have been unsuccessful in learning
what sites were used in one of three paleoclimate studies
illustrated in the IPCC Third Assessment Report (Briffa et
al 2001). These sites were recently been used by Mann and
coauthors, who have also failed to even disclose the location
of the sites.
The reason why data access and replication should be of
concern to you is that:
(1) peer review at journals is very limited and does not
constitute sufficient due diligence for policy reliance;
(2) IPCC does not carry out due diligence on articles.
(3) In order to properly assess a study, it needs to be
replicated. Placing obstacles in the way of access to data
and code makes this either impossible or simply impractical for
people with less than infinite patience.
(4) Because much of the work is funded by the U.S. federal
government, there are direct and practical steps that can be
taken with NSF and DOE that would have an immediate impact
in improving the quality of due diligence in this field.
MR. WHITFIELD. Thank you. Dr. Gulledge, you are recognized
for 5 minutes.
DR. GULLEDGE. Thank you, Mr. Chairman, Ranking Member, and members
of the committee. I am Jay Gulledge. I am a Senior Research Fellow
with the Pew Center on Global Climate Change, and an Adjunct
Assistant Professor at the University of Louisville, where I
conduct research on the carbon cycling. I just want to try to
provide a little bit of context here today. I am not a
paleoclimatologist or a statistician, but I am a professional
scientist observing--I am a generalistic climate change scientist
through my duties at the Pew Center on Global Climate Change.
[Slide]
Next slide, please. I just want to reiterate, now
Dr. Cicerone mentioned most of these things, but this is not
about the fundamentals of climate change science and the
hockey stick reconstruction is not a foundation. Chain
activities are increasing greenhouse gases. The Earth is
warming. These are unequivocal facts. The warming over the
past 5 decades has been attributed through sound science to
human activities associated with greenhouse gases. The
effects of warming are being seen today all over the globe,
and this warming is going to continue for a long time even if
we stabilize greenhouse gases in the atmosphere today. Next
slide.
[Slide]
Now the main points I want to make today, the so-called
hockey stick controversy is not a scientific construct. The
controversy is in science and that is because debate is
normal in science and people re-examine each other's methods
and so forth. This is not controversial. It is just not
controversial in science. The criticisms of the hockey stick
scientifically speaking do not undermine the climate, the
science of climate change. It is just not central to our
understanding of it.
The results of the hockey stick actually represent a
gradual development in the understanding in the paleoclimate
community of past climate, not any kind of step change in
the understanding. This is readily demonstrated from the
scientific literature over the past 20 years. And in my
opinion climate change assessments are working well under
the supervision of climatologists.
[Slide]
The next slide, I just want to point out the bottom quote
here from the NAS report that says the surface temperature
reconstructions I have included such as the hockey stick
are consistent with other evidence of global climate change
and can be considered, and this is the operational phrase
here, my point, as additional supporting evidence. It is
not central to climate science. Next slide.
[Slide]
This is the hockey stick as presented in the 2001 IPCC. It
is a reconstruction of the average northern hemispheric
temperature over the last thousand years. Next slide.
[Slide]
And the main conclusions as you have heard over and over
again the 20th Century is the warmest in the past thousand
years. The 1990s were the warmest decade, and even 1998
being the warmest year as represented by the blade of the
hockey stick here. Next slide.
[Slide]
Now the criticisms that have been discussed in this hearing
as leveled by McIntyre and McKitrick have to do with
statistical methodology and whether they were applied properly,
inappropriate use of data, and a general complaint that this
has resulted in an incorrect elimination of the Medieval Warm
Period which would show where the red oval is here. Next
slide.
[Slide]
Now as a result of these criticisms this committee has asked
Mr. Wegman to produce a report along with his colleagues to
examine these criticisms. And the primary objective of this
report, as quoted from the report, is to "reproduce the
results of McIntyre-McKitrick nor to determine whether the
criticisms were valid and have merit." I put in red the
last phrase. I think this has not been accomplished by the
Wegman report at all, and I will illustrate why. Next
slide.
[Slide]
It just seems reasonable that you got to look at what has
happened since this because you are trying to find out the
reliability of the science here. Second, Mann's claims
that McIntyre and McKitrick didn't apply his method
correctly are not addressed in the Wegman report at all but
they certainly are germane. If those criticisms are being
used to question the work then that has to be examined.
Corroborating evidence wasn't looked at. That was the
strength of the NAS report, I would say. And finally in red
here a very important report with regard to the questions of
this committee was really overlooked by this report showing
up only in a footnote on a later page or on a middle page.
But this thing, this study by Wahl and Ammann from the
National Center of Atmospheric Research, actually looked at
all the main criticisms of the McIntyre-McKitrick papers,
and whether they are correct or not, this should have been
examined by any investigation wanting to look into the
merits of the McIntyre-McKitrick criticisms. Next slide.
[Slide]
Now what they are showing is that they are able to reproduce
extremely closely the original Mann 1998 hockey stick. Here
in gray is the original Mann result, and if you can't see
it it is because it is under the red line, which is their
emulation. They did this writing their own code in the R
programming language, and they made a very faithful
reproduction. Next.
[Slide]
Now using their reproduction they then tested whether or not
the McIntyre-McKitrick criticisms had an effect on the
result of the reconstruction. In this figure they have
corrected for the de-centering problem prior to the PC
analysis, and also they removed the gaspe tree ring series
that was questioned by McIntyre and McKitrick. And the
result is the only change that occurred that has any
significance is in the 14th Century. You see the red line
is their emulation of Mann and the blue, which is sticking
up a little bit on the very left hand of the graph, is
the effect of the corrections.
Now this really just doesn't change--and these green and
magenta are the 95 percent confidence intervals. This
really just doesn't change the picture of the 20th Century
being unique. Now it does leave the impression that
perhaps there is a trajectory of warming as you move back
in time. Maybe that continues to go up and the Medieval
Warm Period, which isn't even shown here, maybe got warm.
Next slide, please.
[Slide]
I asked Dr. Ammann yesterday whether or not he had used
these corrections and taken them back in time. He said
that he had, that he has a paper that is submitted for
review on this, and I want to make clear that this hasn't
been peer reviewed yet. It is the same correction applied
to the data going back a thousand years, and this is the
result. The blue line is the emulation of Mann 1999. The
red line is the result. And in fact it does not continue
to go up. And this is going to be my last slide so don't
be concerned. There are a lot more slides in your
handout. I want to point out here that if you look at
the medieval times here which would be the first couple
of frames from the left in that graph it is warmer than
what you see to the right of that. There is a Medieval
Warm Period on this graph. It is just weak, and that
is completely consistent with the scientific examination
of paleoclimate over the last 20 years. There has been
a consistent trajectory and this is completely consistent
with that. Thank you.
[The prepared statement of Dr. Jay Gulledge follows:]
PREPARED STATEMENT OF DR. JAY GULLEDGE, SENIOR RESEARCH FELLOW,
PEW CENTER ON GLOBAL CLIMATE CHANGE
Mr. Chairman, Ranking Member, and Members of the Committee:
Thank you for the opportunity to speak today. I am Jay Gulledge,
Ph.D., Senior Research Fellow for Science and Impacts at the Pew
Center on Global Climate Change. I am also an Adjunct Assistant
Professor at the University of Louisville, which houses my academic
research program on carbon cycling.
The Pew Center on Global Climate Change is a non-profit,
non-partisan and independent organization dedicated to providing
credible information, straight answers and innovative solutions in
the effort to address global climate change. In our eight years of
existence, we have published almost seventy reports by experts in
climate science, economics, policy and solutions, all of which have
been peer-reviewed and reviewed as well by the companies with which
we work.
Forty-one major companies sit on the Pew Center's Business
Environmental Leadership Council, spanning a range of sectors,
including oil and gas (BP, Shell), transportation (Boeing, Toyota),
utilities (PG&E, Duke Energy, Entergy), high technology (IBM, Intel,
HP), diversified manufacturing (GE, United Technologies), and
chemicals (DuPont, Rohm and Haas). Collectively, the 41 companies
represent two trillion dollars in market capitalization and three
million employees. The members of the Council work with the Pew
Center to educate the public on the risks, challenges and solutions
to climate change.
If you take nothing else from my testimony, please take these three
points:
1. The scientific evidence of significant human influence on
climate is strong and would in no way be weakened if there were no
Mann hockey stick.
2. The scientific debate over the Medieval Warm Period (MWP) has
been gradually evolving for at least 20 years. The results of the
Mann hockey stick simply reflect the gradual development of thought
on the issue over time.
3. The impact of the McIntyre and McKitrick critique on the
original Mann paper, after being scrutinized by the National Academy
of Science, the Wegman panel and a number of meticulous individual
research groups, is essentially nil with regard to the conclusions
of the Mann paper and the 2001 IPCC assessment.
The science of climate change is an extraordinary example of a
theory-driven, data-rich scientific paradigm, the likes of which,
arguably, has not occurred since the development of quantum
mechanics in the first half of the twentieth century. The product
of this strong scientific framework is a body of strong,
multifaceted evidence that man-made greenhouse gases are causing
contemporary global warming, and that this warming trend is
inducing large-scale changes in global climate. The primary evidence
is based on physical principles and observational and experimental
analysis of contemporary climate dynamics, as opposed to analyses
of past climates, which are the subject of this hearing. We can
now say with confidence that the evidence of human influence on
climate is strong, as described by Dr. Cicerone.
Although paleoclimatology - the study of ancient climates - is an
important part of the climate science frame work, reconstructions
of temperature over the past millennium play a secondary,
expendable role in the larger body of evidence, as stated in the
recent NAS report titled, Surface Temperature Reconstructions for
the Last 2,000 Years: "Surface temperature reconstructions are
consistent with other evidence of global climate change and can
be considered as additional supporting evidence" (National
Research Council 2006, p. 23; hereafter referred to as the NAS
report). Dispensing with such reconstructions entirely or
proving them fundamentally flawed would have little, if any,
impact on our understanding of contemporary climate change. This
statement does not imply that millennial climate reconstructions
are unimportant, but their main influence will be in the future,
when their potential to reveal how climate varied across the
earth's surface from year-to-year in the past (i.e. an annual
record of spatially explicit climate dynamics) is fully realized.
At that point, such reconstructions will be used in a manner
parallel to thermometer records today. This capability would
contribute significantly to resolving the current genuine debate
in climate science, which is not about whether humans are
changing the climate-a point over which there is no scientific
controversy-but is about how much human influences will change
the climate in the future as a result of greenhouse gas
accumulation and other forcings we apply to the climate system.
In other words, the goal of spatially explicit paleoclimate
reconstructions is to help climatologists determine how
physical forcings, such as solar radiation, volcanic eruptions,
land-use changes, and changes in atmospheric greenhouse gases,
have affected the planet in the past, so that we can improve
estimates of how they will do so in the future.
The early MBH reconstructions (Mann et al. 1998; Mann et
al. 1999; hereafter referred to as MBH98 or MBH99 or,
collectively, MBH) were the first to offer spatially explicit
climate reconstructions and therefore represented a
breakthrough in climate change science that continues to
develop and promises to further our understanding of climate
physics in the future. The Wegman report's conclusion that
paleoclimatology "does not provide insight and understanding
of the physical mechanisms of climate change" (p. 52), fails
to appreciate that the purpose of Dr. Mann's research is to
improve our knowledge of physical mechanisms of climate
change by examining how they operated in the past.
Turning our attention to the methodological issues this
hearing seeks to investigate, in my opinion, the Wegman
report failed to accomplish its primary objective, which
was "to reproduce the results of [McIntyre & McKitrick] in
order to determine whether their criticisms are valid and
have merit" (p. 7). Although the panel reproduced MM's
work-verbatim-it only partially assessed the validity, and
did not at all assess the merits, of the criticisms
directed toward the MBH reconstructions. For instance,
MM (McIntyre and McKitrick 2003; McIntyre and McKitrick
2005; heafter referred to collectively as MM) allege that
the so-called MBH "hockey stick" result is biased by
methodological errors that undermine the conclusion that
the late 20th century was uniquely warm relative to the
past 1000 years. This critique only has merit if, after
correcting for the errors pointed out by MM, the resulting
reconstruction yields results significantly different from
the original result that can no longer support the claim
of unusual late 20th century warmth. However, the Wegman
Report takes no steps to make such a determination.
Fortunately, a different group, one well qualified both
statistically and climatologically to tackle this question
of merit, had already performed the task several months
before the Wegman Report was released. The study by Wahl &
Ammann (In press; hereafter referred to as WA06), was
peer-reviewed and accepted for publication in the journal,
Climatic Change, early last spring, and has been publicly
available in accepted form since last March
(http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/
WahlAmmann_ClimChange2006.html). This study, titled,
Robustness of the Mann, Bradley, Hughes Reconstruction of
Northern Hemisphere Surface Temperatures: Examination of
Criticisms Based on the Nature and Processing of Proxy
Climate Evidence, carefully reproduced the MBH98
reconstruction and then used their faithful reproduction
to test MM's suggested corrections. They tested each of
the criticisms raised by MM in all of their published
papers, including both the peer-reviewed and non-peer-
reviewed papers. Given that this report specifically
examined MM's criticisms, including the decentering issue
that was the main focus of the Wegman report, it is
unfortunate that the Wegman report dismissed it in a
footnote (p. 48) as "not to the point."
WA06 have performed a meticulous and thorough evaluation
of MBH98, and the answers that this committee seeks about
the MBH reconstructions are to be found within this report.
After examining each of MM's three methodological
criticisms, WA06 accepted two of them as valid, and have
used them to correct the MBH98 reconstruction. I will now
show you what effect these corrections have on the MBH98
reconstruction, and then reconsider the uniqueness of the
late 20th-century warming trend in the light of these
corrections.
The original MBH98 "hockey stick" is shown as a gray line
(Fig. 1). The WA06 reproduction of MBH98 is shown in red
(Fig. 1). Except for a couple of minor simplifications,
WA06 remained faithful to the original MBH method and
retained all of the original MBH data, including the original
instrumental temperature series from 1992. They wrote their
own computer code to perform the calculations, using the R
programming language, as recommended by the MM and the Wegman
report, rather than the original Fortran language used by
Dr. Mann. As you can see, the two reconstructions are
materially the same. This result demonstrates that MBH98 can
be reproduced based on information available in the original
MBH papers and supplemental information and data available
on the Internet.
Fig. 2. WA06 corrections of MBH98 for accepted MM corrections.
The left frame shows original WA06 emulation of MBH in red
and the corrected reconstruction accounting for decentering
and excluding the Gaspe tree-ring series in blue. The right
frame shows the same but with the bristle cone pine series
removed (green line). Instrumental data are shown in black.
With this successful reproduction in hand, WA06 were able to
test the effects of each of MM's criticisms on the outcome
of the MBH98 reconstruction. After carefully considering the
validity of MM's three criticisms of MBH's reconstruction
methodology, WA06 agreed that 1) decentering the proxy data
prior to Principle Component analysis and 2) including the
poorly replicated North American Gasp� tree-ring series from
1400-1449 both affected the MBH results. After correcting for
these effects, WA06 obtained the results shown in blue
(Fig. 2, left frame). The result is a slightly warmer (0.1
�C) early 15th century, with no other time period affected.
MM's third methodological criticism surrounding the inclusion
of the bristlecone/foxtail pine series was rejected for
several reasons. The right frame in Fig. 2 illustrates that
excluding these series has little effect on the MBH98
reconstruction, except to force it to begin in 1450 instead of
1400, because of lack of a data. Since the exclusion had
little effect, and losing these data series would hinder
reconstructions of earlier climate, WA06 rejected this
criticism.
Fig. 3. Wahl-Ammann corrections of the MBH99 reconstruction
(Ammann & Wahl, submitted). The original MBH99 reconstruction
is shown in blue and the corrected WA version is shown in red.
Corrections were made for the decentering issue and the Gaspe
tree-ring series. Instrumental data are in black.
The additional 15th-century warmth revealed by making the
valid MM corrections still does not approach the warmth of
the late 20th century, so MM's critique cannot yet be said
to have merit. However, the corrected result creates the
impression of an upward temperature trend backward in time
before 1400, begging the question of what would happen to
the Middle Ages in the 1000-year MBH99 reconstruction if it
were also corrected? Answering that question is requisite for
determining the merit of MM's critique of MBH. The original
1000-year MBH99 reconstruction is shown in blue and the
corrected version is shown in red (Fig. 3; Ammann & Wahl,
submitted). Carrying the correction back to the full
millennium reveals that the largest effects remain in the
early 15th century, and both earlier and later periods were
less affected. Therefore, there is very little difference
between the corrected MBH98 and MBH99 reconstructions and the
originals, and the original observation that the late 20th
century is uniquely warm in the context of the past 1000 years
is not affected. Hence, the valid methodological caveats that
MM pointed out do not undermine the main conclusions of the
original MBH papers or the conclusion of the 2001 IPCC
assessment.
The scientific debate over the Medieval Warming Period (MWP)
has been on the same trajectory for at least 20 years, with
early indications that the MWP was not a globally coherent
event becoming more solid over time. The MBH99 reconstruction
represented an evolutionary step-not a revolutionary change-in
this established trajectory. The 1990 IPCC figure that
Mr. McIntyre, the Wall Street Journal editorial page, and
Dr. Wegman have used in their own assessment of past climate
is a cartoon, as stated by Dr. Wegman in his testimony last
week. I have confirmed this with a number of individuals who
were involved with the 1990 IPCC report or with versions of
the schematic that pre-dated the 1990 IPCC report. The
schematic is not a plot of data and is inappropriate as a
comparison to MBH. The text of the 1990 IPCC report clearly
states that the figure is a "schematic diagram" and that "it
is still not clear whether all the fluctuations indicated
were truly global" (p. 202). Furthermore, only three sources
of information were cited and those sources conflicted on
whether the Northern Hemisphere was warm or cold: "The late
tenth to early thirteenth centuries... appear to have been
exceptionally warm in parts of western Europe, Iceland and
Greenland... China was, however, cold at this time, but South
Japan was warm..." Clearly, this report certainly did not
paint a picture of any consensus regarding a Medieval Warm
Period as a hemisphere-wide phenomenon and characterizing it
as such reveals a fundamental misunderstanding of climate
science.
The 1992 and 1995 IPCC reports continued this same trajectory
of thought. Four years before MBH99, citing 6 papers-still a
very limited number by twice as many as were cited in 1990-the
1995 report stated:
There are, for this last millennium, two periods which have
received special attention, the Medieval Warm Period and the
Little Ice Age. These have been interpreted, at times, as
period of global warmth and coolness, respectively. Recent
studies have re-evaluated the interval commonly known as the
Medieval Warm Period to assess the magnitude and geographical
extent of any prolonged warm interval between the 9th and
14th centuries... The available evidence is limited
(geographically) and is equivocal. ...a clearer picture may
emerge as more and better calibrated proxy records are produced.
However, at this point, it is not yet possible to say whether,
at a hemispheric scale, temperatures declined from the 11-12th
to the 16-17th century. Nor, therefore, is it possible to
conclude that the global temperatures in the Medieval Warm
Period were comparable to the warm decades of the late 20th
century" (p. 174).
Remember that this was written by a team of climatologists as a
consensus statement. The consensus at this time, as in 1990,
was that there was no strong evidence of a hemisphere-wide MWP.
Continuing the same trajectory, the 2001 IPCC Third Assessment
Report examined evidence from 10 cited sources for the MWP.
The consensus at this point seemed to be turning to the
conclusion that the there actually was a generally warm
Northern Hemisphere during the Middle Ages, but that it was
not a strong, coherent pattern of warming:
It is likely that temperatures were relatively warm in the
Northern Hemisphere as a whole during the earlier centuries
of the millennium, but it is much less likely that a
globally-synchronous, well defined interval of "Medieval
warmth" existed, comparable to the near global warmth of the
late 20th century... Marked warmth seems to have been confined
to Europe and regions neighboring the North Atlantic.
Since the MBH reconstructions were hemisphere-wide, and the
MWP probably was not, it should not surprise us that the
reconstructions lack a strong MWP (MBH99 does show slightly
warmer temperatures in the 9th to 14th centuries than in the
15th to 19th centuries).
All available evidence indicates that the situation during the
Middle Ages was fundamentally different that what is happening
with climate today, which is a well-documented, globally
coherent warming trend that is happening North, South, East,
and West; at low latitudes and high latitudes; over land and
over-and into-the sea. There are new data, published earlier
this year, indicating that the atmosphere above Antarctica has
warmed dramatically in recent decades (Turner et al. 2006).
