[House Hearing, 110 Congress]
[From the U.S. Government Publishing Office]




        CLIMATE CHANGE: ARE GREENHOUSE GAS EMISSIONS FROM HUMAN
                       ACTIVITIES CONTRIBUTING TO
                       THE WARMING OF THE PLANET?

=======================================================================

                                HEARING

                               BEFORE THE

                 SUBCOMMITTEE ON ENERGY AND AIR QUALITY

                                 OF THE

                    COMMITTEE ON ENERGY AND COMMERCE
                        HOUSE OF REPRESENTATIVES

                       ONE HUNDRED TENTH CONGRESS

                             FIRST SESSION

                               __________

                             MARCH 7, 2007

                               __________

                           Serial No. 110-14


      Printed for the use of the Committee on Energy and Commerce

                        energycommerce.house.gov
                                 ______

                     U.S. GOVERNMENT PRINTING OFFICE
                            WASHINGTON : 2007
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                    COMMITTEE ON ENERGY AND COMMERCE

                   JOHN D. DINGELL, Michigan, Chairman

HENRY A. WAXMAN, California           JOE BARTON, Texas                  
EDWARD J. MARKEY, Massachusetts         Ranking Member                   
RICK BOUCHER, Virginia                RALPH M. HALL, Texas               
EDOLPHUS TOWNS, New York              J. DENNIS HASTERT, Illinois        
FRANK PALLONE, Jr., New Jersey        FRED UPTON, Michigan               
BART GORDON, Tennessee                CLIFF STEARNS, Florida             
BOBBY L. RUSH, Illinois               NATHAN DEAL, Georgia               
ANNA G. ESHOO, California             ED WHITFIELD, Kentucky             
BART STUPAK, Michigan                 BARBARA CUBIN, Wyoming             
ELIOT L. ENGEL, New York              JOHN SHIMKUS, Illinois             
ALBERT R. WYNN, Maryland              HEATHER WILSON, New Mexico         
GENE GREEN, Texas                     JOHN B. SHADEGG, Arizona           
DIANA DeGETTE, Colorado               CHARLES W. ``CHIP'' PICKERING,     
    Vice Chairman                       Mississippi                      
LOIS CAPPS, California                VITO FOSSELLA, New York            
MIKE DOYLE, Pennsylvania              STEVE BUYER, Indiana               
JANE HARMAN, California               GEORGE RADANOVICH, California      
TOM ALLEN, Maine                      JOSEPH R. PITTS, Pennsylvania      
JAN SCHAKOWSKY, Illinois              MARY BONO, California              
HILDA L. SOLIS, California            GREG WALDEN, Oregon                
CHARLES A. GONZALEZ, Texas            LEE TERRY, Nebraska                
JAY INSLEE, Washington                MIKE FERGUSON, New Jersey          
TAMMY BALDWIN, Wisconsin              MIKE ROGERS, Michigan              
MIKE ROSS, Arkansas                   SUE WILKINS MYRICK, North Carolina 
DARLENE HOOLEY, Oregon                JOHN SULLIVAN, Oklahoma            
ANTHONY D. WEINER, New York           TIM MURPHY, Pennsylvania           
JIM MATHESON, Utah                    MICHAEL C. BURGESS, Texas          
G.K. BUTTERFIELD, North Carolina a    MARSHA BLACKBURN, Tennessee        
CHARLIE MELANCON, Louisiana           
JOHN BARROW, Georgia                  
BARON P. HILL, Indiana                
                                    ____

                            Professional Staff

                   Dennis B. Fitzgibbons, Chief of Staff
                     Gregg A. Rothschild, Chief Counsel
                        Sharon E. Davis, Chief Clerk
                   Bud Albright, Minority Staff Director

                                  (ii)



                 Subcommittee on Energy and Air Quality

                    RICK BOUCHER, Virginia, Chairman

G. K. BUTTERFIELD, North Carolina    J. DENNIS HASTERT, Illinois,
    Vice Chairman                         Ranking Member
CHARLIE MELANCON, Louisiana          RALPH M. HALL, Texas
JOHN BARROW, Georgia                 FRED UPTON, Michigan
HENRY A. WAXMAN, California          ED WHITFIELD, Kentucky
EDWARD J. MARKEY, Massachusetts      JOHN SHIMKUS, Illinois
ALBERT R. WYNN, Maryland             JOHN B. SHADEGG, Arizona
MIKE DOYLE, Pennsylvania             CHARLES W. ``CHIP'' PICKERING, 
JANE HARMAN, California                  Mississippi
TOM ALLEN, Maine                     STEVE BUYER, Indiana
CHARLES A. GONZALEZ, Texas           MARY BONO, California
JAY INSLEE, Washington               GREG WALDEN, Oregon
TAMMY BALDWIN, Wisconsin             MIKE ROGERS, Michigan
MIKE ROSS, Arkansas                  SUE WILKINS MYRICK, North Carolina
DARLENE HOOLEY, Oregon               JOHN SULLIVAN, Oklahoma
ANTHONY D. WEINER, New York          MICHAEL C. BURGESS, Texas
JIM MATHESON, Utah                   JOE BARTON, Texas (ex officio)
JOHN D. DINGELL, Michigan (ex 
    officio)
                                 ------                                

                           Professional Staff

                      Sue Sheridan, Chief Counsel
                    Laura Vaught, Policy Coordinator
                 David McCarthy, Minority Chief Counsel


                             C O N T E N T S

                              ----------                              
                                                                   Page
Hon. Rick Boucher, a Representative in Congress from the 
  Commonwealth of Virginia, opening statement....................     1
Hon. J. Dennis Hastert, a Representative in Congress from the 
  State of Illinois, opening statement...........................     2
Hon. John D. Dingell, a Representative in Congress from the State 
  of Michigan, opening statement.................................     3
Hon. John Shimkus, a Representative in Congress from the State of 
  Illinois, opening statement....................................     5
Hon. Tammy Baldwin, a Representative in Congress from the State 
  of Wisconsin, opening statement................................     6
Hon. Michael C. Burgess, a Representative in Congress from the 
  State of Texas, opening statement..............................     7
Hon. Joe Barton, a Representative in Congress from the State of 
  Texas, prepared statement......................................     8

                               Witnesses

James W. Hurrell, director, Climate and Global, Dynamics 
  Division, National Center for Atmospheric Research, Boulder, CO    10
    Prepared statement...........................................    91
Michael Oppenheimer, professor, geosciences and international 
  affairs, Princeton University, Woodrow Wilson School, 
  Princeton, NJ..................................................    12
    Prepared statement...........................................    75
Gabriele Hegerl, associate research professor, Earth and Ocean 
  Sciences Division, Duke University, Durham, NC.................    13
    Prepared statement...........................................    65
Roni Avissar, professor and chair, Department of Civil and 
  Environmental Engineering, Duke University, Durham, NC.........    15
    Prepared statement...........................................    49
John R. Christy, professor and director, Earth System Science 
  Center, NSSTC, University of Alabama in Huntsville, Huntsville, 
  AL.............................................................    17
    Prepared statement...........................................    54

                           Submitted Material

Intergovernmental Panel on Climate Change, ``Climate Change 2007: 
  The Physical Science Basis''...................................   115





 
  CLIMATE CHANGE: ARE GREENHOUSE GAS EMISSIONS FROM HUMAN ACTIVITIES 
               CONTRIBUTING TO THE WARMING OF THE PLANET?

                              ----------                              


                        WEDNESDAY, MARCH 7, 2007

                  House of Representatives,
            Subcommittee on Energy and Air Quality,
                          Committee on Energy and Commerce,
                                                    Washington, DC.
    The subcommittee met, pursuant to call, at 10:00 a.m., in 
room 2322 of the Rayburn House Office Building, Hon. Rick 
Boucher (chairman) presiding.
    Members present: Representatives Butterfield, Melancon, 
Barrow, Waxman, Markey, Inslee, Baldwin, Ross, Hooley, Dingell, 
Hastert, Upton, Whitfield, Shimkus, Buyer, Walden, Sullivan, 
Burgess and Barton.
    Staff present: Sue Sheridan, Laura Vaught, Bruce Harris, 
Lorie Schmidt, Chris Treanor, David McCarthy, Kurt Bilas, and 
Peter Kielty.

  OPENING STATEMENT OF HON. RICK BOUCHER, A REPRESENTATIVE IN 
           CONGRESS FROM THE COMMONWEALTH OF VIRGINIA

    Mr. Boucher. The subcommittee will come to order.
    Today we examine the scientific evidence regarding global 
temperature changes and their relationship to human activity. 
At a later date the subcommittee will examine scientific 
opinion on the effects of temperature changes on weather 
patterns, ocean levels and habitat.
    The scientists on our panel today are all noted experts in 
their field and we welcome them to the subcommittee this 
morning. Their presentations will address the questions of 
whether global temperatures are increasing and to what extent 
any changes in temperatures are a consequence of human activity 
rather than natural climate variability and how future 
temperatures may be affected by current and future human 
activity. Over the past several decades, a vigorous debate has 
occurred over whether global temperatures are rising and 
whether any increases are being caused by human activity. The 
scientific opinion now appears to be solidifying with 
widespread agreement that temperatures are rising and that 
human activity is the principle cause. The recently released 
Intergovernmental Panel on Climate Change report reflects that 
consensus. It concludes with more than 90 percent certainty 
that temperatures are rising and that human contributions are 
causing most of the observed increases. This conclusion stands 
in sharp contrast with the panel report of several years ago 
reaching the same conclusions but only with a certainty of 66 
percent.
    Today's witnesses will comment on the IPCC report and on 
relevant research findings and conclusions which can be drawn 
from those research findings. I appreciate the attendance this 
morning of our expert witnesses and I very much look forward to 
hearing from them.
    We have at about 11:00 this morning a joint meeting between 
the House of Representatives and the Senate for the purpose of 
hearing from a visiting head of state, and under the rules of 
the House, we will not be able to continue the subcommittee 
hearing during the pendency of that joint meeting between the 
House and the Senate and so Mr. Hastert and I have agreed that 
what we will do is, go as far as we can in this hearing, recess 
during the pendency of the joint hearing between the House and 
Senate and then come back to finish this hearing at such point 
as that joint meeting of the House and Senate has been 
concluded.
    With those comments, I am pleased now to recognize the 
ranking member of this subcommittee, the gentleman from 
Illinois, Mr. Hastert, for 5 minutes.

 OPENING STATEMENT OF HON. J. DENNIS HASTERT, A REPRESENTATIVE 
             IN CONGRESS FROM THE STATE OF ILLINOIS

    Mr. Hastert. Thank you, Chairman Boucher.
    This morning we begin the science of global warming. 
Today's hearing is actually the beginning, in my view, of a 
thorough examination we must perform before moving forward with 
legislation proposing far-reaching economic implications. In 
fact, Mr. Chairman, I know you wanted to hold this hearing 
earlier in the process but you were forced to reschedule due to 
last month's severe winter storms, an irony lost on few. We 
just couldn't get the witnesses here.
    The question before us concerns the nature, extent and rate 
of global warming that has been observed and how human 
emissions of greenhouse gases figure into these observations. 
As we dig into the questions of man's contribution to global 
warming, I believe it is essential that we develop a broader 
perspective on what we know about climate effects, both natural 
and manmade.
    Many climate scientists acknowledge the deep complexity and 
limits of human knowledge of the climate system. This contrasts 
with the overly simplistic reporting of global warming and the 
climate change risks that we see in the mass media, whose 
treatment of the subject is often superficial and sensational. 
For policymakers, that is a dangerous combination.
    Mr. Chairman, we must avoid falling prey to the 
sensational. We must not miss out on the important questions or 
the practical opportunities that can help us address the 
challenges of global warming in an economically prudent 
fashion.
    In 2001, the National Research Council released its 
reported entitled ``Climate Change Science and Analysis of Some 
Key Questions.'' The NRC made an important observation in their 
report, and here is a direct quote: ``The most valuable 
contribution U.S. scientists can make is to continually 
question basic assumptions and conclusions, promote clear and 
careful appraisal and presentation of the uncertainties about 
climate change as well as those areas in which science is 
leading robust conclusion.''
    We should heed the advice of our top scientists. We need to 
keep asking, are we focused on the right science questions, are 
we focused on the right policy issues. For example, should we 
be concerned with just our own unilateral steps to reverse 
climate trends or should we address the effect of climate 
change more broadly as it relates to regions and local areas 
regardless of the temperature? How should we understand human 
influence in this broader context of the climate?
    I am hopeful the witnesses today can shed some light on 
these questions, that they can help us determine if we are 
looking at the issue properly. I am particularly interested in 
hearing whether we have a good handle on the relative 
contribution of greenhouse emissions to climate change compared 
with other human and natural resources. I would like to learn 
about the limits of our ability to attribute greenhouse gas 
emissions to global warming and what is needed to improve that 
ability. I would like to learn more about where the latest 
research is leading and how that might be changing the 
assumptions scientists have had about the issue.
    Last month the United States Intergovernmental Panel on 
Climate Change said, in effect, global warming is unequivocal; 
details to follow. I happen to believe, however, that saying 
global warming is unequivocal doesn't end the discussion; it 
begins it. How exactly do man's labors and industry connect to 
that warning? Is that connection the most relevant issue for us 
to address? Can we effectively change climate, address climate 
without forsaking our ability to deal with the other challenges 
of nature and human development that will confront us? We have 
to adapt to climate change no matter what is the cause, it is 
the way it has been forever, and energy policy plays an 
important role in that ability to address it. Energy animates 
our economic vitality. It is that vitality that gives us the 
ability to meet the challenges that nature delivers upon us.
    Let me thank the distinguished scientists before us today 
who have taken time from their busy schedule to attend the 
hearing. I look forward to your insights in these matters and I 
thank you, Mr. Chairman.
    Mr. Boucher. Thank you very much, Mr. Hastert.
    The gentleman from Michigan, the chairman of the full 
committee, Mr. Dingell, is recognized for 5 minutes.

OPENING STATEMENT OF HON. JOHN D. DINGELL, A REPRESENTATIVE IN 
              CONGRESS FROM THE STATE OF MICHIGAN

    Mr. Dingell. Mr. Chairman, thank you for your kindness and 
thank you for calling a very worthwhile series of hearings on 
climate change. It will be most helpful as we go forward to the 
consideration of this legislation.
    Now, I would like to also thank our panel. Ladies and 
gentlemen, thank you for being here and thank you for your time 
and for your assistance to the committee.
    Today we will examine the scientific question of whether 
greenhouse gas emissions from human activities are contributing 
and will continue to contribute to a warming of this planet. 
While many of us have had significant doubts about the question 
in the past, today it seems to us that science on the question 
has been settled.
    The extent of scientific consensus on this matter is well 
reflected by the recently published findings of the 
Intergovernmental Panel on Climate Change, IPCC, which was just 
released and entitled ``Summary for Policymakers'' for its 
fourth assessment report. The report was produced by some 600 
authors from 40 countries, over 620 expert reviewers and a 
large number of government reviewers also participated. 
Representatives from 113 governments, including the United 
States, reviewed and revised the summary line by line before 
adopting it and accepting the underlying report.
    The IPCC found that the warming of the climate system is 
unequivocal and that most of the observed increase in globally 
average temperatures since the mid-20th century is very likely 
due to the observed increase in anthropogenic greenhouse gas 
emissions. By ``very likely'' the IPCC means a nine in 10 
chance. For the future, the IPCC found that changes in the 
global climate system in the 21st century would very likely be 
larger than those observed in the 20th century. Indeed, even 
the administration seems to be in agreement with this point. 
Right after the IPCC report was released, Secretary of Energy 
Samuel Bodman was reported as saying, ``We are very pleased 
with it. We are embracing it. We agree with it.'' He went on to 
add that ``human activity is contributing to the changes in our 
Earth's climate and that issue is no longer up for debate.''
    Last month I had a fascinating discussion with some of the 
scientists responsible for the IPCC report. I asked detailed 
questions, some technical and some challenging. The answers I 
received were forthright. They explained that they had looked 
at changes in solar radiation, volcanic eruptions, urban heat 
islands and many other phenomena that are contributing to 
climate change. They explained that some of these factors are 
important for local temperature but that the only explanation 
for the large increase in global temperatures are the 
greenhouse gases which we are adding to the atmosphere. The 
scientists explained that there are some areas where scientific 
uncertainty exists. On the central question of man's 
contribution to the increase of global temperature due to 
greenhouse gas emissions, however, the issue is clear.
    It is important for the committee to probe renowned 
scientists to better understand what the science is telling us 
and how we are to answer the questions that are now before us. 
We need to find out where the science gives us clear answers 
and where the science gives us fuzzy answers. Today we are 
focusing on the threshold question of the extent to which 
greenhouse gas emissions from human activities are causing an 
increase in global temperature. At a future hearing we will 
explore the consequences of global warming for the Earth's 
systems. In other words, we will be asking why it matters that 
we are increasing global temperatures.
    In closing, Mr. Chairman, I hope that the members will use 
this opportunity to ask tough questions and to seek answers for 
any uncertainty they may have about the science of climate 
change.
    I thank you again for the hearings, and I thank also again 
our panel for their assistance to us.
    I yield back the balance of my time.
    Mr. Boucher. Thank you, Mr. Dingell.
    Mr. Shimkus for 5 minutes.

