[House Hearing, 110 Congress]
[From the U.S. Government Publishing Office]
EPA BLACK CARBON AND GLOBAL WARMING
=======================================================================
HEARING
before the
COMMITTEE ON OVERSIGHT
AND GOVERNMENT REFORM
HOUSE OF REPRESENTATIVES
ONE HUNDRED TENTH CONGRESS
FIRST SESSION
__________
OCTOBER 18, 2007
__________
Serial No. 110-86
__________
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COMMITTEE ON OVERSIGHT AND GOVERNMENT REFORM
HENRY A. WAXMAN, California, Chairman
TOM LANTOS, California TOM DAVIS, Virginia
EDOLPHUS TOWNS, New York DAN BURTON, Indiana
PAUL E. KANJORSKI, Pennsylvania CHRISTOPHER SHAYS, Connecticut
CAROLYN B. MALONEY, New York JOHN M. McHUGH, New York
ELIJAH E. CUMMINGS, Maryland JOHN L. MICA, Florida
DENNIS J. KUCINICH, Ohio MARK E. SOUDER, Indiana
DANNY K. DAVIS, Illinois TODD RUSSELL PLATTS, Pennsylvania
JOHN F. TIERNEY, Massachusetts CHRIS CANNON, Utah
WM. LACY CLAY, Missouri JOHN J. DUNCAN, Jr., Tennessee
DIANE E. WATSON, California MICHAEL R. TURNER, Ohio
STEPHEN F. LYNCH, Massachusetts DARRELL E. ISSA, California
BRIAN HIGGINS, New York KENNY MARCHANT, Texas
JOHN A. YARMUTH, Kentucky LYNN A. WESTMORELAND, Georgia
BRUCE L. BRALEY, Iowa PATRICK T. McHENRY, North Carolina
ELEANOR HOLMES NORTON, District of VIRGINIA FOXX, North Carolina
Columbia BRIAN P. BILBRAY, California
BETTY McCOLLUM, Minnesota BILL SALI, Idaho
JIM COOPER, Tennessee JIM JORDAN, Ohio
CHRIS VAN HOLLEN, Maryland
PAUL W. HODES, New Hampshire
CHRISTOPHER S. MURPHY, Connecticut
JOHN P. SARBANES, Maryland
PETER WELCH, Vermont
Phil Schiliro, Chief of Staff
Phil Barnett, Staff Director
Earley Green, Chief Clerk
David Marin, Minority Staff Director
C O N T E N T S
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Page
Hearing held on October 18, 2007................................. 1
Statement of:
Jacobson, Mark Z., professor of civil and environmental
engineering, Atmosphere/Energy Program, Stanford
University; Tami C. Bond, assistant professor of civil
engineering, University of Illinois at Urbana-Champaign; V.
Ramanathan, professor of climate and atmospheric sciences,
Scripps Institute of Oceanography, University of San Diego;
Charles Zender, associate professor of Earth system
science, University of California at Irvine; and Joel
Schwartz, professor of environmental epidemiology, Harvard
University................................................. 12
Bond, Tami C............................................. 30
Jacobson, Mark Z......................................... 12
Ramanathan, V............................................ 49
Schwartz, Joel........................................... 78
Zender, Charles.......................................... 68
Letters, statements, etc., submitted for the record by:
Bond, Tami C., assistant professor of civil engineering,
University of Illinois at Urbana-Champaign, prepared
statement of............................................... 32
Davis, Hon. Tom, a Representative in Congress from the State
of Virginia, prepared statement of......................... 9
Jacobson, Mark Z., professor of civil and environmental
engineering, Atmosphere/Energy Program, Stanford
University, prepared statement of.......................... 15
Ramanathan, V., professor of climate and atmospheric
sciences, Scripps Institute of Oceanography, University of
San Diego, prepared statement of........................... 51
Schwartz, Joel, professor of environmental epidemiology,
Harvard University, prepared statement of.................. 81
Watson, Hon. Diane E., a Representative in Congress from the
State of California, prepared statement of................. 110
Waxman, Chairman Henry A., a Representative in Congress from
the State of California, prepared statement of............. 3
Zender, Charles, associate professor of Earth system science,
University of California at Irvine, prepared statement of.. 70
EPA BLACK CARBON AND GLOBAL WARMING
----------
THURSDAY, OCTOBER 18, 2007
House of Representatives,
Committee on Oversight and Government Reform,
Washington, DC.
The committee met, pursuant to notice, at 10:06 a.m. in
room 2154, Rayburn House Office Building, Hon. Henry A. Waxman
(chairman of the committee) presiding.
Present: Representatives Waxman, Maloney, Cummings,
Kucinich, Tierney, Norton, McCollum, Hodes, Davis of Virginia,
Shays, Mica, Duncan, Issa, and Bilbray.
Staff present: Phil Schiliro, chief of staff; Phil Barnett,
staff director and chief counsel; Greg Dotson, chief
environmental counsel; Earley Green, chief clerk; Teresa
Coufal, deputy clerk; Caren Auchman and Ella Hoffman, press
assistants; Leneal Scott, information systems manager; David
Marin, minority staff director; Kristina Husar, minority
counsel; Larry Brady, minority senior investigator and policy
advisor; Patrick Lyden, minority parliamentarian and member
services coordinator; Brian McNicoll, minority communications
director; Benjamin Chance, minority clerk; and Ali Ahmad,
minority deputy press secretary.
Chairman Waxman. The meeting of the committee will please
come to order.
Today's hearing will focus on the issue of black carbon and
global warming. Black carbon is commonly known as soot. It is
emitted from our diesel trucks, our trains, planes, ships, and
even our fireplaces. Over the years, Congress and the
Environmental Protection Agency have focused on tiny particles
like black carbon because it cut short the lives of our seniors
and sickened our children; however, black carbon is also
important because of the ongoing role it plays in the warming
of the Earth.
Today we will hear that black carbon may be responsible for
almost 20 percent of the warming the planet is currently
experiencing. Experts will tell us that black carbon may be the
second most significant global warming pollutant after carbon
dioxide; yet controlling black carbon has not been seriously
examined at the Federal level as a way of possibly mitigating
global warming.
At today's hearing we will explore what may seem to be an
overwhelmingly complex issue involving atmospheric chemistry,
global climate modeling, and literally millions of sources of
air pollution.
It may seem complex, and indeed there are complexities and
unanswered questions, but it is manageable. Here is what we
know: Global warming is happening and carbon dioxide is the
principal pollutant of concern. Other pollutants, like black
carbon, also contribute to the problem. Because black carbon
doesn't stay in the Earth's atmosphere as long as carbon
dioxide, controlling it may achieve major benefits in the short
term.
We may need short-term benefits in order to prevent
irreversible impacts from occurring. Reducing particulate air
pollution, like black carbon, could also achieve major public
health benefits.
This is not a theoretical issue. We can now see the impacts
of global warming with our own eyes. To illustrate this last
point, I have several slides of glaciers that I would like to
put up on the screen.
This first is of Carroll Glacier in Alaska. As you can see,
this glacier has basically disappeared in the 97 years between
when these photographs were taken. As you can see it is a
straight glacier untouched by any warming, complete ice, no
deterioration. We will soon see a photograph that shows a very
different picture.
We also have photographs which we will exhibit in the near
term, and these photographs are of McCall Glacier, which has
receded dramatically over the last 45 years, and then there is
also Toboggan Glacier that has vanished over the course of 90
years.
The glaciers of the world are receding. These receding
glaciers are one measure of the warming that we now know to be
occurring, but it isn't the only one. What is happening in the
Arctic is alarming.
We have a time-lapsed animation of Arctic sea ice. This
animation shows the last 30 years of summer sea ice, based upon
data compiled by the National Snow and Ice Data Center. It
begins in 1978 and runs through 2007. While Arctic sea ice has
been consistently declining over the years, this past summer
was truly stunning.
If you look on the right, you can see the area that has now
been lost, which has opened up perhaps sea lanes that we never
expected, but problems that we should definitely be concerned
about.
Global warming is happening, and the planet's natural
systems are giving us every reason to pay attention to this
problem.
Today we have a very distinguished panel and I thank you
all for being here and for paying attention to this problem. I
am very pleased that they have agreed to appear, and we look
forward to your testimony.
We want to bring in part of the debate on global warming
that has not been the focus of attention yet on the Hill, and
we think this hearing will give us the opportunity to do that.
[The prepared statement of Chairman Henry A. Waxman
follows:]
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Chairman Waxman. Mr. Davis.
Mr. Davis of Virginia. Thank you, Mr. Chairman, and thank
you for holding today's hearing to consider the relationship
between black carbon emissions and climate change.
Climate change is a critically important issue, and as
policymakers it is our job to consider all sensible options to
reduce the emission of climate-warming pollutants. My head is
not in the sand on this issue. I am not one who denies the
reality of climate change, and I am motivated to learn more
about what we can do to advance the debate and come up with
some potential solutions. Therefore, I think this hearing can
serve as an example of how we as a committee can work together
to rationally investigate the facts surrounding climate change,
and at the same time seek agreement on the best way forward.
While the United States and the world have focused
attention on reducing carbon dioxide emissions, it appears that
not enough attention has been focused on controlling black
carbon and its effects on the climate.
According to the witnesses scheduled to testify, there is
significant scientific evidence that black carbon is the second
leading cause of climate change after carbon dioxide. In
layman's terms, black carbon is soot. It is emitted into the
air during fossil fuel and biofuel combustion and biomass
burning. Developing nations like China and India are the
leading source of black carbon emissions, while the United
States is only responsible for about 6.1 percent.
Unlike some ways of controlling CO2 emissions,
technology already is available to reduce emissions in black
carbon. That technology has reduced by a factor of five the
soot emissions in this country since the 1950's. We need to
find ways to ensure the developing world has access to this
technology.
One witness will tell us that reductions in black carbon
emissions could buy us significant time to reduce
CO2 emissions. That would be a welcome respite to
allow the world to develop consensus solutions that don't stall
growth or give some nations competitive advantages over others.
Because the developing world is the major source of black
carbon emissions, this hearing serves as a reminder that any
future international treaties on climate change must include
China and India. Failure to do so would forfeit a prime
opportunity to bring about meaningful changes in behavior that
both include quality of life and reduce the immediate impact of
climate change on the planet.
Moreover, as we look for ways to mitigate harmful
greenhouse gases, we must do so while acknowledging that energy
is essential to the economic activity that sustains and
improves our quality of life.
