[House Hearing, 110 Congress]
[From the U.S. Government Publishing Office]
THE STATE OF CLIMATE CHANGE SCIENCE 2007
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HEARINGS
BEFORE THE
COMMITTEE ON SCIENCE AND TECHNOLOGY
ONE HUNDRED TENTH CONGRESS
FIRST SESSION
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February 8, April 17, and May 15, 2007
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Serial Nos. 110-2, 110-20, and 110-30
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Printed for the use of the Committee on Science and Technology
U.S. GOVERNMENT PRINTING OFFICE
32-966 WASHINGTON : 2008
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COMMITTEE ON SCIENCE AND TECHNOLOGY
HON. BART GORDON, Tennessee, Chairman
JERRY F. COSTELLO, Illinois RALPH M. HALL, Texas
EDDIE BERNICE JOHNSON, Texas F. JAMES SENSENBRENNER JR.,
LYNN C. WOOLSEY, California Wisconsin
MARK UDALL, Colorado LAMAR S. SMITH, Texas
DAVID WU, Oregon DANA ROHRABACHER, California
BRIAN BAIRD, Washington KEN CALVERT, California
BRAD MILLER, North Carolina ROSCOE G. BARTLETT, Maryland
DANIEL LIPINSKI, Illinois VERNON J. EHLERS, Michigan
NICK LAMPSON, Texas FRANK D. LUCAS, Oklahoma
GABRIELLE GIFFORDS, Arizona JUDY BIGGERT, Illinois
JERRY MCNERNEY, California W. TODD AKIN, Missouri
PAUL KANJORSKI, Pennsylvania JO BONNER, Alabama
DARLENE HOOLEY, Oregon TOM FEENEY, Florida
STEVEN R. ROTHMAN, New Jersey RANDY NEUGEBAUER, Texas
MICHAEL M. HONDA, California BOB INGLIS, South Carolina
JIM MATHESON, Utah MICHAEL T. MCCAUL, Texas
MIKE ROSS, Arkansas MARIO DIAZ-BALART, Florida
BEN CHANDLER, Kentucky PHIL GINGREY, Georgia
RUSS CARNAHAN, Missouri BRIAN P. BILBRAY, California
CHARLIE MELANCON, Louisiana ADRIAN SMITH, Nebraska
BARON P. HILL, Indiana VACANCY
HARRY E. MITCHELL, Arizona
CHARLES A. WILSON, Ohio
The State of Climate Change Science 2007: The Findings of the Fourth
Assessment Report by the Intergovernmental Panel on Climate Change
(IPCC), Working Group I Report
C O N T E N T S
February 8, 2007
Page
Witness List..................................................... 2
Hearing Charter.................................................. 3
Opening Statements
Statement by Representative Bart Gordon, Chairman, Committee on
Science and Technology, U.S. House of Representatives.......... 7
Written Statement............................................ 8
Statement by Representative Ralph M. Hall, Minority Ranking
Member, Committee on Science and Technology, U.S. House of
Representatives................................................ 9
Written Statement............................................ 11
Prepared Statement by Representative Jerry F. Costello, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 12
Prepared Statement by Representative Eddie Bernice Johnson,
Member, Committee on Science and Technology, U.S. House of
Representatives................................................ 13
Prepared Statement by Representative Daniel Lipinski, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 13
Prepared Statement by Representative Mike Ross, Member, Committee
on Science and Technology, U.S. House of Representatives....... 13
Prepared Statement by Representative Russ Carnahan, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 14
Prepared Statement by Representative Harry E. Mitchell, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 14
Prepared Statement by Representative Vernon J. Ehlers, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 15
Prepared Statement by Representative Randy Neugebauer, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 15
Panel I:
The Honorable Nancy Pelosi, Speaker of the House of
Representatives
Oral Statement............................................... 16
Written Statement............................................ 19
Discussion
Economic Impacts of Climate Change............................. 21
Select Committee on Energy Independence and Global Warming..... 22
Nuclear Energy................................................. 23
The International Banking Environmental Protection Act......... 24
Question and Answer Session: Congressional Customs............. 25
Panel II:
Dr. Susan Solomon, Co-Chair, IPCC, Working Group I: The Physical
Basis of Climate Change; Senior Scientist, Earth System
Research Laboratory, Office of Oceanic and Atmospheric
Research, National Oceanic and Atmospheric Administration, U.S.
Department of Commerce
Oral Statement............................................... 28
Written Statement............................................ 30
Biography.................................................... 46
Dr. Kevin E. Trenberth, Coordinating Lead Author, IPCC, Working
Group I, Chapter 3: Observations: Surface and Atmospheric
Climate Change; Head, Climate Analysis Section, National Center
for Atmospheric Research
Oral Statement............................................... 46
Written Statement............................................ 49
Biography.................................................... 55
Dr. Richard B. Alley, Lead Author, IPCC, Working Group I, Chapter
4: Observations: Changes in Snow, Ice and Frozen Ground; Evan
Pugh Professor of Geosciences and Associate of the Earth and
Environmental Systems Institute, Pennsylvania State University
Oral Statement............................................... 56
Written Statement............................................ 57
Biography.................................................... 61
Dr. Gerald A. Meehl, Coordinating Lead Author, IPCC, Working
Group I, Chapter 10: Global Climate Projections; Senior
Scientist, National Center for Atmospheric Research
Oral Statement............................................... 61
Written Statement............................................ 63
Biography.................................................... 66
Discussion
The IPCC Process............................................... 67
Glacier Melt Accelerations..................................... 67
Global Warming Trends.......................................... 70
More on the IPCC Process....................................... 73
More on Global Warming Trends.................................. 74
Greenhouse Gas Production: Country Comparisons................. 77
Climate Research............................................... 77
Carbon Sequestration........................................... 79
Advancements in Climate Research............................... 81
Cooling in Antarctica.......................................... 81
Impact on the Western United States............................ 81
Thermal Expansion of Seawater.................................. 82
Mitigating Climate Change...................................... 82
Ocean Circulation Changes...................................... 83
Tropical Storms................................................ 85
Social and Economic Impacts of Climate Change.................. 86
More on the IPCC Process....................................... 86
Global Impacts of Climate Change............................... 87
Managing Water Resources....................................... 88
More on Climate Research....................................... 89
Opposition to Climate Change................................... 90
Climate Change Scenarios....................................... 93
More Climate Change Scenarios.................................. 93
Scientific Consensus........................................... 94
Impact on the Southwestern United States....................... 96
Regional vs. Global Modeling................................... 97
U.S. Leadership in Mitigating Climate Change................... 98
More on Climate Science........................................ 100
Appendix: Answers to Post-Hearing Questions
Dr. Susan Solomon, Co-Chair, IPCC, Working Group I: The Physical
Basis of Climate Change; Senior Scientist, Earth System
Research Laboratory, Office of Oceanic and Atmospheric
Research, National Oceanic and Atmospheric Administration, U.S.
Department of Commerce......................................... 106
Joint responses by Dr. Richard B. Alley, Lead Author, IPCC,
Working Group I, Chapter 4: Observations: Changes in Snow, Ice
and Frozen Ground; Evan Pugh Professor of Geosciences and
Associate of the Earth and Environmental Systems Institute,
Pennsylvania State University; Dr. Kevin E. Trenberth,
Coordinating Lead Author, IPCC, Working Group I, Chapter 3:
Observations: Surface and Atmospheric Climate Change; Head,
Climate Analysis Section, National Center for Atmospheric
Research; Dr. Gerald A. Meehl, Coordinating Lead Author, IPCC,
Working Group I, Chapter 10: Global Climate Projections; Senior
Scientist, National Center for Atmospheric Research; and Dr.
Susan Solomon, Co-Chair, IPCC, Working Group I: The Physical
Basis of Climate Change; Senior Scientist, Earth System
Research Laboratory, Office of Oceanic and Atmospheric
Research, National Oceanic and Atmospheric Administration, U.S.