  OPENING STATEMENT OF HON. JOHN SHIMKUS, A REPRESENTATIVE IN 
              CONGRESS FROM THE STATE OF ILLINOIS

    Mr. Shimkus. Thank you, Mr. Chairman, and at the risk of 
trying to be as funny as my friend Mr. Markey, who I had great 
discussions with yesterday and then after the hearing, I was 
hesitant to say this, Ed, but we had hearings like this over 
many years and it was always in July, and if I heard Ed say it 
once, I heard him say it a hundred times: it is ironic that we 
are having a global warming hearing on the hottest day, in the 
hottest month, in the hottest year and the hottest century. It 
is snowing on March 7 and I would venture to say that it has 
been a pretty the cold February and March than what we have 
been used to in the last couple years. So for levity's sake, I 
throw that out, Ed, and Ed and I are going to have a good fun 
time in the next couple years in this whole debate.
    I want to draw attention also to the February 5 Wall Street 
Journal editorial and I think this sums up kind of where a lot 
of us are: ``The IPCC report should be understood as one more 
contribution to the warming debate, not some definitive last 
word that justifies radical policy change. It can be hard to 
keep one's head when everyone else is predicting the apocalypse 
but that is all the more reason to keep cool and focused on 
actual science,'' and that is why you are here today. We hope 
to ask and hear from you noted scientists.
    Most of us aren't that knowledgeable in the science. We are 
laymen who will try to move the country into good policy 
direction. There are always unintended consequences of 
legislative action which could be devastating and so we have to 
try to find balance. We want this to be a deliberative process. 
I think the committee is taking it in all the seriousness that 
is intended. We want to make sure we understand the reliability 
of knowledge and do our job in making sure we are gathering all 
the evidence from all the factors. This is our second hearing 
of this committee and we have many more to go. We appreciate 
your attendance. I look forward to hearing your testimony.
    Mr. Chairman, I yield back my time.
    Mr. Boucher. Thank you very much, Mr. Shimkus.
    Mr. Waxman from California for 3 minutes.
    Mr. Waxman. Thank you, Mr. Chairman. I am going to forego 
an opening statement in exchange for a lengthier time to 
question the witnesses.
    Mr. Boucher. Thank you, Mr. Waxman, and I would note that 
any member who desires to waive his opening statement will have 
3 minutes added to his questioning time for the panel of 
witnesses.
    The gentleman from Massachusetts, Mr. Markey, for 3 
minutes.
    Mr. Markey. I pass.
    Mr. Boucher. Mr. Markey waives.
    For 3 minutes, the gentleman from Washington, Mr. Inslee, 
is recognized.
    Mr. Inslee. I will pass.
    Mr. Boucher. Mr. Inslee passes.
    Mr. Barrow from Georgia.
    Mr. Barrow. I will pass.
    Mr. Boucher. Mr. Barrow also passes.
    The gentlewoman from Wisconsin, Ms. Baldwin, for 3 minutes.

 OPENING STATEMENT OF HON. TAMMY BALDWIN, A REPRESENTATIVE IN 
              CONGRESS FROM THE STATE OF WISCONSIN

    Ms. Baldwin. Thank you, Mr. Chairman.
    I want to express my gratefulness for this opportunity in 
this hearing today because for years undue political 
considerations have really kept us from reaching this point. 
Naysayers ignored clear warnings that human activity was 
creating significant changes in regional and global climate. 
They dismissed calls for action, claiming that alarmists were 
simply trying to focus attention on everything green. But the 
tides have turned and those of us who long ago committed 
ourselves to focusing on global changes in climate now have the 
backing of the congressional leadership and the international 
community in calling for action.
    The IPCC report is of vast importance. Not only does it 
confirm that climate change is real but it also confirms that 
human activities are the main cause. This report is not the 
work of politicians nor the work of zealots. Rather, it is a 
consensus of the scientific community of representatives from 
more than 113 countries of nearly 600 authors. These are the 
experts who have been to the top of the mountains, the bottom 
of the oceans, across deserts and icy fields, crisscrossing our 
planet to analyze the Earth's changing climate. In reaching 
their conclusions, they have surveyed climate data, observed 
geographic conditions and evaluated severe weather trends. 
These scientists have clearly done their work uninfluenced by 
politics or personal agenda and now it is time for us to do 
ours.
    We must take the knowledge and the data that has been 
presented to us and create sound policy that will result in a 
reduction of our greenhouse gas emissions. It won't be easy. We 
have questions to answer. For instance, what role will 
renewable energy play in our future and how can we begin to 
conserve energy now through efficient changes in the way we 
power our homes, operate our appliances or run our vehicles. 
While there are challenges ahead, our Nation, our businesses, 
our communities are in the best position to reshape our future. 
We understand the consequences of inaction and we are prepared 
to take steps necessary to preserve our planet for future 
generations. As stewards, protecting our environment has been 
our responsibility and now we are making it a priority.
    I look forward to hearing from our experts here today about 
how they reached their conclusions about their recommendations 
and for how we can reverse course and reduce our greenhouse 
gases, ensuring a healthy planet for generations to come.
    Thank you, Mr. Chairman, again. I yield back the balance of 
my time.
    Mr. Boucher. Thank you, Ms. Baldwin.
    Mr. Buyer for 3 minutes.
    Mr. Buyer. I pass.
    Mr. Boucher. Mr. Buyer passes.
    Mr. Upton for 3 minutes.
    Mr. Upton. I pass.
    Mr. Boucher. Mr. Upton passes.
    Mr. Burgess for 3 minutes.

OPENING STATEMENT OF HON. MICHAEL C. BURGESS, A REPRESENTATIVE 
              IN CONGRESS FROM THE STATE OF TEXAS

    Mr. Burgess. Thank you, Mr. Chairman, and I too want to 
thank you for convening this hearing. I think these hearings 
have been extremely informative and this morning's science 
hearing is essential to what we are doing here on the 
legislative process so I am glad we were able to reschedule 
this hearing, canceled last month due to an ice storm and put 
in jeopardy by a snowstorm but it is a timely hearing 
nevertheless.
    I am really kind of puzzled why this wasn't actually our 
first hearing. Instead of starting from the beginning with the 
science, we started with the solutions, cap and trade proposals 
and carbon sequestration, but now that we have finally gotten 
around to it, this is critical for part of our discussion.
    If I could, I think have one slide to put up on the screen 
in the brief time allotted to me, and that is not it. Well, we 
will get this handed out. But according to EPA data, water 
vapor accounts for 95 percent of greenhouse gases. There it is.
    [Slide shown.]
    Ocean biologic activity, volcanoes, decaying plants are an 
additional 4.72 percent and the last small sliver is the human 
contribution, less than one-third of 1 percent. But today we 
are going to focus like a laser beam on that less than one-
third of 1 percent but I think it is important that we don't 
forget the context in which we are working. The human additions 
to the greenhouse gas emissions come from multiple sources 
including livestock, land use changes, fire suppression 
systems, electricity plants and tailpipes. I believe that Dr. 
Avissar from Duke University will be focusing his testimony on 
this broader context.
    I realize that this is a topic that will be addressed in a 
future hearing by the subcommittee but I think it is important 
that as we begin to examine the causes of global climate 
change, we not forget the economic consequences of policy 
decisions made by this body as we look at this legislation.
    Regardless of the reason, whether you are a fan of global 
warming, of peak oil or just feel it is a cause for a national 
security concern, removing some carbon from the economic 
equation is an idea that has merit, but at the same time, we 
must not sacrifice our economy as we make that transition, 
because after all, it is the health of our economy that will 
allow us to make that transition, and I think that is an 
important point to keep in mind but also I would just share 
this concern: Global warming and climate change are not 
interchangeable terms. They are not synonymous and we are going 
to hear more in this hearing about the differences from some of 
today's witnesses, and I believe Dr. Christy is going to be 
talking about as we discussed some in our oversight hearing 
last year.
    Thank you, Mr. Chairman, and I will yield back my remaining 
12 seconds.
    Mr. Boucher. Thank you very much, Mr. Burgess.
    Mr. Shadegg from Arizona is recognized for 3 minutes.
    Mr. Shadegg. Mr. Chairman, I will pass other than to 
commend you for holding this hearing. I think it is important 
that we look at the science, both the science as to the cause 
of whatever warming is occurring and the science as to how we 
can deal with it, and I commend you.
    Mr. Boucher. Thank you very much, Mr. Shadegg.
    That concludes the time for opening statements. Statements 
for the record will be accepted at this time.
    [The prepared statement of Mr. Barton follows:]

  Prepared Statement of Hon. Joe Barton, a Representative in Congress 
                        from the State of Texas

    Thank you, Chairman Boucher, for this initial hearing on 
the question of man's contribution to global warming.
    I commend you and Chairman Dingell for putting together a 
series of hearings on global warming science and policy. Our 
committee's tradition of open process has historically enabled 
us to take on the tough economic and public health issues 
despite our geographic, ideological, and political diversity.
    We are addressing global warming, but we're not doing it in 
a vacuum. We're also charged with make sure that people in 
America have the energy that powers our jobs and, through them, 
our people's opportunity to succeed. If we do our jobs, people 
will keep their jobs.
    I hope today's hearing and the ones that follow will help 
each of us reach rational conclusions, based on real evidence, 
about the reliability of our knowledge that CO\2\ has the sort 
of impact on planetary temperature as people say.
    It's important to recognize that this is not about the 
weather on any given day. When we met to examine the dubious 
statistical validity of some global warming forecasts last 
summer, it was very hot. I think we picked one of the hottest 
days of the year. Today the weather is uncharacteristically 
cold. I'm sure some would prefer to wait until the weather 
matches the theory, but this is serious business and I hope we 
can each concede that any day's weather has nothing to do with 
the issue.
    There has been significant scientific debate about this 
issue, including discussion before this committee. In last 
summer's hearings, we asked about the historical temperature 
records and other climate observations. We asked whether the 
most politically influential modeling conclusions were 
adequately supported by those observations.
    I said then that I accept that the science on this matter 
is uneven, uncertain, and evolving. That certainly hasn't 
changed, but now we seem to be pressuring ourselves, or someone 
is pressuring us, to legislate first and get the facts later. I 
hope we won't do that. I want to make sure we get the best 
information available so we have a full and accurate definition 
of the problem before we start making decisions that will be 
among the toughest of our careers.
     The key question we face is how our decisions affect the 
lives of the people who send us here. They expect us to make 
decisions, and they do not expect us to make wrong ones.
    I will follow the guidance of my friend, Chairman Dingell: 
``First, do no harm.''
    We have to be clear about the issues before us. Discussion 
of capping CO\2\ often misses an essential fact. Carbon 
dioxide, unlike carbon monoxide and other compounds ending in 
``oxide,'' is not toxic. It is not a pollutant. It is not only 
natural, it is indispensable for life on this planet.
    What we need to understand is:

     1. How does CO\2\ fit into the atmospheric mix? I'm told 
all CO\2\ is only 0.038 percent of atmospheric gases;
     2. How does the CO\2\ from fossil fuel combustion fit into 
the total annual CO\2\ increase in the atmosphere? I'm told 
it's only 0.4 percent of this amount.
    3. How does U.S. fossil fuel consumption fit into mankind's 
overall share of fossil energy use? I'm told it's 22 percent 
and shrinking; That means if we shut down 100 percent of all 
fossil fuel use in the United States, we would only reduce 
CO\2\ growth in the atmosphere by 0.088 percent. That's 0.0003 
percent of the atmospheric gases, and China will be filling in 
the gap, and then some.
     4. How much will any legislation we consider actually 
change the total U.S. emissions and, in turn, change total 
human emissions and, in turn, effect global greenhouse gas 
concentrations?

    In that real world context, we must ask: what legislation, 
if any, can we enact this year that will plainly and 
significantly improve the health and lives of people around the 
world a hundred years from now?
    What will it cost? The people who will pay for our policy 
decisions are taxpayers and consumers and workers. What amount 
is the right amount to take from them and their families for 
our policies?
    We also have to weigh what the opportunity cost might be in 
terms of other global problems we neglect because of our huge 
economic and political investment in this issue.
    And we need to understand whether well-meaning steps to cap 
CO\2\ here and now will simply drive industry offshore where 
control of actual pollution such as SOx, NOx, mercury, and 
particulate is far more lax.
    Whether we like it or not, CO\2\ correlates to national 
economic activity. That means jobs, and the ability of working 
families to thrive is defined by jobs. Despite impressive gains 
in energy intensity over the past few years, a basic reality is 
that with the technology mix deployed today, to cap CO\2\ 
emissions restrains economic output, jeopardizes economic 
growth, and eliminates people's jobs.
    Now there are three camps in the political discussion about 
capping CO\2\. One camp doesn't care. Its members are either 
indifferent or hostile to economic growth. Some of them see the 
de-industrialization of the U.S. and they welcome it.
    The opposite camp strongly favors economic growth and 
opportunity for America, as well as for people around the 
world, and worries that this Congress could put domestic growth 
and opportunity at risk.
    The middle camp, however, is the most troubling. They're 
the ones who want so badly to believe we can easily and 
inexpensively innovate our way out of the linkage between CO\2\ 
and economic vitality that they are willing to say, ``Cap now, 
details to follow.''
    That's why we must study the science, the policy proposals, 
the costs, and the benefits, and assess them all carefully. 
That is the path you, Chairman Boucher and Chairman Dingell, 
have outlined for us.
    I welcome our witnesses. Your views are critical for us to 
understand what the state of science is. Please be clear with 
us, and don't hesitate to separate the certainties from the 
uncertainties.
    Thank you, Mr. Chairman.
                              ----------                              

    Mr. Boucher.We are now pleased to welcome our panel of 
witnesses. I will say a brief word of introduction about each 
of them.
    Dr. James Hurrell joins us from the National Center for 
Atmospheric Research in Boulder, CO, where he is a senior 
scientist and the director of the Climate and Global Dynamics 
Division. He was a contributing author to both the third and 
fourth assessment reports of the Intergovernmental Panel on 
Climate Change. He was a lead author on the U.S. climate change 
science program's synthesis and assessment product on 
temperature changes in the lower atmosphere and he is currently 
serving on a National Research Council committee that is tasked 
to provide strategic advice.
    Dr. Gabriele Hegerl joins us from Duke University where she 
is a research professor at the Nicholas School of the 
Environmental and Earth Sciences. She was a lead author in the 
IPCC's third assessment report. For the fourth assessment 
report, she was a coordinating lead author for the chapter that 
focuses on determining the causes of observed climate changes.
    Dr. Michael Oppenheimer joins us from Princeton University 
where he is the Albert G. Milbank professor of geosciences and 
international affairs. He is affiliated with the Department of 
Geosciences, the Woodrow Wilson School of Public and 
International Affairs and the Princeton Environmental 
Institute. He was a lead or contributing author to various 
chapters of the IPCC's third assessment report and is a lead 
and contributing author to the fourth assessment report.
    Dr. Roni Avissar also joins us from Duke University where 
he is the W.H. Gardner professor and chair of the Department of 
Civil and Environmental Engineering. His research is focused on 
development and evaluation of various environmental fluid 
dynamics models to study ocean, land, atmospheric interactions 
at the various spatial and temporal scales.
    Dr. John Christy joins us from the University of Alabama in 
Huntsville where he is a professor and director of the Earth 
Systems Science Center. He is also Alabama's State 
climatologist. He was a lead author of the IPCC's third 
assessment report and is a contributor to the fourth assessment 
report.
    We welcome each of our witnesses. Your prepared written 
statements will be made a part of the record and we would be 
pleased to receive your oral summaries of approximately 5 
minutes.
    Dr. Hurrell, we will be pleased to begin with you.