There is no large region on Earth where large-scale 20th century
warming has not been detected, which simply cannot be said of
the MWP.
Wahl and Ammann (2006) have demonstrated that the results of
MBH are robust "down in the weeds":
Our examination does suggest that a slight modification to the
original Mann et al. reconstruction is justifiable for the
first half of the 15th century (~ +0.05�), which leaves entirely
unaltered the primary conclusion of Mann et al. (as well as many
other reconstructions) that both the 20th century upward trend
and high late-20th century hemispheric surface temperatures are
anomalous over at least the last 600 years.
The NAS has affirmed the MBH results are also robust in the
bigger picture, as well:
The basic conclusion of MBH99 was that the late 20th century
warmth in the Northern Hemisphere was unprecedented during at
least the last 1,000 years. This conclusion has subsequently
been supported by an array of evidence that includes both
additional large-scale surface temperature reconstructions and
pronounced changes in a variety of local proxy indicators,
such as melting on icecaps and the retreat of glaciers around
the world, which in many cases appear to be unprecedented
during at least the last 2,000 years. Not all individual proxy
records indicate that the recent warmth is unprecedented,
although a larger fraction of geographically diverse sites
experienced exceptional warmth during the late 20th century than
during any other extended period from A.D. 900 onward. (p. 3)
Examination of the IPCC reports through time, as well as the
primary scientific literature, reveals why the MBH results are
so robust-MBH simply assimilated all the available evidence into
a quantitative reconstruction-evidence that had already been
evaluated qualitatively as lacking a coherent MWP.
This committee is seeking to know the significance of the
criticisms leveled at the MBH reconstruction for climate change
assessments. The significance is that these criticisms have
resulted in the most thoroughly vetted single climate study in
the history of climate change research. Dr. Tom Karl summarized
the impact most succinctly in his testimony to this committee
last week when he said that he would stand by the IPCC's
original assessment: "If you ask me to give qualifications
about the findings in the 2001 report with the same caveat in
terms of defining likelihood, I personally would not change
anything." Hence, the impact of the MM critique, after being
scrutinized by the NAS, the Wegman panel, and a number of
meticulous individual research groups, is essentially nil with
regard to the conclusions of MBH and the 2001 IPCC assessment.
Also relevant to this committee's questions about climate
change assessments is the revelation that climate scientists
do know their business, and that a lack of knowledge of
geophysics is a genuine handicap to those who would seek to
provide what they deem "independent review." If the assessment
of climate science presented in Mr. McIntyre's presentation to
the NAS committee, the Wegman Report, and the WSJ is an example
of what can be expected from those who have not conducted
climate research, then the investigation launched by this
committee has demonstrated clearly that "independent review"
by non-climate scientists is an exceedingly ineffective way to
make climate change assessments.
References
Mann, M E, R S Bradley and M K Hughes (1998). "Global-scale
temperature patterns and climate forcing over the past six
centuries." Nature 392(6678): 779-787.
Mann, M E, R S Bradley and M K Hughes (1999). "Northern hemisphere
temperatures during the past millennium: Inferences, uncertainties,
and limitations." Geophysical Research Letters 26(6): 759-762.
McIntyre, S and R McKitrick (2003). "Corrections to the Mann et
al. (1998) proxy data base and northern hemisphere average
temperature series." Energy & Environment 14(6): 751-771.
McIntyre, S and R McKitrick (2005). "Hockey sticks, principal
components, and spurious significance." Geophysical Research
Letters 32(3).
National Research Council, C O S T R F T L, 000 Years. (2006).
"Surface temperature reconstructions for the last 2,000 years."
from http://www.nap.edu/catalog/ 11676.html.
Turner, J, T a Lachlan-Cope, S Colwell, et al. (2006).
"Significant warming of the Antarctic winter troposphere."
Science 311: 1914-1917.
Wahl, E and C Ammann (In press). "Robustness of the Mann,
Bradley, Hughes reconstruction of northern hemisphere surface
temperatures: Examination of criticisms based on the nature
and processing of proxy climate evidence." Climatic Change
(accepted).
MR. WHITFIELD. Dr. Wegman, you are recognized for
5 minutes.
DR. WEGMAN. Thank you. Good afternoon. I would like to begin
by summarizing our previous testimony. Let me first begin by
circumscribing the substance of our report. As you know, we
were asked to provide an independent verification by
statisticians of the critiques of the statistical methodology
found in the papers of Dr. Michael Mann, Raymond Bradley, and
Malcolm Hughes, published respectively in Nature and Geophysical
Review Letters. These two papers have commonly been referred
to MBH98 and 99. The critiques have been made by Stephen
McIntyre and Ross McKitrick published in Energy and Environment
in 2003, and in that same journal and also in Geophysics Research
Letters in 2005. We refer to these as MM03, 05A, 05B, respectively.
We were also asked about the implications of our assessment.
We were not asked to assess the reality of global warming,
and indeed this is not an area of our expertise. Our panel
was composed of myself from George Mason University,
Dr. David W. Scott from Rice University, and Yasmin Said,
Dr. Said, from the Johns Hopkins. This ad hoc panel has
worked pro bono, has received no compensation, and has no
financial interest in the outcome.
The debate over Dr. Mann's principal components methodology
has been going on for nearly 3 years. When we got involved,
there was no evidence that a single issue was resolved or
even nearing resolution. Dr. Mann's RealClimate.org website
said that all of Mr. McIntyre and Dr. McKitrick claims had
been discredited. UCAR had issued a news release saying that
all their claims were unfounded, by the way, based on the
Ammann paper just referred to.
The situation was ripe for a third party review of the types
that we and Dr. North's NRC panel have done. Because of the
very high visibility of the original study, we see no harm
and much advantage of having two independent analyses of the
situation, from quite different perspectives.
While the two studies overlap on the important topic of
Mann's principal components methodology, Dr. North's NRC
panel considers topics that were outside the scope of our
study, such as other temperature reconstructions. Where
we have commonality, I believe our report and the NRC
panel essentially agree. The error in the use of principal
components methodology, the NRC panel reported under some
conditions, the leading principal component can exhibit a
spurious trend in the proxy-based reconstruction.
The NRC panel illustrated this with their own spurious
hockey stick in Figure 9-2 on page 87 of the report. Our
explanation of this phenomenon was similar, the authors
make the seemingly innocuous and somewhat obscure
calibration assumption. Because the instrumental temperature
records are only available for a limited window, they use
instrumental temperature data from 1902-1995 to calibrate
the proxy data set. This would seem reasonable except for
the fact that temperatures were rising during this period.
So that centering on this period has the effect of making
the mean value for any proxy series exhibiting the same
increasing trend to be decentered low.
Because the proxy series exhibiting the rising trend are
decentered, the calculated variance will be larger than
their normal variance when calculated based on centered
data, and hence they will tend to be selected
preferentially as the first principal component. The
centering of the proxy data is a critical factor in using
principal components methodology.
The effect of decentering was illustrated by us in
Figure 2, which is Figure 4.3 in our report. The top panel
represents the North American Tree Ring PC1 as calculated
based on the MBH98 methodology. The bottom panel illustrates
the PC1 based on the same set of tree ring proxies with the
centered PCA computation. We believe that our discussion,
together with the discussion from the NRC report should take
the centering issue off the table. The decentering
methodology is simply incorrect mathematics as was
illustrated in our Appendix A as well as with ample
simulation evidence in both our report and that of the
NRC report.
I am baffled by the claim that incorrect method doesn't
matter because the answer is correct anyway. The method
wrong plus answer correct is just bad science. But with
the centering issue off the table, the question then
shifts from principal component analysis to which proxies
exhibit the hockey stick shape and whether these proxies
contain valid temperature signals. We agree with Dr. Mann
that the hockey stick shape is in some proxies.
Figure 4 is an image that I showed in our previous
testimony showing just six bristlecone pine proxies used
in the construction of the North American PC1 series. The
hockey stick shapes are clearly visible in the last two
proxies. Given our discussion, it is clear how the
decentering methodology will select these and give them
prominence in PC1. So the question is are these valid
temperature proxies. I quote from our report, "Graybill
and Idso, 1993, specifically sought to show that
bristlecone pines were CO2 fertilized. Bondi et al.,
1999, suggest bristlecones are not reliable temperature
proxy for the last 150 years as it shows an increasing
trend in about 1850 that has been attributed to
atmospheric CO2 fertilization." We also know that IPCC
1996 report stated that the possible confounding effects
of carbon dioxide fertilization need to be taken into
account when calibrating tree ring data against climate
variations. At the very least, the effect of these
proxies on temperature reconstruction should be examined.
Figure 5 shows Dr. Mann's own illustration, MBH, Internet,
2003, of the direct effect of North American tree ring
data on reconstruction results in the 15th century.
Indeed, it is our understanding as outsiders that all
parties agree as to the significance of this tree ring
network to final results, and that has made the use of
the tree ring network a disputed issue as Mr. McIntyre has
just pointed out.
Figure 6 is also a repeat graphic from my previous
testimony. Please note that the Bristlecone/Foxtail PC1
proxy is used not only in MBH, but in virtually every
subsequent reconstruction. We do not claim to be experts
in dendrology either but it seems to us as outsiders that
there are sufficient confounding factors that proxies based
on bristlecones should be avoided. We should add that we
were specifically asked to resolve the differences between
MPH98/99 and the McIntyre and McKitrick papers. There is
a bewildering array of subsequent work that we were not
asked to consider, but which probably deserves much more
intense scrutiny. We would include such refereed papers
as Rutherford et al., 2005, and Wahl and Ammann, 2006,
which are purported to be written by independent teams,
but which are co-authored by Dr. Mann himself in Rutherford
et al. and by Dr. Mann's student Dr. Ammann in Wahl and
Ammann.
MR. WHITFIELD. Dr. Wegman, excuse me for interrupting. You
are about 3 minutes over on the testimony, and we did hear
your testimony last week and we have it in the record. And
we genuinely appreciate your being back here today, and I
am sure we will have some questions for you.
DR. WEGMAN. Thank you, sir.
MR. WHITFIELD. And you adequately covered last week also
the social network and which we appreciate very much.
[The prepared statement of Dr. Edward J. Wegman follows:]
PREPARED STATEMENT OF DR. EDWARD J. WEGMAN, DIRECTOR, CENTER FOR
COMPUTATIONAL STATISTICS
Good morning. I would like to begin by summarizing our previous
testimony. The debate over Dr. Mann's principal components
methodology has been going on for nearly three years. When we got
involved, there was no evidence that a single issue was resolved
or even nearing resolution. Dr. Mann's RealClimate.org website
said that all of the Mr. McIntyre and Dr. McKitrick claims had
been "discredited". UCAR1 had issued a news release saying that
all their claims were "unfounded". Mr. McIntyre replied on the
ClimateAudit.org website. The climate science community seemed
unable to either refute McIntyre's claims or accept them. The
situation was ripe for a third-party review of the types that we
and Dr. North's NRC panel have done. Because of the very high
visibility of the original study, we see no harm and much
advantage of having two independent analyses of the situation,
from quite different perspectives.
While the two studies overlap on the important topic of Mann's
principal components methodology, the Dr. North's NRC panel
considers topics that were outside the scope of our study, such
as other temperature reconstructions. Where we have commonality,
I believe our report and the NRC panel essentially agree. On the
error in the use of principal components methodology, the NRC
panel reported, "...under some conditions, the leading principal
component can exhibit a spurious trend in the proxy-based
reconstruction. To see how this can happen, suppose that instead
of proxy climate data, one simply used a random sample of
autocorrelated time series that did not contain a coherent signal.
If these simulated proxies are standardized as anomalies with
respect to a calibration period and used to form principal
components, the first component tends to exhibit a trend, even
though the proxies themselves have no common trend. Essentially,
the first component tends to capture those proxies that, by
chance, show different values between the calibration period and
the remainder of the data."
The NRC panel illustrated this with their own spurious hockey
stick in Figure 9-2 on page 87. Our explanation of this
phenomenon is similar. "... the authors make a seemingly innocuous
and somewhat obscure calibration assumption. Because the
instrumental temperature records are only available for a limited
window, they use instrumental temperature data from 1902-1995 to
calibrate the proxy data set. This would seem reasonable except
for the fact that temperatures were rising during this period.
So that centering on this period has the effect of making the
mean value for any proxy series exhibiting the same increasing
trend to be decentered low. Because the proxy series exhibiting
the rising trend are decentered, the calculated variance will be
larger than their normal variance when calculated based on
centered data, and hence they will tend to be selected
preferentially as the first principal component. ... The centering
of the proxy series is a critical factor in using principal
components methodology."
The effect of decentering was illustrated by us in Figure 2, which
is Figure 4.3 in our report. The top panel represents the North
American Tree Ring PC1 as calculated based on the MBH98
methodology. The bottom panel illustrates the PC1 based on the
same set of tree ring proxies with the centered PCA computation.
To illustrate that this spurious decentering effect is not limited
to just hockey sticks we created an additional illustration based
on the IPCC 1990 temperature curve. With 69 uncorrelated white
noise proxies and one IPCC 1990 curve, it is clear that decentering
can overwhelm the remaining proxies and preferentially select the
one anomalous one.
We believe that our discussion together with the discussion from
the NRC report should take the "centering" issue off the table. The
decentered methodology is simply incorrect mathematics as was
illustrated in our Appendix A as well as with ample simulation
evidence in both our report and that of the NRC report. I am baffled
by the claim that the incorrect method doesn't matter because the
answer is correct anyway. Method Wrong + Answer Correct = Bad Science.
But with the centering issue off the table, the question then shifts
from principal component analysis to which proxies exhibit the hockey
stick shape and whether these proxies contain valid temperature
signals. We agree with Dr. Mann that the hockey stick shape is in
some proxies.
Figure 4 is an image that I showed in our previous testimony showing
just six sample Bristlecone pine proxies used in the construction of
the North American PC1 series. The hockey stick shapes are clearly
visible in the last two proxies. Given our discussion, it is clear
how the decentering methodology will select these and give them
prominence in PC1. Are these valid temperature proxies? I quote from
our report, "Graybill and Idso (1993) specifically sought to show that
Bristlecone Pines were CO2 fertilized. Bondi et al. (1999) suggest
[Bristlecones] 'are not a reliable temperature proxy for the last
150 years as it shows an increasing trend in about 1850 that has been
attributed to atmospheric CO2 fertilization.' ... We also note that
IPCC 1996 report stated that 'the possible confounding effects of
carbon dioxide fertilization need to be taken into account when
calibrating tree ring data against climate variations.'" At the very
least, the effect of these proxies on temperature reconstruction
should be examined.
Figure 5 shows Dr. Mann's own illustration (MBH, Internet, 2003) of
the direct effect of North American tree ring data on reconstruction
results in the 15th century. Indeed, it is our understanding as
outsiders that all parties agree as to the significance of this tree
ring network to final results. And that has made the use of the tree
ring network a disputed issue.
Figure 6 is also a repeat graphic from my previous testimony. Please
note that the Bristlecone/Foxtail PC1 proxy is used not only in MBH,
but also in virtually every subsequent reconstruction. We do not
claim to be experts in dendrology, but it seems to us as outsiders
that there are sufficient confounding factors that proxies based on
Bristlecones should be avoided. We should add that we were specifically
asked to resolve the differences between MBH98/99 and MM03/05a/05b.
There is a bewildering array of subsequent work that we were not asked
to consider, but which probably deserves much more intense scrutiny. We
would include such refereed papers as Rutherford et al. (2005) and Wahl
and Ammann (2006), which are purported to be written by independent
teams, but which are co-authored by Dr. Mann himself in Rutherford et
al. and by Dr. Mann's student Dr. Ammann in Wahl and Ammann.
Indeed, far from there being uniform agreement on the hockey stick
shape, B�rger and Cubasch (2005) have reported that a discomforting
array of different results can be obtained from MBH proxies under
minor methodological differences. Figure 7 illustrates that while
there may be reasonable consensus on warming since 1900, i.e. the
calibration period, as the NRC report suggests, paleoclimate
temperature reconstruction past 1600 is much more problematic.
Indeed, on the matter of consensus, the NOAA website titled A Paleo
Perspective ... on Global Warming has the following contradictory
statements: "The latest peer-reviewed paleoclimatic studies appear
to confirm that the global warmth of the 20th century may not
necessarily be the warmest time in Earth's history, what is unique
is that the warmth is global and cannot be explained by natural
forcing mechanisms."
From http://www.ncdc.noaa.gov/paleo/globalwarming/paleobefore.html
Also from the same website: "In summary, it appears that the 20th
century, and in particular the late 20th century, is likely the
warmest the Earth has seen in at least 1200 years."
From http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html
We do agree with Dr. Mann on one key point: that MBH98/99 were not
the only evidence of global warming. As we said in our report, "In
a real sense the paleoclimate results of MBH98/99 are essentially
irrelevant to the consensus on climate change. The instrumented
temperature record since 1850 clearly indicates an increase in
temperature." We certainly agree that modern global warming is
real. We have never disputed this point. We think it is time to
put the 'hockey stick' controversy behind us and move on.
I would like to make it clear that our role as statisticians in
the hockey stick game is not as players in the hockey game, but
as referees. What we have seen and continue to see is that, not
withstanding the efforts by Dr. Nychka and others at NCAR, there
is relatively little interaction between the statistical community
and the climate science/meteorology communities although the
latter frequently use statistical techniques. Statisticians in
general have to pay their mortgages just like everyone else and
in general cannot afford to do pro bono work such as we have been
doing. We advocated in our report that if statistical methods are
being used, then statisticians ought to be funded partners engaged
in the research to insure as best we possibly can that the best
quality science is being done. Drs. Nychka and Bloomfield, the
statisticians involved with the NRC report, raise other issues on
calibration, validation, and full quantification of uncertainty in
these studies. Indeed there are a host of fundamental statistical
questions that beg answers in understanding climate dynamics.
Sampling
How were the 70 trees in NOAMER 1400 selected?
4 Arkansas
4 Arizona
13 California
12 Colorado
3 Georgia
1 Louisiana
1 Montana
1 North Carolina
5 New Mexico
14 Nevada
3 Oregon
1 South Dakota
3 Utah
1 Virginia
4 Wyoming
How representative are these trees of the population of trees
that grew from 1400-2000? In terms of geography, altitude, and
type. If these trees seemed "interesting" to various individuals
who took the core samples, do you believe those trees can/should
be treated as a "random sample"? Are there biases in the selection
of these trees? Presumably many trees could not be sampled because
they had died or been harvested. What is the effect of this
"censoring" on your data (and your analysis)? Similar questions
exist about ice cores and how representative such data might be.
What are the effects of gas diffusion in the ice core layers?
Analysis
What is the correlation between temperature and tree ring growth?
What calibration studies have been performed? The rescaling steps
taken seem to suggest that the correlation must be near 100%. Is
that the case? The temperature proxy search is a regression
problem. Why did you choose to use principal components (not
appropriate for finding a nonstationary mean)? What weights do you
use to combine different proxy types? Why? If the data are not a
random sample, then what confidence can be given to any modeling
and to any "error bars"?
Forecasting and Modeling
CO2 modeling shows a rapid increase in the near term. What do the
models show in the longer term? Given the apparent high
correlation between CO2 and temperature in the model outputs, how
direct is the link in the model itself? What is the difference
between a true forecast and a "model run"? Do you believe your
model runs have any statistical validity? The output looks like
a Taylor series with no higher order terms?
Planning Experiments
What data should be collected that would be most cost-effective in
increasing our understanding of the climatic models and the
underlying physics (and statistics)? Is all data valuable? How does
one avoid the desire to collect data at sites that appear
"interesting" beforehand? What are the parallels between modern
experimental science and experimental medical research of the 1960's?
How many surgeons were "certain" their treatments were superior or
that drugs were safe and found out otherwise with carefully designed
and controlled studies? Is the risk of global warming so acute that
such studies are deemed unwise?
Our report is not aimed at criticizing Dr. Mann or his colleagues,
but in outlining a path for doing the science better. We note that
the American Meteorological Society has a Committee on Probability
and Statistics. I believe it is amazing for a committee whose focus
is on statistics and probability that of the nine members only two
are also members of the American Statistical Association, the premier
statistical association in the United States, and one of those is a
recent Ph.D. with an assistant professor appointment in a medical
school. The American Meteorological Association recently held the
18th Conference on Probability and Statistics in the Atmospheric
Sciences (January, 2006). Of the 62 presenters at a conference with
a focus on statistics and probability, only 8 (12.9%) are members of
the American Statistical Association. I believe these two communities
should be more engaged and if nothing else our report should highlight
to both communities a need for additional cross-disciplinary ties.