Department of Commerce......................................... 107
The State of Climate Change Science 2007: The Findings of the Fourth
Assessment Report by the Intergovernmental Panel on Climate Change
(IPCC), Working Group II: Climate Change Impacts, Adaptation and
Vulnerability
C O N T E N T S
April 17, 2007
Page
Witness List..................................................... 112
Hearing Charter.................................................. 113
Opening Statements
Statement by Representative Bart Gordon, Chairman, Committee on
Science and Technology, U.S. House of Representatives.......... 119
Written Statement............................................ 119
Statement by Representative Ralph M. Hall, Minority Ranking
Member, Committee on Science and Technology, U.S. House of
Representatives................................................ 120
Written Statement............................................ 121
Prepared Statement by Representative Jerry F. Costello, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 122
Prepared Statement by Representative Nick Lampson, Chairman,
Subcommittee on Energy and Environment, Committee on Science
and Technology, U.S. House of Representatives.................. 122
Prepared Statement by Representative Harry E. Mitchell, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 123
Prepared Statement by Representative Vernon J. Ehlers, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 123
Witnesses:
Dr. Cynthia Rosenzweig, Senior Research Scientist, NASA Goddard
Institute for Space Studies, The Earth Institute at Columbia
University
Oral Statement............................................... 125
Written Statement............................................ 126
Biography.................................................... 130
Dr. William E. Easterling, Professor of Geography and Agronomy;
Director, Penn State Institutes of Energy and the Environment,
Pennsylvania State University
Oral Statement............................................... 130
Written Statement............................................ 134
Biography.................................................... 137
Dr. Virginia Burkett, Chief Scientist for Global Change Research,
U.S. Geological Survey, U.S. Department of the Interior
Oral Statement............................................... 138
Written Statement............................................ 143
Dr. Shardul Agrawala, Princeton University and Organisation for
Economic Co-operation and Development (OECD)
Oral Statement............................................... 154
Written Statement............................................ 156
Biography.................................................... 158
Dr. Roger S. Pulwarty, Program Director, National Integrated
Drought Information System (NIDIS), Office of Oceanic and
Atmospheric Research, National Oceanic and Atmospheric
Administration, U.S. Department of Commerce
Oral Statement............................................... 158
Written Statement............................................ 160
Biography.................................................... 164
Dr. Stephen H. Schneider, Melvin and Joan Lane Professor for
Interdisciplinary Environmental Studies; Professor, Department
of Biological Sciences; Senior Fellow, Center for Environmental
Science and Policy at the Woods Institute for the Environment,
Stanford University
Oral Statement............................................... 165
Written Statement............................................ 170
Biography.................................................... 179
Discussion
Dangerous Anthropogenic Interference........................... 180
Potential Mitigation of Climate Change......................... 181
Climate Change Impacts......................................... 181
Anthropogenic Causes of Climate Change......................... 181
Climate Change Impacts: Drought................................ 182
Climate Change Impacts: The Great Lakes........................ 183
Carbon Sinks................................................... 184
Impacts on the Fishing Industry................................ 184
Energy Concerns................................................ 186
International Efforts.......................................... 187
Adaptation and Mitigation Strategies........................... 189
Climate Change Impacts: Agriculture............................ 191
Climate Change Impacts: Water Availability..................... 191
Climate Change Impacts: Coastal Louisiana...................... 194
Air Indexing in Third World Countries.......................... 196
Global Dimming................................................. 197
Climate Change Impacts: Southern Arizona....................... 198
Sunspots....................................................... 199
Sea Walls...................................................... 201
The IPCC Process............................................... 201
Appendix 1: Answers to Post-Hearing Questions
Dr. Cynthia Rosenzweig, Senior Research Scientist, NASA Goddard
Institute for Space Studies, The Earth Institute at Columbia
University..................................................... 206
Dr. Virginia Burkett, Chief Scientist for Global Change Research,
U.S. Geological Survey, U.S. Department of the Interior........ 208
Dr. Roger S. Pulwarty, Physical Scientist, Climate Program
Office, Office of Oceanic and Atmospheric Research, National
Oceanic and Atmospheric Administration, U.S. Department of
Commerce....................................................... 212
Dr. Stephen H. Schneider, Melvin and Joan Lane Professor for
Interdisciplinary Environmental Studies; Professor, Department
of Biological Sciences; Senior Fellow, Center for Environmental
Science and Policy at the Woods Institute for the Environment,
Stanford University............................................ 217
Appendix 2: Additional Material for the Record
More Trees, Less Global Warming, Right?--Not Exactly, Scientific
American, April 10, 2007....................................... 222
Why So Gloomy?, by Richard S. Lindzen, Special to Newsweek, April
16, 2007....................................................... 224
The State of Climate Change Science 2007: The Findings of the Fourth
Assessment Report by the Intergovernmental Panel on Climate Change
(IPCC), Working Group III: Mitigation of Climate Change
C O N T E N T S
May 16, 2007
Page
Witness List..................................................... 228
Hearing Charter.................................................. 229
Opening Statements
Statement by Representative Bart Gordon, Chairman, Committee on
Science and Technology, U.S. House of Representatives.......... 237
Written Statement............................................ 238
Statement by Representative Ralph M. Hall, Ranking Minority
Member, Committee on Science and Technology, U.S. House of
Representatives................................................ 238
Written Statement............................................ 240
Prepared Statement by Representative Jerry F. Costello, Member,
Committee on Science and Technology, U.S. House of
Representatives................................................ 241
Prepared Statement by Representative Eddie Bernice Johnson,
Member, Committee on Science and Technology, U.S. House of
Representatives................................................ 241
Witnesses:
Dr. Mark D. Levine, Division Director of the Environmental Energy
Technology Division at Lawrence Berkeley Laboratory
Oral Statement............................................... 242
Written Statement............................................ 244
Biography.................................................... 247
Dr. William A. Pizer, Fellow at Resources for the Future and
Senior Economist at the National Commission on Energy Policy
Oral Statement............................................... 247
Written Statement............................................ 250
Biography.................................................... 259
Mr. Steven E. Plotkin, Transportation Energy Analyst with the
Center of Transportation Research at the Argonne National
Laboratory
Oral Statement............................................... 260
Written Statement............................................ 262
Biography.................................................... 265
Dr. Roger A. Pielke, Jr., Professor of Environmental Studies
Program at the University of Colorado and Director of the
Center for Science and Technological Policy Research
Oral Statement............................................... 265
Written Statement............................................ 270
Biography.................................................... 280
Discussion
Biofuels....................................................... 280
Fuel Economy Standards in China................................ 280
International Efforts.......................................... 281
The Advanced Research Projects Agency-Energy (ARPA-E).......... 282
Adaptation and Mitigation Strategies........................... 282
The IPCC Process............................................... 283
Adaptation and Mitigation Strategies in China.................. 284
Green Employment Opportunities................................. 285
Building Efficiency............................................ 285
More on International Efforts.................................. 286
Efficiency Technologies........................................ 288
More on Building Efficiency.................................... 289
Anthropogenic Causes of Climate Change......................... 290
Mitigation Obstacles........................................... 292
Mitigation Costs............................................... 293
Developing Countries........................................... 294
More on Building Efficiency.................................... 294
China's Coal Energy Production................................. 295
Energy Efficiency Priorities................................... 297
Nuclear Energy................................................. 299
Future IPCC Reports............................................ 301
Appendix: Answers to Post-Hearing Questions
Dr. Mark D. Levine, Division Director of the Environmental Energy
Technology Division at Lawrence Berkeley Laboratory............ 304
Dr. William A. Pizer, Fellow at Resources for the Future and
Senior Economist at the National Commission on Energy Policy... 306
Mr. Steven E. Plotkin, Transportation Energy Analyst with the
Center of Transportation Research at the Argonne National
Laboratory..................................................... 310
Dr. Roger A. Pielke, Jr., Professor of Environmental Studies
Program at the University of Colorado and Director of the
Center for Science and Technological Policy Research........... 314
THE STATE OF CLIMATE CHANGE SCIENCE 2007: THE FINDINGS OF THE FOURTH
ASSESSMENT REPORT BY THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE
(IPCC), WORKING GROUP I REPORT
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THURSDAY, FEBRUARY 8, 2007
House of Representatives,
Committee on Science and Technology,
Washington, DC.
The Committee met, pursuant to call, at 10:00 a.m., in Room
2318 of the Rayburn House Office Building, Hon. Bart Gordon
[Chairman of the Committee] presiding.
hearing charter
COMMITTEE ON SCIENCE AND TECHNOLOGY
U.S. HOUSE OF REPRESENTATIVES
The State of Climate Change Science 2007:
The Findings of the Fourth Assessment
Report by the Intergovernmental Panel
on Climate Change (IPCC),
Working Group I Report
thursday, february 8, 2007
10:00 a.m.-12:00 p.m.
2318 rayburn house office building
Purpose
On February 8, 2007, the Committee on Science and Technology will
hold a hearing on the first section of the 2007 Assessment Report,
Climate Change 2007: The Physical Science Basis of Climate Change,
prepared by Working Group I of the Intergovernmental Panel on Climate
Change (IPCC). Released in Paris, France, on February 2, 2007, this
document presents a comprehensive appraisal of the current state of
scientific knowledge of climate change.
The Committee will hear testimony from four witnesses who were
involved in the preparation of the Working Group I Report. The
witnesses will present the findings of the Report and discuss the
relationship between the current findings and those of past IPCC
reports on the state of climate change science.
Key Findings of the 2007 Working Group I Report
On February 2, 2007 the Intergovernmental Panel on Climate Change
(IPCC) released the first section of its Fourth Assessment Report,
entitled ``The Physical Science Basis of Climate Change.''
This first section of the IPCC Fourth Assessment Report builds upon
information contained in the previous reports. It updates information
from the Third Assessment Report based upon research conducted over the
past six years. Uncertainties in some areas have been reduced (e.g.,
quantitative estimates of radiative forcing). Climate models have
improved, and expanded observations, data and information have enabled
the IPCC to increase the level of confidence in some earlier findings
(e.g., attribution of warming to human-induced increases in greenhouse
gas concentrations). In other areas (e.g., changes in frequency of
tropical cyclones) uncertainties remain and further research is needed
to determine what patterns, if any, exist.
Despite remaining uncertainties, the Fourth Assessment Report
represents a significant expansion in our knowledge of the influence of
human activity on the Earth's climate. It is almost 30 years since the
first international scientific conference on climate suggested that
human activity could be impacting the Earth's climate. This report
confirms the original suspicions raised by scientists participating in
the 1979 climate conference as has every report of the IPCC from the
first report in 1990 to the present.
The 10 key findings in the 2007 report are:
Atmospheric concentrations of greenhouse gases have
increased significantly due to human activities since 1750 due
to fossil fuel use and land-use change.
Our understanding of human-induced influences on
climate has improved since the 2001 Assessment. There is now
very high confidence that Earth is warming.
Evidence that Earth is warmer includes: increase in
global average air temperature and ocean temperature,
widespread melting of snow and ice, and rising global average
sea level.
Long-term changes in climate have been observed
including: changes in Arctic temperatures and ice, changes in
the amounts of precipitation, ocean salinity, and wind patterns
and changes in extreme weather events such as droughts, heavy
precipitation, heat waves, and intensity of hurricanes and
typhoons.
Changes in diurnal temperature ranges, Antarctic sea
ice extent, meridional overturning circulation of the global
ocean, and localized extreme weather events such as tornadoes,
lightning, and dust storms have not been observed.
The interpretation that the warming of the last 50
years is unusual in at least the previous 1,300 years is
consistent with paleoclimate information. During the last
period when polar regions were significantly warmer than
present for an extended period of time (about 125,000 years
ago), reduced volume of polar ice led to sea level rise of four
to six meters.