Renewable energy shows great promise, and biofuels have
provided some relief from our dependence on traditional energy
sources that contribute to climate change. However, the only
fuels that have a realistic growth potential--solar, wind,
biomass--only make up about 3.5 percent of the Nation's energy
supply. Even with healthy growth, these energy sources will not
cure our dependence on coal and oil. Accordingly, policymakers
must look to technologies that decrease the externalities
associated with the use of energy so that we can limit
emissions that contribute to climate change.
There is no question that we live in a challenging world
and we only have real-world options available to us to address
the twin challenges of climate change and energy independence.
This committee and this Congress should devote more time
and attention to exploring these options so that we can craft
effective, real-world solutions. Reducing black carbon
emissions around the world may be an overlooked, cost-effective
solution that will provide enormous benefits.
Finally, I want to thank our distinguished panel who will
be testifying today for their dedication to the science of
climate change and for taking the time to share their knowledge
with us and their expertise.
Thank you.
[The prepared statement of Hon. Tom Davis follows:]
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Chairman Waxman. Thank you.
We have a very distinguished panel.
Mr. Issa, did you want to say anything? If not, we will
proceed to the panel.
Mr. Issa. That would be fine just to proceed.
Chairman Waxman. OK.
We have Dr. Mark Jacobson, who is the co-founder and
director of the Atmospheric Energy Program at Stanford
University's Department of Civil and Environmental Engineering,
where he has been a faculty member since 2004. His research is
dedicated to addressing atmospheric problems such as climate
change and urban air pollution. Since 1994, he has published
two textbooks and more than 70 peer-reviewed journal articles
on related topics. We are pleased that you are here.
Dr. Tami Bond leads a research group at the University of
Illinois at Urbana-Champaign focused on aerosols and the global
environment. She is well known for her work identifying black
carbon emission sources. We are pleased that you are here.
Dr. V. Ramanathan has been researching climate and
atmospheric science for more than 30 years. Among other
positions, he currently serves as a member of the World Clean
Air Congress Advisory Board as co-chief scientist for the
Atmospheric Brown Cloud Project and is Chair to the National
Academy of Science's Committee on Strategic Advice on the U.S.
Climate Change Science Program. He is a distinguished professor
of atmospheric and climate sciences at the Scripps Institute of
Oceanography at the University of California, San Diego.
Dr. Charles Zender is the director of the Earth System
Modeling Facility and leads the Climate Health, Aerosols,
Radiation, and Micro-Physics Group at the University of
California, Irvine. His recent research focuses on the impact
of aerosol deposits on snow and ice in the Arctic, and he holds
a Ph.D. in astrophysics, planetary, and atmospheric science
from the University of Colorado at Boulder. We are pleased you
are here.
And Dr. Joel Schwartz is a professor of environmental
epidemiology at the Harvard University School of Public Health.
He has conducted research on the adverse health impacts of air
pollution all over the world, including studies in the United
States, the European Union, Canada, Israel, and Turkey, among
others. Dr. Schwartz, it is good to see you, as well.
It is the practice of this committee to ask all witnesses
that appear before us, because we are an investigative
committee, to testify under oath. It seems a bit awkward with
scientists, because you are going to give us theories and ideas
that may change. In fact, you may change your minds as you look
at some of these matters further. But we will keep with our
practice and ask you to please stand and raise your right
hands.
[Witnesses sworn.]
Chairman Waxman. The record will reflect that each of the
witnesses answered in the affirmative.
Dr. Jacobson, let's hear from you first.
STATEMENTS OF MARK Z. JACOBSON, PROFESSOR OF CIVIL AND
ENVIRONMENTAL ENGINEERING, ATMOSPHERE/ENERGY PROGRAM, STANFORD
UNIVERSITY; TAMI C. BOND, ASSISTANT PROFESSOR OF CIVIL
ENGINEERING, UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN; V.
RAMANATHAN, PROFESSOR OF CLIMATE AND ATMOSPHERIC SCIENCES,
SCRIPPS INSTITUTE OF OCEANOGRAPHY, UNIVERSITY OF SAN DIEGO;
CHARLES ZENDER, ASSOCIATE PROFESSOR OF EARTH SYSTEM SCIENCE,
UNIVERSITY OF CALIFORNIA AT IRVINE; AND JOEL SCHWARTZ,
PROFESSOR OF ENVIRONMENTAL EPIDEMIOLOGY, HARVARD UNIVERSITY
STATEMENT OF MARK Z. JACOBSON
Mr. Jacobson. Thank you, Chairman Waxman, Ranking Member
Davis, and the committee for inviting me to testify today. I
will speak on the role of black carbon in global climate change
and methods of reducing black carbon emissions.
Fossil fuel and biofuel burning soot particles containing
black carbon have a strong probability of being the second
leading cause of global warming after carbon dioxide and ahead
of methane. Because of the short lifetime of soot relative to
greenhouse gases, control of soot, particularly from fossil
fuels, is very likely to be the fastest method of slowing
global warming. Because soot particles are generally small, and
small aerosol particles are the leading cause of air pollution
mortality, controlling soot emissions will not only slow global
warming but also improve human health.
The U.S. soot contributions to global warming may exceed
each of its methane and its nitrous oxide contributions to
global warming. Despite soot regulations to date based on
health grounds, the United States has significant room to
reduce soot emissions further, thereby reducing health and
climate problems further.
Soot is an aerosol particle emitted during fossil fuel,
biofuel, and biomass combustion. Soot particles contain black
carbon, organic carbon, and smaller amounts of sulfur and other
chemicals. Soot particles warm the air by converting sunlight
into infrared or heat radiation and emitting the heat radiation
to the air around them. This differs from greenhouse gases,
which heat the air by absorbing the Earth's infrared radiation
but not sunlight.
When soot particles age in the atmosphere, they become
coated by other chemicals, increasing their size and their
ability to heat the air, but also their ability to form clouds.
Soot particles that end up on snow or sea ice surfaces also
darken those surfaces, contributing to their warming and
melting.
The figure now on the screen shows the relative
contributions of greenhouse gases, soot, the urban heat island
effect, and cooling particles to global warming, as determined
by recent detailed computer model simulations. About half of
actual global warming today is being marked by cooling
particles which contain sulfate, nitrate, ammonia, certain
organic carbon, and water primarily. Thus, as cooling particles
are removed by the cleanup of air pollution, much global
warming will be unmasked; nevertheless, the removal of such
particles is still desirable for improving human health.
The figure also shows that fossil fuel plus biofuel soot
may contribute to about 16 percent of gross global warming,
which is the warming before cooling is subtracted out, but its
control and isolation could reduce 40 percent of net global
warming.
Soot particles also differ from greenhouse gases in that
soot particles have relatively short lifetimes of around 1 to 4
weeks. This compares with 30 to 43 years for carbon dioxide and
8 to 12 years for methane. The lifetime of a chemical is the
time required for its concentration in the air to decay to
about 37 percent its original value.
Because of soot's short lifetime and strong climate
impacts, reduction in its emissions can result in rapid climate
benefits. This is illustrated by the figure now on the screen,
which shows that controlling soot could reduce temperatures
faster than controlling carbon dioxide for up to 10 years, but
controlling carbon dioxide has a larger overall climate benefit
over 100 years.
Whereas the United States emits about 21 percent of global
anthropogenic carbon dioxide, it emits about a little over 6
percent of global fossil fuel plus biofuel soot. Nevertheless,
the warming due to U.S. soot appears to exceed the warming due
to U.S. methane and nitrous oxide.
Proposed methods of controlling fossil fuel soot have
included improving engines, changing fuels, adding particle
traps, and changing vehicle types. Recent emission regulations
in the United States have begun to address reducing particle
emissions, but more needs to be done.
It is thought that because diesel vehicles contain better
gas mileage than gasoline vehicles, using more diesel will slow
global warming; however, this concept ignores the larger
emissions of fossil fuel soot from diesel and the resulting
climate effects. Further, the addition of a particle trap to
diesel vehicles, while decreasing particles significantly,
increases carbon dioxide, and the ratio of NO2 to NO
in exhaust, thereby increasing ozone in most of the United
States.
Improvements in neither gasoline nor diesel vehicles can
contribute significantly to reducing carbon dioxide emissions
by 80 percent, the level needed to stabilize atmospheric carbon
dioxide, while accounting for future economic growth. A more
certain method is to convert from fossil fuel to electric,
plug-in hybrid, or hydrogen fuel cell vehicles, where the
electricity or hydrogen is produced by a renewable source such
as wind, solar, geothermal, hydroelectric wave, or tidal power.
Such a conversion would reduce global warming and improve human
health simultaneously.
The figure on the screen shows results for the first wind
mapping study of North America at 80 meters above the ground.
This is all from data. The Great Plains has long been known as
the Saudi Arabia of wind, but the figure identifies other ares,
particularly coastal, of intense winds that were previously
unknown. The data indicate that the United States has twice as
much wind energy than total energy consumed from all sources,
and ten times as much wind energy as electricity consumed in
locations where wind is economical.
The United States could replace all its on-road vehicles
with battery electric vehicles powered by 71,000 to 122,000 5-
megawatt wind turbines, which is less than the 300,000
airplanes produced during World War II by the United States.
The land area needed for such wind turbines is 0.5 percent
of the United States, much less than the 15 percent of the
United States that has fast wind. The wind area required is
also 1/30th of that required for corn ethanol and 1/20th of
that required for cellulosic ethanol to replace the same
vehicles. The land area required for solar energy is also very
low.
In sum, an effective method of reducing the combined
effects of carbon dioxide and soot on climate and health is to
convert as many combustion devices as possible to those powered
by renewable energy.
Thank you again for considering my testimony.
[The prepared statement of Mr. Jacobson follows:]
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Chairman Waxman. Thank you. We appreciate that testimony.
Dr. Bond, we would like to hear from you.
STATEMENT OF TAMI C. BOND
Ms. Bond. Chairman Waxman, Ranking Member Davis, and
members of the committee, I have spent the last 12 years
modeling and measuring sources of black carbon, and I am
pleased to share my expertise about the role of black carbon in
climate change.
I commend your committee for continuing this discussion at
a national level, and I am honored to participate. Thank you
very much for your invitation.
I will speak to you on sources of black carbon, its role in
the climate system, and the potential for mitigation. These are
the major points of my presentation, which are supported
further in my written testimony: First, the major sources of
black carbon are known.
Second, historically clean alternatives reduce black carbon
emissions. This transition occurs naturally during economic
development, but it can be accelerated.
Third, black carbon and other products of incomplete
combustion should be considered together with greenhouse gases.