MR. WHITFIELD. So at this time I will start off the questions,
and I would direct my first question to Dr. Mann and
Dr. Christy and Dr. Cicerone. If you look at the 1990 U.N.
report from the Intergovernmental Panel on Climate Change, it
is quite pronounced the so-called Medieval Warming Period.
And so the first question I would ask was there a Medieval
Warming Period, Dr. Mann?
DR. MANN. Let me tackle that first. Actually the graphic
you are referring to in the 1990 report was not an actual
numerical estimate. It was a schematic based on very limited
evidence in some parts of the globe, and that was actually
emphasized in the report that they based that schematic on very
limited information. Another interesting thing about that
plot is that it actually ends in 1975. Now there has been
roughly .5 degrees C of additional warming in the climate in
the Northern Hemisphere since 1975. And if you superimpose--
MR. WHITFIELD. How much since then?
DR. MANN. Point 5 degrees C additional warming since 1975.
MR. WHITFIELD. Point 5 degrees. Okay.
DR. MANN. Yes. So if you superimpose that on the end of
that 1990 curve where it stops in 1975 actually the modern
warmth is above the medieval peak. So it actually reinforces
the later conclusions shown in the 1996 report and the 2001
report.
But we have learned a lot since then. For example, we know
that the so-called Medieval Warm Period was actually fairly
cold in the tropical Pacific. There is coral data that tell
us that it was a La Nina like period. Now that means that
there were large parts of the global surface that were cold
at that time. As we learn more about the regional detail,
we realize that it is incorrect to simply label that period
as the Medieval Warm Period, and that is why most scientists
now call it the Medieval Climate Anomaly.
MR. WHITFIELD. Okay. Dr. Christy, would you make comment
about it?
DR. CHRISTY. Yes. Regarding the 1990 picture--
MR. WHITFIELD. The Medieval Warming Period.
DR. CHRISTY. Some places were obviously warm, other places
weren't, and it is one that doesn't look like it has a warm
period at that time but there were other places that were
warmer than today, I think.
MR. WHITFIELD. Okay. And Dr. Cicerone.
DR. CICERONE. I have nothing to add. I went back and looked
at the cartoon after last week's hearing and read all the
surrounding pages and I have nothing to add.
MR. WHITFIELD. Okay. Now Mr.--
CHAIRMAN BARTON. Mr. Whitfield, could I--
MR. WHITFIELD. Yes, sir. Yes, sir.
CHAIRMAN BARTON. Why do we call that a cartoon and these
others something different? I know the methodology is
different but I would assume that the 1990 graphic was based
on some mathematical evidence. It may not have been as
complicated with as many variables as Dr. Mann's later work,
but I don't think they just pulled that out of the air, did
they?
DR. MANN. Let me comment. Actually it is a schematic. It
is a cartoon. It was not a numerical estimate.
CHAIRMAN BARTON. They threw spaghetti up on the wall and
wherever it stuck is what they put in the chart.
DR. MANN. Guided by some qualitative interpretations of
historical climate records in a few locations in the Northern
Hemisphere. It was not a quantitative estimate of climate.
CHAIRMAN BARTON. There is no averaging, there is no data to
back it up?
DR. MANN. There is no numerical estimate that I am familiar
with that went into that calculation that went into that
graphic. There was no calculation.
DR. GULLEDGE. Mr. Barton, I have some--if you please. I
actually spoke to some scientists who a couple have actually
retired now who were involved in a 1975 NAS report on climate
change that actually used a figure like this. And I spoke to
Dr. Tom Webb who remembers the development of this figure and
it actually originated from somebody's lecture notes at one
time from the early '70s.
CHAIRMAN BARTON. There is no data set?
DR. GULLEDGE. That is correct. There is no data set that is
used in the production of this plot. There were studies where
they said it looks like the north Atlantic was warm. There
are studies that say China was cold. You know, we are
proposing that there may have been a warm period in the Middle
Ages, and to quote from the 1990 IPCC report in reference to
this figure it says specifically, "It is still not clear
whether all the fluctuations indicated in the diagram were
truly global." And that is directly from the report referring
to this diagram.
CHAIRMAN BARTON. Thank you, Mr. Whitfield.
MR. WHITFIELD. Yes, sir. Just referring to Mr. Inslee's chart
about CO2 concentration levels and temperatures going back
400,000 years, it is constantly up and down, constantly up and
down. Now is that something that we normally expect that CO2
emissions constantly go up and down for 400,000 years? Would
someone reply to that?
DR. CICERONE. May I respond?
MR. WHITFIELD. Yes, sir.
DR. CICERONE. The CO2 data comes from extracting gas
dissolved in ice as was explained last week.
MR. WHITFIELD. And where is the Vostock ice core, where is
that?
DR. CICERONE. It is at a particular region in Antarctica
where the ice is so thick that you can actually go back that
many years and do reasonable dating. It doesn't mean that
every year is exactly one year but it is pretty good resolution
so they crush the ice or melt it. The problem with melting is
some of the gas can dissolve in liquid so probably the safest
technique is to crush the ice and extract the air. The CO2
record is absolutely quantitative. It shows that through the
last four ice ages if you go back to 650 or 700,000 years when
the Earth was cold the CO2 amounts were low.
When the Earth was warm in between the ice ages the CO2 got
higher, and the range was about 180 to 280 parts per million.
Those are the natural cycles of the Earth. People have tried
very hard to say did the CO2 increase cause the warming or the
cooling or did the warming and cooling cause the CO2. The only
evidence that seems clear is that there were times when the
warming preceded the CO2 and the cooling preceded the loss in
CO2 but they are nearly linked in time. So people are
scratching their heads, what are the feedbacks that cause this?
How did these ice ages start? What triggered them? How do we
get out of them?
Methane amounts also track perfectly. When Earth was warm
methane was two-thirds of a part per million. When it was
cold it was one third of a part per million. Now we are at
five-thirds of a part per million so we are out of that range.
That is about all I can say. So the biological process that
release CO2 and methane were probably responsible.
MR. WHITFIELD. So it is continually going up and down. Would
you anticipate that it would go down at some point in the
future or do you feel like it is going to continue to go up?
DR. CICERONE. Well, the CO2 that is in the air now is 385
parts per million, which is 200 parts per million larger than
the 180 minimum at cold times and 100 larger than the CO2
maximum at hot times. It is going to take 200 years for that
CO2--if we quit putting CO2 in the atmosphere today and all
the plants decomposed, it would take a couple hundred years
for the CO2 to fall back to that region. It is not going to
happen.
MR. WHITFIELD. And what percent of all the CO2 being emitted
today would you say is man-made and what percent is natural?
DR. CICERONE. Well, the decay in biota and respiration and
geological processes put 100 gigatons of CO2 carbon in the
air each year. Combustion of fossil fuels puts in 6 or 7.
So the natural inputs are larger by far but the equilibrium
of the system as established as Professor North mentioned last
week is the processes that suck it up are about 100, so the
imbalance is the 6 or 7 and about half of that shows up in
the air and the other half seems to go in the oceans every
year.
MR. WHITFIELD. But the natural emissions are overwhelmingly
larger than man made but the man-made part is what messes up
the equilibrium.
DR. CICERONE. Well, numerically they are overwhelmingly
larger but the atmosphere seems to think otherwise because
the atmosphere is responding to the increase.
MR. WHITFIELD. Right. Now, Dr. Christy, you have done some
work on satellites, observations of the Earth's surface, and
I read a book a number of years ago entitled "A Moment on the
Earth" by a guy named Greg Easterbrook, and there was some
part of that where he talked a lot about the satellites were
not--the models being used to project global warming and the
satellite observations were not in sync. I am sure I am not
expressing it in the proper scientific way but hopefully you
may know what I am referring to.
And I know that some of the work that you did, you received a
lot of criticism or not criticism, but people were taking
shots at you also because you had an error in your work
relating to satellites and you were off like .035 percent of
one degree or something. But would you elaborate a little bit
about the satellite observations today and how that matches up
with the global warming that we hear about from a scientific
standpoint?
DR. CHRISTY. Yeah, it is curious. I have a couple papers
coming out this year, in fact, in which we show that the
evidence indicates the atmosphere is not warming as fast as
it is typically thought from enhanced greenhouse gases
particularly in the tropics, so that is the short answer.
MR. WHITFIELD. Okay. And these papers will be coming out
when?
DR. CHRISTY. I turned the page proofs back for one yesterday
so it is probably a couple months. The other one will
probably be about 3 months.
MR. WHITFIELD. Okay. My time has expired. Mr. Stupak.
MR. STUPAK. Mr. Chairman, as a courtesy to Mr. Waxman I am
going to yield my time to Mr. Waxman, and I will assume his
time when his time comes.
MR. WAXMAN. Thank you very much, Mr. Stupak. Mr. Chairman,
it is interesting that you are citing Gregg Easterbrook as
someone who in the past had been a skeptic, and he recently
wrote where he said "as an environmental commentator, I have
a long record of opposing alarmism. But based on the data I
am now switching sides regarding global warming, from skeptic
to convert."
MR. WHITFIELD. Well, I mentioned his name so you could bring
that up, Mr. Waxman.
MR. WAXMAN. All right. Dr. Mann, your work was extensively
criticized by Dr. Wegman last week. He criticized certain
statistical aspects of your work and provided testimony on
global warming more generally. However, Dr. Wegman isn't a
climatologist, and I would like to give you the opportunity
to respond to some of his statements from last week's hearing.
He stated, "Carbon dioxide is heavier than air." And "if the
carbon dioxide is close to the surface of the Earth it is
not reflecting a lot of infrared back." Would you care to
respond to that statement?
DR. MANN. Yes. It is a somewhat problematic statement on
a couple levels. First of all, of course the greenhouse
effect is not based on the reflection of radiation, it is
based on the absorption of outgoing radiation. Rather than
escaping to space it is radiated back towards the surface
and the surface has to warm up in response to that. So
reflections isn't involved at all. It is the process of
absorption, selective absorption.
The other problem with that statement is that the well
mixed atmospheric constituents, oxygen, nitrogen, carbon
dioxide, their distribution, their vertical distribution
in the atmosphere doesn't have to do with their weight or
their relative masses. It just has to do with the basic
force balances that act in the atmosphere. There is gravity
and then there are gradients due to the pressure of the
atmosphere and these two things have to balance out. And it
turns out that all of the well-mixed gases decay with the
same vertical profile falling to about one-third of their
surface concentration at roughly eight kilometers up in the
atmosphere. And that is true for CO2 as well as oxygen.
MR. WAXMAN. I thought that at the time, and I am glad to
hear your response because I knew there was something wrong
with that statement. When Dr. Wegman was asked about your
research since 1999 he stated that you had circled your
wagons "and tried to defend this incorrect methodology." I
would like to know if this is true. Did you continue to
use the same methodology or have you worked to improve your
approach since 1998?
DR. MANN. Thanks for the question. It is another troubling
statement that you quote there because of course my
collaborators and I have far from circling our wagons, we
have been spearheading efforts to develop more sophisticated
statistical methodologies for reconstructing climate and
rigorously testing those methods using climate model
simulation. We published a number of papers that show that
the methods we used performed very well in the context of
climate model simulations where we know the answer. We
don't have to guess because we have the simulation. There
were some other statements--
MR. WAXMAN. Well, let me asks you about some of the other
statements because he attempted to impeach your statistical
background by complaining that you used non-standard
statistical phrases in your research like "statistical
skill." Can you help us understand? Is this an unusual
phrase as Dr. Wegman suggests?
DR. MANN. That was another very odd statement on his part,
and I found his lack of familiarity with that term somewhat
astonishing. The American Meteorological Society considers
it such an important term in the context of statistical
weather forecasting verification that they specifically
define that term on their website and in their official
literature. And in fact it is defined by the American
Meteorological Society in the following manner: "A
statistical evaluation of the accuracy of forecasts or the
effectiveness of detection techniques." Several simple
formulations are commonly used in meteorology. The skill
score is useful for evaluating predictions of temperatures,
pressures, et cetera, et cetera, so I was very surprised
by that statement.
MR. WAXMAN. Dr. Wegman testified he thought global
warming "is probably less urgent than some would have it
be." He also discounted the impact of increasing the
planet's temperature by 2 degrees testifying that he would
"challenge anybody to go out and tell the difference
between 72 and 74 degrees Fahrenheit." Dr. Mann, the
impacts of climate changes are a well studied area. Does
Dr. Wegman have any basis for being so cavalier about
global warming?
DR. MANN. Well, just to provide some context. The
difference between the height of the last glacial period
when there was more than a kilometer of ice sitting above
New York City global temperatures were probably only about
4 degrees colder than they are today so that gives you
some idea of the dramatic nature of climate associated
with fairly moderate changes in global mean temperature.
Those changes in global mean temperature are often
associated with much larger changes in certain very
important regions like the Arctic where the warming over
the last century is much greater than the global mean,
and we have seen melting of perma frost and other impacts
of that.
MR. WAXMAN. He also said that global warming "must be
understood in the context which is that we have relatively
speaking a Little Ice Age, which everybody seems to
acknowledge, and so it is not so surprising that it is
warming if we are coming out of a Little Ice Age." Does
Dr. Wegman's statement accurately reflect the scientific
consensus?
DR. MANN. No. In fact, the implications are just about
the opposite of what he had stated. In fact, we know with
the climate models that we have today that embody the
basic physics of the atmosphere and the ocean and the
interactions between them, actually we can describe, we
can predict and explain the factors that underlied the
Little Ice Age and the fact that certain regions like
Europe cooled somewhat more dramatically than the rest of
the globe some time between the 17th and 19th Century.
It turns out that that is the response of the climate to
the changes in natural factors like explosive volcanic
eruptions and small changes in solar radiants that were
relevant to the past. Those same models that so successfully
describe the Little Ice Age tell us that there is no way to
explain the warming of the last century without the influence
of human beings on concentration of greenhouse gases in the
atmosphere.
MR. WAXMAN. So I shouldn't be nostalgic for that Little Ice
Age.
DR. MANN. Perhaps not.
MR. WAXMAN. Did Dr. Wegman ever contact you to talk about
your work or ask for any further explanation from you about it?
DR. MANN. No.
MR. WAXMAN. Some have criticized you for lack of willingness
to disclose your data and computer code. Could you briefly
tell us how you have handled the availability of your research?
DR. MANN. Well, first of all I would like to draw a
distinction between data and code. The statement was made
earlier here that I didn't make my data available until 2004,
and that is simply incorrect. Our entire data set was
available on the worldwide web several years before that. Now
a code, well, that is a different sort of thing. It is a
matter of intellectual property because it takes a lot of work
to implement the algorithm that one might be using to perform
a certain sort of operation, but as long as the algorithm is
available then other people can independently reproduce your
work without having the actual physical code.
And, in fact, that is what Dr. Wahl and Dr. Ammann have shown.
They have independently implemented our algorithm in a
different programming language that is available to anybody
who wants to go to their website to access it. As a matter
of fact, over the past few years we have been making all of
our codes available for all of the calculations that we do,
and that is actually a standard that many others in our
community, the climate research community, haven't really
followed, so we are sort of leading the way there.
MR. WAXMAN. Thank you. I want to ask Dr. Christy about this
because you stated that you provided your computer code to
other researchers when it has been requested, and you
specifically mentioned providing your code to Remote Sensing
Systems or RSS. Is that accurate?
DR. CHRISTY. We provide the part of the code that was in
question.
MR. WAXMAN. Well, I contacted RSS about your testimony and
Mr. Frank Wentz sent me a letter last night, and he wrote to
say, "Dr. Christy has never been willing to share his
computer code in a substantial way," and he provides the text
of a 2002 e-mail exchange between RSS and yourself. And
according to this letter when asked for your code, you replied
"I don't see how sharing code would be helpful because there
are at least seven programs that are executed (several
thousands lines of code) and we would be forced to spend a
considerable amount of time trying to explain coding issues
of the spaghetti we wrote." In light of this letter,
Dr. Christy, I would be interested if you care to clarify your
testimony because Mr. Wentz wrote further, "I think the
complexity issue was a red herring. My interpretation of
Dr. Christy's response is he simply didn't want us looking over
his shoulder, possibly discovering errors in his work. So we
had to take a more tedious trial-and-error approach to
uncovering the errors in his methods."
And then he went on to explain "RSS manages data software from
a large array of climate satellites." What do you say about
that? That sounds inconsistent with what you have told us.
DR. CHRISTY. We shared with them the parts of the code that
they were most concerned about. What is called the drift
effect was one of them. Because ours were machine dependent
and so on like that but we did share not only that but we
also shared the intermediate data to say, okay, if you
implement this code this is the intermediate data you should
get, and that is what they published.
MR. WAXMAN. I must say I am a politician as all the people
here at our dais are and all of us engage in politics as we
know it, but here is a session with scientists, and you went
ahead and attacked Dr. Mann, who is an accomplished and
respected climate researcher. I think you and Dr. Wegman
attempted to smear his good name. Now I just got a letter
from another person--
MR. WHITFIELD. The gentleman's time has expired.
MR. WAXMAN. --in your field who says that you haven't been
forthcoming, so I just want to point out to all of you, we
don't do the back biting as frequently as it seems to me that
some of you scientists seem to do to each other.
MR. WHITFIELD. But Dr. Christy did say that he shared part of
the code that he asked for.
DR. CHRISTY. Yes. They got what they wanted.
MR. WAXMAN. May I ask unanimous consent to put the letter
from Dr. Wentz in the record?
MR. WHITFIELD. Without objection.
MR. STEARNS. I would object, Mr. Chairman.
MR. WHITFIELD. Okay. Objection.
MR. STEARNS. I object just because I think staff should have
an opportunity to see the letter first.
MR. WHITFIELD. Okay.
MR. WAXMAN. I certainly would share it with staff. Assuming
staff sees no objection from the letter that I received last
night, I would like to--
MR. STEARNS. Mr. Chairman, you remember last time that I asked
a letter to be submitted to the record and they objected until
they saw it--
MR. STUPAK. But we put the letter in.
MR. STEARNS. I know, but I produced a letter for the gentleman.
MR. WHITFIELD. If I could have order a minute. We will look at
the letter. We will have staff look at the letter. In the
meantime I recognize the Chairman of the full committee for
10 minutes.
[The information follows:]
CHAIRMAN BARTON. We are about truth, and my guess is
Mr. Waxman's letter helps the truth so we will almost
certainly put that in the record. Dr. Mann, I read your
prepared testimony and I have listened to your synopsis, and
you said something that I didn't see in the prepared testimony.
Maybe it was there. You talked about scientists trying to
make certain they don't make categorical statements. I don't
know exactly but it sounded, to coin a phrase, plausible what
you said. Now in our opening statements my friends on the
other side, and they really are my friends. We get along a
lot better off camera than we do on camera.
Their opening statements seem pretty categorical to me.
Their minds seem to me to be pretty made up, that this is a
major problem and it is time to stop foot dragging and let's get
on and fix it. I don't quite have that religion yet. I haven't
been born again quite yet. And that is what this is all about.
If in fact all these things that my friends, Mr. Inslee and
Ms. Schakowsky and Mr. Waxman, believe so fervently are
literally factually true without question then we need to move
to problem solution.
But I look at these data sets, I look at these data points, I
look at these theories and things, and I see a sign curve
phenomenon where the Earth gets warmer, the Earth gets cooler,
the Earth gets warmer the Earth gets cooler. It certainly
appears that it is getting warmer faster in this century. It
is certainly plausible that it has got to be partially caused
by man-made emissions. But I think it is a little early to
categorically make some of the statements that my friends on
the Minority side are making.
And the reason that we asked you to try to provide your data
sets and your codes and stuff is because yours was the very
first one and it is referred to. Now there may be a hundred
since then and maybe we ought to look at all hundred of them
, but yours is the one even in the National--the science
review--Research Council review. It talks about that in the
executive summary. So do you feel--from everything I can
find out about you is that you are a very fine person and an
excellent scientist and totally dedicated to your work, but
do you think it is fair to ask you to try to let other people
verify that first study since it seemed to have such an
impact on the community?