Most of the observed increase in globally averaged
temperatures since the mid-twentieth century is very likely due
to the observed increase in anthropogenic greenhouse gas
concentrations. Discernible human influences now extend to
other aspects of climate, including ocean warming, continental-
average temperatures, temperature extremes and wind patterns.
Analysis of climate models coupled with constraints
of observations enables an assessed likely range to be given
for climate sensitivity for the first time and provides
increased confidence in the understanding of the climate system
response to radiative forcing. The likely global average
surface warming associated with a doubling of CO2
concentration is in the range 2 to 4.5+C. It is very
unlikely that climate changes of at least the seven centuries
prior to 1950 were due to variability generated within the
climate system alone.
For the next 20 years a warming of 0.2+C
per decade is projected for a range of emission scenarios. Even
if the concentrations of all greenhouse gases and aerosols had
been kept constant at year 2000 levels, a further warming of
about 0.1+C per decade would be expected.
Continued greenhouse gas emissions at or above
current rates would cause further warming and induce many
changes in the global climate system during the twenty-first
century that would very likely be larger than those observed
during the twentieth century.
Background
Prior to the establishment of the IPCC, the World Meteorological
Organization (WMO) convened two international meetings on greenhouse
gas emissions and global climate. In 1979, the first World Climate
Conference issued the following concern: ``continued expansion of man's
activities on Earth may cause significant extended regional and even
global changes in climate.'' In 1985 the United Nations Environment
Program (UNEP), WMO, and the International Council for Science (ICSU)
organized a joint conference on the ``Assessment of the Role of Carbon
Dioxide and of Other Greenhouse Gases in Climate Variations and
Associated Impacts.'' This conference concluded that ``as a result of
the increasing greenhouse gases it is now believed that in the first
half of the next century (twenty-first century) a rise of global mean
temperature could occur which is greater than in any man's history.''
In response to the findings of these earlier conferences, the IPCC
was created by WMO and UNEP in 1988. The IPCC was created to provide
assessments of scientific, technical and socio-economic information
relevant to understanding the risk of human-induced climate change, its
potential impacts and options for adaptation and mitigation.
The IPCC is organized into a Plenary which meets once a year and is
attended by officials and experts from relevant ministries, agencies,
and research institutions from member countries and from participating
organizations. This body makes the decisions about preparation of new
reports, their scope and content, and accepts reports prepared by
expert teams. It elects the IPCC Chair, currently Rajendra K. Pachauri,
and the members of the IPCC Bureau. It also establishes IPCC principles
and procedures, designs the work plan and budget for the Panel and its
activities. The IPCC Secretariat is located in Geneva, Switzerland.
The IPCC relies upon primarily peer reviewed, published scientific
and technical literature. The IPCC also prepares special reports and
technical papers on topics where independent scientific information and
advice is deemed necessary. The panel operates within extensive peer
review and governmental review, thus ensuring a high level of
transparency, scientific credibility, and policy relevance. Hundreds of
experts from around the world contribute to the assessment reports as
authors, contributors, and reviewers. Participants are selected by the
members of the IPCC Bureau (30 members each from a different nation)
who are all elected for five to six years and who are all experts in
climate change. Participants may be nominated by governments or
participating organizations or they may be chosen due to their
recognized expertise.
The IPCC published the First Assessment Report in 1990,
Supplementary Reports in 1992, a Special Report in 1994, a Second
Assessment Report (SAR) in 1995, and a Third Assessment Report (TAR) in
2001. Each of the assessment reports are comprised of three volumes
from three corresponding working groups (I, II and III).
First Assessment Report
The First IPCC Assessment Report was completed in 1990 and provided
policy-makers with a comprehensive assessment of what was then known,
and not known, about human influence on climate. The report provided
the main scientific basis for the negotiation of the Framework
Convention on Climate Change (UNFCCC). The 1992 United Nations
Framework Convention on Climate Change was ratified by the United
States and called for a ``non-binding,'' voluntary goal for
industrialized countries to stabilize their emissions of greenhouse
gases at 1990 levels by the year 2000.
The 1990 IPCC report, as well as two Supplementary Reports (1992
and 1994) supplied critical information for the United Nations
Conference on Environment and Development in Rio de Janeiro in June
1992. The Convention went into effect in March 1994 and the first
session of the Conference of the Parties (COP) was held in Berlin in
April 1995.
In the 1990 assessment, the authors' wrote, ``The size of the
warming is broadly consistent with predictions of climate models, . .
.but the unequivocal detection of the enhanced greenhouse effect from
observations is not likely for a decade or more.'' The report projected
an increase in average global temperature during the twenty-first
century of 0.3 degrees Celsius per decade and discussed the possible
consequences of that temperature change in relation to rising sea
levels, increase in extreme weather events, and serious pressure on
aquatic and terrestrial ecosystems.
Second Assessment Report
Completed in 1995, the Second IPCC Assessment Report expanded on
the findings of the 1990 assessment. The Second Assessment Report
stated that the climate of the Earth had changed over the past century,
increasing the global mean surface air temperature somewhere between
0.3 and 0.6 degrees Celsius. The report stated that climate was
expected to change further in the future and projected an increase of
1.0 to 3.5 degrees Celsius by 2100.
In the 1995 report, the IPCC concluded that ``. . .the balance of
evidence suggests that there is a discernible human influence on global
climate.'' This second assessment provided key input to the
negotiations that led to the adoption of the Kyoto Protocol in 1997.
More than 160 nations, parties to the Framework Convention on Climate
Change, adopted the Kyoto Protocol, with legally binding obligations to
limit emissions of industrialized nations for the years 2008 to 2012.
The Protocol's emissions targets are hailed as important first steps
toward the Framework Convention's objective of avoiding dangerous
climate change.
Third Assessment Report
The Third Assessment Report, ``Climate Change 2001'' consisted of
three working group reports on ``The Scientific Basis,'' ``Impacts,
Adaptation and Vulnerability,'' and ``Mitigation.'' The findings also
contained a synthesis report, which addressed a range of policy
relevant scientific and technical questions. This third report
emphasized the findings from the previous five years and projected that
average global temperature would rise from 1.4 to 5.8 degrees Celsius
over the next century. In addition, authors explained how precipitation
patterns are expected to change, the degree to which sea level is
expected to rise, and the possibility of the increases in extreme
weather events.
By the release of the 2001 report, confidence in the ability of
models to project future climate increased and authors concluded,
``There is new and stronger evidence that most of the warming observed
over the last 50 years is attributable to human activities.''
Furthermore, extensive and wide-spread evidence is present
demonstrating that the Earth is warming and clear signals of a changing
climate exist.
Witnesses
Dr. Susan Solomon of the National Oceanic and Atmospheric
Administration (NOAA):
Dr. Susan Solomon serves as Co-Chair of Working Group I of the
Intergovernmental Panel on Climate Change (IPCC), providing scientific
information to the United Nations Framework Convention on Climate
Change. Her current research includes climate change and ozone
depletion, and she served as an overall coordinator for the report.
After receiving her Ph.D. in chemistry from the University of
California at Berkeley in l98l, she has been employed by the National
Oceanic and Atmospheric Administration as a research scientist. Her
scientific papers have provided not only key measurements but also
theoretical understanding regarding ozone destruction, especially the
role of surface chemistry.
Dr. Solomon will provide an overview of the key findings of the
report. Working Group I's contribution to the Fourth Assessment Report
includes 11 chapters. Each chapter has two Coordinating Lead Authors
who are responsible for pulling together the material for the chapter.
In addition to the Coordinating Lead Authors, there are a number of
Lead Authors as well as numerous contributors and reviewers associated
with each chapter.
Each of the other IPCC authors, Dr. Trenberth, Dr. Alley, and Dr.
Meehl will discuss the findings with a focus on their respective
chapters.
Dr. Kevin Trenberth of the National Center for Atmospheric Research
(NCAR):
Dr. Kevin Trenberth served as a Coordinating Lead Author for
Chapter 3 of the report entitled: Observations: Surface and Atmospheric
Climate Change. Currently, Dr. Trenberth is Head of the Climate
Analysis Section at the National Center for Atmospheric Research (NCAR)
in Boulder, Colorado. From New Zealand, he completed his undergraduate
degree in mathematics at the University of Canterbury, Christchurch,
New Zealand, and obtained his Sc.D. in meteorology in 1972 from
Massachusetts Institute of Technology, Cambridge, Massachusetts.
Dr. Richard Alley of the Department of Geosciences, Pennsylvania State
University:
Dr. Richard Alley served as a Lead Author for Chapter 4 of the
report entitled: Observations: Changes in Snow, Ice, and Frozen Ground.
Dr. Alley is Evan Pugh Professor of Geosciences and Associate of the
Earth and Environmental Systems Institute at The Pennsylvania State
University, University Park, where he has worked since 1988. He
received his Ph.D. in 1987 from the University of Wisconsin-Madison and
his M.Sc. (1983) and B.Sc. (1980) degrees from The Ohio State
University-Columbus, all in Geology. Dr. Alley teaches, and conducts
research on the climatic records, flow behavior, and sedimentary
deposits of large ice sheets, to aid in prediction of future changes in
climate and sea level.
Dr. Gerald Meehl of the National Center for Atmospheric Research
(NCAR):
Dr. Meehl is a Coordinating Lead Author for Chapter 10 of the
report: Global Climate Projections. Dr. Meehl received his Ph.D. in
Climate Dynamics from the University of Colorado in 1987. His expertise
is in the field of climate modeling. He has been a scientist on staff
at NCAR since 1979. He has been a member of the Working Group I Report
Group since 1989 and has participated in the development of previous
IPCC assessment reports.
Definitions:
Radiative forcing--an external disturbance in the radiative energy
budget of Earth's climate system brought about by changes in
atmospheric concentrations of greenhouse gases, changes in solar
radiation, or changes in the surface reflective properties of Earth.