Fourth, mitigation options that address black carbon,
particularly in developed countries, are not always cost
effective compared to greenhouse gases when climate benefits
alone are considered.
Fifth, some options can economically reduce warming. These
offer major co-benefits in terms of human health and local
environmental protection.
The first slide there is showing that black carbon
emissions in 2000 came from four categories: diesel engines for
transportation or industrial use; solid fuels, such as wood and
coal, for cooking and heating; open forest and savannah
burning, both natural and for land clearing; and solid fuel use
in industrial combustion.
The comparative magnitude of each contribution will change
as these estimates improve, but the major sources will neither
vanish nor grow to dominate the whole picture.
Fuel use in the United States has grown phenomenally since
World War II, but black carbon emissions have decreased due to
cleaner technology and fuels. Estimates of the North American
emission trend are broadly consistent with the Arctic record.
History suggests a consistent trajectory during a nation's
economic development. Initially, emissions come from solid
fuels for heating and cooking. These fade as incomes increase
and clean household energy is introduced.
Next, emissions from the industrial sector increase and are
reduced by regulation. In the meantime, internal combustion
engines for transportation and other mobile power proliferate
and eventually dominate.
It is rarely possible to reduce greenhouse gases alone,
aerosols alone, or black carbon alone. Evaluating all emissions
from a single source is more comprehensive and more accurate
than looking at the effects of individual chemical species such
as carbon dioxide only.
No current efforts on climate mitigation are evaluated in
this way; however, rapid changes such as those occurring in the
Arctic suggest that no opportunity should be missed.
Particles from diesel engines and cook stoves are strongly
light absorbing and therefore warming, despite the presence of
non-absorbing cooling particles from these sources. Particles
from open biomass burning, however, are on the border between
cooling and warming.
This figure shows a very preliminary evaluation of cost-
effectiveness in terms of CO2 equivalent reductions.
Here I discuss only methods of eliminating existing black
carbon emissions.
Mitigation options for solid fuel combustion include
improving wood cook stoves and promoting cleaner fuels,
including distillate fossil fuels. This would also reduce
exposure to indoor smoke, a major health hazard.
Reducing vehicle emissions is possible through accelerated
retirement, retrofits, and targeting of high emitters.
The figure I show supports some optimism, because some
costs are close to worthwhile, even from a climate protection
perspective. Some reductions appear affordable, while some
appear costly; however, consideration of immediate benefits,
health and environmental protection, and Arctic snow forcing
will decrease the costs, as well. However, caution is also
necessary.
First, many of the least-expensive mitigation actions can
be found in developing countries. Industrialized countries have
already enacted many of the least-expensive aerosol reductions,
and the remaining black carbon is expensive to mitigate. Thus,
acknowledging the role of black carbon in the climate system is
unlikely to detract developed countries from reducing
greenhouse gases.
Second, reductions may be challenging, despite strong
justification for climate protection. The two measures that
appear most promising--reducing diesel emissions and improving
cooking fuels--involve millions of small sources and operators,
whose ability to afford the relatively low-cost investments is
limited.
In conclusion, black carbon reductions can contribute to
climate protection, and exploration of this possibility should
proceed rapidly, although cautiously. Reducing emissions can
eliminate warming quickly, and in some cases economically.
These measures also result in major health and environmental
benefits; however, they are not always cost effective for
climate purposes, alone, especially in industrialized
countries, and they reduce warming only in the short term.
Thank you.
[The prepared statement of Ms. Bond follows:]
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Chairman Waxman. Thank you very much, Dr. Bond.
Dr. Ramanathan.
STATEMENT OF V. RAMANATHAN
Mr. Ramanathan. Honorable chairman and members of the
committee, I am really honored to be here. I am going to talk
about more the global and regional effects of these black
carbon particles.
They basically start off as soot as an urban or rural haze,
and then fast atmospheric transport spreads this haze far and
wide in a matter of a week over an entire subcontinent or an
ocean basin. My basic work is to use satellite measurements to
track these plumes and then launch aircraft to make detailed
measurements of their effects on climate.
In atmosphere, black carbon is mixed with other particles
such as sulfates, nitrates, and together the mix of manmade
particles are sometimes referred to as atmospheric brown
clouds, or ABCs.
First, touching on the global warming issue, BC is one of
the strongest absorbers as far as particles are concerned of
solar radiation in the atmosphere. My own estimates of BC
heating from observations is that the current solar warming
effect of BC is maybe as much as 60 percent of that current
CO2 greenhouse warming effect.
I want to point out that the estimates of the BC warming
effect are uncertain by a factor of three or more, as well as
our understanding of the emissions.
Now, digressing to the whole mix of particles, I want to
comment on the global water budget. These brown clouds lead to
large reductions in the amount of sunlight in the surface, and
we call it dimming, and the corresponding increase in the solar
heating. They both are two sides of the same coin. Together,
the ABC dimming leads to a weaker hydrological cycle and drying
of the planet, which connects ABCs, or atmospheric brown
clouds, directly to availability of fresh water.
Moving on to the regional climate impacts, the regional
effects of brown clouds are estimated to be particularly large
over Asia, Africa, and the Arctic. Since the dimming and
atmospheric heating are non-uniform in space and time, modern
studies have linked the black carbon effects on climate to the
Saharan drought, the decrease in monsoon rainfall over India,
and drying of modern China. These are all recent model studies.
A more recent study by my group employing unmanned aerial
vehicles [UAVs], shows from direct observations that black
carbon enhances atmospheric solar heating by about 50 percent.
This heating may have contributed as much as greenhouse warming
to the glacier retreat, which is a major, major issue for the
Asian region.
I want to comment next to last on the black carbon
reductions and its effect on global warming. I basically
consider this not as a mitigation in complete, more as buying
time, because the BC warming effect may offer an opportunity to
reduce the projected warming trends in the short term.
The lifetime of BC is about a few weeks, so its effect
would manifest almost immediately. The reduction of BC
emissions is also important to public health, and I defer to my
colleague, Dr. Schwartz, for that.
Let me proceed to understand, because of the uncertainty,
by a careful and well-documented, scientific study of the
impact of black carbon reduction. Toward this goal we have
teamed up with a team of NGO's and public health experts and
proposed a project in the Periyar PURA region in India where we
are going to adopt a large rural area with 20,000 population
and provide alternate cooking and biogas plans and measure the
impact of this on the atmosphere.
Last, I want to comment that the black carbon reduction is
not proposed as an alternative to CO2 reduction; at
best, it is a short-term measure to probably buy a decade or
two, time for implementing CO2 emission reduction
strategies.
The problem is highly uncertain, so I wanted to summarize
with what is it we have reasonable consensus on. First, the
lifetime of black carbon is about a few days to a few weeks is
generally agreed upon, and globally black carbon has a net
warming effect on the climate system, that is also generally
agreed. However, the magnitude of the current warming effect is
subject to a large uncertainty ranging from 15 percent to as
much as 60 percent of the warming effect of CO2.
Next also there is a consensus BC adds solar heating to the
atmosphere but causes dimming of the surface.
The fifth point--again, reasonable consensus--is
atmospheric brown clouds'--this is ABCs--own particles lead to
dimming of the surface, and the global average effect of this
is to decrease rainfall.
And the last point, which will be addressed by my
colleague--we have reasonable consensus on that--deposition of
BC on sea ice and snow darken the surface and leads to more
solar absorption and melting of sea ice and snow.
Prior confirmation is the regional effects of BC on shifts
in the rainfall patterns and the retreat of the Himalayan
glaciers. These need additional studies.
Thank you, Mr. Chairman.
[The prepared statement of Mr. Ramanathan follows:]
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Chairman Waxman. Thank you very much for your testimony.
Dr. Zender.
STATEMENT OF CHARLES ZENDER
Mr. Zender. Thank you Chairman Waxman, Mr. Davis, and
members and staff of the committee for hearing my testimony
regarding the effects of black carbon on Arctic climate.
The Arctic is warming about twice as rapidly as the rest of
Earth. Although long-lived, manmade greenhouse gases are the
dominant cause of Earth's recent warming, short-lived black
carbon particles explain a significant fraction of the observed
Arctic warming.
My colleagues have described what BC is, where it comes
from, and how effectively BC reductions could slow near-term
global warming. The four points most relevant to black carbon
in the Arctic are: First, that most Arctic black carbon comes
from fossil fuel combustion, not from open fires; second, black
carbon appears to warm the Arctic more than any other agent
except CO2; third, Arctic climate is very sensitive
to the surface warming of the type that black carbon causes;
fourth, reducing Arctic black carbon now will cool the planet
more than will a delayed reduction.
We know that economic and technological factors affect
Arctic black carbon concentrations. From 1880 to 1950,
industrial emissions increased black carbon concentrations in
Greenland's snow sevenfold relative to pre-industrial levels.
Black carbon concentrations in Greenland have been lower since
about 1950, likely due to North American shifts in combustion
fuels and technology, combined with wildfire suppression.
Black carbon decreased in some Arctic regions from the late
1980's and early 1990's during the decline of industrial
activity in the former Soviet Union. Late 20th century
increases in Greenland black carbon may be linked to increased
coal combustion in the rapidly expanding Asian economies.
There are three reasons why black carbon warms the Arctic
more than any agent except CO2. First, black carbon
absorbs sunlight and warms the Arctic atmosphere by
approximately the same amount as human injected CO2.
This happens in spring and summer when snow and ice are most
vulnerable to melting.
Second, black carbon also warms the Arctic, including in
winter, by thickening low-level clouds that then trap more of
Earth's emitted heat.
Finally, black carbon warms the Arctic after it lands on
the surface. Uniquely, surface black carbon is an impurity that
darkens the otherwise bright Arctic snow and ice, causing them
to absorb more sunlight. This dirty snow, seen in the picture,
warms and melts the Arctic's surface very efficiently, because
the heat is trapped at the surface by the strong Arctic
temperature inversions and by the insulating properties of the
snow, itself.
Over the course of the Arctic spring, black-carbon-
contaminated snow absorbs enough extra sunlight to melt
earlier, weeks earlier in some places, than clean snow.
Melting Arctic surfaces uncover the darker, underlying
surfaces such as tundra and ocean. These dark surfaces then
absorb even more sunlight, triggering a powerful climate
warming mechanism known as the ice-albedo feedback.
In the pre-industrial climate, black carbon was less
effective than wind-blown dust at triggering ice-albedo
warming, but, as shown in this slide, manmade greenhouse gases
have not only warmed the Arctic; they have exacerbated its
vulnerability to warming by other pollutants such as black
carbon.