  STATEMENT OF JAMES W. HURRELL, DIRECTOR, CLIMATE AND GLOBAL 
  DYNAMICS DIVISION, NATIONAL CENTER FOR ATMOSPHERIC RESEARCH

    Mr. Hurrell. Mr. Chairman, I thank you, Ranking Member 
Hastert and the other members of the subcommittee for the 
opportunity to speak with you today on observed and likely 
future changes in climate and the contribution from human 
activity to those changes.
    Although uncertainties continue to exist, significant 
advances in the scientific understanding of climate change now 
make it clear, as recently stated by the IPCC, that the warming 
of the climate system is unequivocal and that this warming goes 
beyond the range of natural variability.
    The globe is warming dramatically compared with natural 
historical rates of change. Global surface temperatures today 
are more than 1.4 degrees Fahrenheit warmer than at the 
beginning of the 20th century and rates of temperature rise are 
greatest in recent decades. Eleven of the last 12 years rank 
among the 12 warmest since 1850 and four of the warmest 5 years 
on record have occurred since 2001. This past year, 2006, was 
the warmest on record over the United States. There is a very 
high degree of confidence in these numbers. Urban heat island 
effects, for instance, are real but very local and they have 
been accounted for in the analyses. There is no urban heat 
island effect over the oceans where the warming has been very 
pronounced at both the surface and at depth. Moreover the ocean 
warming causes seawater to expand and thus contributes to 
global sea level rise of more than 1.3 inches since 1993 and 
6.7 inches over the last century.
    A key point is that an increasing number of many 
independent observations give a consistent picture of a warming 
world. There has been a widespread reduction in frost. There 
have been more warm extremes and decreases are occurring in 
snow cover, Arctic sea ice extent and thickness, and mountain 
glacier mass and extent. Increases in atmospheric water vapor 
content and resulting heavier precipitation events, increased 
drought and increasing atmospheric temperatures above the 
surface are other signals of a warming world.
    Today's best climate models are now able to reproduce these 
major climate changes of the past century. Climate models are 
not perfect and some models are better than others. 
Uncertainties arise from shortcomings in our understanding of 
climate processes and how best to represent them. Other 
forcings need to be more fully considered such as historical 
and likely future changes in land use. Yet in spite of these 
uncertainties, giving good replication to the past, climate 
models are extremely useful tools for understanding and 
determining the changes in forcing that are driving the 
observed warming.
    Forcings imposed on the climate system can be natural in 
origin such as changes in solar luminosity or volcanic 
eruptions or human-induced such as the buildup of greenhouse 
gas concentrations in the atmosphere. These concentrations have 
increased markedly as the result of human activities and they 
are now higher than at any time in at least the last 650,000 
years.
    Climate model simulations that account for such changes in 
climate forcings have now shown that surface warming of recent 
decades is mainly a response to the increased concentrations of 
greenhouse gases and sulfate aerosols in the atmosphere. When 
the models are run without these forcing changes, the remaining 
natural forcings and intrinsic natural variability fail to 
capture the almost linear increase in global surface 
temperature over the past 25 years.
    Moreover, observed increases in continental and ocean basin 
scale temperatures as well as observed changes in precipitation 
and other measures such as climate extremes are only stimulated 
by models that include anthropogenic forcings. These 
simulations have therefore convincingly shown that climate is 
changing in ways that cannot be accounted for by natural 
variability or by changes in natural forcings such as changes 
in the sun. Moreover this attribution of the recent climate 
change has direct implications for the future. Because of the 
very long lifetime of carbon dioxide in the atmosphere and the 
slow equilibration of the oceans, there is a substantial future 
commitment to further global climate change even if 
concentrations of greenhouse gases in the atmosphere remain at 
current levels.
    In summary, the scientific understanding of climate change 
is now sufficiently clear to show that climate change from 
global warming is already upon us. Uncertainties do remain, 
especially regarding how climate will change at regional and 
local scales, but the climate is changing and the rate of 
change as projected exceeds anything seen in nature in the past 
10,000 years.
    Thank you again for this opportunity to address the 
committee, and I look forward to answering your questions.
    [The prepared statement of Mr. Hurrell appears at the 
conclusion of the hearing.]
    Mr. Boucher. Thank you, Dr. Hurrell.
    Dr. Oppenheimer.

 STATEMENT OF MICHAEL OPPENHEIMER, PROFESSOR, GEOSCIENCES AND 
          INTERNATIONAL AFFAIRS, PRINCETON UNIVERSITY

    Mr. Oppenheimer. Thank you, Mr. Chairman, and I would like 
to thank the other members of this committee for this 
opportunity to testify.
    In addition to responding to the questions posed by the 
committee, my testimony addresses the subject of ice sheets and 
sea level rise which received considerable attention in the 
wake of the publication of the IPCC report. Finally, I will 
report some recent findings from the peer-reviewed literature 
on the question of the time remaining to avoid levels of 
climate change that some research has characterized as 
dangerous.
    I want to emphasize that I am testifying in my capacity as 
an individual scientist and not a representative of IPCC or for 
that matter Princeton University. The conclusions drawn here 
are my own.
    On the first question, are global temperatures increasing, 
IPCC's answer is unequivocal and I agree, global temperatures 
are certainly increasing. Furthermore, the warming and the 
associated sea level rise have accelerated and a pervasive 
global climate change is underway.
    On the second question, to what extent is the increase 
attribute to greenhouse gas emissions from human activity, here 
again I fully support IPCC's conclusion that it is very likely 
that most of the recent climate change is attributable to human 
activities, particularly the emissions of greenhouse gases and 
aerosol particles. Natural climate variability and changes in 
the sun and volcanic emissions have played a much lesser role.
    On the third question, how do we expect future global 
temperatures to be affected by greenhouse gas emissions, during 
this century global mean temperatures are likely to increase by 
amounts that are larger and occur faster on a sustained basis 
than any in the history of civilization and reach levels 
perhaps not seen in tens of millions of years when ice sheets 
were much reduced and sea level was much higher than today. The 
temperature change would be largest on land and at high 
latitudes which includes large parts of the United States. The 
climate change is expected to broadly affect key aspects of the 
climate system and simply put, would remake the face of the 
Earth.
    I am particularly concerned about the fate of the great ice 
sheets in Greenland and Antarctica. Because our ability to 
apply modern numerical computer modeling techniques to ice is 
much weaker than our ability to model the atmosphere, we must 
rely on other information, particularly from climates of the 
past. IPCC notes that sea level was likely 13 to 20 feet higher 
about 125,000 years ago the last time Earth was about as warm 
as today, actually a little bit warmer, mainly due to the 
retreat of polar ice when polar temperatures were 5 to 9 
degrees Fahrenheit higher than at the present. Additional 
global warming of only about 3 to 4 degrees Fahrenheit may 
bring a return of such polar warmth. Accordingly, and here I go 
beyond the remit of Working Group I of IPCC into the general 
peer-reviewed literature, I conclude that a warming of no more 
than 3 to 4 degrees Fahrenheit above present global mean 
temperatures may represent a plausible objective for avoiding 
dangerous climate changes.
    What does such a limit imply for actions to reduce 
emissions? The answer is that the chances of avoiding such a 
warming appear to be less than 50/50 if atmospheric 
concentrations of carbon dioxide are permitted to exceed 450 
parts per million, noting that we are currently around 380 
parts per million. Unless the growth in global emissions is 
reduced soon, first through reductions in emissions in 
developed countries like the United States, coordinated with or 
followed closely by measures in developing countries, global 
temperature is likely to eventually climb beyond the 3- to 4-
degree Fahrenheit limit. Then the ice sheets may gradually 
shrink, causing sea level to rise 13 to 20 feet, possibly over 
a period as brief as several centuries but possibly over a 
millennium or more, and if the warming were allowed to 
continue, that would be only the beginning of a processes that 
may eventually lead to total loss of both the Greenland and the 
West Antarctic section of the Antarctic ice sheets and a much 
larger sea level rise.
    Only prompt and sizable reductions in global emissions, 
hopefully carried out with the leadership of the United States 
and in collaboration with other large emitting countries such 
as the EU, Japan, China and India would avoid such an 
eventuality. I point to the 5-, 10- and 15-year mandatory 
emissions reduction targets embodied in the proposal from USCAP 
as plausible initial steps to meet this challenge.
    It is apparent to me and I hope to everyone else that the 
U.S. and all other countries ought to prepare to deal with a 
warmer world in any event. It is even more important to note 
that the window of opportunity to avoid potentially dangerous 
climate outcomes may be closing fast.
    Thank you.
    [The prepared statement of Mr. Oppenheimer appears at the 
conclusion of the hearing.]
    Mr. Boucher. Thank you, Dr. Oppenheimer.
    Dr. Hegerl.

  STATEMENT OF GABRIELE HEGERL, ASSOCIATE RESEARCH PROFESSOR, 
       EARTH AND OCEAN SCIENCES DIVISION, DUKE UNIVERSITY

    Ms. Hegerl. Thank you, Mr. Chairman, and thank you, members 
of the committee, for giving me the opportunity to testify 
today about global warming.
    To address your questions, I would like to draw your 
attention to some slides. May I see the first slide, please?
    [Slide shown.]
    This slide shows you that evidence for warming in the 
climate system is widespread. The top left panel shows you the 
observed warming over the 20th century from the surface 
temperature record, the top right panel, the observed warming 
from atmospheric temperatures and the bottom shows you warming 
from the ocean temperature measurements. This widespread nature 
of the warming and the way it is consistent between different 
components of the climate system led us to the conclusion that 
warming of the climate system is unequivocal. Furthermore, the 
pattern of warming being quite uniform, the warming in each 
individual component of the climate system being much larger 
than we expect due to natural climate variability such as El 
Nino led us to the conclusion that it is extremely unlikely 
that such a warming in all major components of the climate 
systems would occur without external forcing, and we also 
concluded that it is very unlikely due to natural causes alone.
    Can I see the second slide, please?
    [Slide shown.]
    Climate models incorporate our best understanding of how 
the climate system works and driven with observed changes in 
radiative force such as changes in greenhouse gases, aerosols, 
volcanic and solar forcing reproduce the 20th century 
temperature record quite well. What you see at the top right 
panel model simulations from a large number of modeling centers 
and from a large number of models, some of them including 
smaller forcings like land use change, differing in details of 
forcing and model physics. The observed warming shown in black 
lies quite well within the model framework. You can also see 
that the climate models respond similarly the observations to 
individual events like volcanic eruptions shown by the gray 
bars--you can see the records go down a little bit in response 
to that--and at the bottom panel you see that if driven with 
natural forcings only such as solar and volcanic forcing, 
climate models can not reproduce the 20th century warming.
    To conclude, however, what caused the 20th century warming, 
we resort to quite different methods. We do not resort to 
modeling alone but we try to estimate the effect of the 
different external influences such as greenhouse gases from the 
observed change so we look for fingerprints of warming as we 
expect due to increases in greenhouse gases or other forcings 
based on these sophisticated studies which focus on the 
observations allow for the possibility that the response to a 
forcing could be larger or smaller than anticipated in models, 
that it could be somewhat different in pattern and it could be 
not present at all. Carefully investigating alternative 
physical explanations for the observed warming, we came to the 
conclusion that it is very likely that most of the observed 
warming was caused by the greenhouse gas increase. This 
conservatively accounts for the remaining uncertainty of which 
we are quite aware.
    Can I see briefly the next slide, please?
    [Slide shown.]
    We can also draw this type of analysis now based on space 
and time patterns of warming on individual continents, 
concluding for example that North America is quite outside the 
range of where we would be due to natural variability alone at 
this point in time.
    Can we move one slide on, please?
    [Slide shown.]
    The last slide shows you the predicted future warming in 
the context of the 20th century simulated warming based on 
observed records of warming from the 20th century from cooling 
in the last glacial maximum. From various studies we can 
conclude that the sensitivity of the system to external forcing 
is not small. Climate responds substantially to changes in 
radiative forcings such as changes in greenhouse gases. Based 
on this, we concluded that it is very unlikely that climate 
sensitivity is less than one and a half, pretty much ruling out 
various model responses of the climate system in the future and 
future warming depends on the emissions scenarios we take on 
and ranks from one and a half to nine times the observed 
warming over the 20th century.
    [The prepared statement of Ms. Hegerl appears at the 
conclusion of the hearing.]
    Mr. Boucher. Thank you, Dr. Hegerl.
    Dr. Avissar.

 STATEMENT OF RONI AVISSAR, PROFESSOR AND CHAIR, DEPARTMENT OF 
      CIVIL AND ENVIRONMENTAL ENGINEERING, DUKE UNIVERSITY

    Mr. Avissar. Thank you, Mr. Chairman and members of the 
committee.
    May I have the slides, please? The next one.
    [Slide shown.]
    The point that I would like to make here as an introduction 
first of all is that I am not disputing the results or most of 
the results of IPCC and of my colleagues. In other words, the 
climate seems to be indicating an increase of the temperature 
over the past years and IPCC has very eloquently reported on 
all the studies that demonstrate that. The questions that have 
been asked in front of us, are global temperatures increasing, 
I would answer based on the report of IPCC, yes.
    The second question, if global temperature increasing, to 
what extent is the increase attributed to greenhouse gases 
emission from human activity is where I start having slightly 
different opinion and so the question, how do we expect the 
future global temperature to be affected by greenhouse gases. I 
believe that in spite of the fact that the models are an 
essential tool to be able to evaluate the climate and are 
probably the only good tool that we can have to speculate about 
what is going to happen in the future climate, there are still 
a lot of uncertainties in these models, and because of those 
uncertainties and the way that they are built, we have 
difficulty to estimate exactly what is the proportion of the 
greenhouse gas contribution to the overall climate versus many 
other activities that are taking place from the human activity.
    On this report of IPCC, I guess that the lower bar that 
indicates the overall contribution of the human activity 
indicates an overall contribution with a lot of uncertainty and 
then the proportion of the different components is where maybe 
we need to look at a little bit more carefully. In order to do 
that, I am going to use just a simple representation of land 
cover change and demonstrate to you how in fact the models that 
we are using to make these assessments can be mistaken. If I 
can have the next slide, please?
    [Slide shown.]
    What you see here is a scenario of deforestation of the 
Amazon basin, in part due to the intention of investing much 
more in biofuels as a replacement maybe to traditional oil, and 
this is a scenario that was produced based on socioeconomic 
development for 2050, so about 50 years down the road. And you 
can see here that most of the basin is going to be deforested 
to be replaced with agriculture areas and other areas. Next 
slide, please.
    [Slide shown.]
    The study that we have conducted with models that are 
better designed to look into those particular processes, higher 
resolution models, indicates present results that are slightly 
different than what the global climate models are providing, 
and what you see here is a sequence of precipitation for the 
past 30 years--that is the upper graph--that shows that over 
the past 4 years we had as sequence of high precipitation and 
then in 1998 a very low precipitation in the Amazon basin, that 
is showing an El Nino year, and then 2 years that were somewhat 
close to the average precipitation.
    When we use this sequence of precipitation and we feed with 
the meteorology that has been observed over the area, those 
mesoscale models, and we combine that with the land cover 
change, we see the sheet of precipitation that you have on the 
lower left figure. In other words, what you notice there is 
that there are areas that receive much less precipitation and 
in fact the areas that are mostly deforested receive much more 
precipitation than what was originally obtained.
    When you combine all those results and you look at the 
impact that that has with the global climate models that are 
currently used versus the original models, you can notice 
especially, you look the lower right curve, you can notice that 
in fact the global climate models just for that particular 
phenomena indicates a difference of precipitation that is twice 
more severe than what you would get with a model that is better 
capable of representing the clouds and radiation system. Next 
picture, please.
    [Slide shown.]
    All right. The point that we were asked to answer is what 
do we think is the next direction for research. I guess that I 
would like to advocate here for better models, and in 
particular, models that are capable of representing much better 
the cloud radiation feedback, the models that are capable of 
representing the biosphere and the hydrosphere a little better 
and models that can account for process that are extremely 
significant on the climate system like aerosols, fires and all 
kinds of other processes that are significant.
    So I think that the scientific community is going that 
direction. I think that we may get some surprises from these 
models when we can combine all the human activities that we 
have.
    Thank you.
    [The prepared statement of Mr. Avissar appears at the 
conclusion of the hearing.]
    Mr. Boucher. Thank you, Dr. Avissar.
    Dr. Christy.
    Mr. Barton. Mr. Chairman, we have bits and pieces of what 
the witness just showed us but we don't have it in the coherent 
form. Could we get him to give that to us?
    Mr. Boucher. Dr. Avissar, would it be possible for you to 
reproduce your slides as prints and provide those to the 
committee.
    Mr. Avissar. Sure.
    Mr. Boucher. Thank you, Mr. Chairman, and we will share 
them with you.
    Dr. Christy.