Meridional overturning circulation--the circulation system of the
world's oceans driven by variations in temperature and salinity. Cold,
dense water formed in polar oceans sinks and is replaced by warmer,
less dense surface water from temperate latitudes.
Chairman Gordon. Well, good morning, and welcome to this
hearing on the Intergovernmental Panel on Climate Change, or
IPCC, Report on the current state of our knowledge on climate
change.
This is the first opportunity Congress has to examine the
findings of this important report.
The first warnings about the potential for climate change
came in 1979 when the first international conference on climate
change expressed the concern that human activity might lead to
significant regional and global changes in climate.
Now, almost 30 years later, increasing evidence confirms
this warning is real.
The importance of this report cannot be overstated. The
Report provides overwhelming evidence that global warming is
real and that human activity is the driving force.
The Report's findings may be alarming, but it is not the
work of alarmists. The Report's findings were endorsed
unanimously by the representatives of 113 nations, including
the United States, and it is the product of the work of nearly
300 scientists. In short, this is a unanimous, definitive
statement that global warming is real and it is very likely
that humans have contributed to it.
And let me just make that clear. This is a unanimous,
definitive statement. That meant that every nation, every
scientist had to agree to that. And so the Nation that might be
the most naysaying, the scientists that might be the most
skeptical still had to agree to this Report. So, at a minimum,
this is a conservative report about climate change.
The scientific experts have provided us with a diagnosis of
the problem and a prognosis for our nation's health. If we
continue along our current path, the prognosis is ominous.
The scientists have done their job. Now, it is time for us,
the policy-makers, to do ours.
We face a big challenge. We must explore ways to reduce
emissions, to adapt to coming changes, and to mitigate the
negative effects of climate change. We cannot accomplish all
this overnight, but we must begin in earnest now to address
this serious issue. And with some bit of irony, today, the
Science Committee has a bill of mine on the Floor in about an
hour that will be the first bill that will address renewable
energy. We hope it will be--we don't hope, we know it will be
the first of many bills.
The IPCC Report tells us that if we fail to act, our
children, my five-year old daughter, Dana's triplets, Brian's
twins, and Madame Speaker, your little four-month-old son, or
grandson--you look wonderful--they are all going to be
affected, and they are going to live in a very different world.
And let me just say, this is not hypothetical. When you start
talking about 10 years, 20 years, 50 years, maybe 100 years, it
seems like it is a long time off, but the actuaries tell us
that our children are all going to live to the end of this
century. And certainly, our grandchildren are going to live
beyond that. So this is real. This is not hypothetical. We are
talking about something that is going to affect all of us in a
very personal way, because they are going to inherit a world
which has much more severe droughts in some regions, greater
flooding in others, and very different coastlines due to a
higher sea level.
And two days ago, my daughter spent the afternoon in my
office. We were looking out at the Capitol and I am hoping that
when she is older she is going to remember that view.
And I don't want to look in my daughter's eyes in 10 or 20
years and try to explain why I didn't take advantage of the
opportunity to address global warming while I was in Congress.
We need to improve existing technologies and to develop new
technologies and to reduce emissions and to make our economy
and our society more energy efficient. And we must understand
the impacts of climate change on our ecosystems that support
all life on Earth.
Continued scientific research is imperative. We need
better, more refined regional assessments to understand the
climatic vulnerabilities of communities, ecosystems, and our
economy. We must continue to gather information on greenhouse
gas emissions and the Earth's response to them and to further
expand our understanding of climate and weather.
These four eminent scientists are a select few representing
the efforts of thousands of scientists from all over the world.
And as I said earlier, they have done their job. They have set
the scientific information before us. We must now move forward
and act upon this information.
We, on the Science and Technology Committee, can and must
play a role by ensuring that the science and research continue
to provide us the information we need to understand climate
change and to respond to it.
However, we must also begin with the information and tools
in hand today to adapt to the changing climate and to buy
ourselves time to adapt and to innovate by reducing emissions
and energy use.
We are world leaders in science and innovation. I intend
for this committee to ensure we maintain that leadership and
lead the world to address it with us.
On behalf of the Committee, I want to thank all of our
witnesses for joining us today and for the work you have done
in preparing this paper.
[The prepared statement of Chairman Gordon follows:]
Prepared Statement of Chairman Bart Gordon
Good morning and welcome to this hearing on the Intergovernmental
Panel on Climate Change (IPCC) report on the current state of our
knowledge on climate change.
This is the first opportunity Congress has to examine the findings
of this important report.
The first warning about the potential for climate change came in
1979 when the first international conference on climate change
expressed the concern that human activity might lead to significant
regional and global changes in climate.
Now, almost 30 years later increasing evidence confirms this
warning is real.
The importance of this report cannot be overstated.
The Report provides overwhelming evidence that global warming is
real and that human activity is driving this change.
The Report's findings may be alarming, but it is not the work of
alarmists.
The Report's findings were endorsed unanimously by the
representatives of 113 countries, including the United States.
And is the product of the work of nearly 600 scientists.
In short, it is a unanimous, definitive statement that global
warming is real and that it is very likely humans have contributed to
it.
The scientific experts have provided us with a diagnosis of the
problem and a prognosis for our planet's health. If we continue along
our current path, the prognosis is ominous.
The scientists have done their job. Now, it is time for us--the
policy-makers--to do ours.
We face a big challenge. We must explore ways to reduce emissions,
to adapt to coming changes, and to mitigate the negative effects of a
changing climate.
We cannot accomplish all this overnight, but we must begin in
earnest now to address this serious issue.
The IPCC Report tells us that, if we fail to act, our children--my
five-year-old daughter, Dana's triplets, and Brian's twins--will live
in a much different world.
A world with more severe droughts in some regions and greater
flooding in others. And much different coastlines due to a higher sea
level.
Two days ago, my daughter spent the afternoon with me in my office.
We were looking out at the Capitol and I am hoping that when she is
older, she will remember that view.
I don't want to look in my daughter's eyes in 10 or 20 years and
try to explain why I didn't take advantage of an opportunity to address
global warming while I was in Congress.
We need to improve existing technologies and to develop new
technologies to reduce emissions and make our economy and society more
energy efficient.
And we must understand the impacts of climate change on the
ecosystems that support all life on Earth.
Continued scientific research is imperative. We need better, more
refined regional assessments to understand the climatic vulnerabilities
of communities, ecosystems, and our economy.
We must continue to gather information on greenhouse gas emissions
and the Earth's response to them to further expand our understanding of
climate and weather.
These four eminent scientists are a select few representing the
efforts of thousands of scientists from around the world. As I said
earlier--they have done their job. They have set the scientific
information before us. We must now move forward and act upon this
information.
We, on the Science and Technology Committee can and must play a
role by ensuring that the science and research continue to provide us
the information we need to understand climate change and to respond to
it.
However, we must also begin with the information and tools in hand
today to adapt to the changing climate and to buy ourselves time to
adapt and innovate by reducing emissions and energy use.
We are world leaders in science and innovation. I intend to ensure
this committee works to ensure we maintain that leadership. I believe
we can meet this challenge and we can, and should, lead the world to
address it with us.
On behalf of the Committee, I want to thank all of our witnesses
for agreeing to come before us this morning. I believe most of you have
just returned from the meeting in Paris. We appreciate the work you
have done and your willingness to appear today.
Chairman Gordon. And at this time, I will recognize our
very distinguished Ranking Member, Mr. Hall, for an opening
statement.
Mr. Hall. Good morning. And I thank you, and I thank the
Chairman for organizing this hearing about the very important
topic of global warming, or as some prefer to call it, climate
change.
Let me start by thanking all of the witnesses for being
here today. This will be a key issue in the 110th Congress, and
I hope that I speak for all of the Committee Members in saying
that we appreciate the time that you all give us. Madame
Speaker, we appreciate your appearing before us. I was amazed
at the crowds outside there. At my age, I was fearful that
someone had discovered I might have been one of the Lindbergh
kidnappers. I didn't know what everybody was doing there. But
you are all welcome. I see Sherry Boehlert, our former
Chairman, in attendance, a great leader and a man that gave
much of his time to this committee, and to this Congress, and
to this nation. Thank you, Sherry.
There will be a lot of debate in this Congress about what
policies the United States should adopt to deal with the
potential impacts of climate change. While today's hearing is
focused primarily on the latest science related to climate
change, it also is a public forum, and I expect Members will
stray from the science and offer their opinions on various
policy options that have been proposed.
So in that vein, let me set the record straight from the
beginning. I am skeptical about mandatory regulation of
greenhouse gases, which some of my colleagues are promoting as
the best solution to the problem of climate change.
As a nation, we can't figure out how to write a cap-and-
trade bill that does not cause an immediate spike in natural
gas prices, a spike that endures for several years at the very
least. The result would be the closing of more factories, the
closing of steel mills, paper mills, lumber mills, and many
others. Gas price increases over the last six years, even
without carbon regulation, have already caused millions of
permanent layoffs. Factories won't compete with utilities to
buy gas. Rather, they will move to China and India where there
are no pollution controls, inevitably worsening global
emissions. In the meantime, Americans will be paying the price.
Clearly, we need to make the American people fully aware of
the cost of mandatory emission caps. The discussion of
mandatory caps comes down to one question: what is the maximum
cost to the U.S. economy in dollars per family in a global
warming bill, and what is the minimum effect on world-wide
temperatures our country is willing to accept at such cost?
Of course, in order to fully answer that question, we will
need to factor into the equation the contribution, or lack of
contribution, of those countries who produce much of the
pollution problems and seem unwilling to be a part of the
solution. I would like to see this committee address this
important equation in the near future.
We have an historic opportunity to use American innovation
to help address the problem, and our committee is poised to
offer competitive solutions. I would like to see more
discussions on how technology, especially alternative energy
technologies, can help address the issue of energy independence
and climate change. I would also like to explore how we can
encourage the development of technologies to use existing
domestic resources more cleanly, effectively, and efficiently.