The diagram shows that darkening of snow and ice by human-
injected black carbon has warmed the Arctic by about half a
degree centigrade since the pre-industrial era. Warm snow is
darker than cold snow, so the ability of a cleaner Arctic
surface to cool the planet will diminish as the Arctic warms.
Snow and ice retreat also weaken black carbon's leverage over
Arctic climate; hence, the diagram shows that reducing the
concentration of black carbon now will cool the Arctic
significantly more than a delayed reduction.
Nothing in climate is more aptly described as a tipping
point than the zero-degree centigrade boundary that separates
frozen from liquid water--the bright, reflective snow and ice
from the dark, heat-absorbing ocean. Arctic snow, glaciers, and
sea ice are, on average, about 1.5 degrees centigrade warmer
than in the pre-industrial era. This may not sound like a lot,
but each above-freezing day causes more melt, which amplifies
the strong Arctic warming effects.
Greenhouse gas and black-carbon-induced warming are
inexorably pushing more of the Arctic, earlier in the year,
toward its zero-degree centigrade tipping point.
In summary, because of its short life time and strong
effects, reducing Arctic black carbon concentrations sooner
rather than later is the most efficient way that we know of to
retard Arctic warming.
Thank you for your attention.
[The prepared statement of Mr. Zender follows:]
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Chairman Waxman. Thank you very much, Dr. Zender.
Dr. Schwartz.
STATEMENT OF JOEL SCHWARTZ
Mr. Schwartz. Thank you very much, Chairman Waxman, Mr.
Davis, members of the committee. I am pleased to be here to
talk to you about the health effects of black carbon, if I can
get my slides up.
Chairman Waxman. I want to congratulate all of you on the
successful slides that you have had available to you in your
presentation. It is very helpful to be able to follow the
slides and actually see them.
Mr. Schwartz. I want to start off by showing you what we
are talking about. Particulate air pollution is, in fact, the
only manmade object that is visible from space, and you can see
it here over Bangladesh and the Himalayas up in the north.
You have heard a lot about what those particles do when
they are up in the atmosphere in terms of absorbing heat, but I
want to point out that the highest concentration of those
particles is about at that altitude here where people breathe,
and so I want to talk about what we know about the health
effects of breathing those particles.
One of the things we know comes from the Harvard Six Cities
Study, and this has now been replicated in a bunch of other
cohort studies, and that is that breathing particles shortens
people's life expectancy, and by non-trivial amounts. This is
after controlling for hypertension, smoking, individual risk
factors. The life expectancy in six U.S. cities versus the
PM2.5 concentration--which is the total concentration of all
combustion particles, not just the black ones--you can see more
than a 2-year difference in life expectancy between the most-
polluted and the least-polluted of these U.S. cities.
Again, this has been seen in multiple studies.
What is most interesting is what we saw when we went back
to those cities and looked at another 10 years of followup in
this cohort of individuals we had been studying. That was that,
as air pollution levels declined in U.S. cities, the mortality
rates--not life expectancy, but mortality rates on the Y axis--
went down. And in the cities such as Stubenville with the ``S''
where there was a large drop in particle concentrations, there
was a large change in mortality rates, whereas in Topeka with
the ``T'' you can see a small drop in particle concentrations
and a small drop in mortality rates.
So not only do we see that particles shorten life; we see
that controlling particles results in a reduction in the
mortality rate relatively quickly. So just as we get the global
warming effects quickly, we get the mortality benefits quickly.
Now, again, this is talking about all combustion particles.
What do we know about black carbon in particular? Not nearly as
much, because we have only recently started to look at
different kinds of combustion particles. But there was a study
in the Netherlands where they estimated black carbon
concentrations outside the homes of people based on models they
fit using their monitoring data, and they also found that long-
term exposure to black carbon was associated with a shortened
life expectancy.
But what was interesting is the effect of the size that
they saw. The amount of shortening was bigger per unit
reduction in black carbon than what we saw per unit reduction
of all combustion particles, suggesting that these particles,
which in Europe and North America are predominately from
diesel, are more toxic than average. Getting rid of them has
more health benefits than average.
We did a study in eastern Massachusetts where we also put
out 83 monitoring stations around the Boston metropolitan area
measuring black carbon and developed a model to estimate the
variation in black carbon concentrations over space and time,
and then we got data on all the deaths in eastern
Massachusetts, and we geocoded everybody's addresses. Looking
at the people who died out-of-hospital, we found that, at the
75th percentile of black carbon concentration, 2.3 percent more
deaths per day occurred than at the 25th percentile of black
carbon concentrations.
Again, this is larger than what we see for all combustion
particles when we look at these short-term effects. And in this
study everyone was their own control. We looked at the black
carbon outside the address of the subject the day before they
died versus a week earlier when they didn't die. On average, it
was higher the day before they died. That is what drove those
results.
Since black carbon is expensive to measure but since it
predominately comes from traffic, there have also been studies
that have looked at traffic as a surrogate marker for this
exposure. So we looked at all of the confirmed cases of heart
attack in Worcester County over a period of a couple of years
based on a heart attack registry they have, and we did a case
control study with 5,000 cases and 10,000 controls. We found
that, again, going from the 25th to the 75th percentile,
traffic density within 100 meters of your house, increased your
risk of having a heart attack by 4 percent, and at the same
time controlling for that, every kilometer closer you lived to
a major highway increased your risk of a heart attack by
another 5 percent.
We followed people who had been admitted to the hospital
for heart failure, which is a growing disease in the United
States, and looked at their survival rate. We again found that
doubling the traffic within 100 meters of the home increased
their risk of dying in the next 5 years by 5 percent, and
doubling the distance to a bus route cut the risk by 3 percent,
so a significant contributor to mortality risks.
Now, that is in the United States, but, as you heard, most
of the black carbon emissions are actually coming from
developing countries, and what can we say about them?
First of all, heart disease is an increasing cause of death
in China and in India, and so increasing risks for those matter
to them, too.
Second, we did a randomized trial of people in Guatemala in
the highlands retrofitting a chimney stove into their homes
where they cooked without a chimney before and reducing their
exposure to all of this biomass soot. What we saw in adult
women in those homes was that doing that reduced their blood
pressure by about 3.5 millimeters of mercury. That is half as
much as you can get from giving people drugs to treat
hypertension.
So, as heart disease is a growing cause of death in the
developing world, there are opportunities there for them to
improve the health of their subjects and reduce mortality
substantially by doing things to control black carbon.
I would like to end by saying that the conundrum with
carbon dioxide control is that everyone gets to benefit, even
if you are the only one who pays. So we all want the other guy
to pay. But you only get the benefit of the health effects of
reduced exposure to black carbon if you are the one who reduces
the exposure, because these things occur locally.
So China and India are the ones that are going to reap the
health benefits of controlling black carbon in the future, and
I think that has great prospects for helping us to convince
them that it is time to act now.
Thank you.
[The prepared statement of Mr. Schwartz follows:]
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Chairman Waxman. Thank you very much.
I am going to start off the questions.
In 2002 the National Snow and Ice Data Center in Boulder,
CO, reported that summertime melting in the Arctic was at a
record level. If the Arctic sea ice continued to shrink at the
same rate, they predicted that the Arctic could be ice-free in
the summer of 2050.
In February of this year the Inter-Governmental Panel on
Climate Change confirmed this view, projecting that it was
possible that the Arctic could be ice free in summertime by the
latter part of this century. Many around the world were shocked
to think that we could see such a turn of events as soon as
2050, but then the summer of 2007 brought unexpected melting.
Arctic sea ice plummeted to the lowest level ever recorded,
shattering the previous record by nearly 25 percent. According
to the National Snow and Ice Data Center, sea ice may have
fallen by as much as 50 percent from the 1950's.
On October 1st the Center reported that the sea ice is in a
downward spiral and may have passed the point of no return. As
a years go by, we are losing more and more ice in summer and
growing back less and less in winter.
The Center went on to say that the Arctic Ocean could be
ice-free in summer as soon as 2030. According to some
scientists, we may lose the Arctic sea ice even sooner than
that.
Dr. Zender, you testified that the Arctic is warming about
twice as rapidly as the rest of the Earth. Can you tell us if
we need to be concerned about what is happening in the Arctic?
And also how important is black carbon in what is happening in
the Arctic?
Mr. Zender. Well, certainly the recent trends in Arctic sea
ice extent are quite troubling. As you mentioned, the long-term
trend until the last 1 or 2 years was about 8 percent per
decade. With this year's record retreat, there is 23 percent
less sea ice in the arctic than there was in 2005, the year of
the previous record low.
What is troubling about these trends is that they are in
agreement with model predictions that predict a steady decline
followed by an abrupt tipping point, or complete disappearance
of summertime Arctic sea ice.
The disappearance of summertime Arctic sea ice would be
hard to imagine. It would be difficult to imagine a plausible
mechanism to restore that sea ice in the future. Melting of
Arctic ice surfaces is what you might call a wet process. It
can occur very quickly. Ice can slide into the ocean very
quickly, whereas restoration of such ice, sea ice, and glaciers
is a slow, dry process that takes an order of magnitude longer
to occur.
Conservative estimates which placed summertime ice-free
Arctic in about the year 2040 a few years ago have reevaluated
their findings. Many scientists think that an ice-free Arctic
could occur much sooner, perhaps as quickly as 20 years.
I think the overall concern that is unique to the Arctic
about warming is that when ice on land--not sea ice, but ice on
land--melts, it contributes directly and immediately to sea
level rise. Sea level rise is, of course, something that
affects everyone worldwide who lives near the coast.
Chairman Waxman. The ice, if it melts in the water, would
not contribute to the increasing ocean levels?
Mr. Zender. That is true; however, the ice that melts in
the water does have an effect on the ocean circulation. By
melting the sea ice, we then uncover the underlying ocean,
which warms up. One of the critical areas in the Arctic that we
are worried about is the temperature of the ocean near the
Northern Hemisphere's greatest ice sheet, Greenland. Warming
ice near Greenland could reduce the buttressing that the sea
ice shelves have, which maintain the land glaciers that drain
Greenland ice. If those buttresses disappear, then Greenland's
ice balance will quickly turn more negative.
Chairman Waxman. Let me ask Dr. Jacobson, you testified
that because of black carbon's short lifetime in the
atmosphere, a reduction in its emissions can result in rapid
climate benefits. If we want to forestall the warming we are
seeing happen in the Arctic, is reducing black carbon part of
the solution? And would we be able to achieve results as
quickly by focusing solely on carbon dioxide?