DR. MANN. Well, no, I don't think it is unfair at all to
expect the scientific community to validate previous results
and to refine them, and that process has been occurring over
the past 10 years since our work was begun. I think the
National Academy members at their press conference said
something to the effect that they felt that the scientific
process had worked quite well in this area in that methods
have been refined, new proxy data have become available.
Multiple estimates are now available where there were three
at the time of the IPCC 2001 report. There are now more
than a dozen different estimates. There are also independent
model simulations--
CHAIRMAN BARTON. You don't think it is unfair to have a
little scrutiny to the--if it is a conclusion, anybody has a
right to a conclusion and an opinion but when it gets into
the mainstream that it is just a given that is what I take a
little exception to even today. Now I want to ask a
follow-up question. Dr. Wegman said when he tried to get
enough information to try to verify the model, verify the
algorithm, he says he had some trouble getting that. Now you
talked about codes and algorithms. What is the difference,
and I am not a statistician and I am not a climatologist or a
paleoclimatologist. What is the difference between a code
and an algorithm?
DR. MANN. Okay. Let me try to use an analogy.
CHAIRMAN BARTON. Use a simple one.
DR. MANN. I will do my best.
CHAIRMAN BARTON. The simpler, the better.
DR. MANN. Well, let's think of an algorithm is--suppose you
were trying to build a house. And you wanted to build a house
and the data would be the materials you need to build the
house, the nails, the wood, et cetera. The algorithm would be
the architectural plan. Now what would the code be? Well,
imagine that instead of builders you had a computer to make your
house for you. Well, the code would be implementing the
architectural plan by telling the computer to pick up the
hammer, pick up the nail, hammer it in. And so the code is
simply implementing the algorithm but the real scientific
process is embodied within the algorithm, and the algorithm is
what has been independently reproduced.
CHAIRMAN BARTON. What is proprietary about a formula or
mathematical model that tries to compute something as
gargantuan as world climate over 2,000 years? I don't see
anybody making any money on that. I mean if you put it out
there and said this is what is happening and try to predict
the future, why should that not all be made available in some
public way that independent reviewers can try to replicate it?
DR. MANN. Well, let me preface this by putting out that we
now as a matter of course do make available our codes that we
have written to implement these different methods and so the
Rutherford et al. paper that was shown earlier reproduces
essentially the original reconstruction, that entire code can
be downloaded from our website.
CHAIRMAN BARTON. If we asked, which we are going to, asked
Dr. Cicerone--we are going to ask him to review some of these
recommendations that Mr. McIntyre and Dr. Wegman and others
have made, but one of them is going to be that because the
stakes are so big and the consequences are so big that these
models and data sets and things be made available in some way
that they can be verified. Do you have a problem with that?
DR. MANN. No. I think this is a bigger question than one
that should be asked of me. There are bigger questions about
intellectual property rights, and people--the scientific
community and the policy makers need to work that out, what
is the balance between making sure that scientists are
allowed to write a code, spend a whole lot of time doing it
and be able to implement it and use it without immediately
having to turn it over to somebody else who suddenly then
gets all of their intellectual contributions over a several
year period. So I think there is a balance there. I don't
disagree with the premise of what you are saying.
And I think there is the issue that Dr. Christy brought up
earlier, if you take, for example, our 1998 work, well, that
was a program, I think you alluded to this last week, it was
written in Fortran and a fairly--
CHAIRMAN BARTON. I was stunned to know that that program
was still in existence.
DR. MANN. It is still more widespread than you might think
actually.
CHAIRMAN BARTON. What generation is it now because I was
up to Fortran 4.
DR. MANN. It was 90 and then--and we were back in F77,
Fortran 77 is what we wrote this program in. So there is the
issue of platform dependence. And now we are getting away
from that. For example, we write all of our codes now in MAT
Lab, which is a portable programming language and anybody who
has MAT Lab can implement it. And that is the direction
things are moving but to apply the standard to work that was
done 10 years ago may be unfair because the standards have
changed.
CHAIRMAN BARTON. Dr. Christy, I read your testimony, and I
want to compliment you on its preparation and your
forthrightness. On page 11 you talk about, in the second
paragraph, that the issue of climate model evaluation has
been performed mostly by the modelers themselves. It is
my view, this is you speaking here, and recommendation that
policy makers would learn much from independent hard-nosed
assessments of these model simulations by those who are not
directly vested in the outcome. Some of this is going on
but the level of support is minimal. Do you still stand by
that?
DR. CHRISTY. Yes, I do. I think probably any scientific
endeavor could stand with independent eyes looking over it.
CHAIRMAN BARTON. Dr. Cicerone, do you agree with that
statement?
DR. CICERONE. The more the merrier. I have done a lot of
mathematical modeling maybe 15 or 20 years ago, and I
remember efforts to try to compare models where
unfortunately what happened was everybody said, well,
let's put the same assumptions in the models and see how
they do. And I think it worked against the science because
it created less independence. So to do this kind of
exercise I think we have to take everything into account but
generally it is a good idea in my opinion.
CHAIRMAN BARTON. I know I am over time. I want to read one
more paragraph in Dr. Christy's testimony because it kind of
encapsulates the policy dilemma that we are faced with and
ask the panel to comment on it. And I am quoting, "To
understand the scale of what we are dealing with this serves
as a rough example. We know that we on Earth benefit from
10 terawatts of energy production today. To achieve a
reduction of the CO2 representing 10 percent, 1 terawatt, of
that production we need 1,000 nuclear power plants at 1,000
megawatts each. Massive implementation of wind and solar
does not achieve this result and would not provide the
baseload power needed by the economies today in any case.
Thus, to have a 10 percent impact on emissions from energy,
that is growing at the same time, will require a tremendous
and difficult and expensive restructuring of energy supplies."
So even if we accept the problem and move to solution to get
a 10 percent reduction in CO2 takes 1,000 megawatt nuclear
power plants and it probably doesn't have any impact for 50
to 100 years. Do you all want to comment on that, anybody,
other than Dr. Christy, which you can. It is your statement.
DR. CHRISTY. I would just say the energy committee is where
a lot of this is going to be done and that is just to give
you an idea of the scale of what you are going to be
tackling, I think, in the next few years.
CHAIRMAN BARTON. That is why I am still a skeptic. I don't
want to jump in there especially if this is a naturally
reoccurring phenomenon that is exacerbated by human emissions
but it is going to happen regardless of what we do.
Dr. Cicerone.
DR. CICERONE. The numbers that you just summarized from
Dr. Christy are really intimidating. I agree with you. I
would like to see us all get together with the elements of a
win-win strategy. There are some actions we can take as
first steps, I think, which are truly win-win, and they have
to do with energy efficiency. Just look at it from the
United States point of view. If we could decrease our
dependence on foreign energy we would improve national
security, we would decrease the trade deficit, we would, I
think, stabilize geo politics a little, we would increase
national competitiveness by making our manufactured products
cheaper.
When energy prices are high you know better than I our
manufactured products have to bear that increase. We could
develop new products which would create new world markets
and we could be leaders. We would decrease the energy costs
for households and incidentally slow down the emissions of
CO2. So I think we need a win-win strategy and we can take
a bite out of that 1,000 gigawatts with energy efficiency.
CHAIRMAN BARTON. My time has more than expired so I
apologize. Thank you all for being here.
MR. WHITFIELD. I recognize Mr. Stupak of Michigan.
MR. STUPAK. Thank you. We were talking about that Fortran
4 program, and I was just wondering was that during the
Medieval Warming Period we have been talking about? If I
may, Mr. Chairman, when I gave my opening statement I had a
couple of exhibits. I should have asked at that time that
they be made part of the record with my opening statement.
It is the Interfaith Stewardship Alliance that I mentioned
and how they were funded by ExxonMobil, so if I may without
objection put that as part of my opening statement.
MR. WHITFIELD. And we have a copy of it.
MR. STUPAK. Yes.
MR. WHITFIELD. Thank you.
MR. STUPAK. Dr. Cicerone, just speaking of the Medieval
Warming Period as it was described in the Wall Street
Journal. We talked a little bit about it earlier. In
fact, are we even sure that even happened in the Northern
Hemisphere, that Medieval Warming Period that the Wall
Street Journal talked about, that was that chart there,
the 1990 chart that we had some discussion about earlier.
DR. CICERONE. I am sorry. Were you addressing that to
me, sir?
MR. STUPAK. Yes, sir.
DR. CICERONE. Okay. There were certainly records of
warm places in that period of time.
MR. STUPAK. Warm places and cold places.
DR. CICERONE. The question continues to be how extensive
was it, how long did it last, and how solid is the
evidence. But, yes, there is evidence of a Medieval Warm
Period, but no one can sit here and tell you how
geographically extensive it was with strong evidence and
how long it lasted. But, yes, there was a Medieval Warm
Period.
MR. STUPAK. Dr. Crowley says that even though it was
difficult to unequivocally assert that the current warming
period is significantly greater than the peak warmth of
the Medieval Warm Period there is even less justification
for saying that the medieval period was warmer than it
is today, is that correct?
DR. CICERONE. The committee that Professor North
reported on, Professor North from Texas A&M, last week
representing the National Research Council, I am pretty
sure what they concluded was there was no evidence that
that period was warmer than say the year--the decade of
the 1990s through 2006.
MR. STUPAK. But were considerably warmer?
DR. CICERONE. They could not say with strong evidence
that each year in the 1990s was warmer than then but there
was no evidence that the Medieval Warm Period over an
extensive geographical region was as warm as the Northern
Hemisphere is now.
MR. STUPAK. Is it fair to say then that neither the
pro-hockey stick researchers or the anti-hockey stick
researchers can talk with scientific certainty about this
medieval period, would that be correct?
DR. CICERONE. In certain locations they can where there
were records kept, but the question again is how does one
location compare with all the others. For example, some
proxy indicators from China inferred what the temperatures
were from agricultural crops and stream flows and so
forth, which are pretty extensive, but it is hard to
compare the timing of those with other strong proxies
from elsewhere.
MR. STUPAK. Let me ask you this question then. This is the
second hearing we have had on this hockey stick theory, but
you were on the National Academy of Science panel that looked
at these studies. Are you telling us basically forget the
hockey stick and the Medieval Warm Period, it is a
diversion? Is it your position that global warming is
occurring now in the 20th and 21st Century? Human beings are
at least partially responsible. Our climate will continue to
change during the next century and we ought to pay attention
to it today. Is that fair to say?
DR. CICERONE. Well, I wouldn't say forget the hockey stick
and efforts to reconstruct because what we can learn, and if
we work harder we might be able to learn some more about the
context, it is still important, but, yes, all the other
evidence shows us that the climate is changing and that the
human hand is there causing at least part of the warming and
that everything we know from physics and chemistry and
mathematics is that it is going to continue as long as we
continue to load up the atmosphere with greenhouse gases.
MR. STUPAK. Do you think it is useful then, Doctor, for us
policy makers to hold hearings on just one 8-year old study,
Dr. Mann's study, that your committee found was not even the
principal evidence for the conclusion about current warming
period?
DR. CICERONE. I hope that it has been useful. I have
never seen this kind of interest before. I think a couple--
I have forgotten who said it earlier on about that this
could be--perhaps it was Mr. Bass, who said this could be
the beginning of even more serious interest. So I guess I
will wait and see what happens.
MR. STUPAK. If there is so much interest in this one and if
in the Vice President's book he talks about 928 more peer
reviewed articles, so that means if we have two hearings for
every one of these we would have about 1,800 hearings just
on global warming. I guess that would be a sufficient
amount to get everyone's attention. Let me ask this
question if I can. There has been a lot of discussion about
social networking, and I think it is a practice that is not
utilized, should not be utilized. Peer review and whether
it is an accepted practice, isn't it, in paleoclimatology
field, social networking, Dr. Cicerone?
DR. CICERONE. No. No, that was I guess kind of an original
piece work. It is not common.
MR. STUPAK. Have you looked at or have you reviewed
Dr. Wegman's social network analysis of the paleoclimatology
field?
DR. CICERONE. Last week at the time of the hearing I got a
copy and I read it.
MR. STUPAK. I know that the National Academy of Science
has done research of social networking analysis. Do you
have any views you would care to share with us about the
field of research?
DR. CICERONE. Not today. I think there is probably some
developments that have taken place in the classified arena
that I am not totally up on that I would like to find out
earlier before I would comment.
MR. STUPAK. Is it a relatively new field?
DR. CICERONE. Graph theory, the kind of statistical
patterns, I think so. I haven't seen it applied to this
kind of a field of study before.
MR. STUPAK. What do you think of Dr. Mann's social network
analysis of the paleoclimatology field? Dr. Wegman's. I am
sorry. I said Dr. Mann's. Dr. Wegman's.
DR. CICERONE. I have no further comment.
MR. STUPAK. Okay. Dr. Wegman, in looking at your report
here today and your testimony, I am on page 6, if you would,
sir, and I am looking at the paleo perspective on global
warming. And you say these are contradictory statements, and
I guess I am a little confused on it and maybe you could help
us out. It says the latest--and I am quoting the first here,
the first paragraph on page six. You got it there?
DR. WEGMAN. Yes.
MR. STUPAK. "The latest peer-reviewed paleoclimatic studies appear
to confirm that the global warmth of the 20th Century may not
necessarily be the warmest time in Earth's history, what is unique is
that the warmth is global and cannot be explained by natural forcing
mechanisms." And it says also from the same website, and this is a
NOAA website, "In summary, it appears that the 20th Century, and in
particular the late 20th Century, is likely the warmest the Earth has
seen in at least 1,200 years." How is that inconsistent? You said
contradictory statements. How is that contradicting?
DR. WEGMAN. Well, at one stage people are suggesting that
it is the warmest and another stage it is saying it not
necessarily the warmest. Being likely is a phrase that has
been bandied about quite a bit.
MR. STUPAK. But aren't those really different time frames?
One is talking about 1,200 years, the other one is talking
about the 20th Century and Earth's history, it seems like,
because one says the 20th Century and particularly the late
20th Century is likely the warmest, and the other one is
talking about the earth's history. So that is why I didn't
see it as inconsistent. One is talking about 20th Century,
late 20th Century, and the other one is talking about all of
Earth's history, so that is why I didn't see the
inconsistency. Do you see what I am saying, those two
statements?
DR. WEGMAN. Yes, sir, I see what you are saying.
MR. STUPAK. Dr. Mann, if I may ask you a question. I want
to go back to this social network. Dr. Wegman has
hypothesized that you have a social network of 42 other
scientists and that they cannot independently evaluate your
work because they have at various times co-authored work
with you. This may be based on his belief that people who
interact regularly will foster a common attitude or
identity. What is your response to that?
DR. MANN. Well, frankly, I was a bit baffled by that
finding. My profession is highly competitive. We often
disagree publicly. Scientists disagree publicly and in
our articles, with each other on certain matters, and yet
we can co-author on other areas where we agree so there is
no contradiction in--
MR. STUPAK. Well, do you have peer review of your articles
by people who don't agree with you?
DR. MANN. I have probably had articles rejected because of
reviews by people who were co-authors with me on other
articles. In fact, I am quite certain that is the case. Of
course, Dr. Christy and I are co-authors and yet there are a
lot of issues in the science that we don't agree on. So I
was very surprised by that. I was flattered by that. The
implication that as a post doc when I started this work back
in the late 1990s that I was sort of the center of the entire
field of climate research but it is as incorrect as it is
flattering.
MR. STUPAK. You don't dominate the thinking of the entire
paleoclimatology community, do you?
DR. MANN. Well, I don't know if I do now but I am sure I
didn't back in the late 1990s.
MR. STUPAK. My time is up. Thank you, Mr. Chairman.
MR. WHITFIELD. Thank you. At this time I recognize
Mr. Stearns of Florida.
MR. STEARNS. Thank you, Mr. Chairman. Mr. McIntyre, you
are the only one who doesn't have a Ph.D. here on the table
so I thought I would ask you this question. As I understand
your background, your undergraduate degree is mathematics.
Is that from Oxford?
MR. MCINTYRE. My degree in mathematics was from the
University of Toronto but I attended Oxford subsequently. I
think my stay there probably overlapped with that of
President Clinton's.
MR. STEARNS. Oh, good.
MR. MCINTYRE. I think we might have played rugby against
one another.
CHAIRMAN BARTON. We hope you did a little more studying than
he did.
MR. STEARNS. Well, you know, I just want to give you your
due here. We have heard in testimony that Drs. Wahl and
Ammann have reproduced Dr. Mann's work and shown your
criticism to be invalid, and I guess--is this true and were
your criticism erroneous? I will give you an opportunity to
respond to that.
MR. MCINTYRE. Well, a couple of points. First of all, the
code that we used to emulate Dr. Mann's work reconciles
almost exactly with that of Wahl and Ammann. And so any
conclusions that differ are not because of differences in
how we have emulated the reconstruction. They think that
certain steps are fine, we don't. They have in my opinion
not carefully considered the implication of bristlecones.
Our codes reconcile so right now I am confident in our
conclusions that if you remove the bristlecones you have a
major impact on the final results.
Last December, I met with Ammann in San Francisco and
suggested to him that since our codes reconciled so closely
that it would make sense if we co-authored a paper in which
we set down the points that we agreed on, set down the
points we disagreed on in an objective way so that we didn't
seem to be launching missiles at one another and creating
more controversy. I said that we could declare an armistice
for 6 weeks until we accomplished this, and if we didn't get
to conclusion everybody would go back to square one and that
each of us could write separate appendices, say where we
disagreed.
I formally sent e-mails to him suggesting that. He told me
in San Francisco that if he did that that that would
interfere with his career advancement.
MR. STEARNS. Dr. Wegman, I am going to give you an
opportunity to respond to some of the testimony today. The
testimony of both Dr. Gulledge and Dr. Mann draw upon the
findings of Dr. Wahl and Ammann to suggest your work
doesn't matter. Let me give you an opportunity to respond
to that.
DR. WEGMAN. Well, I think although the social network
analysis has been sort of dismissed the amazing thing to me
is that these supposed independent replications of the
original Mann work are done by Rutherford et al., which
includes the top seven people in the social network that we
identified last week. Every one of them is in there, and
they are frequent co-authors with Dr. Mann. So I can
hardly see how that is an independent replication of his
original work.
Secondly, on Dr. Mann's r�sum� he lists Dr. Ammann as one
of his students as a co-advisor to him although Dr. Ammann
does not list him as an advisor. But it is clear to me
that Wahl and Ammann are not independent agents as well.
MR. STEARNS. And that goes to this idea of the social
network you are talking about?
DR. WEGMAN. Yes. We never claimed, by the way, that
Dr. Mann was, in 1998 as a post doc was the center of the
social network. What we are saying is that subsequently
he has 42 co-authors many of whom, particularly the top
seven in the block we identified, who are frequent
co-authors with him and co-authors with each other, and
there is some element of thinking that if they are frequent
co-authors they are thinking the same way.
MR. STEARNS. Is there anything else that you have heard
Dr. Mann say earlier that you would like to comment on?
You are welcome to go across the spectrum.
DR. WEGMAN. Well, first of all, in the question that
Mr. Waxman mentioned about the carbon dioxide distribution,
that was prefaced by a comment by me that I didn't know
anything about this but I suppose, for example, that carbon
dioxide, so that was purely a hypothetical conjecture which I
did not mean to be taken as testimony. It was also clear in
the discussion that even Dr. North talked about a barrier of
carbon dioxide at high levels of the atmosphere so he gave in
his diagram an illustration that carbon dioxide was not mixed
so that certainly is something that should be clarified. I
did not mean to testify that carbon dioxide sat at the ground
level. That certainly was not what I was saying.
MR. STEARNS. Any other thing that has come up that you wish
to comment on either that Dr. Mann or others have spoken on
or perhaps we as members have spoken on you would like to--
DR. WEGMAN. Well, I stand by the statements that I have made
and particularly in the written testimony that I didn't get a
chance to comment on. My own sense is that if you look at,
for example, this matter of statistical skill, it doesn't
matter that the American Meteorological Society says what
statistical skill is. Statisticians do not recognize that
term. I went around to a whole dozen or so of my
statisticians network and asked them if they knew what they
were talking about. It is my contention that there is a gulf
between the meteorological community and the statistical
community.