In fact, later this morning, we will be considering an
alternative energy technology bill on the House Floor. There is
no limit to American innovation. When we put our minds to
solving a problem, we find answers that not only benefit our
country, but also the world. We have always been leaders in
technology. This should be no exception. I would like to see
this committee promote the development of a wide range of new
technologies to help America become energy independent while
maintaining our competitive edge in the world economy. In the
end, innovation can do a lot, but only so much. World powers
must absolutely do their part. Without this, there can be no
true success in solving the problem of global warming.
I look forward to hearing from our witnesses today and
yield back my time.
[The prepared statement of Mr. Hall follows:]
Prepared Statement of Representative Ralph M. Hall
Good morning. I am glad the Chairman organized this hearing about
the important topic of global warming, or as some prefer to call it,
climate change. Let me start by thanking all of the witnesses for being
here today. This will be a key issue in the 110th Congress and I hope I
speak for all the Committee Members in saying we appreciate your time
and the expertise that you can provide to our discussions.
There will be much debate this Congress about what policies the
United States should adopt to deal with the potential impacts of
climate change. While today's hearing is focused primarily on the
latest science related to climate change, it is also a public forum and
I expect Members will stray from the science and offer their own
opinions on various policy options that have been proposed. So, in that
vein, let me set the record straight from the beginning. I aim
skeptical that mandatory regulation of greenhouse gasses, which some of
my colleagues are promoting, is the best solution to the problem of
climate change.
As a nation, we can't figure out how to write a cap-and-trade bill
that does not cause an immediate spike in natural gas prices--a spike
that endures for several years at the very least. The result will be
the closing of more factories--steel, paper, lumber and many others.
Gas price increases over the last six years, even without carbon
regulation, have already caused millions of permanent lay-offs.
Factories won't compete with utilities to buy gas. Rather, they will
move to China and India where there are no pollution controls,
inevitably worsening global emissions. In the meantime, Americans will
pay the price.
Clearly, we need to make the American people fully aware of the
costs of mandatory emission caps. The discussion of mandatory caps
comes down to one question--What is the maximum cost to the U.S.
economy (in dollars per family) in a global warming bill, and what is
the minimum effect on worldwide temperature our country is willing to
accept at such cost? Of course, in order to fully answer that question,
we will need to factor into the equation the contribution, or lack of
contribution, of those countries who produce much of the pollution
problems and seem unwilling to be a part of the solution. I would like
to see this committee address this important equation in the near
future.
We have an historic opportunity to use American innovation to help
address this problem, and our committee is poised to offer competitive
solutions. I would like to see more discussion of how technology,
especially alternative energy technologies, can help address the issue
of energy independence and climate change. I would also like to explore
how we can encourage the development of technologies to use existing
domestic resources more cleanly, effectively, and efficiently. In fact,
later this morning we will consider an alternative energy technology
bill on the House Floor. There is no limit to American innovation. When
we put our minds to solving a problem, we find answers that not only
benefit our country, but also the world. We have always been leaders in
technology--this should be no exception. I would like to see this
committee promote the development of a wide range of new technologies
to help America become energy independent while maintaining our
competitive edge in the world economy. In the end, innovation can do a
lot, but only so much. World powers must absolutely do their part.
Without this, there can be no true success in solving the problem of
global warming.
I look forward to hearing from our witnesses today and yield back
the balance of my time.
Mr. Sensenbrenner. Mr. Chairman, I have a parliamentary
inquiry.
Chairman Gordon. The gentleman from Wisconsin.
Mr. Sensenbrenner. My parliamentary inquiry, Mr. Chairman,
is are all of the witnesses that will appear today, including
the distinguished Speaker, going to be subjected to questioning
under the five-minute rule, as required by House Rule 11?
Chairman Gordon. The gentleman raises a good question, but
I will excuse the Speaker after her opening remarks.
Mr. Sensenbrenner. A further parliamentary inquiry. Is the
Chair aware that House Rule XI 2.(j)(2)(A) reads as follows:
``Subject to subdivisions B and C, each Committee shall apply
the five-minute rule during the questioning of witnesses and
the hearing until such time as each Member of the Committee,
who so desires, has had an opportunity to question each
witness.''
Chairman Gordon. I am aware of it, and I ask unanimous
consent that the Speaker be allowed to leave after her opening
statement.
Mr. Sensenbrenner. Mr. Chairman, I object, and I request
that House Rule 11, as cited, be applied, because it is
mandatory.
Chairman Gordon. As the gentleman knows, anything can be
waived by unanimous consent.
Mr. Sensenbrenner. Mr. Chairman, I object.
Chairman Gordon. Well, if that is your choice, then you
will be able to do that, and I am sure that the Speaker will
give you a very good answer.
Thank you, Mr. Hall. And Sherry Boehlert, as you can see,
things still don't always change around here, but we welcome
you back. And you prove that you can come home, and that we are
very glad you are here.
I ask unanimous consent that all additional opening
statements submitted by the Committee Members be included in
the record. Without objection, so ordered.
[The prepared statement by Mr. Costello follows:]
Prepared Statement of Representative Jerry F. Costello
Good morning. I want to thank the witnesses for appearing before
our committee to discuss the first section of the 2007 assessment
report, Climate Change 2007: The Physical Science Basis of Climate
Change, prepared by the Working Group I of the Intergovernmental Panel
on Climate Change. This is a sobering report that demands our attention
and I commend Chairman Gordon for moving quickly to hold today's
hearing.
This report gives the Congress added momentum to take meaningful
action to combat global warming, and I look forward to working with my
colleagues as we craft such legislation. This process needs to be one
of consensus, taking a wide view of our current energy realities as
well as the goals we need to reach in the future. As the Working
Group's report states, ``continued greenhouse gas emissions at or above
the current rates will cause further warming causing changes in the
global climate system.'' Given the current state of scientific
knowledge of climate change and prior reports based upon six years of
research, we need to work together to find responsible solutions to
take action to slow this trend.
Toward this end, we cannot ignore the reality that coal is going to
play a role in our nation's energy supply and the world energy supply
for years to come. Coal generates half of the electricity in this
country and is a reliable domestic source of power with a 250-year
supply of coal in the U.S. alone.
To fully maximize our use of coal, we must continue to take steps
that reduce emissions. The only way to achieve this goal is through
advancements in technology. I have been a strong supporter of clean
coal initiatives and programs to advance the research and development
needed to improve coal-based electricity generation. Congress must
continue to support the clean coal programs in the President's FY08
budget, which includes the FutureGen Project, slated to be the world's
first zero-emissions coal plant. Among other things, FutureGen will
demonstrate the ability to sequester carbon dioxide emissions safely
underground. The more coal plants using clean coal technology equals
less harmful emissions in our atmosphere and a reduction of greenhouse
gases.
Clean coal technologies do exist; however, they need the support
and backing from Congress to further develop and demonstrate their
commercial viability. As we consider climate change legislation, I
encourage my colleagues to include coal as part of our energy solution.
Again, I look forward to working with my colleagues as we find
practical solutions that lead us down the path of energy independence
and protection of our environment.
I welcome the panel of witnesses and look forward to their
testimony.
[The prepared statement by Ms. Johnson follows:]
Prepared Statement of Representative Eddie Bernice Johnson
Thank you, Mr. Chairman. Today's hearing brings representatives of
an important body of scientific knowledge on the state of science
regarding climate change.
The Intergovernmental Panel on Climate Change (IPCC) has spent
hundreds, maybe thousands of hours preparing this report. The Panel
gathered the world's leading experts on Earth science and surveyed the
literature.
The Panel took comments from the greater scientific community. All
of this work has resulted in a high quality product that policy-makers
should take seriously.
I have been frustrated by the lack of action--real action--in
dealing with climate change from the legislative standpoint.
Why don't we mandate stricter standards to that all automobiles run
on a greater number of miles per gallon of gasoline? Why haven't we
passed into law good ideas such as the Chairman's on alternative fuel
research and development?
Why haven't we explored and utilized more of our domestic oil
resources in the short-term, while investing heavily in solar, wind,
nuclear, hydrogen fuel research and development?
Why haven't we provided more incentives for the American people to
buy fuel-efficient or hybrid vehicles?
The number of unanswered questions of this nature keeps growing.
I am eager to hear what today's witnesses have to say, and I thank
the Chairman for inviting them to testify today.
[The prepared statement by Mr. Lipinski follows:]
Prepared Statement of Representative Daniel Lipinski
I am pleased that with this hearing today, we will continue the
discussion on the issue of global climate change in the House Committee
on Science and Technology.
The science on climate change has come a long way since the first
international scientific conference on climate almost 30 years ago.
This fourth assessment report by the IPCC represents a significant
expansion in our knowledge of the influence of human activity on the
Earth's climate. The solid scientific conclusions reached in this
report allow us to move beyond debating whether humans are affecting
climate change, and let us begin the discussion of how to resolve the
dilemma before us.
The challenges we face, which are documented in dramatic scientific
detail within this report, highlight the need to act and act now. The
need to find cleaner, less polluting sources of energy to reduce our
impacts on climate change offers us a future of great opportunities,
especially as we seek to compete in the global economy of the 21st
Century.
Fortunately, feasible approaches to reducing carbon dioxide
emissions are no longer out of reach. In the 109th Congress, the House
Committee on Science heard from U.S. businesses that had implemented
energy efficient practices and manufacturing changes to reduce
greenhouse gas emissions. I applauded the voluntary actions of these
businesses for taking the lead even in the absence of mandatory
requirements.
This is a global challenge, and we must do our part to see that the
health of our planet does not deteriorate further. As such, we must
work on providing greater incentives to all U.S. businesses so they
will continue to develop new environmentally friendly technologies and
implement further reductions in greenhouse gas emissions.