Mr. Jacobson. Yes, it is part of the solution. I think, as
I mentioned in my testimony, the global contribution to global
warming by black carbon from fossil fuel and biofuel sources is
about 16 percent or so, and on a global scale. So
theoretically, if you reduce all the black carbon worldwide
from those sources, you could have a fast impact on reducing
maybe proportionately not quite that number in the Arctic.
In the United States's case, U.S.'s contribution is about 6
percent, so there is less of an impact on average.
Of course, it depends on the effect of the Arctic countries
that are responsible for the warming from black carbon, and it
is not easy to tell, but the United States is a portion, and
then there is Europe, and then there is Russia, and there is
Southeast Asia and other parts of Asia that are contributing.
But we have definitely got a beneficial impact by
controlling in the U.S. black carbon. It is not going to be a
huge impact. You have to control the CO2
simultaneously to ensure long-term stability of the Arctic, but
you can get an immediate feedback, so there is a benefit.
Chairman Waxman. CO2 control is not going to be
sufficient alone?
Mr. Jacobson. Definitely not in the short term, because,
because of the long lifetime of CO2, the warming
that is occurring in the atmosphere due to CO2, even
if we eliminated all emissions today of CO2,
anthropogenic emissions, you are not going to see the feedback
on the global climate system for many years to decades to come.
We will see a little bit incrementally, but if you control all
the CO2 emissions today compared to all the black
carbon emissions--and there is a lot more CO2
emitted--it would take at least 10 years before CO2
effects outpace the black carbon effects on this climate
impact. So it is faster cooling if you control the black carbon
compared to the CO2; however, you want to do both
simultaneously.
Chairman Waxman. Yes. Dr. Bond, you worked to understand
the sources of black carbon. Can you tell us if we know which
sources we need to control if we want to reduce the presence of
black carbon in the Arctic?
Ms. Bond. There have been studies done that suggest that
about a third of the black carbon is from the United States and
Europe, and about a third is from the developing world,
especially in south and east Asia, and about a third is from
arboreal forests. Now, these are still uncertain, but those
give you the biggest contributors.
I believe that we know the sources in each of those
regions. In the developed countries, as I mentioned during my
testimony, a lot of it is from transportation, including both
on-road and off-road mobile sources. Both the United States and
Europe have taken action to reduce emissions from these
sources, which means that they will be coming down in the near
future, but it also means that there is experience in
regulating those kinds of sources and in being successful at
bringing the emissions down.
There are also measures to reduce emissions from solid fuel
combustion in developing countries and, as well, from
industrial combustion.
Those are the two major industrial type of sources that can
be reduced. I don't think that we have a clear understanding of
how to reduce black carbon from open biomass burning,
especially remote forest burning. Some of those options have
been looked at in terms of cost and they turn out to be
extremely expensive, so I would say that the transportation and
residential solid fuels would be the place to look first.
Chairman Waxman. Thank you.
Mr. Davis.
Mr. Davis of Virginia. Thank you very much, Mr. Chairman. I
want to thank the panel.
Now, Europeans have really moved to diesel, haven't they,
which is worse for black carbon; is that correct? And so they
may be ahead of us in some ways and kind of behind. Is there
any thought there of scrubbing this and moving to something
else?
Mr. Jacobson. The Europeans, about 40 to 50 percent of all
the passenger vehicles sold are diesel. They emit a lot more
NOx. A diesel vehicle emits a lot more oxides of
nitrogen, maybe ten times more than a gasoline vehicle. Also,
without a control device, a huge amount more, a factor of 5 to
10 more particulate matter----
Mr. Davis of Virginia. You can see it in a diesel.
Mr. Jacobson. Yes. And so a lot of the new cars now, they
put particle traps on a lot of the new cars, but even with the
particle trap, the particle trap decreases the mileage of the
diesel by about 3 to 8 percent, so that means more
CO2 emissions, so there is a tradeoff. By reducing
the particles, you increase the CO2 emissions from
the vehicles, but also you also change this ratio in the
exhaust of the NO2 to NO.
In the United States, what that does is NO2 is a
precursor to ozone in smog. In the United States that really
produces smog right out of tailpipe. In Europe, where it is a
little higher latitude, it is not so much. But in the United
States we did a study looking what the effect would be, and you
increase on average ozone over the United States by adding a
trap to new diesel vehicles.
Mr. Davis of Virginia. Let me ask, I don't know who is best
able to answer this, but what happens to black carbon once it
has reached its life span? Does it just disappear? Does it
settle on ice and continue to trap heat? Does it settle but
stop conducting heat? What happens? What is the life span?
Mr. Jacobson. Most of it is removed by precipitation and
most of it will go over the ocean. Now, the stuff that settles
onto snow, that will have a longer impact if it settles onto
snow or sea ice because it sits there for a while until it gets
buried or it sinks or is covered up by more snow, but even that
more snow will have some black carbon. So most of it is removed
to the oceans eventually, and a lot of it will deposit to the
surface, too, in rain or in just some deposition to the
surface. That stuff, because the surface is soil or blacktop or
whatever it is, it is not going to have much of an impact there
except maybe if it goes over sand in the desert.
Mr. Davis of Virginia. Dr. Ramanathan, let me ask you what
percentage of the melting ice sheets in the arctic can you
attribute to the black carbon? Is it hard to put a percentage
on it?
Mr. Ramanathan. I have not by myself estimated the Arctic
part. I think that is what Dr. Zender was talking about. But
the key thing is in the Arctic, as I think was the point, the
transport comes from all directions. Some comes from east Asia.
We track these. Some comes from North America and eastern
Europe, so all these sources are contributing to that.
The one issue I want to point out which has not come up is
that with the sea ice retreating, there are no talks about new
ships traveling through the open water, and ships are a major
source for black carbon. I am concerned that now there is going
to be an additional source of black carbon directly depositing
and facilitating more ship traffic. That is an issue that has
not come up yet and we need to worry about that, too.
Mr. Davis of Virginia. Let me ask Dr. Bond what respective
roles should the developing and the under-developed nations
play in mitigating the emissions of black carbon? What I am
trying to say is, Was it a mistake not to include that in the
Kyoto Protocol?
Ms. Bond. Was it a mistake? No. The Kyoto Protocol was a
first step. It was never meant to be the ultimate solution.
Mr. Davis of Virginia. The end all. Yes.
Ms. Bond. So I am not going to comment on what we should
have done in the Kyoto Protocol. What matters is what we can do
now and next. I don't believe that we can reduce black carbon
impacts on the global atmosphere without the cooperation of
developing countries, but I think that all of this is
consistent with the Framework Convention on Climate Change,
which refers to differentiated responsibilities between
developed and developing countries.
Mr. Davis of Virginia. Sure.
Mr. Ramanathan. I think we have to remember that close to
80 percent of the black carbon emission comes from developing
nations.
Mr. Davis of Virginia. Right.
Mr. Ramanathan. Asia, Africa, Latin America. Because of the
impact of the black carbon on the local and regional climate
and the glacier retreat, my own experience with India and China
is there is tremendous interest in focusing on the air
pollution issues.
Mr. Davis of Virginia. Yes. I have been to Shihon in China
where people have to wear masks over their faces. That is the
health issues that you addressed earlier, in addition to the
global warming. But the polar caps, how much of this stuff
finds its way up there? Obviously, you are talking about the
steamships and planes, but is there that much other stuff up
there that is generating the black carbon at the polar caps?
Mr. Ramanathan. I will defer to others.
Mr. Zender. The concentrations of black carbon in the
Arctic are relatively low relative to the developing world
where the sources are. The problem in the Arctic is that this
black carbon has essentially a double or even triple lifetime.
Because the Arctic is so very bright, as you know, the sunlight
that it can absorb has two chances to be absorbed by it: on its
way down, and on its way back up being reflected from the ice
sheets. But then that third lifetime that I mentioned is once
it lands on the surface a very, very small concentration of
black carbon--we are talking parts per billion----
Mr. Davis of Virginia. It is just more potent there,
basically? Is that what you are saying?
Mr. Zender. It is just more potent. It is the most potent
warming agent we know of in the Arctic.
Mr. Davis of Virginia. OK. So it may not be significant in
terms of its volume compared to other places, but it just has a
more potent effect there?
Mr. Zender. That is right. The exposure to inhaled black
carbon is very low in the Arctic; it is the atmospheric and
surface effects and their consequences on climate that are of
the most immediate concern, I think.
Mr. Davis of Virginia. Now, the sources for black carbon
for the developed world are basically different from the
developing world? For example, in Africa you have wood-burning
stoves, we are cutting down and burning trees, and it may be
diesel in Europe. Is that fair to say?
Ms. Bond. It is fair. It is a different mix. We still have
fireplaces here.
Mr. Davis of Virginia. Right.
Ms. Bond. So it is not completely different, but for the
most part this country and Europe has the benefit of access to
clean household energy, but we have a lot of transport. We have
a lot more transport because we have more goods. So there is a
different mix, and if you----
Mr. Davis of Virginia. So if you fly a private plane
somewhere, you are creating more black carbon, basically?
Ms. Bond. That is true.
Mr. Davis of Virginia. As opposed to flying coach or first
class or something somewhere else, I mean, just to get into it.
Yes.
If we make these technologies available to the developing
world, are they available now and just not economic? I mean,
what is the issue? I know in China we talked about Shihon. In
Beijing we were there and didn't see the sky for 3 days, the
smog was so bad. I mean, you would think over there if you make
these technologies available somebody would do something about
it. What is the problem?
Mr. Ramanathan. I can comment on rural regions of India.
Mr. Davis of Virginia. OK. India is fine.
Mr. Ramanathan. Major source of biofuel. The government has
connections to gas, natural gas, for cooking, but they can't
afford it, so it is in some parts technology and others just
sheer affordability of it.
Mr. Davis of Virginia. When you said that you meant natural
gas or propane. Propane in the Third World is the preferable
choice if available.
Mr. Ramanathan. This is methane, not propane.
Mr. Davis of Virginia. Thank you, Mr. Chairman.
Chairman Waxman. Thank you, Mr. Davis.
Mr. Cummings.
Mr. Cummings. Thank you very much, Mr. Chairman.
Each of the witnesses today have emphasized that there are
opportunities for mitigating emissions of black carbon. It
seems that if we could reduce emissions of black carbon we
could potentially realize significant climate benefits.
Dr. Jacobson, what is your advice to us as we begin to
explore controls of black carbon emissions?