  STATEMENT OF JOHN R. CHRISTY, PROFESSOR AND DIRECTOR, EARTH 
    SYSTEM SCIENCE CENTER, NSSTC, UNIVERSITY OF ALABAMA IN 
                           HUNTSVILLE

    Mr. Christy. Chairman Boucher, Ranking Member Hastert and 
committee members, I am John Christy, director of the Earth 
Systems Science Center at the University of Alabama in 
Huntsville.
    I lead a group which builds climate data sets from scratch 
with interesting results. For example, in constructing surface 
temperatures in California's Central Valley, we found a 
dramatic rise in nighttime temperatures that did not occur 
nearby in the Sierras. This points to a human fingerprint on 
climate change likely being the massive conversion of dry land 
to irrigated agriculture and urbanization but not greenhouse 
gases. In these and other data sets, we find inconsistencies 
between observations and the output of climate models which 
tried to tell us the climate effect of greenhouse gases.
    Now, I go into detail in my written remarks to answer your 
questions on temperature changes. Yes, the surface temperature 
is rising, an unknown portion of which I believe is due to 
extra greenhouse gases, and the current rate of about 0.15 
degrees Celsius per decade is a sensible projection.
    Now, the implication of these questions, however, leads me 
to discuss both climate and energy use. In 1900, the global 
energy technology supported 56 billion human life-years and 
that is 35-year life expectancy times 1.6 billion people. It is 
an index. Today energy technology supports 426 billion human 
life-years, an eightfold increase, and some of these human 
life-years are mine. I have been allowed to become a 
grandparent, a situation that is now the rule, not the 
exception. An eightfold increase in the global experience of 
human life, that is a spectacular achievement delivered by 
affordable energy. It disturbs me when I hear that energy and 
its byproduct, CO\2\, are being demonized when in fact they 
represent our greatest achievement. Where there is no energy, 
life is brutal and short. When you think about the extra CO\2\ 
in the air, think also about the eightfold increase in human 
life.
    While preparing this testimony, I was reminded of my 
missionary experience in Africa. African women collect firewood 
each day and carry it home for heating and cooking. This 
inefficient and toxic source of energy kills about 1.6 million 
women and children a year. When an African woman carrying 50 
pounds of firewood risks her life by jumping out in front of my 
van in an attempt to stop me to give her a lift, I see the 
value of energy. You see, what I had in my school van in terms 
of the amount of gasoline I could held in my cupped hands could 
move her and her firewood 2 or 3 miles down the road to her 
home. I understood the astounding benefit energy represents and 
to what extent she and her people would go to acquire it. 
Energy demand will grow because it makes life less brutal and 
less short.
    The continuing struggle of the European Union and other 
countries to achieve their self-imposed Kyoto targets, indeed 
falling behind the U.S. in slowing emissions growth, implies a 
lot of things but two that stand out to me are, one, 
underestimating people's demand for energy, and two, 
overlooking the well-known tendency for countries and 
industries to game the system for their own benefits without 
really producing any real emission reduction.
    This body is being encouraged to ``do something'' about 
global warming and the dilemma begins with this: energy demand 
will grow because its benefits are ubiquitous and innumerable. 
The dilemma then is, how can emissions be reduced in a way that 
doesn't raise energy costs, especially for the many poor people 
in my State and the world.
    There are several new initiatives on energy reductions 
being proposed as a benchmark. Those which are in the ballpark 
of the Kyoto-like reductions will produce a small impact on 
emissions and thus a very, very small impact on whatever the 
climate does. I have written a number of papers about the 
precision of our climate records. The impact of Kyoto-style 
reductions will be too small for we scientists to measure due 
to the natural variations of climate and the lack of precision 
in our observing system. In other words, we will not be able to 
tell lawmakers with any confidence that specific regulations 
achieve anything in terms of ``climate control'' in this 
country or the world. And when you think about it, the climate 
system is so complicated, we really can't tweak it for a 
predictable outcome.
    So let me close with this observation from my scientific 
research and life experience. Helping people develop 
economically is the fastest route I see to giving them the 
tools they need to adapt to whatever the climate does including 
that portion of change that may be due to human influences.
    Thank you.
    [The prepared statement of Mr. Christy appears at the 
conclusion of the hearing.]
    Mr. Boucher. Thank you very much, Dr. Christy, and thank 
you to each of the members of our panel for providing 
information to us this morning. We have approximately 5 minutes 
before we must recess the committee for the joint session on 
the floor. I will take that opportunity to ask my set of 
questions to this panel.
    Mr. Barton. Mr. Chairman, a parliamentary inquiry?
    Mr. Boucher. Sure.
    Mr. Barton. What would it take to continue this hearing 
while the joint session is underway? Would a unanimous consent 
request allow us to continue, or is it impossible?
    Mr. Boucher. Mr. Barton, we examined that and I share your 
desire to continue this hearing. Unfortunately, it is a rule of 
the House and it is not waivable by our unanimous consent 
request.
    Mr. Barton. So there is no way?
    Mr. Boucher. I am afraid there is no way.
    Mr. Barton. Thank you, Mr. Chairman.
    Mr. Boucher. But thank you for asking.
    I would like to get a better sense of where our expert 
witnesses agree and so let me ask each of you if you would to 
respond to this group of questions, and for purposes of 
brevity, a simple yes or a no would be desirable by way of 
response.
    First question: In the executive summary that was released 
in February, the IPCC found that--and I quote from the report--
``Most of the observed increase in global averaged temperatures 
since the mid-20th century is very likely due to the observed 
increase in anthropogenic greenhouse gas concentrations,'' in 
other words, those concentrations that came from human 
activity.
    Do you agree or disagree with that conclusion, Dr. Hurrell?
    Mr. Hurrell. Yes, I do agree with that conclusion.
    Mr. Boucher. Dr. Oppenheimer?
    Mr. Oppenheimer. I agree.
    Mr. Boucher. Dr. Hegerl?
    Mr. Hegerl. I agree. My chapter proposed that conclusion.
    Mr. Boucher. Dr. Avissar?
    Mr. Avissar. I cannot answer by yes or no. I would say that 
I tend to agree, but I am not convinced.
    Mr. Boucher. OK. So you lean in favor of that finding?
    Mr. Avissar. I am sure that there is a contribution from 
the greenhouse gases. I have no doubt about that.
    Mr. Boucher. That is good. Thank you, sir.
    Dr. Christy?
    Mr. Christy. A similar answer, the contribution from 
greenhouse gases, but I don't know how much.
    Mr. Boucher. All right. I would note that the IPCC defines 
``very likely,'' which is the language used here, as a 9 in 10 
chance that the finding is accurate.
    Question No. 2: The IPCC also found that--and again I quote 
from the report--``Continued greenhouse gas emissions at or 
above current rates would cause further warming and induce many 
changes in the global climate system during the 21st century 
that would very likely be larger than those that were observed 
during the 20th century.'' Do you agree or disagree, Dr. 
Hurrell?
    Mr. Hurrell. Yes, I do agree with that.
    Mr. Boucher. Dr. Oppenheimer?
    Mr. Oppenheimer. I agree.
    Mr. Boucher. Dr. Hegerl?
    Mr. Hegerl. I agree.
    Mr. Boucher. Dr. Avissar?
    Mr. Avissar. Not enough information to answer.
    Mr. Boucher. All right.
    Dr. Christy?
    Mr. Christy. I think since we are starting at a warm spot 
that the changes will continue.
    Mr. Boucher. All right. Thank you.
    Now, one additional question that I will ask and I will ask 
for a little bit of comment from you on this one. Dr. Avissar 
has testified that regional climate models could be improved by 
incorporating the effects of land use in the area for which 
that regional modeling is being performed. Assuming that you 
agree with Dr. Avissar, do uncertainties about land use effects 
or other regional uncertainties diminish either our 
understanding of how greenhouse gases affect global warming or 
the justification for reducing greenhouse gases? And I would 
ask you not only do you agree but why or why not.
    Dr. Hurrell?
    Mr. Hurrell. Thank you. Yes, I do agree with Dr. Avissar's 
testimony on this point. As several of us have pointed out, 
global climate models are very valuable tools. They are not 
perfect and they can certainly benefit, as I pointed out 
explicitly, from further and more complete considerations of, 
for instance, land surface change and land surface forcing. 
Regional models are one avenue to begin to include those 
processes more completely and the field is moving in that 
direction. With respect to your bottom-line statement, Mr. 
Boucher, I believe that the global climate models indeed given 
their very impressive simulations of the observed hemispheric 
scale and larger-scale temperatures, that is evidence that many 
of the key processes are indeed correct in the large-scale 
models and therefore I believe that the evidence is very 
convincing that the range of changes that we have seen goes 
beyond the range of natural variability and can be attributed 
to anthropogenic influence on large-scale climate but certainly 
regional processes do need to be included better. As we begin 
to try to make comments on regional and local scale changes, 
the role of natural variability becomes larger and there are 
uncertainties in our understanding at that level.
    Mr. Boucher. Thank you very much.
    Dr. Oppenheimer?
    Mr. Oppenheimer. I would generally agree with Dr. Avissar 
and I would add, by the way, that we need to improve our 
ability to model the ice sheets and that is a critical 
component to understanding sea level rise. I have substantial 
amount of confidence in the statements about the importance of 
the greenhouse gases, the projection of future climate and the 
attribution of recent climate changes, not only because of the 
global models and their ability to reproduce past climate 
changes of, say, the last 150 years but also because of the 
wealth of paleoclimate data, that is, data on climate history, 
which basically supports general conclusions from the 
atmosphere, ocean general circulation models.
    Mr. Boucher. Thank you, sir.
    Dr. Hegerl?
    Mr. Hegerl. I agree with Dr. Avissar's testimony that it is 
very important for regional predictions, for reliable regional 
predictions to think about land-use change and incorporated 
also for reliable predictions of rainfall changes. I do not 
think that these changes have a big impact on large-scale 
temperature predictions nor do they affect our assessment of 
what caused the 20th century warming.
    Mr. Boucher. Thank you.
    And Dr. Avissar, let me just modify the question for your 
purposes. I think we are all acknowledging, your colleagues 
are, that there are uncertainties about the accuracy of 
regional models based upon particular land uses in the area 
which are not properly incorporated into those models but the 
real question is, does that uncertainty affect our 
understanding of climate change on a global basis, and should 
that uncertainty about the regional modeling in any way affect 
our decision-making about whether it is proper to go forward or 
not with any kind of control measures?
    Mr. Avissar. And I appreciate that. The point that I want 
to raise here is that I am using the land cover, the original 
scale, just as an example to illustrate what is happening. The 
truth is that the complexity of the climate system and it is a 
chaotic system and we do not know exactly how it is going to 
evolve. We use that with models that are idealized. There are a 
lot of problems in those models. The type of interactions that 
we are talking about that have to do with the land cover but 
with many other processes and it is probably one of the most 
severe ones.
    Mr. Boucher. Thank you, Dr. Avissar. I am afraid time will 
not permit any further explanation but we understand your 
response.
    Dr. Christy?
    Mr. Christy. We have rebuilt data sets in three parts of 
the world very carefully. Climate models don't come close to 
what actual observations have shown so I have a bit of a 
disagreement with the notion that even though climate models 
get some big number right that they don't get the smaller 
regions right. So I do agree with Dr. Avissar's point that the 
regional expectations of current models--or regionalization is 
a way to improve these global climate models.
    Mr. Boucher. Thank you very much. My time has more than 
expired.
    The joint session, I assume is underway, although I do not 
see bells having rung. Do we have any information about that? 
It was supposed to convene at 11:00.
    Mr. Barton. I am ready to keep going.
    Mr. Boucher. I am ready to keep going too but I think we 
have to observe the rule.
    Mr. Barton. I won't tell.
    Mr. Boucher. Why don't we say----
    Mr. Barton. It has not started, my staff says.
    Mr. Boucher. It has not started?
    Mr. Barton. No, sir.
    Mr. Boucher. I think the best course for us at this point 
is in fact to recess, and my apologies to our witnesses for 
this. I hope your patience will enable you to remain here and 
answer additional questions my colleagues will propound. Let us 
reconvene 5 minutes after the joint session has concluded. The 
subcommittee stands in recess.
    [Recess.]
    Mr. Butterfield [presiding]. Come back to order.
    I was not in the session this morning. I understand that 
the witnesses have already testified and we have started the 
questions. Have we done the opening statements? We have done 
the opening statements.
    Let me thank all of you for your patience. This has been a 
disjointed morning this morning. I am sure you have been 
informed that we had a special session of Congress this morning 
at 11:00 and we have just completed that and now we are back to 
work.
    At this time the Chair will recognize the distinguished 
gentleman from Illinois, Mr. Hastert.
    Mr. Hastert. Thank you, Mr. Butterfield. I appreciate that, 
and again, I appreciate all the patience of our people who are 
witnesses who are here to testify today.
    Mr. Oppenheimer, in your statement you were talking about 
the polar ice fields, specifically in Antarctica, and talking 
about the thickness of the sheets and the possibility of I 
think it is 1,000 years that they may melt. Hasn't the 
temperature actually in the South Pole not been affected?
    Mr. Oppenheimer. We really don't have a good picture of 
what temperatures have done over the last 100 years for the 
continent as a whole. We know that temperatures have warmed on 
the Antarctic peninsula which is the furthest north point and 
we know that the limited number of stations, and I think it is 
really only two inland away from the coast did cool for some 
period of time. There is some indication that that trend is 
reversing. So my own judgment on that, and there is not 
complete agreement on this in the community, is that we cannot 
make a statement about what the Antarctic continent as a whole 
has done over the past century. There simply isn't enough data.
    Mr. Hastert. Then if we are talking about the ice fields at 
the South Pole and Antarctic, we need to be careful about what 
we say.
    Mr. Oppenheimer. We need to be careful about how we 
represent what has happened in the past. There is no question 
about that.
    Mr. Hastert. And what happened in part is hard to have the 
prognosis. It almost has to happen in the future.
    Mr. Oppenheimer. We have some idea of what happened in the 
very distant past, not a very firm idea, and we have a better 
idea of what happened in the distant past for Greenland. So 
would you like me to elaborate?
    Mr. Hastert. Well, I am short on time here so I appreciate 
your answer.
    Dr. Christy, in your report and your testimony about land 
use and agriculture changes in the Central Valley of 
California, that they had an impact on temperature and that you 
are starting to see this in other work. When we hear about 
rising temperatures and other climate changes, should we keep 
in mind that that land use may play a more significant role 
than we have talked about?
     I come from the Midwest, an agricultural district, and in 
April when the fields are plowed and you are ready to plant 
corn and soybeans, everything is black. Heat is absorbed by 
that black loam and then of course and by the end of May, and 
the first part of June, it is covered in green. It changes. 
What is the effect?
    Mr. Christy. Well, as a graduate of the University of 
Illinois, I have seen those same fields, and what we found at 
least in the study we have done in California and also now in 
Africa that you alluded to is that that is explaining the 
largest changes that are occurring there, that it is not 
something that can be affected by greenhouse gases. It is 
something that the way in which the warming occurs. It is 
related to what humans are doing to the landscape, not to the 
atmosphere.
    Mr. Hastert. Dr. Avissar, again, another phenomenon that 
exists are clouds. some clouds have a cooling effect, some 
clouds have a heating effect. They hold heat in. Can you 
explain how clouds are treated in the models and are they 
approximated and we can trust the many approximations of real 
process and models to faithfully simulate the real world over 
decades?
    Mr. Avissar. Our understanding of the cloud system is still 
relatively limited, OK. We have some moderate understanding of 
the way that the models of the way that the clouds are behaving 
and we are using that understanding to put that into our models 
so I would say that the best in our models we have a moderate 
capability of representing the cloud system. It is done not 
very well.
    Mr. Hastert. Dr. Christy, the average daily temperatures, 
you suggest in your testimony, are more reliable measures of 
the effects of greenhouse gases in the atmosphere. What do 
these findings suggest about the relative role of carbon 
dioxide and climate change if the research holds up?
    Mr. Christy. OK. The point here is that the temperature 
that occurs at the maximum warming in the afternoon is more 
closely related to the deep atmosphere and therefore to what 
greenhouse gases are doing to the atmosphere and those trends 
are less than what you see in surface temperature maps, for 
example, that were shown earlier. So that indicates that if 
that is the signal of what greenhouse gases are doing in the 
atmosphere that that is a smaller signal than we have been led 
to believe at this point.
    Mr. Hastert. Thank you. My time has expired.
    Mr. Butterfield. The gentleman's time has expired.
    Let me just again thank each one of you for coming today. 
We are going to be completing this hearing this afternoon and 
hopefully all of the Members will come through and have an 
opportunity to ask their questions.
    But let me direct my question very briefly to Dr. Hurrell. 
Dr. Hurrell, as many of the members of this committee can 
attest, we have been around for a long time including the 
decade of the 1970's and during that period of time we were 
given many warnings, many pessimistic warnings that the planet 
was cooling. That was the advice that was given to us by 
scientists during that era, and then they ask why given how 
wrong the scientists were back then, at least some of the 
scientists were back then, why we should trust the scientists 
now when we talk about global warming. How do we explain that 
the science is now different than it was in the 1970's?
    Mr. Hurrell. Thank you very much. There were a handful of 
scientists who were taking about a global cooling signal and 
potential causes for that. A key aspect of this is that the 
climate system does vary and it varies for both natural as well 
as anthropogenic reasons. The fundamental difference now is 
that unlike in the mid-1970's when a few scientists were 
talking about this, we are talking about much stronger evidence 
now, much better understanding and an entire climate community 
or almost an entire climate community who is in agreement on 
the major points. There have been the IPCC assessments. There 
has been National Academy of Science reports. There has been 
U.S. Climate Change science program results and the like that 
all speak to these general conclusions that we are talking 
about today. This is quite different from the situation in the 
1970's where there simply was not nearly as comprehensive and 
expensive look at what could have been causing that bit of 
global cooling that we saw really from a peak in the mid-1940's 
into the mid-1970's.
    Mr. Butterfield. We have just been joined by the gentleman 
from California, Mr. Waxman, and he has informed the Chair that 
he is going to have to leave very shortly and so I am going to 
yield the balance of my time with the unanimous consent of the 
other side to Mr. Waxman, in addition to his time.
    Mr. Waxman. Thank you very much, Mr. Chairman, and I hope 
you will reclaim your time later because I know you are being 
very kind to me in letting me go forward here.
    At several of the hearings, some Members have wondered how 
important human-caused greenhouse gas emissions are when there 
are even larger amounts of naturally occurring greenhouse gas 
emissions each year.
    Dr. Hurrell, can you help us understand this? Can you 
explain why human-caused emissions are so important even though 
every year there is a greater volume of naturally occurring 
emissions?
    Mr. Hurrell. Absolutely. Thank you. Yes, there is a large 
volume of naturally occurring carbon dioxide emissions by 
natural processes in the climate system. These have occurred of 
course throughout time. The key way to think of this problem I 
believe is that the natural system has both sources and sinks 
and it maintains a balance in terms of the natural system. 
Therefore, even though the human contribution in terms of a 
percentage might be relatively small to the total amount of 
carbon dioxide in the atmosphere, it is very significant 
because it is upsetting this natural balance. It is basically 
throwing the system out of whack and so it provides a very 
important radiative forcing on the climate system that the 
climate system must adjust to and it does that by way of 
warming, among other changes.
    Mr. Waxman. Dr. Oppenheimer, from what I heard from Dr. 
Christy, he seems to be saying--and correct me if I am wrong--
that this latest report from the Intergovernmental Panel on 
Climate Change diminishes some of the reasons to be concerned 
about the impacts of climate change. For example, he stated 
reductions in the scariest realization of sea level rises are 
welcomed. I am concerned about the accuracy or your views of 
that position.
    Mr. Oppenheimer. What IPCC did in this report is to narrow 
the range of uncertainty on future sea level rise so that the 
lowest projection of possible sea level rise has been raised 
and the projection of highest plausible sea level rise within 
90 percent confidence has been lowered. On the other hand, IPCC 
was very careful to note that its projections do not account 
fully for processes that we know are going on in Earth's ice 
sheet in Greenland or in West Antarctic and so those 
projections have to be regarded themselves as relatively 
cautious because they assume the ice sheet will not continue to 
accelerate their loss of ice into the sea, which increases sea 
level.
    Mr. Waxman. It is my understanding the IPCC's sea level 
rise projection only includes the melting of glaciers and the 
increased volume of the oceans due to the absorption of greater 
warmth. Is that correct?
    Mr. Oppenheimer. Not quite. There is an attempt to account 
for the fact that over the last decade ice in both Greenland 
and parts of Antarctic have started to move very rapidly into 
the sea. Those are called dynamical changes because they are 
flows like rivers flow. The ice flows like rivers in certain 
spots. The IPCC added to its melt this approximation to sea 
level rise that you get from just looking at melting a small 
amount to account for these extra flows that are occurring in 
the rivers of ice coming off the continents but it did not make 
any estimate for what could happen if those flows increase in 
the future and there is a significant risk that those rates of 
ice flow will in fact increase.
    Mr. Butterfield. Let me ask you to suspend for just a 
minute, please. The gentleman's time has expired, and with the 
unanimous consent of the minority, I would ask that Mr. Waxman 
be allowed to continue with his regular time.
    Mr. Barton. Point of parliamentary inquiry.
    Mr. Butterfield. Yes, sir.
    Mr. Barton. I am not going to object. I know people are 
busy, but would this mean Mr. Waxman would get 5 minutes and 
then we would get 5 minutes for our side.
    Mr. Butterfield. The gentleman had 8 minutes because he did 
not exercise his right to an opening, so it is 3 plus 5.
    Mr. Barton. Three plus 5 or 3 plus 8?
    Mr. Butterfield. Three plus 5. Yes. The gentleman requests 
5 minutes. All right. The gentleman is recognized for 5 
minutes.
    Mr. Oppenheimer. So my point is that in one sense the IPCC 
projections are regarded by many scientists as conservative 
because they are unable to account for the accelerated loss of 
ice into the sea that we know is occurring. We don't have a 
model that can tell us how to project those sorts of changes. 
The best we can do is look at what happened in past climates a 
long time ago when the poles were somewhat warmer than today 
and see what the fate of the ice was. What we know is, the 
Greenland ice sheet was significantly smaller and sea level was 
4 to 6 meters higher, about 13 to 20 feet. We don't know how 
fast that occurred. We don't know whether that process has 
already been triggered in fact.
    Mr. Waxman. So in your view, you don't see any reason that 
this most recent IPCC report should make us less concerned 
about the impacts of climate change than we previously 
believed?
    Mr. Oppenheimer. Overall, it makes me more concerned, and 
the things that are quite uncertain in the report make me 
concerned because they are uncertain and they could wind up 
either turning out smaller or they could turn into very, very 
big hazards in the future.
    Mr. Waxman. Dr. Christy, in your testimony you also discuss 
some new proposals to control greenhouse gas emissions that are 
in the ``ballpark of the Kyoto-like reductions.'' You state 
that these proposals would have a very small and perhaps 
undetectable impact on preventing climate change. One of the 
industry's strongest criticism of the Kyoto protocol was that 
it wouldn't solve the problem. Under the Kyoto protocol, the 
developed world would take one step toward emissions reductions 
by 2012. However, these reductions alone were not enough to 
solve the problem and of course industry was concerned about 
what unknown targets they might face after 2012. When you 
include the lack of targets for the developing world, I can see 
why you would say it is hard to predict the climate outcomes 
associated with Kyoto. Fortunately, we have moved beyond the 
Kyoto debate.
    I have a chart that shows the emissions targets for the 
greenhouse gas reduction bills that have been introduced in the 
109th and 110th Congresses. Would you say that any of these 
bills are in the ballpark of the Kyoto-like reductions?
    [The chart follows:]
    [GRAPHIC] [TIFF OMITTED] T7414.001
    