I look forward to the release of the Working Group II and Working
Group III reports later this spring and welcome the chance to learn how
we might go about mitigating global climate change. It is my hope that
creative and vigorous dialogue in the 110th Congress will yield
concrete results that will put us on the right path toward a more
sustainable future.
[The prepared statement by Mr. Ross follows:]
Prepared Statement of Representative Mike Ross
I would like to first thank Chairman Gordon and Ranking Member Hall
for holding today's hearing on climate change. I would also like to
thank Speaker Pelosi for coming before the Committee today and all of
the witnesses who have come here to discuss their findings on this
topic.
I am honored that our committee will be the first to hear from the
authors of the Intergovernmental Panel on Climate Change's Report on
Global Climate Change.
I strongly believe that our nation must develop a comprehensive
plan that combats climate change by investing in alternative and
renewable fuels and reducing greenhouse gas emissions and I am hopeful
that today's hearing will continue the discussion of climate change to
aid in this process. I also believe in a common sense approach to
imposing regulations that will help to improve our environment and
combat the harmful effects of global warming, while maintaining jobs
and strengthening our nation's economy.
I am hopeful that all of these goals can be met and I look forward
to today's discussion of the IPCC's report, which will provide great
insight into this topic.
[The prepared statement by Mr. Carnahan follows:]
Prepared Statement of Representative Russ Carnahan
Mr. Chairman, thank you for placing this important hearing first on
the calendar of the Committee on Science and Technology for the 110th
Congress. By prioritizing it on our agenda, you have helped to
emphasize the growing importance of climate change on the national
debate.
Speaker Pelosi, it is a tremendous honor to have you appear before
us today and I look forward to hearing your testimony on the state of
climate change. Your presence speaks loudly to your commitment to
bipartisan action on this very important issue. Thank you for joining
us.
The conclusions of the Intergovernmental Panel on Climate Change
(IPCC) have clarified that human-induced influences impact the climate.
With very high confidence, the IPCC now tells us that the Earth is
warming as is indicated by an increase in global average air and ocean
temperature, widespread melting of snow and ice, and rising global
average sea level. While this news is unfortunate, the certainty with
which science now warns that human actions are impacting the climate
should motivate the Congress to move forward on legislative solutions.
I am proud to say that last Congress I was very active on the issue
of global warming, introducing a bipartisan and bicameral Sense of
Congress resolution, H.Con.Res. 453, aimed at addressing global warming
through the negotiation of international treaties. Furthermore, during
debate on the 2005 Energy bill, I attempted to amend the bill by
redrafting and extending the Hybrid tax credit, a credit that was
eventually enacted into law and is a step forward in our efforts to
stem harmful emissions.
St. Louis has one of the highest rates of asthma and respiratory
diseases in the country, the causes of which are directly related to
global warming. For this reason, climate change is an issue of vital
importance to my constituents.
I look forward to hearing the testimony of Speaker Pelosi and the
IPCC witnesses and participating in the conversation of climate change
as we deliberate over legislative solutions in the 110th Congress.
Thank you all for being here today.
[The prepared statement by Mr. Mitchell follows:]
Prepared Statement of Representative Harry E. Mitchell
Thank you, Mr. Chairman.
I think one of the things the American people are hoping from this
Congress is for Democrats and Republicans to work together to take the
threat of global warming to our environment and our national security
seriously.
We are watching our planet rapidly change before our eyes. Once
majestic ice caps are melting. Weather patterns are changing in very
troubling ways. The temperature of our atmosphere is on the rise. The
intensity of rains and drought are more extreme. Hurricanes, such as
Katrina, are becoming more powerful, and more deadly.
The scientific evidence that global warming exists--and that humans
are largely responsible for the change in our climate--is overwhelming.
The report by the Intergovernmental Panel on Climate Change--which
we are hearing more about today--continues to confirm our fears about
global warming.
I hope that as the American people and the international community
continue to learn about this report and the effects of global warming,
our renewed interest in the topic will turn into action.
The United States is the world leader in the emission of greenhouse
gases. That means we have a moral obligation to lead the world to a
solution.
I believe that America's ingenuity, and our unique spirit can be an
incredible asset in this cause. Our action on global warming can also
help restore our authority as a respected global leader.
Developing sound policy on global warming--and investing in new
technologies and clean energy--can help grow our economy too.
This Congress, the President and the American people have a
responsibility, and I hope that we re-dedicate ourselves to meeting
that responsibility.
[The prepared statement by Mr. Ehlers follows:]
Prepared Statement of Representative Vernon J. Ehlers
I am pleased that the Science and Technology Committee is hearing
from scientists who participated in the Intergovernmental Panel on
Climate Change, especially so soon after the Summary for Policy-makers
was released. We're fortunate to receive this information ``hot off the
presses'' (if I am allowed to think that anything ``hot'' is a good
thing given today's topic).
In my mind, there are three big questions related to climate
change. One, is climate change happening? Two, to what extent is it
anthropogenic? And three, what are we going to do about it? I believe
that the research the panelists will discuss today advances our
knowledge of the answers on the first and second of these questions. We
need to hear how the methods of monitoring changes in the Earth have
improved, and what the most recent data indicates, especially since the
last major assessment was finalized in 2001. But an even bigger task
for this committee and our colleagues is to answer the third question:
what are we going to do about climate change? Comprehensive and
continuing science is critical for us to be able to answer that
question. The additional working groups of the IPCC also will help
address the broader policy questions of climate change strategy, and I
look forward to reviewing those results in the spring.
Our planet is a dynamic system, and any attempts to mitigate
warming, adapt to sea level rise, or any other response to climate
change will rely on scientific research and researchers, like those
testifying before us today. These individuals have dedicated not just
hours, but years to the process that results in the full assessment of
climate science due in May. I thank them for that commitment, and look
forward to the opportunity to hearing what they have to say.
[The prepared statement by Mr. Neugebauer follows:]
Prepared Statement of Representative Randy Neugebauer
Mr. Chairman:
Thank you for holding this hearing. I welcome the opportunity to
take part in this important discussion and look forward to hearing from
our distinguished panelists.
Like everyone else, and despite the recent record cold temperatures
here in DC and around the country, I believe the Earth has gotten
warmer over the past century. I don't doubt that there is consensus on
that fact. Beyond that, however, I see a lot of disagreement.
On the one hand, we have the distinguished scientists before us who
have authored key findings of the IPCC's report. They--and others--
believe ``with more than 90 percent confidence'' that, based on their
models and data, human activity is chiefly responsible for global
warming since the 1950s.
On the other hand, we have other distinguished scientists who
disagree with that assessment. Some believe that humans, to varying
degrees, have played a role in global warming. Others believe that
solar activity has been the primary factor, given their models and
data.
The bottom line, Mr. Chairman, is that the scientific community
does not speak with one voice on this important issue. And that's not
unusual. It happens all the time with scientific inquiry. New models
are developed; data is re-examined; new hypotheses are tested. That's
normal and healthy--when you have a robust scientific community free of
political or ideological interference.
But Mr. Chairman, what I've seen lately has been disturbing--and it
should concern every American. Scientists who disagree with the popular
view on global warming are being ostracized. They are being labeled
``global warming deniers.'' We have politicians and activists--most of
whom are not scientists themselves--working to silence highly trained
and accredited scientists. Some call for silencing their disagreement
by revoking professional certifications and removing them from key
positions.
Mr. Chairman, why has the reaction to these differing scientific
findings been so extreme and so reckless? I strongly suspect that
ideology, not scientific disagreement, is behind this reaction.
Mr. Chairman, it is an inconvenient truth that we run a terrible
danger when scientific debate is stifled because it gets in the way of
political goals.
We in Congress, and in this committee especially, are called upon
to make scientific and environmental policy that will affect our
economy, our security, and our general welfare; and not just for us,
but for future generations of Americans, as well.
To the best of my knowledge, none of us sitting on this committee
are climatologists or meteorologists or otherwise competent on our own
merits to claim full knowledge of this complex issue. So, we deserve to
have all the scientific information before us--to consider it, and to
make the wisest policy choices based on all the findings before us.
Mr. Chairman, you have indicated that it's time to end the debate
on this issue. But I respectfully disagree with that assessment. It is
plain that the debate has just begun.
I hope future hearings on global warming will provide the
opportunity to hear opposing views and have a full healthy debate and
dialogue on this issue.
Thank you.
Chairman Gordon. I ask unanimous consent that
Representative Gilchrest, who was a former Member of this
committee, be permitted, at his request, to sit at the dais for
this hearing and that he be permitted to ask questions after
all Members of the Committee have an opportunity to question
the witnesses. Mr. Sensenbrenner, is that okay with you?
Mr. Sensenbrenner. I just want to see the rules followed.
Chairman Gordon. All right. Thank you. Without objection,
so ordered.
Now it is my pleasure and privilege to welcome the Speaker
of the House of Representatives, Nancy Pelosi, to be with us
today. I know this is an issue that you are both informed about
and have a passion about. And we welcome you here for this
hearing and welcome to hear your remarks.
Panel I:
STATEMENT OF THE HONORABLE NANCY PELOSI, SPEAKER OF THE HOUSE
OF REPRESENTATIVES
Speaker Pelosi. Thank you very much, Mr. Chairman.
I thank you and your distinguished Ranking Member, Mr.
Hall, for the courtesy extended here today for me to present my
views before this very important committee.
The last time I was in this room was for the unveiling of
the portrait of Mr. Boehlert, and here we are, portrait and Mr.
Boehlert, as well, and I join you in thanking him for his great
leadership to our country and in working in a bipartisan way to
use science as a basis for progress in our country.
I want to also join in commending the witnesses who will be
presenting today. I thank them for their extraordinary
contribution to understanding of climate change. Their new
report confirms that climate change is indisputably underway
and states with 90 percent certainty that greenhouse gases
released by human activities are the main cause of global
warming.