Mr. Jacobson. Sir, there is the direct way of reducing
emissions, which is adding particle traps to vehicles. In the
United States, it is the off-road vehicles that are creating
the most emissions, the construction machines.
Mr. Cummings. The adding particle traps, is that a very
expensive venture?
Mr. Jacobson. I don't know the exact cost. The number I
heard per tractor was $3,000, maybe to $5,000 or $6,000 if it
is a big tractor, but that was a few years ago. I don't know.
Tami might now.
Mr. Schwartz. You know, for a bus or for a typical sized
piece of construction equipment it is a couple of thousand
dollars to add these things, but then they last for a long
time. That is a capital cost.
Mr. Cummings. When you say cost, you mean perhaps the life
of the bus or the tractor?
Mr. Schwartz. Yes. Or at least a good fraction of the life.
The thing is that the new rules the U.S. EPA put out and the
new Euro Five standards for diesel engines are only for new
diesel engines. There is no retrofit requirement. That is where
the opportunity is. There is an opportunity to retrofit it on
existing engines, because diesel engines often last for 30
years.
Mr. Cummings. Yes.
Mr. Schwartz. That has been done. In London they
retrofitted all 6,000 London buses with particle traps in 2
years. In Massachusetts they are going to retrofit all the
municipal and school buses in a 3-year period. There are
retrofit kits commercially for sale, and it is definitely a
doable thing.
Mr. Jacobson. But let me caution. That is an immediate
step, but there are these unintended consequences, like the
lower mileage, and therefore the higher CO2
emissions resulting from those traps, and also the change in
the NO2 to NO ratio, which affects the ozone. This
is particularly important for these big vehicles, the trucks
especially that are replaced with traps. There you get the
highest ratio of NO2 to NO, which would exacerbate
the smog the most.
But I think even a better maybe--I don't know if it is a
short-or long-term--solution is really if you want to control
both the soot and the CO2 simultaneously and the
other air pollutants coming from these vehicles, it is really
to switch your vehicle types to electric, plug-in hybrids,
hydrogen fuel cell vehicles, because these all can eliminate
simultaneously your CO2, your black carbon, your
ozone precursors, and the ozone and the particulates are the
ones that cause most of the health problems, particulates even
more.
So you can really solve the whole problem by really
focusing on these different types of vehicles rather than
trying to incrementally improve just the emissions of the black
carbon or reduce the black carbon.
Mr. Cummings. Dr. Schwartz, you look like you are trying to
jump out your seat. Did you want to say something?
Mr. Schwartz. Well, I agree that in the long term that is
the way to go, but I need to point out that there are retrofit
kits, particle traps and particle filters, that can be put on
vehicles tomorrow, and that hydrogen fuel cell-powered or all-
electric garbage trucks aren't going to be here for quite a
while, and so there is an opportunity to have a staged strategy
where we do something for the existing fleet with the
commercially available technology that can be implemented in a
couple of years, while developing the new vehicles that replace
those vehicles when they come to the end of their lifetime.
Mr. Cummings. OK.
Dr. Ramanathan, you have studied emissions in Asia. What
can you tell us about the mitigation opportunities there?
Mr. Ramanathan. It is my personal view there are huge
opportunities in terms of trying to mitigate the global warming
potential. When you talk about Arctic, all these discussions
are germane, but when you want to reduce the global warming,
potential black carbon----
Mr. Cummings. Can you keep your voice up?
Mr. Ramanathan. When you want to reduce the global warming
potential of black carbon, your focus has to be on Asia and
Africa and Latin America, because that is where the main
sources are.
Although not an economist, I would venture to speculate it
would be a lot cheaper to try to mitigate black carbon emission
in Asia, particularly India and China in the major focus. For
example, the biofuel emissions, cooking with wood and cow dung
is at least 50 percent of the total emission of black carbon
from south Asia. Replacing those cookers with solar cookers or
biogas plans, the relative cost we have to estimate. That is
what we are trying to do. But I think that is where the huge
potential is there, the emission of black carbon, coal-fired
appliance in China and biofuels in India and Africa.
This is a major vulnerable region. I wish I brought
substance abuse. You will see huge plumes covering most of
central Africa from the savannah burning. That is where I see
major opportunities.
Mr. Cummings. Thank you.
Chairman Waxman. Thank you, Mr. Cummings.
Mr. Bilbray.
Mr. Bilbray. Thank you, Mr. Chairman.
Dr. Schwartz, I have been sort of out of the business, the
air resources business, for a while, so if you can give me a
crash refresher course, when you were talking about the
morbidity related to diesel emissions, referring specifically
to the particulates, I didn't hear you discuss what we ran into
at the Air Resources Board in California, which was that the
true toxic component was the benzene, and that the particulate
was tending to be the carrying agent. Is the benzene still
considered the most toxic component in the diesel emission?
Mr. Schwartz. Well, there is actually more benzene in the
exhaust from gasoline vehicles than from diesel vehicles,
because aromatics tend to have too much octane, and you don't
want octane in a diesel engine, unlike in a gasoline engine,
and so you tend in a refinery to segregate the aromatics more
to the gasoline. But there is certainly benzene in diesel
exhaust, and if you are talking about cancer, then that is
where the action is for sure.
But these deaths that we are looking at are deaths from
heart disease, and that doesn't seem to be related to the
benzene. It seems to be related to something about----
Mr. Bilbray. So yours was specifically to cardiovascular?
Mr. Schwartz. To cardiovascular mortality, and that really
seems to be the particles.
Now, that said, it may well be that it is something that is
carried by these particles other than benzene, like metals or
some other things.
Mr. Bilbray. We found that. I mean, all the talking back in
the 1970's was about dioxins. We found that the benzene in the
diesel trucks was like a magnitude of 10 to 20 over the
toxicity of certain dioxins and whatever, and so all at once we
were realizing that to reduce health exposure we weren't doing
waste incineration. We were sending around three trucks to
recycle materials, and the health impacts were a net negative
rather than a net positive.
When you did your modeling for morbidity, did you consider
socio-economic numbers?
Mr. Schwartz. Yes, we controlled for socio-economics.
Mr. Bilbray. I mean, let's face it, the whole difference in
places like Pittsburgh in 20 years going from a coal/steel
industry to a high-tech industry, you do have a major jump
between socio-economic, and that----
Mr. Schwartz. And when you are talking about exposure to
traffic, you have to remember the people who live on heavily
trafficked streets tend to be poorer than the people who live
in the nice houses.
Mr. Bilbray. And people who are poor tend to have certain
exposures.
Mr. Schwartz. Absolutely. So, for example, in our study we
had individual education for each of the people who died, and
then we had census block group measures of socio-economic
status we also controlled for.
Mr. Bilbray. Yes. The scrubber issue when I was working
with Mexico on Mexico City and we worked with Athens reducing
their emissions, they went through the scrubber originally, but
the natural gas conversion seemed to be the much cleaner
quantum leap sort of between where Mr. Jacobson is and where
you are with the scrubber of being able to use natural gas as
the major source but only using diesel as the igniter. Is there
an environmental problem with shifting off actually from being
your major source of fuel for these mobile sources from diesel
over to natural gas?
Mr. Schwartz. To my knowledge there isn't an environmental
problem. Running buses on natural gas produces considerably
less particles than running buses on diesel with a particle
trap, so the natural gas conversion certainly would make sense.
It makes more economic sense on fleets of vehicles that operate
around the city and then come back to a terminal every day,
either buses or trucks and things where they can fill up with
the natural gas, than on the long-haul trucks where it is not
always easy to find a source of fuel.
Mr. Bilbray. Where infrastructure is there.
Mr. Schwartz. Where the infrastructure is easy to put in.
Exactly.
Mr. Bilbray. I appreciate that.
Dr. Jacobson, the discussion of the transition in
California, we were looking at the zero emission generators.
California, we went to natural gas with our stationary sources
because it was the only way to pencil out a lot of this
generation within our air basins. The question is: the low-
lying fruit is going to be--correct me if I am wrong--has
always been stationary sources are always the place we can get
the most bang for the buck. I mean, if there was any place
historically we have been able to reduce substantially
emissions with much more cost-effectiveness, stationary sources
have been that, hasn't it?
Mr. Jacobson. Well, yes. Historically in California most of
the electricity is natural gas. We don't have much coal. We
have a lot of hydroelectric.
Mr. Bilbray. Let me correct you, sir. You burn coal in
California air basins, you go to prison.
Mr. Jacobson. Right. Yes. There is very little coal.
Mr. Bilbray. Our concept is clean coal is about as logical
as safe cigarettes.
Mr. Jacobson. Right. But there is emissions from natural
gas, but in California there is room for more renewable energy,
of course. That may not be in the question, but we did mapping
of winds offshore locations where you get really strong winds,
and you can combine wind with hydroelectric, geothermal, and
solar and you can power the entire State just about with the
available resources.
Mr. Bilbray. I just want to warn you, we got that issue,
and transmission becomes a hot issue.
Mr. Jacobson. That is the limiting factor, and that is
actually why you kind of need maybe a national grid.
Mr. Bilbray. But I agree with you. I think the big thing
that California is going to have to confront is stop using
natural gas as your stationary source because it will probably
be our transition fuel between what you are talking about and
what you are talking about, and we are burning it at power
plants rather than using it for our off-road, which is now the
big challenge, as Mr. Waxman knows, in California, cracking
down on those off-road emissions.
Thank you very much, Mr. Chairman.
Chairman Waxman. Thank you, Mr. Bilbray.
Ms. McCollum.
Ms. McCollum. Thank you, Mr. Chair.
This is a very interesting discussion, and I want to thank
Mr. Waxman for having it.
Dr. Schwartz, I was feeling pretty good about turning off
the air conditioner, leaving the windows open on a main street
in D.C. where I hear a lot of trucks, and I know I have a lot
of soot because I have to clean here more than I have to clean
in the city of St. Paul, MN, so my trying to save burning
fossil fuels running an air conditioner might lead to my
increased risk of a heart attack, so thank you very much for
not making me feel much better about my decision.
Mr. Schwartz. Unfortunately, turning on the air conditioner
and closing your windows cuts the particle concentrations
coming into your house from outside in half.
Ms. McCollum. And I point that out because this isn't a
one-fix solution; this is going to take a lot of different
scientists such as yourself sitting around the table and a lot
of different people willing to look at different ways and to
change their lifestyle, and businesses in the way that they
operate in order to really tackle this. This is, like I said, a
very interesting discussion, and I thank the Chair for having
it.