We examined, for example, this committee that is on
probability and statistics of the American Meteorological
Society. We found only two of the nine people in that
committee are actually members of the American Statistical
Association, and in fact one of those people is an assistant
professor in the medical school whose specialty is
bio-statistics. The assertion I have been making is that
although this community, the meteorological community in
general and the paleoclimate community in particular, used
statistical methods. They are substantially isolated. They
are using our methods but not talking to us. In contrast,
we are not doing meteorology and--
MR. STEARNS. You are talking to them.
DR. WEGMAN. We are talking to them.
MR. STEARNS. I understand.
CHAIRMAN BARTON. Would the gentleman yield just for
clarification, please? Dr. Mann in his testimony referred to
this Dr. Ammann and Wahl study who said they have recentered
the data and the conclusion is the same if I understood him
correctly. Could you comment on that because one of your
points was when you center it correctly the conclusions don't
follow.
DR. WEGMAN. The studies are done in different ways. There
is the so-called CFR methodology, the CPS methodology, and in
I believe it was Dr. Mann's 2005 report he illustrates several
different studies that do this. One of the things that is
critical is the set of proxy data that you use when you are
trying to replicate these studies. And in fact if you use a
nice set of proxies that all have the same signal in them
then it really doesn't matter a whole lot what methodology you
use. If you use a very mixed set of proxies that have some
noise and different kinds of structure in it then it does
matter what kind of--
CHAIRMAN BARTON. It goes to Mr. McIntyre's point that
depending on the data set you use it is the result you are
going to get.
DR. WEGMAN. That is right.
CHAIRMAN BARTON. If I understood him correctly.
MR. STEARNS. Reclaiming my time. Mr. Christy, Dr. Christy,
have you read Dr. Wegman's report, and, if so, what is your
opinion of his working conclusion? I understand you are one
of the individuals that was in the group that developed the
National Research Council on surface temperature
reconstruction of the last 2,000 years, so I would
appreciate, Dr. Christy, your comment.
DR. CHRISTY. This is the short answer. I have not read
the report.
MR. STEARNS. You have not read the report?
DR. CHRISTY. No, I am sorry.
MR. STEARNS. Okay. Dr. Cicerone, you are the President of
the National Academy of Science. Dr. Wegman is an appointed
member of the National Academy of Science Board of
Mathematical Sciences and Their Application. He is chair
of the NAS Committee on Applied and Theoretical Statistics,
highly credentialed in math and statistics, wouldn't you
say? Shouldn't we take his judgments on statistical matters
very seriously, and don't they carry significant weight?
Would you say his judgment about statistical matters is
important and that he has credibility based upon those
credentials?
DR. CICERONE. Yes.
MR. STEARNS. So there is some attempt by some folks to make
some of his findings not correct but based upon what you just
said this man is highly credible in math and statistics and
we should take his judgment particularly on statistical
matters with a high credibility?
DR. CICERONE. Yes, but not on the mixing of gases.
MR. STEARNS. Not on the mixing of gases. All right. Thank
you, Mr. Chairman.
MR. WHITFIELD. The chair recognizes Mr. Inslee. Oh, no,
Ms. Schakowsky. I am sorry. Ms. Schakowsky.
MS. SCHAKOWSKY. Thank you, Mr. Chairman. I want to begin
by referring to the end of Dr. Christy's testimony where you
drew on a certain kind of expertise where you were a
missionary in Africa, and you end with a plea. And I just
want to quote from the testimony. It says, speaking of the
people in Africa you say, "They are far more vulnerable to
the impacts of poverty, water, and air pollution, and
political strife than whatever the climate does." I actually
found that to be a pretty strange comment from someone who
is the chair of the Earth System Science Center and deal
with climate.
And I wanted to actually ask Dr. Cicerone don't those issues
of certainly of water and air pollution, et cetera, are they
unrelated entirely to issues of climate?
DR. CICERONE. No. Of course they are related. I don't
know what Dr. Christy would answer to the question of what
he meant, but, yes, it is clearly related.
MS. SCHAKOWSKY. So I was really confused by that because,
first of all, I have to tell you I resented that a little
bit. I close with a plea to remember the needs and
aspirations of the poorest amongst us when energy policy is
made as if to say that those of us who would ask for some
changes in business as usual and energy as usual somehow
are not taking into consideration the poor people of Africa.
So I found that a condescending remark, I have to tell you.
But are not those things--because I have to tell you,
Dr. Christy, that precisely for the reasons of the kind of
impact it will have on human life including drought and
exacerbating poverty and even you mention political strife,
war water actually do worry me a bit. So how do you
segregate that from climate issues?
DR. CHRISTY. Was that water wars?
MS. SCHAKOWSKY. You said political strife. I would say
that if we end up with a situation where people are fighting
over water or limited food supplies because of drought that
that could be related to the climate, could it not?
DR. CHRISTY. We don't know what is going to happen, for
example, with the water cycle as the climate evolves so--
MS. SCHAKOWSKY. The overall statement about water and air
pollution, are they unrelated to climate?
DR. CHRISTY. We know today that people die because of water
pollution, air pollution and those other things. Those are
issues that we know today and can assess and determine how
answers and solutions can be found. So those are critical
things to do today. And I am sorry if that last line came
across condescendingly. When you live with the people as I
did you know that they don't have much of an advocacy in
places.
MS. SCHAKOWSKY. Actually in the Congress they do have a
number of people who care and advocate on their behalf. I
wanted to get to that and it is a perfect lead into the
Chairman's question, and what do we know, this was his
question, and so I wanted to look at Dr. Gulledge's materials
that he provided. And again I would like to ask him or
anyone, it says in your presentation, Dr. Gulledge, human
activities are increasing atmospheric greenhouse gases, that
that is unequivocally agreed to in the scientific community.
The Earth is warming unequivocal at an unprecedented rate,
confident, so somewhat less.
Warming over past five decades caused primarily by man-made
greenhouse gases, confident. So let me add one more preface
to this question that I would like to put to the panel, first
of all, the question of agreement. We have a panel here
where it is three and three, so if there is a reporter
looking at this they would say, well, there is three people
who agree with this, three that don't, so there is a split
here. So part of my question is does the disagreement over
your unequivocal, unequivocal, confident on this panel
reflect the scientific community in any kind of accuracy.
And I would like to just question these unequivocal and
confident ratings.
DR. GULLEDGE. Well, I am not sure if you are describing the
panel as being three against three on whether they agree with
these statements or not, but I suspect that it might not
fall out exactly that way.
MS. SCHAKOWSKY. Okay.
DR. GULLEDGE. It might vary among some of the lower
statements and then--
MS. SCHAKOWSKY. Then let me ask this, let me ask the
panel. Is there anyone who disagrees with the
unequivocal--that it is unequivocal that human activities
are increasing atmospheric greenhouse gases? Is there
anybody? Okay, good. That the Earth is warming? Okay.
And at an unprecedented rate?
DR. CHRISTY. What is the confidence level on that?
MS. SCHAKOWSKY. Confident.
MR. MCINTYRE. I don't know that it is unprecedented.
MS. SCHAKOWSKY. Actually I wanted to ask you--I hope you
don't think this sounds rude but when I looked at the
witness list I see, you know, everyone has got kind of a
credential and then it just says your name, so I wanted
to ask you about your credentials, Mr. McIntyre, and
perhaps it gets into social networks because when I asked
for your resume what I found was: for the last 16 years I
have been an officer and director of several small public
mineral exploration companies, previous to that I worked
for a large international mining company, and that mainly
it is your experience in mineral exploration industry that
you tout in your resume and your background. I don't know
if that gets to social networks or not.
MR. MCINTYRE. Well, in this case this has nothing to do
with any work that I have ever done. I just became
interested in it as a citizen when I read the studies, and
I thought that politicians were facing difficult policy
decisions so I thought that it would be interesting to
examine one particular paper which was being cited by the
Canadian government. It wasn't clear to me how people
knew that 1998 was the warmest year in the millennium, and
I was just interested in how--
MS. SCHAKOWSKY. So are you qualified to make a judgment
on whether or not the Earth is warming at an unprecedented
rate?
MR. MCINTYRE. For the things that I have published on, my
statistical and mathematical skills are adequate for what
I have published on. The findings that we have had about
principal components have been--
MS. SCHAKOWSKY. But are you qualified to comment on whether
or not the Earth is warming at an unprecedented rate?
MR. MCINTYRE. Well, you asked whether the people knew or
didn't know. I am just saying I didn't know.
CHAIRMAN BARTON. Will the gentlelady yield?
MS. SCHAKOWSKY. Yes.
CHAIRMAN BARTON. That group is much more qualified than I am
to comment on these things, and yet I have the responsibility
as Chairman of the committee to put the bill together to
change the way Americans work every day if we decide to do
something about it.
MS. SCHAKOWSKY. Absolutely. Absolutely.
CHAIRMAN BARTON. The least qualified--I will stipulate--
MS. SCHAKOWSKY. And me too. I am with you.
CHAIRMAN BARTON. The quality of the commenters is more on
that side of the dais than at least it is in the Chairman's
chair. I am not going to comment on anybody else's
qualifications but in a democracy anybody with an opinion is
entitled to express that opinion and some are more qualified
than others obviously because of their credentials, but I
don't think we have a standard of witnesses that says unless
you have a Ph.D. you cannot testify before--
MS. SCHAKOWSKY. Well, actually we are having a--reclaiming
my time. Actually we are having a conversation today about
the science here so it is not just about opinion, and it is
relevant, I think, to talk about. And Dr. Wegman has been
pretty up front about what he is qualified to testify to and
what he is not, and I think that that is fair and it is fair
to ask for individual's backgrounds and what their connections
or interests might be. That is the kind of conversation that
we are having.
But what I really wanted to get to was your question about
what is it that we know, and if there is pretty wide agreement
or no comment because you don't know that human activity is
increasing atmospheric greenhouse gases and that the Earth is
warming and that it has certain consequences. Mr. Chairman,
when you said that you are a skeptic the difficulty of the
task at hand to me is not a reason to be a skeptic about the
science.
Admittedly, this is a daunting task, and we heard about the
1,000 nuclear power plants or whatever it could take, but we
also heard practical suggestions from Dr. Cicerone about
energy efficiency that we could make a start on this. And
so if there is widespread agreement that human activity is
contributing to this that this climate--that the warming of
the climate is happening, that it can have very detrimental
effects. I am anxious to understand why we don't just move
toward solution at this point, and that is what I really was
getting to so I have over stepped my time, and I thank you,
Mr. Chairman.
MR. WHITFIELD. Thank you. And at this time I will recognize
Mrs. Blackburn of Tennessee.
MRS. BLACKBURN. Thank you, Mr. Chairman, and you all are
very patient with us. As I said in my opening remarks, I
think a lot of this is born out of curiosity of knowing what
the truth is and being able to have some answers. And I will
tell you one of the reasons I have such an interest in this.
I have a mom who is 81 years old who has been very involved
in conservation efforts all of her life. She won the Keep
America Beautiful Lifetime Achievement Award here about 15
years ago, and she is very careful in her instruction to her
children and her grandchildren that one of the things we
have to be very careful about is environmental extremism
which many times hurts our argument for actually being good
conservationists and leaving this Earth in better shape than
we have found it.
And so when we have studies that seem to go around the horn
and then they can't be substantiated and they are coming out
as government proof as something it does cause us questions.
And as I mentioned, we have been through this thing and we
have talked about it and I have talked about how when I was
growing up in the 60s that, the thing was that it was going--
we were going to be in an ice age or have a return of the
ice age. And then I guess that there were some schooled
scientists, if you will, some of your colleagues maybe who
found that that was not going to be so.
So I think it is important that we have the opportunity to
visit with you and find out what is an item of agreement
and what is not an item of agreement. And, Dr. Mann, if I
could have your attention for just a few moments if you
don't mind, I would like to direct my question, my opening
question, to you. You have said that other studies have
confirmed your results, but it does not appear that their
statistical analysis has been thoroughly examined, and I
wanted to know if you would be open to a review by an
independent team of top statisticians of climate change
papers before those papers get published.
You know, I think Dr. Christy had mentioned that in some of
his work there were some flaws that were found. He mentioned
that in his testimony and then they submitted to that. So if
we are going to put government money into papers should they
be reviewed by others other than your social network before
they are published with government funds and considered to be
the truth?
DR. MANN. Well, I think there is a misunderstanding about
the nature of peer review as it currently exists with
scientific journals, and there have been some misstatements
along these lines in the previous comments by some of the
others on this panel. For example, two of the studies that
have shown that the centering convention in PCA doesn't
make a difference in the reconstruction as shown also by
Dr. Gulledge were done by groups that are entirely
independent of me and my collaborators, von Storch and
Zorita. In fact, von Storch and Zorita and I and my
collaborators have had vigorous disagreements in the peer
reviewed literature.
So one of the studies that actually validated our approach
in showing that the centering convention doesn't make a
difference was by that group. Another scientist at Woods
Hole, Peter Huybers, if I could finish that, also came up
with the same result so there are four different studies,
only one of which I was connected with that came to that
conclusion so the peer review process is actually working
quite well.
MRS. BLACKBURN. My question to you is do you think that
they should be submitted for independent review before they
get published?
DR. MANN. Well, that goes on so again it requires an
understanding of what the peer review process at the major
scientific journals actually is. For example, with Nature
and Science when they receive a paper that involves both
statistics and climatology you can be certain that they
will seek out leaders in the world's scientific community
in all of the relevant areas before they make a decision
about the publication of that paper, and that is standard
in most of the leading journals.
MRS. BLACKBURN. Now let me ask you this then. If your
work were submitted to an independent group and they had
questions or found items that needed to be changed would
you be willing to make those changes prior to that work
being published?
DR. MANN. Again, as I have tried to convey to this
committee in my earlier testimony and some of my earlier
responses to questions, in fact, that has been going on for
more than 10 years now. My collaborators and I have been
re-examining the data. Other groups have been re-examining
the data, testing different methods, testing the methods
with climate models simulations, figuring out which methods
perform well, which methods don't perform so that process
is ongoing. It has been going on for more than a decade
now and that is how scientific progress works.
MRS. BLACKBURN. Thank you. Dr. Wegman, your thoughts on
those questions?
DR. WEGMAN. Well, I think, first of all, we disagree on,
you know--Dr. Mann did not answer your question which was
if--
MRS. BLACKBURN. Absolutely he did not answer my question.
DR. WEGMAN. If you would submit to a statistical review
panel, would you be willing to do that. He did not answer
that question. And one of the troubling aspects of this
paleoclimate and the meteorological community in general
is that they don't have interaction with statistical
people even though they used statistical methods heavily.
We have examined this group in general as I mentioned
before with Mr. Stearns. We have tried to examine this
to see the engagement of the meteorological community,
the paleoclimatology community with the statistical
community, and it is almost non-existent, so they are not
interacting with our group although they are using methods
that are based in the statistical literature.
I would like to see, frankly, I would like them to be
engaged with us. I think it would be a good idea. What we
were trying to do in our testimony was create a path to a
better way of doing the science essentially saying that
these are two groups that should be interacting and in some
sense it behooves the meteorological community to be
interacting with us. They are using our methods. We are
not using their methods. So I think it would be an
important thing to do and I--
MRS. BLACKBURN. Let me ask you very quickly too, I had
Michael Crichton's testimony that he had before the
Senate. Let's see, I think this was in '05. And he was
talking about having a--that government grants should
require a replication package which would provide some
transparency as part of their funding where posting that
package online so that saying that if it is funded with
government money there is no reason to exclude anyone from
reviewing the data that is found in research. Is that the
type thing that you think would be appropriate for
transparency?
DR. WEGMAN. As I said last week in one of our conclusions,
basically when there is important public policy and human
health implications this stuff ought to be subject to
exceptionally more intensive review. We drew the NIH model
out last time talking about the FDA and how the FDA requires
some statistical consultation just to that the drug issue,
and it seems to me that in this climate arena this has
incredibly important implications for society in general,
the world in general, and I think it ought to be carefully
reviewed. The fact is Dr. Mann continues to appeal to
peer review but the fact is the peer review process
failed in the 1998 paper.
MRS. BLACKBURN. And you would say that was primarily
because it was not an independent and separate review
outside of that social network?
DR. WEGMAN. I believe that is the case.
MRS. BLACKBURN. Okay. Thank you very much. Dr. Christy,
let me ask you this. There is an article we have gone to
a couple different times in my office, Energy, Environment
and Economics. It was Dr. Soon wrote an article, Ten
Myths of Global Warming. I don't know if you have seen
that or not. Are you--
DR. CHRISTY. Sorry, ma'am. I haven't seen it.
MRS. BLACKBURN. Okay. I know there is so much here that
has been written. We have killed a lot of trees using
all this paper, haven't we? Okay. And he talks about
showing the Medieval Warm Period, and I was going to ask
you to comment on this but since you have not and my time
has basically expired I will just let that pass. And I
thank you. Thank you, Mr. Chairman.
MR. WHITFIELD. Thank you. At this time I recognize
Mr. Inslee for 10 minutes.
MR. INSLEE. Thank you. I think this really is an amazing
hearing. It is amazing because all six people at this
table have all agreed on the fundamental thing that this
Congress has got to figure out, and that is whether CO2
is going up, whether humans are partially responsible for
that, and whether that is part of the reason the Earth is
getting warmer. That is the fundamental issue that
Congress faces. And all six people at this table agree
with those propositions so I have been asking myself why
if we have unanimity on the fundamental question that we
got to ask, has Congress not done diddley to do anything
about this, and I think the answer is fear, because we
fear our inability to deal with it we blind ourselves to
the science.
And I think it is a little bit like a person who is shown
an X-ray of their lung cancer, refusing to believe it
because they don't want to deal with it. And I think that
is a pretty good metaphor of what is going on right
here. I want to ask Dr. Cicerone, because I think he
represents President of the National Academy of Science,
how many scientists are involved in that organization, by the
way?
DR. CICERONE. About 2,000 members, but our work is done
largely by another 6,000 people who are chosen from
expertise from different fields who are non-members.
MR. INSLEE. So I figure there is somewhere between 6,000
and 8,000 scientists that you represent here today, and I
am impressed by that. The consensus as I understand it
in the scientific community is that smoking causes lung
cancer on a more probable than not basis in certain
instances. Is it the scientific consensus now on a more
probable than not basis that increasing CO2 is associated
with global climate change and that humans are responsible
for increasing CO2?
DR. CICERONE. Yes.
MR. INSLEE. So we can say that we have the same level of
probability in our belief as to what humans are doing to
raise temperatures or at least that both are above
50 percent as we do about lung cancer, is that a fair
statement?
DR. CICERONE. I think we understand the mechanics of
CO2 and climate better than we do of what causes lung cancer.
MR. INSLEE. So here we as a country have decided to try to
limit and reduce the tremendous damage that is done by lung
cancer, but we have got as good or better science on a
global cancer and this Congress hasn't done a single thing
to deal with that, and I think that is very, very
disturbing. Now could I put a slide up here, please,
gentlemen, if we can? I want to ask Dr. Cicerone to explain
something to us.
If we look at this slide it is going to show the cyclical
nature--that is not actually the one I want. Yes. If we
look at this slide here it shows the cyclical nature. It
is from Dr. Gulledge's slides. It will show the cyclical
nature going back 450,000 years ago moving forward to
today. We also see CO2 going down, back up, down, back
up, down, back up, and we show a natural variability that
has occurred before the industrial age of from about 190
parts per million to about 290 parts per million, and I
think that is what Dr. Cicerone referred to as the natural
variability that has occurred before we started burning
coal, oil, gas, and wood.
Now what I see since the industrial period I have seen
this vertical curve go up, and it is vertical since the
beginning of the industrial period, so that now we are
at a level, this says about 372. I actually think it is
about 382 today. And as I understand it, it is bound
again on about a vertical curve on this scale to levels
of about 550 PPM double, double the highest level of CO2
in pre-industrial ages back 450,000 years.
So is my understanding of that, Dr. Cicerone, basically
accurate that we have an accelerated rate of CO2 that will
end up about twice as high carbon dioxide, which is a
known heat trapping gas in our atmosphere that is
occasioned since the dawn of the pre-industrial age?
DR. CICERONE. Yes, although I don't think it is necessary
that we will end up at double CO2. And then also we don't
know for sure what happened before this time. This is the
longest instrumental record we have of real data.
MR. INSLEE. So this is going back as far as we can with
real data. We are at higher levels by about 130--excuse
me, more than that, about 170 parts per million, is that a
fair statement?
DR. CICERONE. Above the minimum, yes.