I am very pleased to see on the wall, which in the
excitement of Mr. Boehlert's unveiling, I didn't see that day
several months ago, that you quote Tennyson, who is my favorite
poet, Alfred Lord Tennyson. And it says, ``For I dipped into
the future, as far as human eyes could see, saw the vision of
the world and all the wonder that would be.'' What a wonderful
inspiration to the work of this committee.
You, on this committee, are opening a window into our
future. Looking through that window, we see a future in which
global warming will reshape our planet and our society. We also
see a future in which harsh consequences could be blunted by
prompt action. That is the good news.
This is an issue that is as immediate to the American
people as their own neighborhoods and as global as the planet
itself. It was interesting to me that on a recent visit from
the Executive Committee of the U.S. Conference of Mayors, a
bipartisan Committee, they brought forth their 10-point program
for strong cities, strong families, a strong America. And point
number one in the Conference of Mayors' 10-point proposal was
energy independence, climate change, global warming. That was
their top priority. They had best practices, that they, in a
bipartisan way, are sharing with each other and instituting in
their communities. Again, this is as immediate to the lives of
the American people as their own neighborhoods, and again, it
is as global as the planet. And that--more on that in just a
moment.
On the science of global warming, the level of carbon
dioxide in the atmosphere is by far the highest in 650,000
years. Temperatures are estimated to rise anywhere from two
degrees Fahrenheit to as high as 11.5 degrees by the end of the
century. We can expect rising sea levels, more intense storms,
increased drought in some areas and more floods in others, heat
waves, spread of tropical diseases, extinction of species,
changes in ocean salinity, and melting ice in the polar
regions, and that is already happening.
The catastrophic hurricanes of 2005, Katrina and Rita,
foreshadow the challenges we will face. All along our
coastlines, our great cities and small towns will be threatened
by rising sea levels and intensifying storms.
Not only coastal areas will be affected. Inland communities
will be gravely affected as well by drought and flood. Movement
of climate change refugees from one country to another could
increase political instability in many regions of the world.
These environmental refugees are a real, real concern.
Looking through the window into the future that you have
opened, we also see that we can reshape our activities now and
prevent catastrophic global warming. Where once we thought the
effects of global warming would occur decades away, change is
already underway.
We hold our children's future in our hands, not our
grandchildren, or great-grandchildren, but our own children. As
the most adaptable creatures on the planet, it is time for us
to continue to adapt.
Scientific evidence suggests that to prevent the most
severe effects of global warming, we will need to cut global
greenhouse gas emissions roughly in half from today's levels by
2050. The Bush Administration continues to oppose mandatory
limits on greenhouse gases, restating this position immediately
upon the release of the IPCC report. I respectfully disagree
with the distinguished Ranking Member in his comments, and this
is a wonderful venue for the debate, this very important
committee with these very informed Members.
I do believe, though, Mr. Hall and Mr. Chairman, we cannot
achieve the transformation we need, both in the United States
and throughout the international community, without mandatory
action to reduce greenhouse gas pollution. Many of the
technologies to revolutionize our use of energy are already at
hand, as the distinguished gentleman mentioned, and we can
develop others, waiting on the shelf, or under development.
Restrictions on greenhouse gas emissions will drive these
technologies into the marketplace quickly and cost-effectively,
while simultaneously creating the next generation of good-
paying new jobs.
In addition, we must address land-use policies in the U.S.
and worldwide, since the loss of forests currently contributes
about 25 percent of global carbon dioxide emissions. Older
forests can store more carbon while also providing fuel for
biomass energy in a sustainable manner.
We have a responsibility to work together with countries,
as the distinguished Ranking Member Mr. Hall said, but these
other countries, India and China, to name two, to work with
them for them to reduce the level of carbon dioxide in the
atmosphere. That may be as important to our grandchildren and
our children's future as anything we do here. The United States
and China, as well as India, are the largest contributors of
carbon dioxide emissions in the world, and it is estimated that
China will surpass the United States in three years.
We need to engage the Chinese government by working
cooperatively to develop clean and renewable sources of energy.
I have asked the Chairs of the committees of jurisdiction
to work with their Ranking Members in a bipartisan way with the
Members of the Committees to develop legislation over energy,
environment, and technology policy and to report that
legislation to us no later than June 1 so that we can have an
energy independence global warming package by the 4th of July.
This committee is way ahead of the rest. It has
legislation, as has been mentioned, on the Floor today, and I
commend you for that, Chairman Gordon and Mr. Hall and Members
of the Committee. I know that you have other legislation that
relates to innovation and the innovation agenda, which is
directly related to this issue that will help advance the
technologies needed to help save our planet.
We hope to have legislation that will be a starting point
on global warming and energy independence soon. Again, you have
taken the lead.
I also want to mention that we are creating a Select
Committee on Energy Independence and Global Warming to raise
the visibility of these urgent issues and gather critical
information to protect America's security. This is a national
security issue. The Select Committee will not have legislative
jurisdiction, but will develop policy strategies, technologies
and other innovations intended to reduce the dependence of the
United States on foreign sources of energy, and to achieve
substantial and permanent reductions in emissions and other
activities that contribute to climate change and global
warming. The Select Committee will share its findings with the
legislative committees of the House and with the public, and
they will make a special effort to communicate with younger
Americans by using the most cutting-edge technologies. Young
people are very concerned about the issue of global warming. It
is natural, because the future is theirs, and this has a big
impact on the future.
For 12 years, the leadership in the House of
Representatives has stifled all discussion and debate on global
warming. The long rejection of reality is over, to the relief
of Members, I believe, on both sides of the aisle.
We teach our children, Mr. Chairman and Ranking and other
Members of the Committee, that everything in nature is
connected, and indeed, it is. The Bible tells us in the Old
Testament that, ``To minister to the needs of God's creation is
an act of worship. To ignore those needs is to dishonor the God
who made us.'' Indeed, this planet is God's creation. That is
why large segments of the evangelical movement have become part
of this effort to curb and stop global warming. We have a
responsibility to make an act of worship by protecting God's
creation.
There is a growing chorus of voices, including
evangelicals, in favor of taking serious and sustained action
on global warming, from scientists to Fortune 100 CEOs, from
evangelical Christians to environmentalists, from farmers to
hunters and anglers. We will work together, holding hearings,
developing legislation, and tackling one of America's--
humanity's--greatest challenges yet: global warming.
With that, Mr. Chairman, I thank you, once again, for the
opportunity to present my views as Speaker of the House to you
and to Mr. Hall with the promise that this is not about taking
one point of view and going forward but in trying to work in a
bipartisan way for sustainable initiatives that we can agree
upon and make a difference for our children and see ``the
vision of the world and all the wonder that would be'' in this
important committee. Thank you, Mr. Chairman.
[The prepared statement of Ms. Pelosi follows:]
Prepared Statement of Speaker Nancy Pelosi
Thank you, Chairman Gordon, for holding this important hearing on
the findings of the Fourth Assessment Report by the Intergovernmental
Panel on Climate Change (IPCC). Thank you, Ranking Member Hall, and my
colleagues on the Science and Technology Committee for your attention
to the pressing issue of climate change.
To the witnesses appearing today, thank you for your extraordinary
contributions to our understanding of climate science. Your new report
confirms that climate change is indisputably underway and states with
90 percent certainty that greenhouse gases released by human activities
are the main cause of global warming.
You have opened a window into our future. Looking through that
window, we see a future in which global warming will reshape our planet
and society. We also see a future in which harsh consequences could be
blunted by our prompt action.
The level of carbon dioxide in the atmosphere is by far the highest
in 650,000 years. Temperatures are estimated to rise anywhere from two
degrees Fahrenheit to as high as 11.5 degrees by the end of the
century. We can expect rising sea levels, more intense storms,
increased drought in some areas and more floods in others, heat waves,
spread of tropical diseases, extinction of regions.
The catastrophic hurricanes of 2005, Katrina and Rita, foreshadow
the challenges we will face. All along our coastlines, our great cities
and small towns will be threatened by rising sea levels and
intensifying storms.
Not only coastal areas will be affected. Inland communities will be
gravely affected as well by drought and flood. Movement of climate
change refugees from one country to another could increase political
instability in many regions of the world.
Looking through the window into the future that you have opened, we
also see that we can reshape our activities now and prevent
catastrophic global warming. Where once we thought the effects of
global warming would occur decades underway.
We hold our children's future in our hands--not our grandchildren,
or great-grandchildren, but our own children. As the most adaptable
creatures on time for us to adapt.
Scientific evidence suggests that to prevent the most severe
effects of global warming, we will need to cut global greenhouse gas
emissions roughly in half from today's levels species, changes in ocean
salinity, and melting ice in the polar away, change is already the
planet, it is by 2050. The Bush Administration continues to oppose
mandatory limits on greenhouse gases, restating this position
immediately upon the release of the IPCC report.
We cannot achieve the transformation we need, both in the United
States and throughout the international community, without mandatory
action to reduce greenhouse gas pollution. Many of the technologies to
revolutionize our use of energy are already at hand, waiting on the
shelf, or under development. Restrictions on greenhouse gas emissions
will drive these technologies into the marketplace quickly and cost-
effectively, while simultaneously creating the next generation of good-
paying new jobs.
In addition, we must address land-use policies in the U.S. and
worldwide, since the loss of forests currently contributes about 25
percent of global carbon dioxide emissions. Older forests can store
more carbon while also providing fuel for biomass energy in a
sustainable manner.
We have a responsibility to work together with countries such as
China to reduce the level of carbon dioxide in the atmosphere. The
United States and China are the two largest contributors of carbon
dioxide emissions in the world and it is estimated that China will
surpass the U.S. in just three years.
We need to engage the Chinese Government by working cooperatively
to develop clean and renewable sources of energy.
I have also asked the committees that have jurisdiction over
energy, environment and technology policy to report legislation on
these issues by June. We hope to have legislation that will be a
starting point on global warming and energy independence through the
committees by July 4th, so that this year, Independence Day is also
Energy Independence Day.