In Minnesota we decided to retrofit our school buses--we
are calling it Project Green Fleet--to do what we could to
reduce the amount of carbon. Has there been any studies done,
for example, if all the school districts were to retrofit, what
kind of impact it could have? Would that be a model that we
could look at to maybe figure out some targeted ways where we
could start doing things and also get the word out?
Mr. Schwartz. I don't know of any studies that have looked
at what the impact of just targeting school bus fleets are. I
think that it is such a small fraction of the diesel fuel use
in a given city that you are not going to see very much if you
just go after the school buses as opposed to the construction
equipment and the heavy duty trucks and all the other things,
as well.
Ms. McCollum. But sometimes the way to address the problem
is to get people to realize that there is a problem and to
start talking about it.
Mr. Schwartz. That is absolutely true, and there have been
retrofit programs, and EPA funds some retrofit programs to go
after school buses. One thing that we can do that is a double
winner is all the buses you see lined up on Independence Avenue
idling for 3 hours while the people that they drove to the
museum are inside, if you just turn off the engines of buses
when you are not actually driving some place then you save the
CO2 and the carbon and all sorts of other stuff. So
awareness would be useful.
Ms. McCollum. We have done that, as well, in Minnesota, to
turn the buses off.
Mr. Schwartz. That is good.
Ms. McCollum. The developing world discussion is very
interesting. I have had a fortune of traveling both in Asia and
in Africa. It seems to me that we need to look at doing
something similar to what we did with ozone with the Montreal
Protocol on this.
Dr. Ramanathan, you have done a fabulous amount of work on
this. Can you share with this committee--I also serve on State
and Foreign Operations Appropriations--what we can do in
working with partner countries to help them reduce their health
effects and carbon?
Mr. Ramanathan. Thank you very much for that question.
I first of all would preface it, there is one thing we have
to be aware of. This outdoor haze or this pollution contains
partially black carbon, other particles, sulfates, nitrates,
etc. These are all cooling particles. The black carbon is
heating. When you add all of them together, they have massed as
much as 50 of the global warming from greenhouse gases. What
that means is that we have to be careful when we reduce those
particulates.
See, the EPA, not only in the United States, but the EPAs
of the world, they are focusing on air pollution. Traditionally
when there is air pollution, it is sulfates. For example, I see
in American media we complain about sulfate emissions from
China. The problem is if you cut the sulfates and leave the
black carbon behind, we can have at least a factor of two
amplification in the warming what we will see just from air
pollution regulations, because you are taking off the cooling
particles.
So we have to make sure. I am not saying we should leave
the sulfates behind. They have other ecosystem destruction. But
we should make sure when we remove the sulfates we also remove
the black carbon. That is No. 1 point.
In fact, Dr. Schwartz and I were in a big intercontinental
air pollution meeting in Australia. We tried to bring it up. We
tried to educate the air pollution community. Be careful. What
you do has implications for climate change.
The second point I want to make is that again I don't want
to be misunderstood. We have to cut down sulfate emissions
because of acid rain and others, but please let's take out the
black carbon at the same time because the sulfates, if any, is
shielding the planet from the global warming.
The second is the black carbon emission. I was in a meeting
last week where the Prime Minister was there, the finance
minister, as well as Mr. Jeb Bush, former Governor of Florida.
I was surprised how receptive they were when I talked about
what the black carbon, haze, is doing to the regional climate
and glaciers. As you know, China is now trying to reduce the
emissions in Beijing just before the Olympic, and some of us
are thinking this is a fantastic natural experiment to see
downwind what happens.
For example, we published a study last year: 75 percent of
the black carbon over the west coast of the United States
during springtime comes from long-range transport from east
Asia. So we are trying to see do we see an impact on air
pollution just for this 1-month period.
Although I have not moved in government circles, my
assumption is that they would be very receptive to United
States and European governments trying to approach India and
China on this issue and see how collaborations and resource
sharing would help them bring down the black carbon emission.
Chairman Waxman. Dr. Bond, did you want to comment?
Ms. Bond. I did, if you would allow me to.
Chairman Waxman. Sure.
Ms. Bond. I would like to point out that there is already
collaboration between governments. At the Sustainable
Development Meeting in Johannesburg, the United States and
other countries initiated the Partnership for Clean Indoor Air.
Now, this was not a climate or outdoor air protection
committee; it was a group of organizations that now numbers
about 150 NGO's and government organizations internationally,
and they are working on the problem of household energy and
solid fuels. That is something that has already been started.
Now, the climate benefits have not really been brought into
that picture, but they are very receptive.
Chairman Waxman. Thank you, Ms. McCollum.
Mr. Shays.
Mr. Shays. Thank you. Mr. Chairman, really thank you so
much for holding this hearing. It is rare when we have all
doctors coming before us, so when I say ``doctor'' I will now
have to use a name.
I would first like to ask Dr. Bond if you would turn to
page 4. I am trying to understand where liquified LNG plants--
there is a real effort to bring LNG into the United States, and
it is somewhat controversial, particularly on Long Island
Sound, and I have taken a position against it and others have,
but I begin to wonder. We are at the end of the pipeline. Am I
just making a bad decision here or not?
Liquified natural gas, just explain this middle chart to
me, page 4. ``Energy increases faster than BC due to advances
in technology.''
First you describe different types--biofuel, coal, oil,
Middle East, light, distilled, aviation fuel, natural gas.
Ms. Bond. OK. Let me understand what you are trying to----
Mr. Shays. First explain this chart to me.
Ms. Bond. That chart is the global consumption of energy by
fuel.
Mr. Shays. OK.
Ms. Bond. In history.
Mr. Shays. Now explain to me, in terms of black carbon, is
liquified natural gas a less sooty, more sooty, indifferent?
Ms. Bond. Much less.
Mr. Shays. Much less.
Ms. Bond. Certainly. And the point of that figure was that
it is both improved technology and cleaner fuels that have
contributed to black carbon. This slower increase in black
carbon emissions, if black carbon emissions went up as quickly
as energy did over the last 50 years, we would not be able to
breathe.
Mr. Shays. OK. Let me ask you this. In my house I have gas
coming in. I now have a heating system that they don't want it
to exhaust up through the chimney; they put it through the side
of the house. Could they do that with oil as well, or is it
more likely they can do it with gas?
Ms. Bond. Gas burns a lot cleaner than oil.
Mr. Shays. Right.
Ms. Bond. Especially during the transient periods where the
furnace is turning on and off.
Mr. Shays. Thank you very much.
Dr. Ramanathan, would you explain to me the charges on
eight? It looks like the United States is not that bad a player
compared to others in the charts, these charts up top here. I
am on page 8.
Mr. Ramanathan. Yes.
Mr. Shays. Explain those charts to me, if you would.
Mr. Ramanathan. Right. This is basically using most recent
satellite measurements which give information about
particulates, and look at the total loading of particulates in
the atmosphere.
Mr. Shays. And red would be the worst case?
Mr. Ramanathan. Red is worse. By the time you have seen
those charts green to yellow, you would already see the haze in
the sky as brown clouds.
Mr. Shays. So is that the soot blowing off our coast?
Mr. Ramanathan. Thank you. What you see of the east coast,
this is just not only soot, it is all particulates--sulfates,
nitrates. That is why we call them brown cloud.
Mr. Shays. All particulates. But basically it is in the air
blowing from the United States?
Mr. Ramanathan. Right. And you see that stream is all the
coal plants in the east coast just going across the Atlantic.
Mr. Shays. OK. And then in China and in India we just see a
mass of red.
Mr. Ramanathan. Exactly.
Mr. Shays. And it is all coal?
Mr. Ramanathan. And also I direct your attention to Africa,
the savannah burning.
Mr. Shays. Yes. Now, this is not in defense of the
administration, but it is wanting to understand something. They
are doing a lot of bilateral agreements with various countries.
The United States was told be part of Kyoto, in spite of the
fact that China and India were not. They were told, you know,
just be part of the family. If you can't meet it, at least you
are part of the team.
But my understanding is the United States has done, in
comparison to Europe, not as bad as people would think. That is
kind of a negative way to say it, but actually we keep making
some improvement. Is Europe making a lot more improvement
versus the United States in global warming issues and
particulates? Any of you can answer that, if that is all right.
Mr. Ramanathan. I think as far as the particulates are
concerned, Europe versus the United States, I have the expert
here. I would rather let Dr. Tami Bond respond to that.
Ms. Bond. Are you talking about all global warming
emissions?
Mr. Shays. Yes. Let's do that first.
Ms. Bond. I am not sure I have the background to answer
that, because I haven't really looked at energy intensity in
Europe or the United States.
Mr. Shays. Dr. Jacobson.
Mr. Jacobson. I will try. I think, in terms of air
pollution, the United States has really been in the forefront,
especially California. I mean, California is really the leader
in the world.
Mr. Shays. Mr. Waxman's State?
Mr. Jacobson. Yes.
Mr. Shays. OK.
Mr. Jacobson. Yes, in terms of air pollution control.
Chairman Waxman. As opposed to any other California.
Mr. Jacobson. I am not biased.
Mr. Schwartz. If I could add to that, if you look at the
particle concentrations in urban areas, they are lower in the
United States than they are in Europe. Part of that is because
of their emphasis on diesel engines, in fact, but not entirely.
We have stricter standards on particle emissions in the United
States than Europe.
Mr. Shays. Can I ask one last question, Mr. Chairman?
Chairman Waxman. Sure.
Mr. Shays. I live in an urban area. We have Indonesian
ships that come out way off coast. They transport the coal on
the barge and bring it in to a facility three-quarters of a
mile from my house, maybe a mile from my house. Should I prefer
that they burn--I think I know the answer--the so-called less-
sulfur coal, or liquified natural gas?
Mr. Schwartz. You are going to get less CO2
emission per unit of electricity generated and less particulate
and sulfate emissions per unit of electricity generated burning
liquified natural gas than burning coal, even low-sulfur coal.
Mr. Shays. Thank you.
Mr. Jacobson. Can I comment on that? In Long Island there
was a proposed wind farm offshore, and that would obviously be
better than the other two.
Mr. Shays. Absolutely. Absolutely, but are they mutually
exclusive? That is the question we have to ask.
Mr. Jacobson. Yes.
Mr. Shays. Yes. Thank you very much. Thank you again, Mr.
Chairman.
Chairman Waxman. Thank you, Mr. Shays.
Mr. Hodes.
Mr. Hodes. Thank you, Mr. Chairman. Thank you for having
this very important panel. I want to thank the panel for being
here today.