    Mr. Christy. This is just for the United States, right?
    Mr. Waxman. Yes, bills introduced in the Congress here.
    Mr. Christy. I don't know if I can understand the question. 
Kyoto is the red and it looks like two and three intend to go 
beyond Kyoto out to 2030 or 2040. I mean, I am just reading the 
chart.
    Mr. Waxman. Right.
    Mr. Christy. But I think my point would still be the same, 
is that since this is only the United States, that our ability 
and our observing system is not capable of saying here is a 
change that we can confidently attribute to one of these bills.
    Mr. Waxman. At least five of the bills introduced are not 
Kyoto-like. Let us assume that the U.S. commits to emissions 
cuts in the range called for by these five bills and let us 
assume that on this basis the U.S. positions itself as a world 
leader and convinces other nations to undertake similar 
emissions cuts.
    Dr. Hurrell, do you agree that this range of emission cuts 
on this time frame will have a measurable effect on the 
climate?
    Mr. Hurrell. I personally believe it is essential that 
these kind of trajectories are adopted. I believe that while 
there are uncertainties in our knowledge, as we have already 
discussed widely today, we know quite a bit and I think that 
the potential consequences of global climate change are 
important enough that these kind of reduction proposals should 
be adopted. I agree with your statement that the United States 
can play a leadership position in convincing the rest of the 
world to go along. It has to be a global solution. It can't be 
something that we do alone.
    Mr. Waxman. Dr. Hegerl, based on your expertise on climate 
forcing, would emission cuts in the range of 65 to 80 percent 
over the next 45 years have a measurable effect on the climate?
    Ms. Hegerl. Can I have the last figure of my testimony, 
please?
    Mr. Waxman. Sixty-five to 80 percent over the next----
    Ms. Hegerl. Oh, no, the last figure of my figures, please. 
Next one. So what you see here is in yellow is the lowest limit 
of what we can do physically. This is if we would freeze 
concentrations at the present time and what you see in colors 
are the various emissions. So any bill that would reduce 
emissions beyond the lowest emission there will have a big 
impact on future global temperature rise and with it on the 
impact global warming can make quite a bit of difference 
because impacts are expected to correlate somewhat with the 
global mean temperature increase.
    Mr. Butterfield. The gentleman's time has expired.
    Mr. Waxman. Mr. Oppenheimer, do you have anything on that 
as I ask my last question?
    Mr. Oppenheimer. Yes, I agree, it would have an effect, 
particularly since the U.S. taking leadership I think would 
bring other countries along and then we would have a serious 
global reduction.
    Mr. Waxman. Thank you.
    Thank you, Mr. Chairman.
    Mr. Butterfield. The gentleman's time has expired.
    The gentleman from Texas, the ranking member of the full 
committee, is recognized for 5 minutes.
    Mr. Barton. Mr. Chairman, before I use my time, I would ask 
Dr. Hegerl or Dr. Oppenheimer to provide us with a copy of the 
actual report. They keep referring to it. All we have is the 
summary and this is the 2001 report. What we have is about a 
10-page summary. They have seen it; we haven't. I think we need 
the report and have it in the record of this hearing or at 
least have it available for members of the subcommittee.
    Mr. Oppenheimer. Could I comment on that? I have been 
careful in my testimony to refer only to what is in the summary 
because the actual details are not going to be available until 
May. I wish they were available today but I don't----
    Mr. Barton. Well, your testimony was so specific, you are 
bound to have seen the report. There is no way you could say 
some of the things you have said if you haven't seen the 
report.
    Ms. Hegerl. The U.S. Government has commented extensively 
on the draft report so it has seen the draft reports and----
    Mr. Barton. Well, we are part of the U.S. Government and 
we----
    Ms. Hegerl. Yes, so you could----
    Mr. Butterfield. Point of order. Will you make the report 
available when it is available?
    Mr. Oppenheimer. Certainly.
    Mr. Barton. It is something available now, Mr. Chairman.
    Mr. Butterfield. When do you estimate that to be?
    Mr. Oppenheimer. It will be published publicly in May. I 
don't have the power or the authority to release the report.
    Mr. Barton. But you have read it.
    Mr. Oppenheimer. I have read it but I have been--first of 
all, it may change in some respects between now and May. Second 
of all, I have been extremely careful, as I think these people 
have been too, to refer only to items which can be defended by 
looking at the summary, which is public. Do you want me to go 
over that point by point? I would be happy to.
    Mr. Barton. Mr. Chairman, were based on more than this 
summary. I have read the summary.
    Mr. Butterfield. Let me ask the gentleman to suspend. This 
has extended beyond a parliamentary inquiry. I am going to 
recognize the ranking member for 5 minutes.
    Mr. Barton. Well, I want some definition about how we are 
going to get a copy of this report.
    Mr. Butterfield. Well, the gentleman has said it is not 
available and he will make it available when----
    Mr. Barton. Well, if it available to those people and it 
has been available to parts of the executive branch, it should 
be available to members of this subcommittee under some 
conditions that are acceptable to both the majority and the 
minority. I am not saying we are going to publish it but I 
think we ought to have it available. That is the whole purpose 
of this hearing.
    Mr. Butterfield. From the majority side, if the report is 
available, we will certainly accept it and make it available.
    Mr. Markey. Will the chairman yield briefly?
    Mr. Butterfield. Yes, the gentleman from Massachusetts.
    Mr. Markey. The Bush administration has a copy of the 
report. I recommend that our committee ask the Bush 
administration to give us a copy of the report, which they 
have, and I would make the request from the committee.
    Mr. Barton. Again on my parliamentary inquiry, according to 
our speaker of the legislative branch, we are supposed to 
produce a bill by June. It is early to mid-March. Fifty people 
contributed to this report, according to the summary sheet. 
Only one is with us, Dr. Hegerl, and yet we are asked to make 
major policy decisions on our economy without seeing the base 
documents. That is an impossible situation to put the Congress 
in.
    Mr. Butterfield. Well, it is an impossible situation to put 
the witness in. He said that it is not available and he will 
make it available when it is plausible.
    Mr. Barton. I am not recommending this, Mr. Chairman, but I 
believe if we subpoenaed the report, we could get it.
    Mr. Butterfield. All right. Your comments are in the 
record.
    The gentleman may resume.
    Mr. Barton. Well, start the clock for me, Mr. Chairman.
    Mr. Butterfield. All right. Let us restart the clock. 5 
minutes.
    Mr. Barton. My first question I think is going to be to Dr. 
Hegerl. On page 2 of the summary, down in the middle of it, it 
says that carbon dioxide is the most important anthropogenic 
greenhouse gas. I am probably mispronouncing anthropogenic but 
that means manmade. What is the most important greenhouse gas, 
period, not just manmade but in totality, natural or manmade?
    Ms. Hegerl. That would be water vapor.
    Mr. Barton. Water vapor. And what percent of water vapor is 
manmade?
    Ms. Hegerl. I would defer. I would just repeat what Dr. 
Hurrell just said. Water vapor is a very powerful natural 
greenhouse gas. It would have quite substantially cooler 
temperature on Earth if it weren't for the natural greenhouse 
gas water vapor. Adding CO\2\ to the atmosphere changes the 
balance, the heat balance of the planet.
    Mr. Barton. My understanding is that water vapor is 95 
percent of the greenhouse gas. Would you agree with that?
    Ms. Hegerl. I don't know the exact numbers.
    Mr. Barton. All right. My understanding is that water vapor 
is about 95 percent and that manmade carbon dioxide is about 4 
percent. Does anybody on this panel dispute that?
    Ms. Hegerl. No, but we are changing the balance, the 
overall balance.
    Mr. Barton. But you will agree that of greenhouse gases, 
water vapor is well over 90 percent and manmade CO\2\ is under 
5 percent? That is a factor of approximately 20 to 1.
    Mr. Oppenheimer. Could I clarify? I think what you are 
referring to is the natural emissions of carbon dioxide are 
about 95 percent of total emissions and the human emissions are 
at 4 percent of total carbon dioxide emissions.
    Mr. Barton. Well, I think we have to have some perspective 
because this report, the summary of the report that nobody has 
seen except for 50 very important people and maybe a few in the 
Bush administration is based on manmade emissions. In point of 
fact, natural emissions overwhelm manmade emissions.
    I want to go to page 4 of the summary. I am going to ask 
Dr. Christy a question. These radiative forcing components in 
the charge on page 4 are in watts per meters square. They only 
list manmade forcing components. Is that the way you read that 
chart?
    Mr. Christy. Yes.
    Mr. Barton. OK.
    Mr. Christy. Except for the solar forcing.
    Mr. Barton. Now, what is the most important radiative 
forcing component in totality in terms of temperature change?
    Mr. Christy. Well, you would start with the sun and then 
the water vapor in the atmosphere and clouds and so on are the 
biggest----
    Mr. Barton. And if the manmade component has a positive 
total net radiative forcing change of about 1.5 or 1.6 meters 
squared, if we put the same kind of table for clouds, where 
would that be on the chart?
    Mr. Christy. It would be about this far out from the page.
    Mr. Barton. We can't put ``this far out'' in the record. In 
terms of watts per meters squared, where would it be?
    Mr. Christy. The net effect would be in tens of watts per 
meters squared.
    Mr. Barton. Tens of watts. Now, is water vapor the same 
thing as clouds?
    Mr. Christy. I am talking about the total impact of that.
    Mr. Barton. Dr. Hegerl or Dr. Hurrell, do you disagree with 
what Dr. Christy just said?
    Mr. Hurrell. I agree that water vapor is the dominant 
greenhouse gas.
    Mr. Barton. And do you agree that in order of magnitude, it 
is 100 times larger than the net manmade effect?
    Mr. Hurrell. I am not sure about the factor of 100. I 
believe, as I said, that those are very large effects, that the 
natural system is in balance so the emphasis on the 
anthropogenic part is because it throws the natural balance out 
of whack. That is why the anthropogenic component is important.
    Mr. Barton. Now, my next question I guess will be to Dr. 
Hegerl. Again, back on page 2 down in the footnotes, the very 
last sentence says that a number of uncertainty ranges in the 
Working Group I third assessment report corresponded to 2-
sigma, 95 percent, often using expert judgment. Does that mean 
that the uncertainty range is close to 100 percent?
    Ms. Hegerl. No, that just defines which uncertainty ranges 
are given conventionally in the report.
    Mr. Barton. Well, but if you have a normal bell curve, 50 
percent is right in the middle and then you have these ranges. 
Each sigma range goes out from the center. If I understand 
correctly, if you have got a 2-sigma difference, you could be 
100 percent off or 50 percent off either way. Or my statistics 
wrong? And I could very well be wrong. It has been a long way 
since I took statistics in college but that is the way I 
remember it. When I view it, this basically says you all could 
be way off even using expert judgment. Is that what that says?
    Ms. Hegerl. The 95 percent range indicates a chance of five 
out of 100 or one in 20 to be outside that range, which is a 
quite small chance.
    Mr. Barton. Mr. Chairman, my time has expired. Are we going 
to have a second round?
    Mr. Boucher. Well, I think that depends on how long the 
first one goes and how busy members are and how patient the 
panel is willing to be. So the answer is undetermined at this 
time. We will see.
    Mr. Markey is recognized for 8 minutes.
    Mr. Markey. I thank the Chair very much.
    The average temperature for a human being is 98.6. You 
increase our temperature by 3 degrees, that individual now has 
some problems. They are visiting the doctor, just the 2- or 3-
degree change. Or to think of it another way, on a seesaw, 
there is 1,000 pounds on one side and 1,000 pounds on the other 
side. It is an equilibrium. But you put 20 more pounds on one 
side or the other and it throws the whole system out of whack, 
and that is essentially what is happening whether it be human 
temperature or it be nature itself. When you have relatively 
small changes in something that is in equilibrium, you get 
rather dramatic changes in terms of the whole direction of a 
seesaw or a human being's health.
    So Dr. Oppenheimer, in your testimony you suggest that the 
greatest impact of global warming on the United States and for 
the world may come from rising seas. But you also say that 
there is a lot of uncertainty about how the ice sheets in 
Greenland and Antarctic will behave as the planet continues to 
warm up. If both the Greenland ice sheet and the West Antarctic 
ice sheet were to melt, you say we could see a 40-foot increase 
in sea levels, 23 feet and 17 feet. What would be the 
consequences of that kind of rise in sea levels, Doctor?
    Mr. Oppenheimer. A 40-foot rise would, for instance, bring 
the Gulf Coast up to about the level of Houston and all the 
land between that and the current Gulf Coast would be 
submerged. A third to about half of Florida actually would be 
permanently submerged. It would be a world-shaking change. I 
want to emphasize that I don't think any scientist thinks that 
that kind of sea level rise could play out totally in a matter 
of even a century. It would take at least, by my own reckoning, 
four or five centuries at minimum but the rates of sea level 
rise between now and then would be staggeringly high. They 
would be on the order of a couple of meters per century. We 
can't deal with that.
    Mr. Markey. So you note that the IPCC projection of a 7- to 
15-inch increase in sea level excludes rapid dynamical changes 
in ice flow. Why was that excluded? Was it because the IPCC 
felt those kind of changes were unlikely or because scientists 
didn't know how to model them yet?
    Mr. Oppenheimer. It was because scientists at the current 
time do not have a model and you need a model to project 
forward. They do not have a model that can accurately reproduce 
what has happened to the ice sheets recently in the last few 
decades and therefore they do not trust the projections of 
those models in terms of projecting the behavior of the ice 
sheets over the next several decades and certainly not over the 
next several centuries. So at this point there is a lot of 
scurrying around in the community of glaciologists to try to 
better understand what our observations of the ice sheets mean, 
to construct an advanced model to be able to project better, 
and to interpret climates of the past to tell us what they say 
about what the ice sheets did when Earth was warmer a long, 
long time ago.
    Mr. Markey. So would it be fair to say that there is an 
unknown unknown out there with respect to the melting of those 
polar ice sheets that could make the problem much worse than 
what the IPCC has found thus far?
    Mr. Oppenheimer. I think you are drawing on former 
Secretary Rumsfeld's description of uncertainty and I would 
rather refer to it as a known unknown than an unknown unknown.
    Mr. Markey. But is it a fair conclusion to say that is 
possible?
    Mr. Oppenheimer. Yes.
    Mr. Markey. Regardless of the description of it, is the 
conclusion accurate?
    Mr. Oppenheimer. I am sorry. Could you repeat what the 
conclusion was? I got lost in the metaphor.
    Mr. Markey. Is there an unknown out there or a known 
unknown, as you want to describe it, that the melting of the 
ice sheets could be far worse than the IPCC report?
    Mr. Oppenheimer. Yes, that is certainly true.
    Mr. Markey. OK. Well, that is the important thing to get on 
the record.
    Mr. Markey. For the other panelists, how concerned are you 
about a possible disintegration of the Greenland and West 
Antarctic ice sheets, and do you concur with Dr. Oppenheimer's 
testimony that loss of large parts of the polar ice sheets and 
a very large sea level rise over the course of several hundred 
years rather than over a millennium would occur once the world 
warms up as little as 3 or 4 degrees Fahrenheit. Do you all 
agree on that?
    Mr. Hurrell. I will speak just very briefly. Yes, I agree. 
I agree with Dr. Oppenheimer's main points and again, I point 
to the paleoclimatic evidence going back where we know that for 
instance in the last interglacial, much of the Greenland ice 
sheet was melted and sea levels were indeed much higher than 
they are today and so I think that is a very real possibility.
    Mr. Markey. Thank you.
    The other witnesses quickly?
    Ms. Hegerl. I agree with the overall statement too and I 
would like to remind that the lower limit of sea level rise is 
largely driven by factors we understand much better than the 
disintegration of ice sheets. For example, the simple 
temperature effect on ocean water expanding. So the lower limit 
is far less uncertain than the upper limit.
    Mr. Markey. Thank you.
    Mr. Avissar. Yes, if there is warming, the ice sheet will 
melt and that will increase the sea surface level, no doubt.
    Mr. Markey. Dr. Christy?
    Mr. Christy. This is a very complicated issue but I would 
like to say that a thousand years ago, Greenland was much 
warmer than it is today for centuries at a time and yet it 
evidently did not experience any kind of dramatic change at 
that point.
    Mr. Markey. Thank you. Let me move to you then, Dr. 
Christy. On page 8 of your testimony and in your oral 
testimony, you said, ``It disturbs me when I hear that energy 
and its byproducts such as CO\2\ are being demonized when in 
fact they represent the greatest achievement of our society. 
Where there is no energy, life is brutal and short,'' and you 
are quoting of course the famous philosopher, David Hobbs, who 
actually said that life for man in a state of nature was nasty, 
brutish and short but Hobbs, Doctor, was actually arguing for 
the need to have governments in place to address the needs and 
wants that make this so, lack of food, lack of security, et 
cetera. For Hobbs, government was the leviathan, a huge beast, 
but he argued that it was a necessary beast so our challenge is 
whether governments will respond to the challenge that 
scientists are opposing right now. If we fail, we may well 
return to a Hobbsian state of nature, brutal and short, but 
that is the point he was making, that governments must then 
work to minimize it. So to the extent that yes, science does 
demonize, science has demonized asbestosis. Science has 
demonized tobacco. Science has demonized exposure to radiation. 
It doesn't mean that they all don't have a role but the warning 
comes as to what the negative consequences are as well and so 
if you want to characterize that as demonization, I think you 
have a right to do so but I think you misquote Hobbs and I also 
think you understate the role historically that science has 
played, Doctor, in giving us the warnings not just of the 
benefits of science, the benefits of technological advancement 
but also the negative consequences. So there is a Dickensian 
quality, in other words. It is the best of technologies and the 
worst of technologies simultaneously. It can both do good and 
harm at the same time, and I would just appreciate your comment 
on that.
    Mr. Christy. OK. I didn't see or hear a question but I 
think the basic thing I want to----
    Mr. Markey. No, I asked for a comment.
    Mr. Christy. OK. The basic point I wanted to get across was 
that people like me are alive today and you as well because of 
the technologies energy has brought us and because of that 
CO\2\ that is in the atmosphere now and that is a point that 
needs to be really emphasized, and in my experience in Africa, 
I keep going back to that because energy demand will rise 
tremendously. We see it right now in those countries. And when 
I saw that chart up there about the U.S. emissions, I don't 
think any of those are going to happen, but when you throw in 
the rest of the world, I don't see how something short of a 
global recession or depression would cause CO\2\ emissions to 
fall.
    Mr. Boucher. Thank you very much, Dr. Christy.
    Thank you, Mr. Markey.
    Mr. Shimkus for 5 minutes.
    Mr. Shimkus. Thank you, Mr. Chairman. And I have enjoyed 
this. I am old Army infantry guy and we had the acronym--it is 
not politically correct but it is ``Keep it simple, stupid,'' 
the KISS formula, and that is what a lot of us try to make 
through all this science and stuff. I also, at the risk of 
being defined as a Neanderthal, because a lot of this is 
secular humanist debate, I am a creationist so I believe in the 
big picture; God is in control, but God also calls us to be 
good stewards, and I think that is kind of par of this debate 
which I don't mind and I think it is going to be helpful 
because Mr. Christy's comments about life in a carbon world and 
the benefits provided by a carbon world is undeniable. The life 
that we live as middle-class Americans--maybe I am not in that 
category anymore but my family sure was when I was being 
raised--because electricity and power allowed us to have a 
standard of living that, I am one of seven kids, probably half 
the kids would have died in the Middle Ages if it weren't for 
the carbon world in which we live, and we can't just throw that 
out of this debate, which brings up a lot of great questions 
because we hear the term ``balance'' so the first question--and 
really, the only way we are hearing so far about balancing is 
capping carbon dioxide, capping emissions of carbon dioxide and 
whether that is arguable or not, whether we can do it or even 