MR. INSLEE. Now the projections I have seen would suggest
that if we continue to spew carbon dioxide and methane into
the air or carbon dioxide into the air the best assessments
I have seen we will end about double pre-industrial levels
by the end of the century. Could you give us your best
estimate of that or comment on that at all?
DR. CICERONE. Oh, by the end of the century. It depends
on human population. It depends on our energy usage and
what technologies we are using to produce the energy so you
have to make assumptions about human population, how much
energy we will use, and what the technologies will be.
Double CO2 is certainly plausible. It really depends on
what humans do.
MR. INSLEE. And it depends on what this Congress does, and
what Congress should do is what British Petroleum has
done. British Petroleum 7 or 8 years ago decided they were
going to meet Kyoto targets. Maybe it was 5 years ago.
And in 3 years they met their Kyoto targets in their
internal operations. They reduced their CO2 as much in
their internal operations as the Kyoto targets would
require. You know what they did? They saved $350 million
in wasted energy when they decided to adopt efficiencies of
the type that Dr. Cicerone talked about.
The other thing we will do is try to get these plants
started. Right down the hallway here yesterday I met with
these guys, Iogen Corporation. They are going to open up
the first cellulosic ethanol plant in southeastern Idaho.
When they do that, we will power our cars on E-85
ethanol. We will reduce our CO2 emissions per mile by
80 percent or more. They actually think it may actually
be negative because of some of the stuff you grow actually
takes carbon out of the air and puts it into the soil. It
might actually be negative.
This is the kind of thing we need to do, and we are not
going to do that until we come to grasp what this science
really is. I want to ask--I think there is just such an
overwhelming consensus of--I will just read the Academy of
Science report. "The IPCC's conclusion that most of the
observed warming of the last 50 years is likely to have
been due to the increase in greenhouse gas concentrations
accurately reflects the current thinking of the scientific
community on this issue." That is a direct quote from the
National Academy of Science. Now there has been some
issues brought about Dr. Mann's studies. There has been
some questions about Dr. Christy's studies. I frankly
think there are some legitimate questions about the
statistical assessments, and the first one Dr. Mann did, I
think they have been changed a little bit since then, I
think the same could be said for Dr. Christy, but I guess
the question I have, Dr. Cicerone, if Mr. and Mrs. Mann
had never met and we never had the services of Dr. Mann,
would that have varied the conclusion of the National
Academy of Sciences on these fundamental questions?
DR. CICERONE. You must be referring to his parents and
not his wife.
MR. INSLEE. I am indeed.
DR. CICERONE. I don't think so.
MR. INSLEE. And why do you say that? In other words, if
Dr. Mann's work had just never appeared, and, by the way,
I respect it and I think it has added to the debate but if
his work had never occurred why do you think the Academy
of Science would still reach the same fundamental
conclusions?
DR. CICERONE. Because of the blending of the physical
evidence, the mathematical rigor and the comparisons that
can be made now with the predictions and the actual
records of the last 30 years especially.
MR. INSLEE. And I have a chart here, gentlemen, if you
can put it up here of ice core data. I think it might be
the last slide on the series that I had introduced. If
you have the groupings of the one that I had brought
today. This is just another representation of the CO2.
There should be one more slide. You are not finding it
right now. Let's keep going. Just go through these
quickly. Right there. Okay. This is a slide basically
showing ice core data and we show CO2, and if I can read
this basically this is methane at the top, carbon dioxide
here, from ice core data showing these levels, only it
goes backwards. These are today's dates. This goes back
400,000 years. These are today's dates showing CO2 levels
higher in ice core data than at any time in the last I
believe it is 400,000 years. It should be 600,000 years.
If you can, Dr. Cicerone, can you describe how that ice
core data work through the deuterium isotopes, if you can
just give us a quick description.
DR. CICERONE. I mentioned earlier the way the gases are
pulled out of these dated ice cores. With CO2 you can do
it two ways. With methane you can do it two ways. With
nitros oxide you get similar results, low when it was
cold, high when it was warm. The deduction of temperatures
at the same time depends on the different isotopes, the
different forms of the same chemical like carbon, the same
element in carbon, in this case oxygen and hydrogen where
because the way they evaporate a gas like water evaporates
differently if it has heavy hydrogen in it, deuterium, for
example, or oxygen 18 instead of O-16.
We can go back and infer what the temperature was in the
vicinity of the ice when it formed or the snow in this case
which later becomes ice. These records are pretty widely
used now, and under certain circumstances they are
absolutely the best we can do. They are very
quantitative. The statistics are clear. There is some
concern over whether the temperature at which the snow
formed that made the ice was really a global or a
hemispherically average temperature or did it just reflect
what was happening regionally, but there you can go into
how much O-18 was in the oceans and the changes are big
enough that you can infer a pretty good geographical
validity of these temperature deductions as well as the
carbon dioxide.
MR. INSLEE. Thank you, and thank you all for your
testimony today.
MR. WHITFIELD. We may just have a short second round
here. I am going to recognize the Chairman of the full
committee for 5 minutes.
CHAIRMAN BARTON. Yeah, and I have to go so I apologize
for going out of order. This is today's USA Today
newspaper, the temperature map on the back. It shows
the high temperature was 126 degrees Fahrenheit and the
low temperature was 43 degrees Fahrenheit. That is
yesterday. Is there a model in existence that can
replicate this with any degree of accuracy? This is
yesterday's temperature. Dr. Mann, do you have a model
that can do that? This is just one country.
DR. MANN. I personally do not.
CHAIRMAN BARTON. We have got an 83 degree difference
on one day out of 365 days in one country.
DR. MANN. If I can just talk a little bit to that.
CHAIRMAN BARTON. I only have 4 minutes and--
DR. MANN. I will make it quick.
CHAIRMAN BARTON. Dr. Christy, you are the meteorologist,
I think, for Alabama. Do you have a model that could
even do this in Alabama?
DR. CHRISTY. No, sir, we wish we did.
CHAIRMAN BARTON. Okay. Now did you want to comment,
Dr. Cicerone?
DR. CICERONE. I would. Chairman Barton, you said any
degree of accuracy. That gives us some room. The
British meteorological office is probably the world's
best. They are in the Ministry of Defense in England.
Their models have pretty good predictive capability.
If you average over a few days and you say let's not
argue about the difference between San Francisco and
Marin County or San Antonio and El Paso. If you average
over enough space in time they can hit that. The models
at Penn State University are excellent. The National
Weather Service can give you some degree of accuracy and
predictability, and they can reproduce a lot of those
patterns.
CHAIRMAN BARTON. Well, my point is, and I am not trying to
be cute about this, in preparing for last week's hearing I
read the summary and I read most of the report of the
National Academy of Sciences here, the National Research
Council. I read Dr. Wegman's report. And somewhere in
those two reports it said the data sets they use to base
all these models on in the whole world there are like 60
or less data sets. There are just not a lot of data, and
we are trying to make predictions over thousands of
years. Even where we have really good records for the
last hundred years, and some of the most advanced
satellites and smart people that put these computer models
together with hundreds of variables, we can't really
predict after the fact yesterday's weather with too much
accuracy, and yet to go to Dr. Christy's point if we
accept Congressman Inslee's point that we need to be in
solution mode a thousand nuclear power plants by themselves
is a trillion and a half dollars, and that will get you a
CO2 reduction of 10 percent.
There are somewhere between 5,000 and 10,000 power plants in
this country. Now I don't know exactly but I know there
are only 100--I think 112 operating nuclear plants of those
between 5,000 and 10,000. And that is just one part of the
economy. We have got 300 million cars and trucks. We have
a lot. I mean, it is not scientifically accurate but we have
got a boon' doggle worth of economic consequences if we
really go where Mr. Inslee says we ought to be going. And
I am not dogmatic about it. I am concerned when I hear
Dr. Cicerone say that the parts per billion of CO2 in the
atmosphere is 100 parts per million higher than it ever has
been.
Now that has got to give anybody pause to think, but I look
at all these charts and all these data sets and I can't back
it up, but it would certainly appear to me to be plausible,
to use that term again, that the Earth is always changing
temperature. It is either in a warming period or a cooling
period. It appears that it is a curve function. It
appears that it is over the same general period of time and
it certainly appears that in the last 100 years that the
upward curve has accelerated at a more rapid rate than say
a thousand years ago. But it is not clear what, if
anything, we can do to change that basic system. And so
before we go off the deep end I really do want to make sure
that these models are independently reviewed and really are
scientifically accurate and really can be replicated. And
I really do want to know what the confidence levels are.
We are going to get to problem solution, and we are going
to have a huge debate about that. But since we can't even
predict with much accuracy what yesterday's temperature was,
it is a little bit much to ask us to make multi-trillion
dollar decisions on models that 10 years ago when Dr. Mann
put out his report, he was the first one, and even today
most of the people that are doing the modeling are some
part of his network, which is not a bad thing. It shows you
operate with a lot of smart people that care a lot about
the environment.
But it doesn't mean that the United States government
makes trillion dollar changes in public policy until we
get a little bit more information about that, and that is
why we are doing these hearings. And so I apologize for
going another minute over but I thank you, Mr. Chairman,
for holding this, and I thank the members, Mr. Inslee and
Mr. Stupak and Mrs. Blackburn for being here. I wish every
member of the Oversight Subcommittee was here. I wish we
had more intensity on this so that we could get more
involved. Thank you, Mr. Chairman.
MR. WHITFIELD. Thank you. Dr. Mann, did you want to make
a comment?
DR. MANN. I just wanted to clarify a distinction here in
this discussion. On the one hand we are talking about
weather, and that is the day-to-day fluctuations and the
character of the atmosphere, and in the other cases we are
talking about climate and there is a very important
distinction between the two. Climate is the statistics,
the long-term statistics of the weather, and there are
certain things that we can say very well about climate.
CHAIRMAN BARTON. But your model is predicting temperature
change.
DR. MANN. It is not a model.
CHAIRMAN BARTON. That may be the variable but that is the
variable, and we are talking about catastrophic consequences
with 3 to 4 degree Fahrenheit changes.
DR. MANN. That is the point. It is not a model. A model
is a set of numerical equations that we try to solve the
equations that describe the atmosphere and the ocean. Our
reconstructions aren't that. They are not a model. The
models are a completely different thing, and there are
weather forecasting models as well as climate models, and in
certain things the climate models are quite good. We are
doing very well now in predicting El Ninos.
CHAIRMAN BARTON. What term should I be using? Not model.
Program, algorithm?
DR. MANN. They are statistical reconstructions and data and
then there are the models, and I just wanted to make that
distinction.
CHAIRMAN BARTON. I stand corrected.
MR. WHITFIELD. I just have one other question I would like
to ask because we have heard a lot today about core samples,
and I have been sort of interested in this chart that
Mr. Inslee brought in showing CO2 concentrations and from
that extrapolating temperatures. And I would just ask Mann
and Christy and Cicerone once again, I didn't really ask
this question before, but I would like for you to tell us
the facts about the reliability of the ice core samples.
And we have heard a lot of comments about using that to
determine CO2 and then the question is using ice core
samples as historical thermometers. Can they really be
considered accurate thermometers. Can you take those
CO2 levels from ice cores and extrapolate in an accurate
way?
DR. MANN. I will take the first stab at that. There are
certain physical processes and there are basic physical
processes that control the ratio of different isotopes,
of oxygen in the ice, the water that is in solid form, it
is ice trapped in those ice cores, and so it is on a
somewhat different footing from some of the other sorts
of proxies like tree rings that we use where we are
relying on some biological relationship.
In the case of ice core isotopes it is really physics.
It is physics that is controlling the ratio of the different
isotopes of oxygen and that is telling us something about
the sea surface temperatures when the water evaporated from
the ocean because the ice that is deposited at some point
had to evaporate from the ocean surface. It also tells us
something about the local conditions when the ice was
deposited. Both the evaporation and the deposition depend--
they influence the ratio of those isotopes.
DR. CHRISTY. Just in terms of the temperatures, reproducing
temperatures from them?
MR. WHITFIELD. Yes.
DR. CHRISTY. The closer you get to the poles, the better the
temperature relationship is. I think in the NAS report we
show six tropical and Tibetan ice cores and they are all
different. All six of them are different. But the closer
you get to the poles the relationship looks a lot better
there.
MR. WHITFIELD. Okay. Do you have anything to add,
Dr. Cicerone? Okay. Yes. Mr. Waxman had asked we enter
into the record the remote sensing system letter which we
will do and you asked about the interface stewardship
alliance which we will do. And then we are going to keep the
record open for 30 days. And does anyone else have any
comments?
MR. STUPAK. If I may, Mr. Chairman. We were talking
earlier, I was going to start off my questioning and we were
talking about the Fortran, and I was joking with the
Chairman so I forgot to ask these questions. Dr. Wegman,
in your report you state that, and I am quoting now, "We
judge that the sharing of research materials data and results
by Dr. Mann was haphazardly and grudgingly done." You also
go on to state that Dr. Mann--you had trouble reading
Dr. Mann's code in part because it was in Fortran and that
you had trouble understanding some of the data that
Dr. Mann used.
Did you or your co-authors contact Mr. McIntyre and get his
help in replicating his work?
DR. WEGMAN. Actually, no. What I did do was I called
Mr. McIntyre and said that when we downloaded his code we
could not get it to work either, and it was unfortunate that
he was criticizing Dr. Mann when in fact he was in exactly
the same situation. Subsequently, he reposted his code to
make it more user friendly and we did download it
subsequently and verified that it would work.
MR. STUPAK. And then after you re-downloaded and verified
it worked, did you have any further contact with
Mr. McIntyre then?
DR. WEGMAN. Well, as I testified last week, Dr. Said and
myself had gone to one of the meetings where he was talking,
and we spoke with him but did not identify who we were at
the time. This was early in the phase. Subsequently, I had
had no contact with him until basically last week.
MR. STUPAK. Okay. Any of your co-authors that you know of,
Dr. Said or any others, have contact with Mr. McIntyre other
than that one time at this convention or wherever he was
speaking?
DR. WEGMAN. One of my graduate students, John Rigsby, who
did the code for us, worked the code for us, did have some
interaction with him in order to verify some of the details
of the code.
MR. STUPAK. So you, Dr. Said and this Mr. Rigsby would be
the people who had contact with Mr. McIntyre then?
DR. WEGMAN. That is correct, yes.
MR. STUPAK. Thank you. Nothing further.
MR. WHITFIELD. Mr. Inslee, do you have any--
MR. INSLEE. I just want to comment in response to Chairman
Barton's comment about the 1,000 or 10,000 nuclear plants
he posited might be necessary. I really--and I don't want
to get in debate about nuclear but I am really much more
optimistic about that, and the reason I say that is that we
have been so successful in improving the efficiency of our
economy because of the intellectual capital of men and women
like you who have helped us develop technologies to be much
more efficient. Let me give you an example.
We actually per unit of gross domestic product use almost
half as much energy as we did in 1973. You think about
that. Since 1973 our economy produces twice as much
domestic product with the same amount of energy that it did
in 1973, and there is just no reason on this green Earth
that all of a sudden we got stupid, that we are not going
to be able to continue as the most brilliant society on
Earth and innovation to continue those efficiency
innovations.
And they are not rocket science. Three of my neighbors
drive cars that have already reduced their transportation
related CO2 by 50 percent. The Chairman talked about the
need to reduce our emissions by 40 percent to meet Kyoto.
Three of my neighbors and myself, I may add, have already
reduced ours by 50 percent in our transportation sector.
Simple. They are on the lots today. This is no new
technology. So I just want to say in partial closing
that I am a person, as my comments have indicated, who
believe this is a major challenge for us and that we have
to act, and it is well past the date where we need to
move to solutions rather than debating the problem.
But I also believe that I am an optimist because I totally
believe it is in the human--it is capable because of our
intellectual ability to invent our way out of this
pickle. And those who are people of great faith, because
the faith community is now becoming engaged in this debate,
because we are stewards of God's creation, and they are
starting to urge Congress to act as well. We also ought
to be optimists and believe we can do it.
And I got to tell you, in the last 3 weeks I have met five
people, one in cellulosic ethanol, one in wave power, one
in efficiency in cars, one in efficiency in airplanes the
Boeing 787 we are building in Seattle is going to get
20 percent better fuel mileage than their last model.
These are the kind of things that America is going to do
when we tackle this. So I just hope that this is a first
step toward moving just one quick question, Dr. Cicerone.
I have heard there has been some new evidence about
finding large amounts of energy in the ocean that has
suggested that this is sort of new research to indicate
in the last 12 months. Is this something I am dreaming or
is there new research in that regard?
DR. CICERONE. Maybe methane clath rates would be the only
thing I am--
MR. INSLEE. I am sorry. What I mean is as far as we found
temperature increases in the oceans that have--
DR. CICERONE. Oh, yeah. The result was reported about a
year and a half ago about over the last 40 or 45 years the
oceans, the upper 700 meters or so have warmed up, and I
summarize it very briefly in my testimony, yes.
MR. INSLEE. And I will put in the record a study called
Penetration of Human-Induced Warming into the World's
Oceans. It is published in Science in July, 2005. Many
people thought this was sort of the nail in the coffin of
skeptics about global warming. And again thank you for
your testimony.
[The information follows:]
DR. GULLEDGE. Mr. Inslee, if I may just may make a
comment. Also regarding Mr. Barton's comments, I realize
he is gone. I am also from Texas and I use scientific terms
from down there. There are whole passels of money to be
made on alternative energy, and it is not just about being
expensive. Also, there are real serious costs to inaction
that have not been figured into this equation here.
MR. INSLEE. And I just want to compliment the Chairman's
humor about this. As I was walking off the field at the
baseball game this year and he was at third base, and I
just pulled my hamstring. As I was walking by he says,
well, Inslee, I suppose that was because of global warming
too. So he has a great finely tuned sense of humor and we
will look forward to using it as the debate goes on.
Thank you.
MR. WHITFIELD. Thank you, Mr. Inslee. I would like to
stipulate that in my district we just opened up two new
ethanol plants as well. So I want to thank you all very
much for your patience. We got documents to enter here.
MR. STUPAK. Mr. Chairman, that is a request to put in an
abstract of an article. I would suggest we just get the
whole article, put it in there, and then we have the
complete article for everyone to see.
MR. WHITFIELD. Okay. Without objection.
MR. STUPAK. That can serve as a place holder until I get
the whole article.
MR. WHITFIELD. So ordered. And then we will keep the
record open. Mr. Inslee.
[The information follows:]
MR. INSLEE. Mr. Chairman, I would like to submit an essay. It is
published in Science called the Scientific Consensus of Climate
Change. It relates to that 928 papers as well as the article I
ust made reference to. Thank you.
MR. WHITFIELD. Okay. Without objection. And we will
keep the record open for 30 days.
[The information follows:]
MR. WHITFIELD. Thank you all again for your testimony. We
look forward to working with you as we move forward. That
concludes today's hearing.
[Whereupon, at 6:48 p.m., the subcommittee was adjourned.]
RESPONSE FOR THE RECORD OF DR. MICHAEL E. MANN, ASSOCIATE PROFESSOR
AND DIRECTOR, EARTH SYSTEM SCIENCE CENTER
Question No. 1. I understand that although your current practice
is to make your computer code available publicly, many researchers
in your field do not do so. Although computer code may not have
commercial value, why would a researcher not want to release his
code?
Answer:
This is a question that my colleagues and I have wrestled
with over the years. As the question acknowledges, for the
past five years or more, my colleagues and I have made
public our computer codes, just as we made public our code
for the 1998 study last year. Our decision to make our
code public comes at a time when there is increased
standardization in codes, and the need to tailor codes to
accommodate the various and often idiosyncratic computer
systems that were used in the 1990s has diminished. But
even today, many, perhaps most, climate scientists do not
share their codes. In my view, there are legitimate
reasons for reaching that decision, even though it is not
the decision my colleagues and I have made.
For one thing, most code is written to enable scientists
to perform specific functions, and thus code is generally
written in a form of short-hand that is not easily
understood by others. To make code usable by other
researchers, the code writer has to undertake significant
additional work, in the form of documentation, testing for
potential platform dependence, tidying, and so forth, that
places a significant burden on the code writer. Many
scientists do not think that undertaking that additional
burden is worth it.
