[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

                               __________

Printed for the use of the Committee on Oversight and Government Reform


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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

                              ----------                              
                                                                   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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