maintain it. Is there a way to put a balance without capping 
carbon dioxide? Why don't we just go quickly though because I 
don't have that much time.
    Dr. Hurrell, do you think there is a way to reclaim this 
balance without--my staff is going to have to give me the 
formula, CO\2\ and all the different strata of the atmosphere 
and what is going on. Can we emit something up into the 
atmosphere to help create a balance? Is there something 
proactive we can do that would be less costly that would create 
more balance than just destroying our ability to use the fossil 
fuel society and which we benefit from?
    Mr. Hurrell. Yes. I don't think any of us are interested in 
destroying the society and the technology that we benefit from. 
There is a certain level of climate change that we are 
committed to, as Dr. Hegerl spoke to.
    Mr. Shimkus. I apologize. I only have little more time. Is 
there something that we can do other than capping carbon?
    Mr. Hurrell. If you are referring to geo-engineering 
techniques, other things that we can do to help restore this 
balance, that is a topic of discussion that was very, very 
early my concern. With all of those approaches, there can be 
unintended consequences.
    Mr. Shimkus. OK, I don't have time to go through all of the 
whole panel. Is there anybody that feels strongly on this 
debate?
    Mr. Oppenheimer. Yes, I would just say that ultimately, we 
have to come to grips with the carbon problem, but that that 
could include efforts like the ones you heard of yesterday at 
carbon capture and storage or enhancing terrestrial sinks, or 
in other words, increasing biological production in forests. 
There are many ways to skin the cat, but in the end, carbon 
dioxide has to be limited.
    Mr. Shimkus. I understand the report is not going to be 
made until May and I understand that, but it is in the releases 
of what people think is coming out. One would be that the 
hockey-stick aspect is not going to be part of this second 
report. Can you confirm or deny? And if is not, why?
    Ms. Hegerl. The report has a section that talks the 
paleoclimatic perspective about our understanding of how 
temperatures in the last half-century compared to temperatures 
in the last I think 1,300 years. It is on page 10.
    Mr. Shimkus. So you are telling me it is going to be 
included?
    Mr. Hegerl. The discussion of temperature over the last 
millennium is definitely included.
    Mr. Shimkus. So the hockey-stick graph and the proposals on 
that premise will be in this next report?
    Mr. Hegerl. The report discusses temperature changes over 
the last millennium, and we understand a lot more about how 
temperature evolved over the last thousand years and also what 
caused many of these changes. Many of these changes were 
influenced by things----
    Mr. Shimkus. OK, let me ask one last question, and I 
apologize again. I have have 5 seconds left.
    I had dinner with a classmate of mine who is a NASA 
astronaut, and of course, he has been up twice now, and what he 
says, which is an interesting perspective, is when you are up 
in space and you look at the atmosphere, and it is very thin, 
we are our own little spaceship traveling through time. Does 
any of this global warming affect the destruction of atmosphere 
as we know it? We are talking about climate change and 
temperatures, but would it affect the breakup of atmosphere as 
we know it? Does anybody think it is part of that?
    Mr. Oppenheimer. Are you asking whether it would affect the 
breakup?
    Mr. Shimkus. Yes. I mean, is Earth at risk of just 
destroying and being a rock plummeting through space now?
    Mr. Oppenheimer. Probably not.
    Mr. Shimkus. Thank you.
    I yield back, Mr. Chairman.
    Mr. Boucher. Thank you, Mr. Shimkus.
    That was certainly a reassuring answer.
    Mr. Oppenheimer. With 90 percent confidence.
    Mr. Shimkus. How many sigmas?
    Mr. Boucher. Mr. Inslee is recognized for 8 minutes.
    Mr. Inslee. I defer.
    Mr. Boucher. Mr. Inslee chooses to defer, and we will 
return to you at a later point. Mr. Burgess is recognized for 5 
minutes.
    Mr. Burgess. Thank you, Mr. Chairman, and I thank the panel 
for a lively and thought-provoking discussing. Now, unlike the 
chairman who got a full summary, I only got two pages, so I 
don't want anyone to think I am intellectually constrained, 
only talking about two pages, but that is all I was given.
    Now, Dr. Christy, can I ask you, I was most intrigued in 
your testimony. I didn't actually find in it in the written 
part that you submitted for us about the discussion that we 
just had with Mr. Markey about how life was brutal and short 
without adequate energy and how energy does make a difference 
and has made a difference to the quality of life that we all 
experience and has allowed us all to live longer and healthier 
lives. If we were willing to sacrifice that and said that is 
not something that is of any value, and we were wanted to go 
with metaphysical certainty to where Kyoto would have taken us 
and beyond, let us say we were to go to 60 percent below the 
1990 levels, and say we could do that in the next couple of 
years. A hundred years from now, have we really helped things?
    Mr. Christy. Well, I don't think you would be reelected if 
you ran on that platform and actually did it. The economy would 
be almost totally destroyed if you are talking about 60 percent 
reduction in CO\2\ emissions right now. The only way I see 
something like that happening is a massive nuclear power----
    Mr. Burgess. But if we did?
    Mr. Christy. It would be very, very tiny if just the United 
States was doing what you said.
    Mr. Burgess. Well, would we prevent a hurricane? Would we 
prevent a Katrina?
    Mr. Christy. No, Hurricane Katrina was a category 3 when it 
hit the coast.
    Mr. Burgess. Well, then I guess it leads the question, are 
we thinking about this problem in the correct way? If our goal 
is to eliminate carbon from the atmosphere in the form of 
carbon dioxide and the only way to go about it is to scale back 
the economy in ways that are really almost incomprehensible to 
me because of the costs of human suffering that would be 
involved, are we going about this the right way?
    Mr. Christy. Well, that I don't know. I don't sit in your 
seat and see all that you are doing.
    Mr. Burgess. Well, therein is part of the problem. And 
Chairman Barton alluded to it. And I mean under the summary for 
policymakers, I have got pages 9 and 10, and on page 9, which 
has the table 2 for policymakers, we have the likelihood of a 
trend occurring the last 20th century, second column, 
likelihood of a human contribution to an observed trend, and 
column 3, the likelihood of future trends based on projections 
of the 21st century. And on that middle column, I guess, is 
where I would like to concentrate, and if you would look at the 
last four areas that are studied. We are left with a designate 
of ``more likely than not.'' And this includes heat waves, 
heavy precipitate, areas affected by drought, tropical cyclones 
increase, and increased incidences of extreme high sea levels. 
All of those things scored more likely than not. Have I got 
that right of what you have got on that table? Help me 
understand--and you already alluded to my reelection--to me 
more likely than not more mean 50.1 percent if it was a two-
person race, but could be as low as, as we saw in Texas, 39 
percent, if you have a four-person race. So what is the percent 
of more likely than not?
    Mr. Christy. As I understand it, it is 51 percent. Is that 
right?
    Ms. Hegerl. It is greater than even odds, so 50 percent or 
greater.
    Mr. Burgess. Fifty percent, but that is only assuming that 
there are two eventualities. If there were a third in there, 
then that would reduce it even further, correct?
    Ms. Hegerl. No, the four last instances are based on 
aspects of the climate system which we don't model very well, 
and which we cannot very confidently, at this point, 
attribute----
    Mr. Burgess. Mr. Chairman, I am going to run out of time. I 
guess what I would like to ask, if it is possible, and I may 
not have asked this very well, but I will try to submit this in 
writing to the entire panel. I would like to get your thoughts 
on that.
    And just finally one last question--and I know this is true 
because I read it on a blog on the Internet--we are assuming 
that there is an absolute constant. I guess, Dr. Christy, you 
said in regards to global warming that solar radiation is the 
number one source for global warming. Is that a fair statement?
    Mr. Christy. It is the source of our energy that runs our 
system, yes.
    Mr. Burgess. Correct, well, assuming that none is coming 
from the Earth's core, and I don't know if that is still molten 
or not. It was when I when I was in high school. It may not be 
anymore. Of that solar radiation, is that an absolute constant?
    Mr. Christy. No, solar radiation varies, but what varies 
more would be, for example, the cover and constitutes in the 
atmosphere that would affect the Earth more.
    Mr. Burgess. But all of these assumptions, at least to my 
uninitiated eye, would mean that the solar contribution is an 
absolute constant, that it never changes.
    Mr. Oppenheimer. No, that is not true. IPCC looks around 
carefully at that question, and we know very well what the 
solar variations have been over the last 30 years or so because 
we have satellites that stare at the sun all the time. And they 
have given us the indication that the sun's variation in the 
last 30 years when Earth has been warming a lot has been tiny. 
A tiny percentage, it can account for only a very, tiny 
percentage of the warming. And even looking back 250 years, 
changes in the sun could only account for less than 10 percent 
of the warming that has occurred.
    Mr. Burgess. Which brings me to the blog on the Internet 
and that apparently Mars too is afflicted with global warming 
and the reduction in size of their ice cap. Are humans 
responsible for the Mars problem as well?
    Mr. Oppenheimer. Mars is afflicted with a greenhouse 
effect, just like we are, but we have an increase in greenhouse 
effect. And Mars probably doesn't.
    Mr. Burgess. Thank you, Mr. Chairman. You have been very 
indulgent.
    Mr. Boucher. Thank you, Mr. Burgess. I totally neglected 
the time, but I am confident you used it well. Mr. Whitfield is 
recognized for 8 minutes.
    Mr. Whitfield. Thank you, Mr. Chairman, and appreciate the 
panel being with us today. On this intergovernmental panel, the 
ICCP, whatever the initials are, how many scientists are on 
that panel? Anyone that knows the answer.
    Ms. Hegerl. Hundreds of--depends on how you define the 
panel, the lead authors, or hundreds of lead authors. Do you 
remember that exact number?
    Mr. Hurrell. There were 152 lead authors and 400 
contributing authors to working group one, which deals with how 
the climate has been changing and the role of human activities 
in that.
    Mr. Whitfield. My understanding that, of course, you have 
the lead authors for different segments of these reports. And I 
remember we had a hearing, an oversight investigation about a 
year ago, and there was some discussion about the impact of 
global warming on hurricanes and flooding and so forth. And 
some members of the IPCC that were making the big report had a 
press conference evidently at Harvard University, and one of 
them made the comment that global warming has an impact on the 
frequency of hurricanes. And as a result of that, the lead 
author of the hurricane section ended up resigning from the 
panel because he said this is more of a political statement 
than anything based on science. And he resigned from the panel. 
Are any of you familiar with that situation at all?
    Ms. Hegerl. Sir, I don't think this refers to the IPCC but 
to the U.S. CCSP report, right?
    Mr. Christy. No, this was the IPCC, and he was not a lead 
author. He was a contributing author.
    Ms. Hegerl. He was a contributing author?
    Mr. Whitfield. He was a contributing----
    Mr. Christy. Yes, what was his name?
    Mr. Whitfield. Chris Landsea.
    Mr. Christy. Yes.
    Mr. Whitfield. Now, do any of you have any comment about 
that? I mean one of the issues about all of this global warming 
is that it seems to be becoming immersed in total politics. For 
example, there have been some IPCC reports that have said that 
anything below three degrees of warming in our climate, that 
developed countries will benefit economically and developing 
countries will not benefit economically. Are you all familiar 
with that statement?
    Mr. Oppenheimer. Yes, I just want to point out that that is 
the arena that the second IPCC working group, which is not 
going to report until April deals with. And so there will be 
updates on that view, but they are not finalized yet so I can't 
discuss them.
    Mr. Whitfield. But in 2001 or 2000, they did make that 
statement.
    Mr. Oppenheimer. It is a statement. I can't remember the 
exact number. Up to a certain temperature, there could be 
benefits in certain areas, and the developing countries would 
more likely start to suffer before developed countries like the 
United States did.
    Mr. Whitfield. When the Kyoto Protocol was being agreed to 
by some countries and not agreed to by other countries, there 
was a cry around the whole world about how catastrophic this 
would be. But 10 years ago in an article in ``Geophysical 
Research Letters'' they estimated that if every nation on Earth 
lived up to the United Nations Kyoto Protocol on global 
warming, it would prevent no more than .126 degrees Fahrenheit 
of warming every 50 years.
    Mr. Oppenheimer. Yes, the Kyoto Protocol was viewed by 
those who signed it as only the first step, and it was 
recognized that much larger reductions would be needed if a 
significant difference was going to be made in global climate. 
And those could only have an effect over many, many decades. So 
while it is technically correct that the Kyoto Protocol would 
not have had much, if any, measurable effect on climate if that 
was all that was ever done, the expectation among the 
signatories was that wasn't the last step but only the first.
    Mr. Whitfield. Yes, I think that as Members of Congress, 
not only in United States but around the world, it is helpful 
if we all could be less emotional on this issue because when 
the U.S. failed to sign this Kyoto Protocol, it sounded like 
the world was coming to an end. The U.S. was being so 
irresponsible. So I think if we can make this less sensational 
in any way possible, that we all benefit from that. And then a 
second part of this that certainly concerns all of us is the 
cost of global warming and the cost of preventing global 
warming. And I know at one time the IPCC, they looked at cost/
benefit analysis, and then they reach a point where they said 
we are not going to consider cost at all. And then you had 
some, I guess, people who developed some models to look at 
cost, one referred to as Dice, now, tell me about Dice.
    Mr. Oppenheimer. Dice is an economic model which attempts 
to look at the balance between costs of reducing emissions and 
the damages from not reducing emissions and seek what the 
optimum balance is over the course of the next century.
    Mr. Whitfield. Now, why would the IPCC not be involved in 
looking at that as well?
    Mr. Oppenheimer. Well, in fact they have been, and again 
the report on economic consequences won't be out until May. And 
I am not involved with it, so I can't speak about it. But the 
last IPCC report, they did publish different ways to look at 
that balance, and a crude way to look at it is if the 
atmosphere, the cost of restricting warming to remain near 
those lower curves that you showed before, would be several 
percent of global GDP cumulative over the next 50 years. That 
is not several percent per year. That is several percent 
cumulative over 50 years, and the cost of the known damages 
were roughly the same; that is, excluding things like a large 
rise in sea level due to the loss of the ice sheets. So many 
economists said well, if those two things are in balance, we 
ought to start doing something about it. And that is what the 
Dice model shows, that a current investment makes sense.
    Mr. Whitfield. OK.
    Mr. Boucher. The time of the gentleman has expired.
    Mr. Whitfield. Thank you.
    Mr. Boucher. Mr. Inslee for 8 minutes.
    Mr. Inslee. Thank you. Just kind of a bonehead question. 
CO\2\ warms the planet. What would the mean temperatures of the 
planet be if there were no CO\2\ in the atmosphere? Dr. 
Hurrell, do you want to start on that? Just, by an order of 300 
percent.
    Mr. Hurrell. Yes, it is like a 33-degree Celsius 
difference, I believe, with no greenhouse gases.
    Mr. Inslee. So no----
    Mr. Hurrell. Fifty-one?
    Mr. Hastert. Are we talking about----
    Mr. Hurrell. I was talking about the total greenhouse----
    Mr. Hastert. He just asked about CO\2\.
    Mr. Inslee. Yes, let us start with greenhouse gases. 
Roughly how much colder would it be?
    Mr. Hurrell. Total greenhouse gas?
    Mr. Inslee. Yes, total greenhouse gas.
    Mr. Hurrell. Thirty-two degrees.
    Mr. Inslee. OK, how about carbon dioxide any ideas at all? 
Just don't know.
    Mr. Hastert. Can I ask it would be 32 degrees colder?
    Mr. Hurrell. Yes, the planet is warmer by 32 degrees 
Celsius because of the greenhouse gas effect. That includes the 
natural greenhouse gas effect from water vapor as well as----
    Mr. Hastert. And so if we are at zero Celsius right now, 
just say we are, we would be 32 degrees Celsius below the point 
we are at now?
    Mr. Hurrell. Right. Well, go ahead.
    Ms. Hegerl. Well, there wouldn't be an atmosphere so we 
would have no weather.
    Mr. Inslee. So the reason that concerns me is that we are 
going to be about twice pre-industrial levels of at least one 
major greenhouse gas, CO\2\, in the next century or so unless 
this Congress pulls its head out of the sand and does 
something. So that means if you go down with somewhere in the 
neighborhood of 30 Celsius, there is going to be big impacts in 
the world if we don't do something. And that may not be a one-
to-one correlation, but I am just telling you how one 
congressman looks at that concern about how significant 
greenhouses gases are to the climatic systems of the Earth. We 
are going to be at double the levels that we had in pre-
industrial times. Now, I am really glad that Dr. Christy came 
here because I----
    Mr. Barton. Would the gentleman yield?
    Mr. Inslee. If you will give me some more time.
    Mr. Barton. Your questions are very important, and you are 
one of the most knowledgeable congressmen on this issue. I mean 
you really are. You were very patient in the minority, and you 
have every right to be a lot more impatient in the majority. 
But I want it to be clear that this 32-degree Celsius change, 
most of that is natural. It is not manmade CO\2\. It is water 
vapor that 95 percent is natural water vapor.
    Mr. Inslee. I understand that, and I want to come back to 
Mr. Barton's comment, which I think is probably accurate, that 
only about 5 percent of the CO\2\ emitted in the atmosphere is 
from anthropomorphic sources. Now, the reason that statistic is 
cited because it sounds like a diminimus amount.
    However, that is a 5 percent unnatural, if you will, 
increase to the net zero that occurred in pre-industrial times. 
That means it is like eating doughnuts for the next 20 years. 
If we all ate enough to gain 5 pounds a year, enough doughnuts, 
which I will call the unnatural part of our diet in our 
atmosphere, we are adding carbon dioxide doughnuts. And every 
year it goes up 5 pounds, or 5 percent. Now, that means in 20 
years, I would weigh 400 pounds. So that 5 pounds didn't sound 
like much, but what I am pointing out here is we are heading to 
a level of double the CO\2\. And CO\2\, if we look backwards, 
when you double something, it has a major impact. We know we 
could be in a frozen planet if we had half as much CO\2\, and 
if we have double the amount CO\2\, it is very concerning. That 
is my reaction to this.
    Now, I want to ask Dr. Christy a question. I am glad you 
came because listening to your testimony, what I am hearing you 
saying is yes, carbon dioxide is playing a role. I don't think 
you said the majority role, but some of the role of climate 
change. And you talked about your work that I respect as a 
missionary in Africa, and what I take from you is you sort of 
assume that if we do something about CO\2\, we are going to all 
go back and live like the people do in Africa in that terrible 
poverty that you worked diligently to aid.
    But I want to quote a group called Christian Aid. It is an 
evangelical missionary and development organization. They have 
worked in Africa for 50 years, and here is what they say. ``It 
is vulnerable people in poor countries that are affected first 
and most seriously. Climate change is the most significant 
single threat to development. It could undo decades of progress 
in fighting poverty.'' Christian Aid believes that a new global 
agreement must be reached to cut emissions and provide help to 
poor people who are on the receiving end of global warming. Any 
such agreement must be based on scientific, not political, 
targets.
    Now, what I understand your sort of working hypothesis, Dr. 
Christy, is for us to do something about this, we are going to 
have to go back and live in the stone ages. And the reason is 
that you just don't believe that mankind has been given an 
intellectual capability sufficient enough by the creator to 
develop technologies to deal with this that don't put CO\2\ in 
the atmosphere. Now, that is the working assumption that sort 
of underpins your testimony. So I want to ask you do you about 
the Nanosolar Corporation out in California?
    Mr. Christy. I was delighted to hear that you were on the 
subcommittee.
    Mr. Inslee. Just answer the question. Do you know about 
Nanosolar Corporation?
    Mr. Christy. I probably read about it, but I could not 
recall anything.
    Mr. Inslee. Do you know about the A123 Battery Company?
    Mr. Christy. No, I don't.
    Mr. Inslee. OK, just so you will know, they are a company 
that has developed a lithium ion battery that could potentially 