I want to focus first on black carbon international
agreements. There has been some mention here, but as I
understand it black carbon is not explicitly covered by
international environmental agreements. Now, black carbon
doesn't deplete the ozone layer, so it isn't covered by the
Montreal Protocol. And black carbon isn't technically a
greenhouse gas, so it is not covered by the United Nations
Framework Convention on Climate Change. And the Kyoto Protocol
requires the developed world to reduce its emissions of certain
greenhouse gases, but the protocol doesn't include black
carbon.
Given the depth of the problem which you have now
graphically outlined for us, as we engage in new negotiations
aiming toward the possibility of future international
agreements that will succeed the Kyoto Protocol, should we be
seeking to include black carbon in the agreement or agreements
that hopefully we will participate in? I can start with Dr.
Jacobson, and then anybody else on the panel. I would be
interested in hearing your thoughts.
Mr. Jacobson. I definitely think we should. Even though the
United States' portion of the black carbon emissions is on the
order of 6 percent--not the largest--it is a good example to
set for the rest of the world. I strongly feel we should
include it, because we know it is a warming agent, and, as you
mentioned, it is not being controlled internationally, so it
will have dual benefits of health and climate, and I think it
should be controlled.
Mr. Hodes. Dr. Bond.
Ms. Bond. First of all, I agree with Dr. Jacobson, not just
because we want to control all the warming agents, but I think
we really want to look at what we are doing when we undertake
specific actions. And, as Dr. Jacobson has shown, you can
decrease carbon dioxide and increase warming if you don't
consider the black carbon. So I think we should at least be
comprehensive.
Second, I don't agree that black carbon is not in the
Framework Convention. I would say it is not part of the
objective, which refers to stabilization of greenhouse gases.
We don't really want to stabilize black carbon anyway. However,
the Framework Convention does say that we should be
comprehensive and that we should consider all sources, and
sources include aerosols in their definition. So I don't think
that what we are talking about is inconsistent, and I do think
that future agreements could be conducted under that
convention.
Mr. Hodes. Could I just clarify for one moment? I
appreciate the clarification, but it sounds like we need to be
more specific about including black carbon as one of those
sources which is of concern and not leave it perhaps to the
generalized framework that you referred to. Do you agree?
Ms. Bond. I would agree with that. At the time the
Framework Convention was written, this issue was not anywhere
on the radar screen.
Mr. Hodes. Great. Thank you.
Mr. Ramanathan. I participated in the Intergovernmental
Panel on Climate Change. In addition, I run a United Nations
environmental program called Atmospheric Brown Clouds focused
on Asia. We have all the nations participating in this
research, and I can give you a flavor of what Asians think
about. We have Chinese. We have Indians. We have Koreans. We
have Japanese.
I think my feeling is pushing the black carbon issue at the
same level as the carbon dioxide in the international
agreements may be premature for this one small reason: the
first definitive study of the CO2 effects on climate
was published 40 years ago. It took us hundreds if not
thousands of studies before we came to the state where there
was some general consensus. I don't have to remind you
scientists rarely agree on anything. When you get five of us
together in a room, you get conflicting opinions.
Compared to that, the black carbon issue is in its infancy.
For example, the study you heard by Professor Zender, my own
study, and Jacobson's study, they are all less than 10 years
old, and science is confirmed by repeatability, many trying to
repeat our results.
There is still a wide uncertainty, so when we take the
black carbon issue to the table the ones who are opposed to
that could take the lowest estimate, which say it is not that
important.
It has not been properly vetted through the IPCC process.
My feeling is there could be more success than this by
bilateral working within United States, Europe, India, and
China, and try to make progress on that because Dr. Schwartz'
research shows us there are health problems and my research
shows it has regional problems, things like glacier melting and
rainfall. So I think it may be easier to push it on the
regional impacts issue than on the global issue.
Mr. Hodes. I appreciate the difficulty of reaching
agreement on those issues. It sounds a lot like working in
Congress. We often disagree.
It sounds like you are addressing really the strategic
implications of how we deal with the issue, but is it fair to
say that, at least in your mind and that of the other
panelists, there is no disagreement about the importance of
dealing with black carbon?
Mr. Ramanathan. Yes, I agree with you. I agree with the
opinions which were raised here. I am more thinking about the
scientific uncertainty being larger so it poses strategic
difficulties.
Mr. Hodes. Thank you. I appreciate that.
Mr. Chairman, may I just give the other panelists a brief
opportunity to finish the question?
Dr. Zender.
Mr. Zender. Thank you for the opportunity.
I agree with the panelists who summarized some of the
conditions that led to the Framework Convention being oriented
toward the mitigation of greenhouse gases, which, after all,
were at the time known to be the primary cause of global
warming. Since that period perhaps we have gained enough wisdom
and knowledge through the scientific process to understand that
not all the agents forcing the climate system cause an equal
response in terms of climate, precipitation, and temperature
per unit forcing.
If there were one thing that I could recommend be done
differently in the next round of treaties, it would be to
consider the response of the climate system, to look at the
temperature effects of each forcing agent by sector and by time
scale.
To reiterate, one of the conclusions I think that the panel
has shared is that black carbon presents a unique opportunity
because it can offset or mitigate warming on a very quick time
scale, giving us an additional decade or perhaps two to
struggle with the more complex emissions such as carbon dioxide
that our infrastructure depends on to such a critical degree.
Mr. Hodes. Thank you.
Dr. Schwartz.
Mr. Schwartz. Thank you very much for the opportunity.
I agree with basically what has been said. I think that we
are relatively much more uncertain about black carbon than
about CO2 in terms of climate change and stuff, but
I think the existence of very substantial health benefits means
we can afford to make that investment. It is justified on the
health, alone, and so we can live with that uncertainty and
incorporate it into one of the strategies going forward.
Mr. Hodes. I thank you all very much.
Mr. Chairman, thank you for the additional time.
Chairman Waxman. Thank you, Mr. Hodes, for your questions.
Let me ask a few more questions, if I might.
Dr. Zender, if we look at the Arctic where we can see the
dramatic level of destruction that is taking place in a
timeframe that no one imagined, and we try to attribute how
much of that warming is due to the black carbon, can you give
us any estimate? Is that possible?
Mr. Zender. I think it is possible based on the results of
our best understanding, which come from these general
circulation or climate models which incorporate, as closely as
they can, all processes known to contribute to the problem in
the Arctic. My best guess is that up to 30 percent of the
warming in the Arctic since pre-industrial can be attributed to
manmade black carbon injections into the Arctic. This is an
uncertain number and certainly greenhouse gases are playing the
dominant role, especially CO2.
What is interesting at the Arctic and why it is changing so
rapidly is that it is more susceptible, more vulnerable to a
tipping point situation because you have the ice that, once it
melts, uncovers these dark surfaces.
So the current data showing record sea ice retreat, showing
acceleration of glacial outpouring into the oceans around
southern Greenland and around the west Antarctic ice sheet, are
all indicators that you would expect to see from these same
models that give us these estimates; that the models are doing
something right there. They have a degree of skill there.
So my best estimate would be that sitting on top of a
dominant greenhouse gas contribution is the role of short-lived
pollutants, not only including black carbon in the Arctic, but
also ozone and methane. Some of those are clearly causing quit
a bit of warming in the Arctic.
Chairman Waxman. We hear a lot about tipping points with
regard to global warming. You are talking about the tipping
point in the Arctic, which is quite sobering, but we have heard
from some researchers that tell us that if we don't deal with
carbon emissions overall we are going to have a tipping point
so that when we start dealing with it seriously the time lag
before we see the benefits may be too late to stop irreversible
damage.
Do any of you want to comment on that? Dr. Jacobson.
Mr. Jacobson. Sir, I guess the three major tipping points
are one, with regard to the coral reefs, like if we raise the
temperatures another one degree celsius you might bleach the
corals, and that would cause a lot of irreversible damage to
fisheries, for example.
And then the second is the sea level rise due to, just as
we are talking, if you melt all this Arctic ice, and in
particular if you go down to the Antarctic and the west
Antarctic ice sheet goes, then you are going to raise the sea
level significantly. But in the case of the Arctic, because of
the positive feedback, once you melt that ice you are warming
the surface more, and make it harder to cool down.
This is a serious problem with the Arctic. Once you have
melted that ice, you have all your sunlight warming the
surface, so I am really concerned about that.
But I also want to point out that black carbon has a bigger
effect on the Arctic than it does kind of on the rest of the
world per unit meter or some kind of unit like that, but so
does CO2. CO2 actually also has a larger
effect on the Arctic and over snow and sea ice compared to over
land surfaces. You can see that just in numerical simulations
over Russia and over the Arctic and over even in other places
where there is snow. So I am concerned about the tipping point,
but also I think you really need to control the CO2
and the black carbon simultaneously, because both of them have
super linear effects over snowy or highly reflective surfaces.
Chairman Waxman. So as we look at this global warming
problem, if we deal with the black carbon we will get a more
immediate benefit, maybe delay the tipping point that we are
fearful about, and give us some additional time to avoid some
of the irreversible damage to the planet that has been
predicted?
Mr. Jacobson. Yes. It would give additional time, but I
guess I wouldn't want that to be translated into, OK, then we
don't have to control the CO2.
Chairman Waxman. Right.
Mr. Jacobson. Which is the concern. It really needs to be
done simultaneously I think with CO2 controls. It is
not really an either/or.
Chairman Waxman. OK. Thank you.
Mr. Davis, did you have any other questions?
Mr. Davis of Virginia. No. I just want to thank the panel
for helping to illuminate us on this situation, and I hope that
we can respond accordingly.
Thank you, Mr. Chairman.
Chairman Waxman. Thank you.
Ms. Norton, did you want to ask some questions?
Ms. Norton. No questions.
Chairman Waxman. No questions. OK.
This has been a terrific education for us and we hope to
share this hearing record with the rest of our colleagues in
the Congress and others who are looking at the whole question
of how do we come to terms with the global warming problems. I
think you make a compelling case that we need to look at
controlling black carbon as part of that solution.
I want to do some housekeeping.
I want to ask unanimous consent that all members of this
committee will have an opportunity to enter an opening
statement in the record if they wish to.
Second, I would like to be able to give the opportunity to
Members to submit questions in writing to the panel and have
you respond in writing to them if you would.
I thank you so much. I think you have done an excellent
job, and I think this is an important hearing for the debate
that we are continuing to have in the Congress of the United
States. Thank you.
That concludes our business and the committee stands
adjourned.
[Whereupon, at 11:50 a.m., the committee was adjourned.]
[The prepared statement of Hon. Diane E. Watson follows:]
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