Second, access to computer codes is not necessary to
replicate a study. I realize that some of my critics have
argued otherwise, but it is just not the case that
scientists need access to computer codes to replicate
studies. As I tried to make clear in my testimony before
the Committee, a study may be replicated if the scientists
conducting the initial study make available both the
underlying research data and an algorithm that gives a
step-by-step account of how that data was analyzed. As my
testimony pointed out, the 1998 and 1999 work by my
colleagues and me was recently replicated by a team of
scientists (Wahl and Ammann) who did not have access to our
codes, but who were able to replicate our work without
difficulty. So replication does not depend on access to
computer codes.
Moreover, scientists, like entrepreneurs, corporations, and
others engaged in the production of intellectual capital,
are competitive, and rightly so. Competition in the
marketplace of ideas is what science is all about. We would
all like to make our greatest possible contributions to
advancing the forefront of our scientific disciplines.
Indeed, we are rewarded (in terms of grants, promotions,
academic recognition, and do forth) in proportion to the
contributions we make in the advancement of science. Asking
scientists to release their codes before they have had an
opportunity to apply them to a number of potential
interesting problems is asking them to sacrifice their
competitive advantage. This would be no different than
asking Microsoft to release the code for its latest
operating system as soon as it reaches the market. Microsoft
is not about to do that, and most people would consider a
requirement that Microsoft freely dispense its intellectual
property --- its codes --- as antithetical to the principles
of a free market. The argument is no different in the case
of scientists and their computer codes or other tools of
their trade.
Question No. 2. Dr. Wegman states that paleoclimatologists do not
interact with statisticians. Do you have any response to that
statement? What steps, if any, is the paleoclimatology field taking
to ensure that it is using appropriate statistical methodologies?
Answer:
Unfortunately, Dr. Wegman made this claim without engaging
in any effort to ascertain the extent to which climate
scientists interact with statisticians. To the contrary,
Dr. Wegman simply assumed --- without data, indeed, without
any basis at all --- that climate scientists, and
paleoclimatologists in particular, do not interact with
statisticians.
Dr. Wegman's accusation could not be further from the truth.
The participation of statisticians in climate science has
become so routine that there is an entire field of climate
research known as "statistical climatology," which involves
the collaboration of large numbers of statisticians and
climate scientists. There are even textbooks dedicated to
the study of statistical climatology. In his testimony
before the Committee, Dr. Hans Von Storch found it necessary
to inform Dr. Wegman of this fact. And Dr. Von Storch
should know; he and Dr. Francis Zwiers (a Ph.D. statistician
specializing in climate applications) have written one widely
used textbook on statistics and its applications to climate
studies. Another statistician, Professor Dan Wilks of
Cornell University, has written an additional textbook on
statistics and its applications to the atmospheric sciences.
The extensive collaboration between climate scientists and
statisticians is also reflected in the academic literature.
Hundreds of papers have been published in the climate and
paleoclimate literature involving the collaboration of
statisticians and climate scientists. These are all
publicly available and could have been identified by
Dr. Wegman in a few hours of research. Two members of the
NRC committee that reviewed paleoclimate reconstructions
in its recent report (Dr. Douglas Nychka and Dr. Peter
Bloomfield) are statisticians (both of their doctorates are
in statistics) who have published in the climate literature
and who have actively collaborated with climate scientists.
Had Dr. Wegman bothered to make even the slightest inquiry, he would
have found that there are in fact many statisticians (that is,
individuals with doctorates in statistics) who have been and remain
active members of the community of researchers in the areas of
atmospheric science and climate research. Even a cursory review of
the structure of our community reveals this readily. I have been
informed that many of my statistical climatologist colleagues are
deeply offended by Dr. Wegman's unfounded pronouncements to this
Committee, pronouncements which effectively deny their contribution
to the advancement of science.
Moreover, the American Meteorological Society --- the
leading professional organization of atmospheric
scientists --- has a Committee on Probability and
Statistics, and members of the committee are drawn from
both atmospheric/ocean/climate scientists and
statisticians. I was a member of that committee for a
3-year term (2003-2005) that recently ended. The
committee's website can be found here:
http://www.isse.ucar.edu/ams/ams_ps.html, and the committee
members' biographies are available here:
http://www.isse.ucar.edu/ams/ams_ps.html#members. The chair of
the committee, Dr. Rick Katz is a statistician (with his
doctorate in statistics from Penn State University) and senior
scientist at NCAR. Other statisticians on the committee include
Dr. Tilmann Gneiting (Department of Statistics, University of
Washington), and Dr. William Briggs (Adjunct Assistant Professor of
Statistical Science, Cornell University). These statisticians are
active members of the climate research community.
Equally important, one of the primary centers for climate
research in the U.S., NCAR, has maintained a thriving
Geophysical Statistics Project ("GSP"), which was founded
more than a decade ago. This program has been funded by
the National Science Foundation's Division of Mathematical
Sciences, which has recognized for some time the importance
of encouraging statisticians to collaborate actively with
atmospheric scientists/climate scientists. I participated
as a graduate student in GSP's inaugural workshop in 1994.
Many leading statisticians (e.g., Dr. Grace Wahba,
Dr. Arthur Dempster, and Dr. Noal Cressie) were
participants. The GSP has since thrived, providing an
important opportunity for collaboration between
statisticians and climate researchers. More information
can be found at the GSP webpage: http://www.image.ucar.edu/GSP/.
It bears noting that the project has now produced more than
two dozen Ph.D. statisticians who have become active
researchers in the atmospheric, oceanographic, and
climate sciences. Its members and visitors have included
dozens of statisticians who have worked collaboratively
with atmospheric scientists and climate researchers. The
leader of the project, Dr. Douglass Nychka, was one of
the members of the aforementioned NRC panel. He was also
a consultant in the recent paper by Wahl and Ammann that
refutes the oft-cited criticisms of the Mann et al. work
by McIntyre and McKitrick.
Question No. 3. Dr. Wegman has hypothesized that the peer review
process failed and allowed publication of your 1998 and 1999
studies without adequate vetting of the study. This was based in
part on his social network analysis that showed you have
connections with 42 other authors in paleoclimatology. Of the
42 co-authors identified by Dr. Wegman, how many of them were
co-authors with you in or before 1999?
Answer:
Dr. Wegman's accusations are so riddled with flaws that
it's hard to know where to begin in response. But let me
first address the specious accusation by Wegman that the
peer-review process somehow "failed" with respect to our
'98 and '99 studies. It is bewildering that Dr. Wegman
(who has no expertise in the area of atmospheric
science/climate, and indeed was wholly unable to correctly
answer some of the most basic questions about climate
science during the hearings) would characterize the
publication of our work as a "failure." One would
assume that an academic would avoid rendering judgments
in fields in which he is demonstrably unknowledgeable.
Certainly the scientific community has reached the
precisely the opposite conclusion. Our 1998 and 1999
studies are widely cited, and the conclusions stated in
them have been repeatedly reaffirmed. Just one example
of the scientific support for these works should
suffice: The National Research Council panel in their
recent Report characterized our study as
"groundbreaking", and the panel concluded that its key
conclusions have held up over nearly a decade of
exhaustive and independent follow-up research. That is
a pretty good track record by any standard. Thus,
judged by experts who understand climate studies,
Wegman's efforts to disparage our work as "failed" are
nothing short of silly.
Let me next address Wegman's equally specious and
unsupported claim that scientists who work in a given
field cannot objectively review the work of their
colleagues and competitors in that field. By way of
illustration, I have attached (as Attachment 1 to these
Responses) the famous 1927 photograph of attendees of the
Solvay Physics meeting in Brussels. It shows a group of
29 physicists engaged in a collegial, small conference.
Virtually every attendee was a driving figure behind our
understanding of modern physics. Appearing in the photograph
are Einstein, Heisenberg, Bohr, Fermi, Dirac, de Broglie,
Born, Pauli, Langmuir, Planck, Curie, Compton, Ehrenfest,
Lengevin, and others of equal prominence. The members of this
group all knew each other, worked with each other,
collaborated on research with one another, visited each other,
went mountain-climbing together, and so forth. Familiarity
did not compromise their contributions to science. While I
do not claim that the group I collaborate with is likely to
duplicate the feats of the scientists who gathered in Brussels
80 years ago, the point remains --- scientific collaboration
does not turn scientists into timid lapdogs unwilling to
criticize the work of their colleagues.
Let me turn now to the specifics of the question. It is
baffling how Dr. Wegman arrived at the number (42) he used to
describe my co-authors. One would think that a statistician
could do simple arithmetic. My curricular vitae (CV) is
available on the internet, and it is clear that Wegman consulted
it (but not me) in the preparation of his paper. Nonetheless,
none of the numbers he uses add up. Part of the problem may
stem from Wegman's ill-advised effort to distinguish between
authors engaged in "paleoclimatology" and "climatology," since
most climate researchers have worked, in some manner, on some
aspect of paleoclimate. So the distinction he attempts to
draw between "paleoclimatologists" and "climatologists" is
illusory at best. This too underscores the hazards of an
amateur seeking to draw conclusions in a field in which he
has no expertise.
But to answer the question Wegman poses, let us consider the
correct numbers (see Attachment 2 to these Reponses) which
are based on all of my peer-reviewed journal publications as
listed on my CV (and not including "gray literature" such as
book chapters, encyclopedia pieces, reports, conference
proceedings, letters to editors, opinion pieces). I published
with 10 co-authors prior to 1993 based on my undergraduate
research in solid state physics. These publications are
unrelated to climate research, and are not included.
So let us consider just my climate-related papers (i.e., post
1993), as Wegman purports to do. In climate research, I had
14 co-authors through the year 1999. I had 101 co-authors
through the end of 2005. So Wegman's calculations, based on
42 co-authors, are off-base by more than a factor of two.
Wegman also appears to have made even more fundamental errors
in his review of the science (a point I address below).
But I believe the question goes to how influential I was in
the field, in a relative sense, at the time of publication of
my '98 and '99 studies. After all, Wegman claims that there
is, in essence, an almost sinister conspiracy of like-minded
climate scientists who act as a cartel to control the published
literature in climate studies. And his "proof" is the fact
that I have published with many prominent scientists who, in
Wegman's view, would be unwilling to criticize my 1998 and 1999
work even if it were seriously flawed. But this theory does
not wash. Apart from the fact that even my closest
collaborators are perfectly willing to criticize my work when
they think it is flawed, Wegman's math just does not support
his theory. As indicated above, the vast majority (86%) of
my co-authorships occurred after my 1998/1999 studies. So
Wegman's effort to suggest that I was influential in the
field at the time these studies were published, or in the
aftermath of their publication, cannot be squared with the
data, and is, in fact, nothing short of absurd.
Question No. 4. Does the scientific community rely exclusively or
primarily on the peer review process conducted before an article
is published to test the robustness and validity of new scientific
discoveries or theories? Or does the development of science depend
on an iterative process that involves not only peer review before
publication, but also review and competing research and analysis
by other scientists after publication?
Answer:
This question raises an important issue that was
unfortunately not adequately aired at the hearing.
Dr. Wegman and others have expressed the view that the
scientific community somehow places exclusive reliance on
the peer review process as the determinant of scientific
truth. But the peer review process is hardly the only, let
alone most important, way that the scientific community
tests the accuracy and reliability of scientific papers.
Indeed, Wegman's contention reflects a fundamental lack of
understanding of the basic principles that govern the
scientific discipline. Science progresses through an
open, self-correcting process whereby scientists place
their ideas in the marketplace, typically by publishing
articles in peer review journals. The peer review process
ensures only that basic mistakes are not made, that the
article acknowledges the existing literature on the subject,
and that it contributes in some way to the exploration of
important scientific issues. But peer review does not and
cannot vouch for the accuracy of the paper. That is the
function of the scientific process, by which other scientists
test out and question the work of their peers. Some ideas
stand the test of time; others do not. Copernicus was proven
right over time; Ptolemy's conception that the Earth forms
the center of the universe was proven wrong. Much of
Einstein's work has stood up to reevaluation, but some of
his theories have been proven to be incorrect as well.
It is relevant in this context to again emphasize that the
key conclusion that my colleagues and I drew tentatively in
our work in the late '90s --- that late 20th century Northern
Hemisphere average warmth was likely unprecedented in at least
the past 1000 years --- has held up for more than a decade,
after dozens of independent studies have reexamined that
claim. So it has passed this important test of time. The
peer-review process is simply a quality control process to
make sure that claims, theories, and ideas that are self-
evidently flawed from the beginning do not clutter the pages
of the legitimate peer-reviewed scientific journals, that is,
to ensure that published papers have potential merit. Peer
review is a simple first step at quality control. It does
not, nor should it, be considered evidence that the
conclusions of a particular published paper are accurate or
not. No single paper should ever be used to establish the
validity of a particular hypothesis or conclusion. The
accuracy of claims, hypotheses, conclusions, indeed theories,
can only be established by examining the collective body of
peer-reviewed research to date on any particular topic, and
the overall thrust of that body of research. Indeed, the
importance of broad-based scientific assessments (such as
those provided by the Intergovernmental Panel on Climate
Change or "IPCC") is to evaluate the entire body of peer-
reviewed literature on a particular topic and to determine
the consensus, if there is one, that emerges in that body
of literature.
Question No. 5. Should all scientific papers be withheld from
publication until the results are independently replicated?
Answer:
This question also raises an important issue that was not
adequately aired at the hearing. Once again, Dr. Wegman
and others suggested at the hearing that scientific pa
pers
be shelved for the time it takes for the results to be
verified independently. This view is misguided, and, if
followed, would seriously undermine the development of
scientific knowledge. It takes considerable time to
replicate a study. Meanwhile, important findings that
would be unavailable to other scholars. Such a requirement
would dangerously slow the progress of science.
As I explained above, in my view development of scientific
knowledge can take place only through an open, self-
correcting process whereby scientists put out ideas, other
scientists test them, and those ideas which stand up to
future tests survive while those that do not are ultimately
rejected. It is important in this context that ideas with
potential merit be placed in the scientific discourse in a
timely manner, so that they can be followed up in a timely
manner by the entire scientific community and not just a few
researchers engaged in replication, and the scientific
process can proceed at an appropriate pace. Were the
suggested requirement to be followed where all papers
required independent replication before publication, this
would bog down the scientific process to a near standstill.
In data-poor areas of science such as paleoclimatology, the added
benefit of new data is much more valuable than the pure replication
of a past study. "Replication" in a pure sense provides very poor
value for money. A good example would be the now- famous GRIP and
GISP2 ice cores from Greenland. These are two different Greenland
ice cores that were drilled at two nearby but distinct locations
by two different (one U.S. and one European) teams. Had the total
available funding simply been used for both teams to drill cores
at the same site, and thereby replicate each other's work, only the
technical accuracy of the coring would have been validated.
Instead, the reproduction of a record that was nearby but separate
gave both support to the main results, but also allowed the groups
to discover a mix-up in dating prior to 100,000 years ago in one
of the two cores. So drilling two different ice cores, rather than
drilling from the same source twice, proved to be a far more
valuable use of the available funding and resources.
The proponents of this idea also ignore the near-
impossibility of its implementation. How would scientists
be persuaded to replicate the unpublished work of others?
What would their incentives be to conduct this work quickly,
especially if it meant sacrificing the time researchers
would prefer to spend on their own work? Would every study
be subject to replication? Or only important studies? And
who would decide which studies required replication prior to
publication? Who would pay for these replications? Would
the government pay for them? Is Congress prepared to double
the size of research budgets for all of the major scientific
funding agencies (e.g. NSF, NIH, NOAA, etc.)? And these
practical problems are only the tip of the iceberg.
My essential plea here is that Congress should not fix that
which is not broken. Since Copernicus' time the scientific
process has successfully weeded out the wheat from the
chaff. It would be dangerous for Congress or any
government body to tamper with that process.
There is another element of this question which raises a
deeply troubling matter with regard to Dr. Wegman's
failure to subject his work to peer review, and Wegman's
apparent refusal to let other scientists try to replicate
his work. Professor David Ritson, Emeritus Professor of
Physics, Stanford University, has found error in the way
that Dr. Wegman models the "persistence" of climate proxy
data. Interestingly, this is the same error Steven
McIntyre committed in his work, which was recently refuted
in the paper by Wahl and Ammann, which was in turn vetted
by Dr. Douglass Nychka, an eminent statistician.
Dr. Ritson has determined that that the calculations that
underlie the conclusions that Dr. Wegman advanced in his
report are likely flawed. Although Dr. Ritson has been
unable to reproduce, even qualitatively, the results
claimed by Dr. Wegman, he has been able to isolate the
likely source of Wegman's errors. What is so troubling is
that Dr. Wegman and his co-authors have ignored repeated
collegial inquiries by Dr. Ritson and apparently are
refusing to provide any basic details about the
calculations for the report (see Attachments 3 and 4 to
this Response). It would appear that Dr. Wegman has
completely failed to live up to the very standards he
has publicly demanded of others.
Moreover, the errors that Dr. Ritson has identified in
Dr. Wegman's calculations appear so basic that they would
almost certainly have been detected in a standard peer
review. In other words, had Dr. Wegman's report been
properly peer-reviewed in a rigorous process where peer-
reviewers were selected anonymously, it likely would not
have seen the light of day. Dr. Wegman has thus
unwittingly provided us with a prime example of the
importance of the peer review process as a basic first
step in quality control.
RESPONSE FOR THE RECORD OF DR. JOHN R. CHRISTY, PROFESSOR AND
DIRECTOR, EARTH SYSTEM SCIENCE CENTER, NSSTC, UNIVERSITY OF
ALABAMA IN HUNTSVILLE
28 August 2006
Hon. Ed Whitfield
Chairman
Subcommittee on Oversight and Investigations
Committee on Energy and Commerce
2125 Rayburn House Office Building
Washington DC 20515-6115
Dear Rep. Whitfield,
Thank you for the opportunity to appear before your Subcommittee
to address issues of global climate change. I especially thank
you for the opportunity to clarify some of the material that was
entered into the official record which appeared to contradict my
testimony. I assure you that what I presented was accurate as
to my experiences and understanding of climate change in general
and dataset construction in particular.
I will be happy and available to answer any further questions
regarding my appearance.
Sincerely,
John R. Christy
Director, Earth System Science Center
Alabama State Climatologist
University of Alabama in Huntsville
Questions from Rep. Whitfield for John R. Christy
(1) During the hearing, Mr. Waxman introduced into the hearing
record a letter from Frank J. Wentz regarding your sharing of
code with Remote Sensing Systems 9RSS). Please explain your
interactions with RSS (and Mr. Wentz) and subsequent interactions
with Dr. Mann, as mentioned in your testimony.
(1) Answer
In the Hearing before the Subcommittee on Oversight and
Investigations of the House Committee on Energy and Commerce on
27 July 2006, I testified about our cooperation with Remote
Sensing Systems (RSS) regarding sharing of satellite data and
code.
Mr. Waxman introduced into the record a letter from Mr. Frank
Wentz of RSS which included an email from me to Mr. Wentz, over
4 years old, implying an apparent lack of cooperation. The
problems here are (a) that this March 2002 email to Mr. Wentz
from me was simply the first in a long series of emails in
which we indeed cooperated, and (b) that this exchange related
to a different dataset than the one I was speaking of in my
testimony. The following discussion describes the way these
two datasets were examined by RSS.
Mid-Tropospheric (MT) Temperature Product
Another RSS Scientist, Dr. Carl Mears (not Dr. Mann), began
constructing an MT product from the raw microwave digital
counts in early 2002, following much of our published
methodology. There were some discrepancies between our two
results. Mr. Wentz asked for the code with which we
constructed our MT data so as to resolve these differences.
As stated in my first email on the subject, shared by
Mr. Waxman in Mr. Wentz's letter, I declined to send the code
for the reasons given. However, there were many further
exchanges of information (in terms of the Hearing language:
there were discussions about the "algorithms") to the point
that RSS understood the three main differences between our
two datasets. Mr. Wentz's description of "trial and error"
in his letter in this process left out the important point
that we were in constant communication on the details and
subtleties of the dataset construction process.
During this time, we discussed at great length matters
concerning (1) the methodology of calculating the strength
of the target-temperature effect, (2) the methodology of
determining intersatellite biases and to a lesser extent (3)
the adjustments for the satellites' east-west drifting
(diurnal effect.)
At a conference in Asheville NC, (Oct. 2003) Dr. Mears
presented a talk entitled "Understanding the difference
between the UAH and RSS retrievals of satellite-based
tropospheric temperature estimate" and stated he was
satisfied as to having understood the main reasons for the
differences between our two datasets. Indeed in this
presentation, Dr. Mears used some of the adjustment files
we had provided to them to help answer questions of how our
adjustment process worked (i.e. diurnal drift files.) He
also displayed our target factor calculations, again provided
to RSS, along with a detailed description of their
computation. It was clear we had provided information to
understand the discrepancies.