run a car for 40 miles with zero CO\2\. Do you know about the 
general compression company?
    Mr. Christy. Americans are innovative, and they can provide 
ways to create energy that doesn't use carbon dioxide. And I am 
all for it if I don't have to pay twice as much.
    Mr. Inslee. Right, so the general compression technology, 
basically they have a way of compressing air to create a 
battery system to use compressed air to become essentially a 
battery for wind turbine technology that they believe could 
increase by a factor of two the efficiency of a wind turbine 
system because it can make an intermittent power to be stable, 
base load power. What percentage increase of technology do you 
believe Americans can create in the next 20 years, per year, as 
an increase, let us say, in efficiency? What number do you 
believe we can increase per year and not reduce our economic 
growth?
    Mr. Christy. I want to respond to that Christian missionary 
thing. I am a Christian missionary and a climate scientist. So 
I can talk about both those sides. I don't think those folks 
can. The problem in Africa is governance.
    Mr. Inslee. Well, let me tell you there is another problem 
in Africa.
    Mr. Christy. The question about if I were just to guess and 
that is all it would be would be a guess, is that to get those 
systems into the current energy distribution and generation 
system would take decades from what I understand the situation 
is now, except for nuclear.
    Mr. Inslee. And I appreciate that comment, and I think to 
some degree it is accurate. But let me suggest that the fact 
that it will take decades for us to rebuild our economy, to be 
largely carbon neutral, is not an argument for delay. It is an 
argument for hastening action. The fact that it is going to 
take us some time and that there are some uncertainties about 
global warming and that there are uncertainties about what 
technologies we are going to use, isn't that an argument to get 
started this year in Congress, rather than an argument to wait?
    Mr. Christy. When you say get started, that is where I 
worry about the people in Alabama who are struggling to pay 
their energy bills now.
    Mr. Inslee. I understand that, and if the people of Alabama 
would adopt some of the things that we have done in other 
States like California, we could reduce our energy by 50 
percent. The people in Alabama have increased their per capita 
consumption, and I don't know Alabama for sure, but nationally, 
by 50 percent over the last 20 years. The people in California 
who are still enjoying hot tubs and they have still got a 
booming economy have had a flat rate of growth in energy per 
capita in the last 20 years because they have responded to 
this. So I am glad you came. Thank you very much.
    Mr. Christy. Thank you.
    Mr. Boucher. Thank you, Mr. Inslee. Mr. Sullivan is 
recognized for 5 minutes.
    Mr. Sullivan. Thank you, Mr. Chairman, and this is 
complicated, climate change, global warming. I am trying to 
learn a lot about it. I don't know much about it, and maybe 
some of you could help me with some of these things. I heard 
today that Chairman Markey said that--or I think Mr. 
Oppenheimer might have said that sea level would go up 40 feet, 
and that scares me. A lot of people would probably die if that 
happened. Also, I think Mrs. Hegerl had said that--you were 
talking about some modeling and some temperatures from 1,300 
years ago until now, and that there has been some dramatic 
change. I like using dynamic economy models here for tax 
relief, and a lot of people don't like those. Say that my 
modeling is wrong, and I think there is always room for error 
in these modelings. Let us talk about 1,300 years ago, Mrs. 
Hegerl. What kind of meteorologists were on the planet and what 
kind of thermometers did they use? And where were the weather 
stations? Let us just say 500 years ago, what kind of 
thermometers? I am just curious.
    Ms. Hegerl. To reconstruct temperatures over the last 
millennium, we use proxy data that, for example, reading that 
approximately respond to changes in temperature. So you can 
reconstruct with uncertainties temperatures over the past based 
on indicators that follow the climate----
    Mr. Sullivan. With uncertainty?
    Ms. Hegerl. With uncertainty. On the other hand, when we 
try to understand what happened in the last millennium, we also 
have indicators of what influenced climate, and those are 
virtually independent. For example, entries in ice course in 
Greenland and Antarctica, that indicated what kind of 
corruption and the correspondence between those two things, 
which are virtually independent really, gives us some 
confidence that we can understand to what extent what happened 
in the past and also that we are not completely blowing 
reconstructing the past.
    Mr. Sullivan. And we talked about this naturally occurring 
phenomenon of the water affecting the environment, and I 
believe 96 percent is natural. Is there anything we can do to 
change that?
    Ms. Hegerl. When we increase CO\2\ in the atmosphere, you 
have a bank with water vapors. The water vapor increases as we 
increase CO\2\. It is a positive feedback, so when we 
exchange----
    Mr. Sullivan. When you say that is climate models.
    Ms. Hegerl. It is also been observed. Both the vapor 
increases have been observed.
    Mr. Sullivan. And so you are saying that you can do these 
models with absolute certainty of temperatures?
    Ms. Hegerl. No.
    Mr. Sullivan. That is what you said earlier.
    Ms. Hegerl. No, I am not saying we are doing with 
certainty.
    Mr. Sullivan. That is neat if you can. I don't know much 
about science. I didn't know that that could happen.
    Ms. Hegerl. No, but the IPCC has predicted through to 
temperatures since 1990, and we have done relatively well 
predicting what would happen in the 15 years since the process 
started. It has been warming, and it is within the range that 
we predicted.
    Mr. Sullivan. And would you agree, any of you, that this is 
pretty complicated stuff, and we need to move cautiously when 
we make major decisions? Would most of you agree with that? The 
Speaker wants us to have a bill by June to fix all this. Do you 
think that that is kind of a rush timeframe to get this done, 
that we should look at this and examine it very carefully?
    Mr. Oppenheimer. I think that is your decision, not ours.
    Mr. Sullivan. But wouldn't you agree?
    Mr. Oppenheimer. I think the problem should be looked at 
carefully, but we have a very large body of knowledge. It has 
been accumulating since 1896 on this problem. There are reports 
stacked that thick--I think it is probably possible with reason 
by June----
    Mr. Sullivan. Well, Doctor, we can fix this tomorrow then?
    Mr. Oppenheimer. You could get advice on how to fix it, but 
it wouldn't be completely fixed for many decades, if then.
    Mr. Sullivan. Well, with all the modeling that you do, do 
you do any modeling of how this will affect the economy and----
    Mr. Oppenheimer. It has been done.
    Mr. Sullivan. And would it be detrimental to the economy?
    Mr. Oppenheimer. There are different views. It is not going 
to happen, but if the U.S. had implemented the Kyoto Protocol, 
the estimates were about a 1 percent decrease in total GDP 
cumulative over the 10 years of implementation, according to 
the midrange of the models. In other words, about a tenth of a 
percent per year.
    Mr. Sullivan. OK. Well, Dr. Christy, is it correct that you 
have constructed observational data sets?
    Mr. Christy. Yes, we build them from scratch.
    Mr. Sullivan. Can you elaborate on what is involved in the 
observational work you do?
    Mr. Christy. We do everything from going to libraries and 
getting the paper records, dusting them off and digitizing 
them, to getting the digital counts from satellites to create 
upper air data sets. I mean we start from scratch, and very few 
people in the world, by the way, actually do that.
    Mr. Sullivan. That is good. Also I guess I am curious, all 
the panelists, how many of you have put together observational 
databases from scratch? What type of actual climate 
observational work, not climate modeling, do you do?
    Mr. Hurrell. I have not put together an observational data 
set from scratch. I am, however, a climate diagnostician. I do 
not build models. I primarily have analyzed observational data 
sets my entire career.
    Mr. Sullivan. So you haven't done it?
    Mr. Boucher. Thank you, Dr. Hurrell. The gentleman's time 
has expired. Mr. Walden for 5 minutes.
    Mr. Walden. Thank you, Mr. Chairman. And I appreciate the 
testimony of the witnesses, and my apologies for having to kind 
of come and go. It is that season here on the hill where 
everybody is in town, and we are generally triple booked. Dr. 
Christy, it appears that models get the global average 
temperature simulations to match some global average surface 
temperature observations. But do models get the patterns of 
warming that has been observed correctly?
    Mr. Christy. In the data sets we construct, the answer is 
no, and it is a little bit misconception to say that they match 
even the global temperature because remember modelers already 
know the answer ahead of time. So matching that was not that 
great of a feat when it was designed to match the last 100 
years of climate records.
    Mr. Walden. Does that mean then that they somehow 
manipulate the data to get to the temperatures that were 
supplied?
    Mr. Christy. No, they don't manipulate the data, but there 
is a level of what we call tuning that occurs to make sure that 
all the things balance right so that the temperature matches 
what was observed in the global average sense.
    Mr. Walden. Do they get the tropical patterns of warming or 
the observations of warming at different altitudes?
    Mr. Christy. Not that we have found, no.
    Mr. Walden. And what is the effect of that on our 
policymaking here?
    Mr. Christy. It would be just to raise great caution about 
using them as predictive tools.
    Mr. Walden. OK.
    Mr. Hurrell. Are we allowed to respond?
    Ms. Hegerl. Yes, I would like to make one comment. The 
ocean heat content data set came out in 2001, so by the time 
many more tools were used to analyze it were built and run, the 
data did show that the ocean content gained heat. And the 
pattern with which it gained it has not been known to the 
modelers. So this is one great example of a completely 
independent data set that wasn't----
    Mr. Hurrell. I would just like to on the record state that 
climate models are put together. They are very complex tools, 
trying to represent the complexity of the climate system. But 
individual processes are modeled based on our best scientific 
understanding. That entire set of processes are then put in 
models, and the models are allowed to freely integrate in time. 
So the very impressive match on global and continental and 
ocean basin scales of today's climate models in replicating 
historical record are a very powerful statement that the models 
have reached a point where they are very, very useful tools. 
And they give us much increased confidence in future 
predictions.
    Mr. Walden. All right, then what should we make of the 
science report this summer that the upper surface of the ocean 
cooled substantially between 2003 and 2005, which cut by about 
one-fifth of long-term upper ocean heat gain between 1955 and 
2003? It doesn't seem to square with the IPCC summary telling 
us, or what the models portray, doesn't it?
    Ms. Hegerl. Variations over a short time scale are very 
difficult to interpret, and it is much more helpful to look at 
the longer timeframes. And those variations are interesting, 
and for us, as scientists, fascinating. But I would warn of 
trying to extrapolate them for a longer time.
    Mr. Walden. Well, do you see short-term variations on some 
of the glaciers and all too? I am thinking in the Northwest 
last summer, we were told in Oregon the glaciers had receded by 
50 percent. And about three weeks ago, they came back with 
revised forecast that it was actually 35 percent.
    Mr. Oppenheimer. One does see short-term variations in 
glaciers, and they are of a surprising degree.
    Mr. Walden. Right.
    Mr. Oppenheimer. It turns out that ice could move much 
faster than we thought. It can accelerate, and it can stop much 
faster than we thought.
     And that is, by the way, one of the reasons we don't have 
a lot of confidence in the models. They don't predict such 
changes. Those are the ice sheet models. That is distinct from 
the atmosphere climate models.
    Mr. Walden. I understand, and I am not necessarily making 
the argument the Earth isn't getting warmer. I mean I believe 
we have had thermometers, and you have got predictive models, 
and they may be up and down and all that. My question though is 
in the limited data that I have been trying to get up to speed 
on, it appears this has been an accumulation during the 
Industrial Age. It has been close to 100 years that we have 
been, if you follow the theory, we have been putting carbon and 
other pollutants into the atmosphere that has caused this to 
occur. I have also read that it could be 100 years if we got 
back to equilibrium before you might see a substantial 
temperature change downward.
    Mr. Oppenheimer. I think a simple way--a cartoon of the 
situation is if you stopped all emissions today, it would take 
many decades, probably about two centuries, for carbon dioxide 
to return to the level of around 300 parts per million.
    Mr. Walden. And if you get much below that, am I not 
correct that we go back into an ice age? Weren't we in an ice 
age in the 50 to 100 parts per million?
    Mr. Oppenheimer. No. The last ice age came to an end about 
10,000 years ago. And since then, climate has had----
    Mr. Walden. No, my question is what was the carbon level in 
the atmosphere during the Ice Age?
    Mr. Oppenheimer. About 200 parts per million.
    Mr. Walden. That is what I was saying. If you got down to 
50 to 100, I had it lower than what you are saying.
    Mr. Oppenheimer. Right, but that is not going to happen.
    Mr. Walden. I didn't ask that. No, that wasn't what I was 
saying. There is a point where you don't want to eliminate all 
carbon out of the atmosphere or you have cooling right? Again 
that was the issue in the 1970's. I remember some of those 
stories, The Coming Ice Age, and all that in ``Time'' magazine.
    Mr. Oppenheimer. The likelihood is we are never even going 
to get back to the pre-industrial level of 280 parts per 
millions. It is simply not going to happen because we put so 
much carbon dioxide in the atmosphere. If we stopped our 
emissions, it would gradually fall out, but we are stuck with 
some of that carbon dioxide for 1,000 years or more.
    Mr. Walden. Some of it lives a very long time.
    Mr. Oppenheimer. Correct.
    Mr. Boucher. The gentleman's time has expired.
    Mr. Walden. Thank you, Mr. Chairman, for your indulgence.
    Mr. Boucher. Mr. Barton has asked for the opportunity to 
propound some additional questions, and at this time, I am 
going to recognize him for an additional 5 minutes of 
questions.
    Mr. Barton. I am going to try to be as quick as possible, 
Mr. Chairman. Thank you for your courtesy. What is the largest 
concentration of CO\2\ in the atmosphere ever as far as we know 
if you go back to prehistoric times?
    Mr. Oppenheimer. Ever?
    Mr. Barton. Ever.
    Mr. Oppenheimer. Ever, there were times in Earth's history 
where there was much more carbon dioxide than today, but in the 
time----
    Mr. Barton. Well, I mean just give me a number. I mean I am 
told that plants are genetically best able to reproduce 
themselves and thrive at 1,000 parts per million of carbon in 
the atmosphere. Is that a true statement or a non-true 
statement?
    Mr. Oppenheimer. We don't actually have a good picture 
because those levels of carbon dioxide haven't recurred for 
millions and millions of years.
    Mr. Barton. But isn't it a fact that in the past we have 
evidence or we at least have theories that carbon has been much 
higher concentration than 380 parts per million?
    Mr. Oppenheimer. Yes, and Earth was much, much, much 
warmer.
    Mr. Barton. OK, and even you would admit those weren't 
driven by manmade emissions?
    Mr. Oppenheimer. Even I would admit that that was natural, 
but it occurred very slowly over millions of years.
    Mr. Barton. Well, but I mean the point is that we are 
taking as a base period 1750 or 1850, which we are in what we 
at one time called the Little Ice Age, and since that time, the 
temperature has been going up, which you would assume, if you 
are coming out of an ice age, it would be going up?
    Mr. Oppenheimer. Excuse me. It was not an ice age. It was a 
small decrease in temperature mostly in the North Atlantic 
Basin.
    Mr. Barton. It was in popular literature until recently it 
has been called the Little Ice Age.
    Mr. Oppenheimer. Right, but it had some effects in the 
North Atlantic Basin and maybe some other places. An ice age 
means 1,000 feet of ice reaching down to New York.
    Mr. Barton. Well, we have had higher concentrations of 
CO\2\ and higher concentrations of carbon than what we have 
today.
    Mr. Oppenheimer. Right.
    Mr. Barton. That is a true statement.
    Mr. Oppenheimer. Sure, and what we perhaps will do over 
this century is return Earth's temperature to levels that were 
near what they were several million years ago.
    Mr. Barton. I want to ask Dr. Christy a question. Are 
clouds critical to how warm or cold the Earth is?
    Mr. Christy. They are critical.
    Mr. Barton. How well do we understand the formation of 
clouds?
    Mr. Christy. Not well at all.
    Mr. Barton. How do we account for clouds in these models 
that the scientists have been talking about?
    Mr. Christy. Well, the grid squares on which calculations 
are done are fairly large, a few hundred kilometers. And so 
clouds cannot be represented in that with a single point 
number. So they are, in a sense, statistically represented in 
terms of their effects on the radiation and so on.
    Mr. Barton. I am told that there are about 20 models that 
portray themselves as being able to model climate in the 
atmosphere and that none of these models accurately account for 
clouds. Is that a true statement or a non-true statement?
    Mr. Christy. Well, it hinges on accurately, and from my 
point of view, I would say that is true.
    Mr. Barton. Dr. Hurrell, would you agree or disagree with 
that last statement?
    Mr. Hurrell. I agree the clouds are a major shortcoming of 
today's climate models.
    Mr. Barton. OK, if you were a policymaker, given the 
uncertainty just in that one variable, how many millions of 
jobs would you put at risk for political correctness? It is a 
fair question. That is what we are being asked to do by the 1st 
of June.
    Mr. Hurrell. I resent the notion that the greenhouse effect 
as a problem involves political correctness. It is, in first 
order, a scientific issue. Whether it is worth doing anything 
about and how much is indeed your own decision.
    Mr. Barton. Well, your own testimony earlier, Doctor, was 
that if we totally eliminated manmade CO\2\ emissions, it could 
be several centuries before we saw any change.
    Mr. Hurrell. No, I didn't say that. I said it would be 
several centuries before carbon dioxide would return even close 
to pre-industrial levels. That is something quite different.
     We could have a substantial change on future climate by 
limiting emissions, and in addition, it needn't bankrupt the 
economy. That is a false comparison, as the progress in 
California has shown. It was referred to by the Member from 
Washington.
    Mr. Barton. My time is about to expire. Let me ask one last 
question.
    Mr. Hurrell. Sure.
    Mr. Barton. Your radiative forcing components in this 
summary shows that there is some manmade forcing components 
that are negative. As a policy option, should we consider doing 
some of the negative things that would balance the positive?
    Mr. Hurrell. If you want people to be breathing dirtier 
air, sure, go ahead. But I don't think people want to solve one 
environmental problem on the back of another.
    Mr. Barton. OK, I thank the Chair's courtesy, and I am 
going to have some written questions for this group.
    Mr. Boucher. Well, without objection, written questions may 
be submitted to this panel. And when they are, we would 
appreciate your expeditious response. Mr. Hastert.
    Mr. Hastert. I just want to thank the panel. This is what 
it is supposed to be, a learning experience. One of the things 
we have learned is that there is not a lot of exactness there. 
There is a lot of maybe and ifs and clouds do this and maybe 
not and ice sheets, and I appreciate the frankness and 
candidness of this panel. It has been very helpful. Appreciate 
everybody being here today.
    Mr. Boucher. And let me second that sentiment. I very much 
appreciate your willingness to spend time with us today. It has 
been a rather long period of time, and we thank you for your 
answers. Mr. Burgess, do you have a comment you would like to 
make?
    Mr. Burgess. Yes, I do have a comment. We have heard some 
rather intriguing science and certainly the level of 
uncertainty around some of these issues that were discussed 
today just leads me to believe that the timeline that we are on 
to produce a legislative product by June or July is absolutely 
untenable. And I hope the chairman will communicate with his 
leadership about the hearing that we have had today and the 
fact that it was well attended, at least on our side. There is 
a genuine willingness there to learn. We are going to need more 
time to develop a legislative product that does not put our 
economy at risk and still serves the needs of generations to 
come.
    Mr. Boucher. Thank you, Mr. Burgess. And let me assure you 
that we are having in-depth discussions on the majority side 
about the schedule.
    Mr. Burgess. I will be glad to show up and help you with 
those discussions.
    Mr. Boucher. Thank you. I might call on you to do that. 
Well, with those comments, we thank our panel, and this hearing 
is adjourned.
    [Whereupon, at 1:40 p.m., the subcommittee was adjourned.]
    [Material submitted for inclusion in the record follows:]