RSS was also able to publish these findings and results
(Mears et al. 2003). I was a reviewer of that paper and
recommended publication. In my view, this closed the episode
on this dataset.
Lower Tropospheric (LT) Temperature Product
In 2005, Dr. Mears also led in the development of a different
temperature product, LT, which UAH had been producing since
1992. He addressed the issues of hot target calibration
coefficients and intersatellite biases to his satisfaction but
was unable to replicate our diurnal effect. He asked for more
information and we supplied the appropriate section of the
code and intermediate adjustment files so he could test the
code against the output. With these in hand he was able to
discover the artifact in the algebra which created the error
most visible in the tropics.
That we supplied these items is inarguable as the paper
published by Mears and Wentz (2005) in Science displays the
UAH adjustment files. Additionally, even though we did not
know the outcome of their study at the time, I granted
permission to publish our files as shown by this following
exchange between Dr. Mears and myself on 13 May 2005 in which
he responds to me for being open in this way.
13 May 2005 8:41 p.m.
Hi Carl:
Anyway, something jogged my memory this morning that you had
asked about using the UAH diurnal adjustments in a paper, and
I didn't respond with a firm answer. Sorry. I think it would
be fine to use and critique ... that's sort of what science is
all about.
[John Christy]
13 May 2005 1:58 p.m.
Hi John
Thanks for permission -- I strongly approve of your view of
science expressed [above]. I think that things that aren't
nutty or poorly explained should be published in the open
literature without too much fuss, so that they can then be
commented on..... Of course, different people have different
opinions about what constitutes nutty.
You[r] global diurnal effect agree[s] pretty much with mine,
but it's the *opposite* sign. The real difference is in the
tropics. I suspect the same calculation for 20S to 20N will
show a much larger effect. With the model-based diurnal
correction, the big disagreement with the surface in the tropics
goes away.
[Carl Mears Remote Sensing System]
So, the apparent contradiction between my testimony and the
letter from Mr. Wentz sprang from a misunderstanding of how
two different datasets were being addressed. One (MT) was
solved without sharing the specific code but for which we did
supply ancillary data files and considerable information. The
other (LT) needed parts of the code to resolve the discrepancy.
In the Hearing, Mr. Waxman dealt with the former while I dealt
with the latter. In both cases, however, UAH did cooperate
with RSS.
Mears, C.A., M.C. Schabel, and F.J. Wentz, 2003: A reanalysis
of the MSU channel 2 tropospheric temperature record.
J. Climate, 16, 3650-3664.
Mears, C.A. and F.J. Wentz, 2005: The effect of diurnal
correction on satellite-derived lower tropospheric temperature.
Science, 309, 1538-1551.
(2) As you were a member of the National Research Council
panel that recently issued the report on millennial temperature
reconstructions:
(a) Where in the report did the panel describe "plausible" as
suggesting roughly a 2/3rds probability of being correct.
(b) In the report, did the panel attach probability estimates
to the term "plausible"?
(c) Why did the panel choose to use the term "plausible," as
opposed for example to terms such as "likely", to describe
confidence in millennial temperature reconstructions?
(2a) Answer
The report did not intend for "plausible" to be equated with
"2/3rds" probability of being correct. My view ,as a panel
member, is that "plausible" was chosen to indicate a lack of
quantifiability in describing confidence in pre-1600 temperatures.
(2b) Answer
"Plausible" was chosen precisely because it implied that
probability estimates could not be assigned to pre-1600
temperature estimates due to (a) the limited amount of proxy
information available and (b) the unknown confidence with which
these proxy records may determine temperature. The current proxies
are mostly consistent with the notion that pre-1600 temperatures
were cooler than late 20th century temperatures, but the evidence
is still too meager and uncertain.
(2c) Answer
As a member of the IPCC 2001 Lead Author team I outlined in my
testimony why the word "likely" was chosen in that document.
"Likely" in the IPCC 2001 terminology had an estimated likelihood
defined as being at least 2/3rds probable. The NRC panel chose
"plausible" for reasons given in (2b) above. My view of the NRC
report is that our IPCC statement was inadequate in that the IPCC
should have separated the last millennium into two periods with
higher than "likely" confidence for post-1600 and lower than
"likely" confidence for pre-1600 estimates.
(3) When considering the panel's findings that it is "plausible"
that recent decades were the warmest in a millennium, is it
correct to interpret that to mean the panel's consensus view was
that plausible means roughly 2/3rds probability of being correct,
as was suggested in the news reports following the press
conference releasing the report?
(3) Answer
I was disturbed when reading the press reports that implied the
panel had endorsed with "likely" confidence statements about the
pre-1600 temperatures. The panel did not conclude that there was
a 2/3rds probability that late 20th century warmth was greater
than at anytime prior to 1600. As noted above, there are
indications that such is the case, but the data do not allow
statements of quantifiable confidence to be made at this point.
(4) In your testimony, you mention your recent study relating to
California regional temperature trends and human influences on
those trends (Christy et al. 2006a). Please describe the purpose
and conclusions of that study.
(4) Answer
As a native of Fresno and an avid weather observer since being a
teenager there, I had an abiding interest in determining the extent
of temperature changes in the Valley. This eventually led to a
study funded by the National Science Foundation. The first part
of the study was a data gathering effort in which every available
long-term dataset for the Valley and nearby Sierras was acquired,
many by manual digitization from paper records. The second part
was the development of a means to merge all of these data into a
regional time series of temperature for daytime and nighttime
temperatures separately, for each season separately and for the
Valley and Sierras separately.
We discovered that Valley nighttime temperatures were rising
rapidly while daytime temperatures were generally falling slightly.
In the Sierras however, there were no real significant trends,
with perhaps a suggestion of nighttime cooling in summer and fall.
This result suggests that the significant changes in the land
surface of the Valley (irrigation and perhaps urbanization) are
causing the changes in the Valley. The fact there were no
long-term changes in the Sierras for this period suggests that
the enhanced greenhouse effect has not been a significant factor
in Central California in terms of temperature changes. (For
regions this small, one must always consider the natural variations
of climate as also being an issue with which to deal, but such
variations should have affected both Valley and Sierra in the
same way.)
(5) Please explain why the measurement of average global (or
average hemispheric) temperature change does or does not represent
an adequate metric for understanding or predicting the risks of
potential climate change impacts.
(5) Answer
Thermometers near the surface will respond to all of the forcing
processes that act upon them. Thus, surface temperature over
land will show responses to changes such as urbanization and other
land-use changes in addition to that of atmospheric forcing from
aerosols or greenhouse gases. As a result, it is difficult to
extract out the impacts of one particular forcing on surface
temperature with high confidence.
Daily temperature is commonly reported as two values, the maximum
and minimum, from which the daily average is calculated. Maximum
temperature is more relevant for climate change as it occurs when
the surface and upper atmosphere are more closely connected
through vertical mixing and thus will give a better idea of what
the general climate system as a whole is doing. Minimum
temperature is more closely related to a shallow layer near the
ground and is thus impacted more by urbanization, aerosol pollution
and other land-use changes. Thus, daily average temperature is
partially dependent on processes that impact minima.
Theoretically, the temperature of the ocean surface is a better
quantity to measure in terms of observing a variable that has a
more direct relationship to a forcing such as greenhouse gases.
However, there are large areas of the ocean that have never been
systematically observed over long-periods, and the manner by which
ocean temperatures have been taken and the associated biases
contain a certain level of uncertainty, especially in the earliest
years.
Surface temperature is one metric for assessing climate variations
and change, but is less informative than others. Indeed the ability
of model simulations to depict surface temperature distributions is
quite primitive at this stage. Focusing on the global average
surface temperature also circumvents the fact that the spatial
distribution of those changes is more important than the overall
average in terms of risk and impact. For example, our work in
California, the SE USA and preliminary work in East Africa indicate
models are not able to replicate what the observations since 1900
have shown, though for the global average they are not in great
error. Additionally, the lowest layer (or boundary layer) of the
atmosphere in which these surface thermometers are positioned, is
an extremely complicated part of the climate system which is not
well-represented in climate models. Average surface temperature,
while valuable in local terms to humans who live on the surface,
is a rather limited and complicated variable, compounding its
lack of utility in providing a high level of understanding about
greenhouse-gas induced climate change.
A much more fundamental measurement needed to assess how various
forcing mechanisms are affecting the planet is the heat content,
which is essentially the number of joules of energy in the
system. So, by counting the number of joules of energy in the
deep atmosphere, ocean (mainly upper ocean), and other components
such as ice caps, one has access to a better metric for
understanding how much extra energy is (or is not) being trapped
in the climate system. Knowing the number of joules, however,
is still a step removed from knowing whether particular
components of the Earth (and human) system might be at "risk"
for a significant impact.
It is a very subjective task to address the idea of "risk" of
potential impacts of a changing climate (either natural or
human-induced) from surface temperature considerations, and
as important, the possible impact of specific policies. The
various processes that affect surface temperature render it a
less-than-optimal gauge of human-induced climate change
impacts, even if concentrating on the better measure - daily
maximum temperature. Thus, it is even more difficult to
assign an observed change in surface temperature to a
particular cause.
Questions from Rep. Supak for John R. Christy
(1) In your written testimony, you stated that the poor of
the world are more vulnerable to the impacts of poverty,
water and air pollution, and political strife (sic) than to
whatever the climate does. You also made a plea that the
poor of the world not be denied the use of energy. A recent
article in the Washington Post recorded the tremendous cost
of subsistence farmers and urban dwellers in Peru because of
the melting of the glaciers that has caused a water crisis.
The loss of glacial ice in the Himalayas will affect 300
million people relying on snowmelt for the water supply.
(See attached, "On the roof of Peru, Omens in the Ice;
Retreat of Once-Mighty Glacier signals Water Crisis, Mirroring
Worldwide Trend," July 29, 2006, A1.)
(a) Is it your position that nothing should be done in the
developed world to control its fossil fuel energy use while
we wait for development to reach these poor people who are
directly suffering today from the effects of climate change?
(b) What do you propose to protect the poor people of the world
today from the effects of climate change, particularly as it
relates to their water supply and ability to raise crops to feed
their families?
This is an important issue to me and I will strive to provide a
policy-relevant answer. Thank you for addressing an issue that
has considerable import to millions.
The questions above are introduced with a Washington Post news
article describing the apparent plight of Peruvians who depend
on annual snow/glacial melting for a portion of their water
needs. These types of articles generally present dramatic
assertions and tend to highlight whatever is alarmist and
attention-grabbing. After all, the ability of the media to
survive is dependent on how many people's attention may be
grabbed. Assertions are not science. Science is numbers
(as Lord Kelvin said.)
Tropical glaciers have been advancing and retreating for thousands
of years, and are not exceptionally good indicators of
temperature. (Note for example: Scientists Unravel Mystery of
Growing Glaciers, 24 Aug 2006, Guardian Unlimited, describing the
growth of glaciers in the western Himalaya, Karakoram and Hindu
Kush mountains.) In Fig. 6.1 of the NRC Surface Temperature
Reconstruction Report (2006 of which I was a co-author), ice
cores of three glaciers are shown for South America and three
for the Tibetan Plateau. Two of the 6 show an increase in the
proxy temperature since 1000 A.D. while the other 4 show level or
declining trends. In particular, the glacier identified in the
Post article (Quelccaya) shows a long decline (cooling) to about
1800 with a rise to about 1950 and fairly level since then which
doesn't match human-induced climate change theories well at all.
Dr. Lonnie Thompson, who studies this glacier more than anyone,
indicated to me that he believed this glacier was about 1,500
years old. Thus, it appears that these glaciers advance and
retreat on many time scales and should not be depended upon for
the long term. This is what the numbers suggest.
A society which depends on the annual melting of "glacial" ice
is therefore dependent on an erratic system. The following
letter to the editor addresses the problems of the Peruvian water
situation, noting that ineffective water management rather than
global warming is the problem.
Peru Shows Why Water Privatization Is Needed
Washington Post
Sunday, August 6, 2006; B06
Doug Struck reported on the water crisis in Lima, Peru, and on the
role that accelerated glacier melting has played in recent years
["On the Roof of Peru, Omens in the Ice," front page, July 29].
But more than a billion people throughout the developing world
lack access to clean water, and that is largely due to the dismal
performance of the public sector, which is in charge of 97 percent
of formal water distribution in poor countries. Water shortages
are even common in Cherrapunji, India, which has been described
as the wettest place on Earth.
In Lima, a quarter of the city's 8 million people don't have
piped water. The article quotes an engineer at Peru's public
monopoly who suggests that if the utility did connect those
2 million people, there would not be enough water to serve them.
The article does not mention that some 40 percent of the water
piped through the public utility is lost to leakages and otherwise
unaccounted for.
Peru's public water utility has failed to serve a huge percentage
of the population for decades. Privatization would increase
access to water, reduce death and diseases, and introduce
accountability and rational pricing, as countless cases of
successful water privatization around the world have shown. The
first to benefit would be Lima's poor, who currently pay
exorbitant black-market prices for water.
IAN V�SQUEZ
Director
Project on Global Economic Liberty
Cato Institute
Washington
The main problem in poor agricultural societies like Peru is that
the country's institutions and regulations encourage wasteful
water usage in rural areas that particularly harm the poor.
Agricultural productivity is mainly undermined by major factors
(lack of property rights, closed economies, civil wars, state
marketing boards, erratic macroeconomic policy, low growth, bad
infrastructure, etc.) that have nothing whatsoever to do with
global warming. In areas like Peru where glacier melting seems
to have reduced water supply, it would be far cheaper to pay for
a range of solutions (a system of dams and irrigation, relocation
of some vulnerable citizens, etc.) than it would to implement
alternatives that would reduce growth in both rich and poor
countries and in the end have no impact on the problem. So the
better approach is to encourage locally-focused solutions at a
far smaller cost than top-down energy suppression measures which
in reality will not impact the climate.
In summary, alarmist articles, such as was as attached with these
questions, are not designed to give hard scientific information
from which policy can be made. The real issues in this arena
often boil down to how public water management entities have
failed to store, allocate and distribute water effectively,
efficiently and sustainably.
(1a) Answer
As indicated in my testimony, it is my view that people should be
given greater access to energy produced by the most efficient
and clean means possible because energy provides longer and better
lives. At present, much of the poor's energy is produced from
biomass burning (wood, dung) which destroys habitat and fouls the
air with toxic smoke. In that context, energy from fossil fuels
can be an environmental and humanitarian step forward. Though
expensive and intermittent, other sources, such as solar or wind,
could help fill part of the gap. However, cost, reliability and
base-load power requirements are three factors that must be
considered and which tend to work against solar and wind.
I do not subscribe to the notion that climate change (about which
we can do anything about) is causing these people serious problems
today. Tropical glaciers are known to have advanced and retreated
many times in the past. People who are dependent on a particular
status quo of a dynamical system like mountain glaciers are
operating in a belief-system that the actual climate cannot
guarantee. The present retreat of several of the glaciers in this
part of the tropics leads one to hope these people can adapt to
such variability. (But note above the growth of glaciers in South
Asia.) Their water still falls as rain and snow, and capturing
that water for dry spells is a prudent plan to pursue. The issue
of water policy goes far beyond Peru and the impacts of climate
change (see below).
(1b) Answer
Let me first say that the future distribution and quantity of
rainfall is unknown. Rainfall patterns have been notoriously
variable over the centuries as evidenced by paleo-climate research
during the period when no human-influence on climate was possible.
Additionally, rainfall in general is more important than temperature
for sustaining life.
Climate models are unable to confidently predict where the rain may
increase, decrease or stay the same. Further, efforts to "control"
climate change are misguided as we have no way to confidently
determine how a particular policy for controlling greenhouse gases
will impact precipitation.
Water policy is a vast and complex issue with climate variability
being only one component. The political aspects of water
availability are significant and the growth of water-dependent
systems (human and agricultural) in desert areas is going to be
a challenge to sustain whatever the climate does (see introductory
comments to these answers). In the U.S. for example, we know that
creating the availability and performance of an acre-foot of fresh
water in California (where over 80% goes to irrigation) costs about
15 times that of creating the same acre-foot in Alabama. Where
then should the country invest its funds for the most benefit, both
financially and environmentally?
The policy-relevant issues for a political body are to determine
(1) where and how much water there is, (2) who owns the water and
therefore who controls its use, (3) what uses are sustainable
environmentally, financially and politically, (4) what
infrastructure may be built to use the available water efficiently,
confidently and sustainably, and (5) what incentives are available
to pay for (4).
I suspect water will become more and more commoditized in the
future, so that some investment will come from the commercial
sector to store and distribute water. How governments, especially
poor governments, take advantage of such investments to provide
clean water for human consumption (and a great leap forward in
health care) will be done on a country-by-country basis, but I
cannot predict how effective that process will be. U.S. policymakers
could facilitate the reduction of water crises by helping governments
answer these 5 questions.
(2) Your published work on satellite-derived lower tropospheric
temperature data was used for several years as evidence that there
is no global warming, since it appeared to show that the
temperatures in the tropics were actually cooling. In 2005,
Dr. Carl Mears and Dr. Frank Wentz of Remote Sensing Systems in
Santa Rosa, California, published an article in Science magazine
showing that, because of orbital drift and decay that was not
controlled for in your study, the temperature measurements were
gradually taken later and later in the day when temperatures
were cooling. The article also found a mathematical error in
your work. When corrected, the data pointed to an increase in
tropical temperatures, not a decrease.
Is you original work still being used as evidence that there is
no global warming? Have you corrected this work?
There are a number of issues intermingled in these comments and
questions that need clarification. Beginning in June 1998 and
for every month since then, the University of Alabama in
Huntsville (UAH) global temperature measurements reported positive
global trends for all versions of the lower tropospheric (LT)
temperature dataset. The tropical trends were not different from
a zero trend when Mears and Wentz began looking at the methodology
of our version 5.1 (v5.1). As noted in my testimony they
discovered an artifact of our adjustments for satellite drift which
created a cooling error in the tropics for LT. (We produce other
temperature products which used the same methodology to account
for this drift but which were not affected by this artifact.)
A fair bit of confusion arose when Mears and Wentz published the
discovery of this error in August 2005 and in the same
publication introduced a new LT dataset of their own. The
implication of this publication was that the error they found
was the difference between our old dataset and their new dataset
which was significant, about 0.10 �C/decade. In other words, the
impression given in the article was that their new dataset
represented a corrected version of our old dataset. Unfortunately,
this was not the case. The actual impact of the error in UAH's
v5.1 was not addressed in their paper. As Roy Spencer and I
published in Science magazine later in 2005, the effect of that
error was small, +0.035 �C/decade (at that time from +0.090 to
+0.125 �C/decade), being within our originally published error
margin assigned to v5.1. In the tropics, the effect was to
increase the trend from +0.00 to +0.05 �C/decade.
We corrected the error in May 2005 and with the publication of
Mears and Wentz put the data on a public website in August 2005,
though it was provided to several scientists before that date.
This new version, v5.2, has been publicly available since that
time. So there are two LT datasets with somewhat differing trends,
UAH's and RSS's.
Of interest to the committee is the fact I will have two papers to
be published shortly which indicate UAH v5.2 is highly consistent
with independent temperature measurements of the LT layer. These
papers show that it is very likely that the tropical atmosphere
is warming at a rate equal to or less than that of the surface, a
characteristic no climate model that we have examined replicates.
Thus, there is evidence that the theoretical ideas of how the
large-scale atmosphere should be responding to the enhanced
greenhouse effect, as embodied in climate models, still have
shortcomings.
As to the first question, we provide only the latest version of
our data to the public. And, since 1998 any version of our lower
tropospheric dataset would have shown a positive global trend.
Thus, if someone is using UAH data to claim no global warming, I
would speculate they are likely using pre-1998 data or are somehow
altering the data to make that conclusion. I don't know of any
current claims to that effect, and UAH has been forthright in
reporting positive trends (and the likelihood that at least part
of that positive trend is due to enhanced greenhouse gases) these
past 8 years.
In answering the second question, the discussion above describes
the events that led to the correction of the drift error and UAH's
corrected data have been publicly available since August 2005.
However, one should be aware that datasets are always subject to
revision, and we look forward to v6.0 of our current dataset, though
there will be little change in the outcome relative to v5.2.