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                    Statement of Michael Oppenheimer

            Professor, Geosciences and International Affairs

                          Princeton University

                             Princeton, NJ


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 Summary of Major Points--Testimony of James W. Hurrell--March 7, 2007

                  Are global temperatures increasing?

    The iconic statement from the observations chapter of the 
IPCC Fourth Assessment Report (AR4) is the ``warming of the 
climate system is unequivocal.'' This is based on an increasing 
number of many independent observations that give a consistent 
picture of a warming world. A limited sample of the evidence 
includes:

       Average global surface temperature has warmed 
over the last 50 years, with a greater rate of 0.17'C (0.3'F) 
per decade since 1979.
       Global average sea surface temperatures have 
warmed 0.35'C (0.6'F) since 1979.
       Global sea level has risen at a rate of 0.31 cm 
per year since 1993.
       Arctic summer sea-ice extents and Northern 
Hemisphere snow cover have decreased, and permafrost layer 
temperatures have increased since the 1980's.
       The number of heat waves globally has increased, 
and there have been widespread increases in the numbers of warm 
nights. Frost days are rarer.

    To what extent is the increase attributable to greenhouse 
gas emissions from human activity as opposed to natural 
variability or other causes?

    Climate model simulations have now reliably shown that 
global surface warming of recent decades is a response to the 
increased concentrations of greenhouse gases and sulfate 
aerosols in the atmosphere. When the models are run with 
natural forcing changes alone, they fail to capture the large 
increase in global surface temperatures over the past 25 years. 
Moreover, the spatial pattern of observed warming, which 
includes greater warming over land than over the ocean, is only 
simulated by models that include anthropogenic forcing. 
Discernible human influences now extend to other aspects of the 
climate as well, including ocean warming, continental-average 
temperatures, temperature extremes, and changes in 
precipitation.

    How will future global temperatures be affected by 
greenhouse gas emissions from human activity?

    The ability of climate models to simulate the past climate 
record gives us increased confidence in simulations of the 
future. Some major conclusions from the IPCC AR4 are:

       The rate of the projected global warming is near 
0.2 Celsius per decade through 2030 regardless of the emission 
scenario. Likewise, warming and significant changes in 
precipitation will continue over each inhabited continent.
       By the middle of the 21st century the choice of 
scenario becomes more important.
       Continued greenhouse gas emissions at or above 
current rates would very likely induce many changes in climate 
much larger than those observed to date.
       Snow cover and sea ice coverage are projected to 
contract.
       It is very likely that hot extremes, heat waves, 
and heavy precipitation events will continue to become more 
frequent.
       Even if greenhouse gas concentrations were to be 
stabilized, anthropogenic warming and sea level will continue 
for centuries.

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