We are creating a Select Committee on Energy Independence and
Global Warming to raise the visibility of these urgent issues and
gather critical information to protect America's security. The Select
Committee will not have legislative jurisdiction, but they will develop
recommendations on policies, strategies, technologies and other
innovations intended to reduce the dependence of the United States on
foreign sources of energy, and to achieve substantial and permanent
reductions in emissions and other activities that contribute to climate
change and global warming. The Select Committee will share its findings
with the legislative committees of the House and with the public, and
they will make a special effort to communicate with younger Americans
by using the most cutting-edge technology.
For twelve years, the leadership in the House of Representatives
stifled all discussion and debate of global warming. That long
rejection of reality is over, to the relief of Members on both sides of
the aisle.
The Bible tells us in the Old Testament, `To minister to the needs
of God's creation is an act of worship. To ignore those needs is to
dishonor the God who made us.'
There is a growing chorus of voices in favor of taking serious and
sustained action on global warming: from scientists to Fortune 100
CEOs, from evangelical Christians to environmentalists, from farmers to
hunters and anglers. We will work together, holding hearings,
developing legislation, and tackling one of humanity's greatest
challenges yet global warming.
Discussion
Chairman Gordon. Speaker, thank you for joining us today.
You are the first Speaker to be before this committee. I have
only been here 22 years, but you are the first Speaker that I
know of in those 22 years to make a presentation before any
committee, and I suspect this may be groundbreaking in the
history of the Congress, which I think demonstrates your
passion and leadership on this issue, and we appreciate you
being here.
My Ranking Member Hall and I have no questions. We are
going to let Mr. Sensenbrenner have his question, and then I am
going to ask that we have unanimous consent that any further
questions be submitted by writing.
Mr. Sensenbrenner.
Well, then Mr. Sensenbrenner will have the first question.
Economic Impacts of Climate Change
Mr. Sensenbrenner. Thank you very much, Madame Speaker.
Speaker Pelosi. Thank you, Mr. Sensenbrenner.
Mr. Sensenbrenner. I welcome you here today.
Speaker Pelosi. Thank you.
Mr. Sensenbrenner. I hope that you and your successors
engage in the debate on the issues before the Congress, and I
think that this is a very welcome development.
I really do have to take issue with your comment in your
statement that for 12 years there was no discussion of global
warming, because during my chairmanship of this committee, and
particularly in 1998 and 1999, we had a number of hearings at
the Full and Subcommittee level relative to the Kyoto protocol,
the science behind it, and the economic consequences this
ratification would entail to the United States and its workers.
One of those witnesses was the head of the Energy Information
Agency in the Department of Energy who was a direct appointee
of President Clinton. And this man testified that the
ratification of Kyoto and the caps that are similar to that
which you are advocating, would cause a 60 to 80 percent
increase in the cost of natural gas, electricity, and fuel oil
to the American consumer. And given the fact that China is not
under any caps and as late as last week said that they didn't
want to do that, I would ask you to look at the impact on
American jobs, because we do not want to have anything we do
result in the outsourcing of American jobs to countries like
China and India and Mexico that have not capped or even slowed
down their growth in greenhouse gas emissions. What are you
planning to do, Madame Speaker, to make sure that we don't
legislate on this area in a way that wrecks the American
economy and costs our workers jobs?
Speaker Pelosi. Thank you, Mr. Sensenbrenner.
Whatever actions we take have to be based, I believe, on
science and on the facts. And one fact is that America must
innovate in this arena for us to be ahead. We look forward to
doing this in a bipartisan way. We know that there will be
impacts on the coal industry, on other sources of energy, and
we want to hear what those industries have to say. So this
isn't about running roughshod. This is about working together.
And hopefully we can work in a bipartisan way with the
President of the United States in order to do this. I see it as
an economic opportunity, a place where green can be gold for
our country where the technologies we develop for dealing with
the coal industry and other industries in our country on which
we are dependent now for energy using their initiatives,
because they are making change, and we have to listen to them
as well, to Mr. Rahall and Mr. Boucher, who represent these
districts, Members of the Republican party who represent them
as well.
So what we want to do is do something where we have as much
unity as possible, and we certainly are sensitive to the issue
of economic growth in our country.
Mr. Sensenbrenner. Well, Madame Speaker, just to follow up,
I would make the observation that there are two sides to the
equation. One is the scientific side and relative to emissions
of greenhouse gases. The other is the economic consequences of
any actions that we take. And you know, I am very fearful the
way this debate has been joined and, given who the witnesses
are following you, that we are looking at one side of the
equation and ignoring the other side, and we can't do that for
the sake of American jobs.
And I yield back the balance of my time.
Speaker Pelosi. Yes, I agree with that, Mr. Sensenbrenner.
We can't ignore it, but we also can't ignore the consequences
of not doing something, because that will have an economic
impact as well.
Select Committee on Energy Independence and Global Warming
Chairman Gordon. Thank you. Mr. Sensenbrenner, I will point
out that the Minority had the right to submit witnesses. I
think that you had one. You withdrew him. And so this was not a
rigged jury, but rather it may be by default. Maybe no one else
wanted to come up and speak. But that is where we are.
Madame Speaker, as we gather together here, I know you had
mentioned earlier, again, your passion for this and that you
wanted to develop a Select Committee. Could you tell us more
about that Select Committee and why it is so important and what
you want to do with it?
Speaker Pelosi. Thank you, Mr. Chairman.
There are eight or nine committees of jurisdiction on this
issue ranging from this important committee, the Ways and Means
Committee, the International Relations Committee, as has been
pointed out by Mr. Sensenbrenner, and the distinguished Ranking
Member, other countries have a big impact on how we go forward
on this issue. And so this Select Committee was designed to try
to get some of the best information possible by communicating
directly in the cities of America where, again, best practices
are being used to address this issue, where the bipartisan
Conference of Mayors is putting forth global warming and energy
independence as their top priority in their 10-point program,
working with the governors, working with leaders around the
world. The European Union is way ahead of us on this issue.
They see it as an economic issue, Mr. Sensenbrenner. They see
it as an economic issue. They know that they want to be out
there in front with the technologies that will enable us to
curb global warming, and that is in our economic interest. The
United Nations, of course we have this report, but the United
Nations has this as a priority as well.
I have asked this--a Select Committee to--whether it is as
local as a neighborhood, as global as the planet, to help
communicate this message, get the best possible information. I
could have done it as a task force within the Democratic party,
but I wanted it to be bipartisan so we had every point of view
represented, different views in our own party as well as views
within the Republican party so that as we go forward, we are
doing so in a way that is understanding the consequences of it.
So it is a way for us to communicate with the next
generation of leaders in our country, to communicate with
countries that have a big impact on global warming like China
and India, communicate to the neighborhoods of America that
everyone is involved in this decision, because everyone is
affected by it. And we want to go forward in a temperate way
but in a bold way to make a difference for our children.
So that is the purpose of it. It does not have legislative
authority. It will end at the end of this Congress, and I think
it will be a force for good.
Chairman Gordon. Mr. Hall.
Mr. Hall. Mr. Chairman, I have no questions for this
speaker. And we did invite, from the United States Chamber of
Commerce one of the great bodies of advice for this committee.
They said they did not have the time to answer the political
questions. They thought it was going to be on science alone. It
is not that. And we will have them before you later.
I yield back any time that you might yield to me.
Chairman Gordon. Well, Mr. Hall, I think you will find that
the IPCC Report is the scientific definitive statement on this
issue and we look forward to hearing that.
Let us see. Is there anyone else on the top row?
Mr. Akin.
Nuclear Energy
Mr. Akin. Thank you, Mr. Chairman.
And I appreciate your allowing us to ask a few questions.
And it is a very interesting debate. Madame Speaker, thank you
for joining us this morning.
Speaker Pelosi. Thank you.
Mr. Akin. Your comments, you laid out a couple of basic
premises that you were assuming. The first premise is that the
Earth is getting warmer. I don't think there is a lot of debate
on that. I think the Earth is getting warmer.
The second one is maybe another question that is
interesting. It is being caused by our burning hydrocarbons.
If, in fact, you apparently believe that to be true, my
question is, do you endorse the expansion of nuclear energy,
because that does not burn hydrocarbons?
Speaker Pelosi. Mr. Akin, in the early days of my life in
the Congress, I was an opponent of nuclear energy, because I
didn't know what was going to be done--how we would dispose of
the waste from it.
Your question is a good one, because the technology has
changed, and I bring a more open mind to that subject now,
because I think we have to look at the technology and really
compare it to what the alternatives. If they are looking at
India and we are looking at China and looking at them putting
on more coal-burning plants than we have in the United States,
that they are just going to even add now, and the alterative
might be nuclear, we have to weigh what that does to the
environment. But I think that the answer is always with
technology. If we can't--if the technology is at a place where
we can dispose of the waste, well, let us at least try to move
it to that place. But I have a different view of nuclear energy
than I did, say, 20 years ago when I came to this----
Mr. Akin. I think what I hear you saying is that you
would--assuming that a reasonable proposal could be made, that
nuclear could be the substitute for burning hydrocarbons.
Speaker Pelosi. Well, I would say I would not, as I did in
my youth, be an active opponent of such a thing, but hope that
we would work together to take it to a place where we can
dispose of the waste. That is the big challenge. But I will say
this. Again, we have to always compare it to if not this, then
what, and what does that do in terms of global warming. So I
think it has to be on the table.
Mr. Akin. That is interesting. I appreciate your open-
mindedness to that alternative.
Speaker Pelosi. I do have an open mind.
The International Banking Environmental Protection Act
Mr. Akin. That is something from an engineering
perspective--I am one of the few engineers, I guess, that
managed to get into Congress. Perhaps by mistake, but that is
something that has always seemed very logical, even though
there was sort of a political prejudice against it. The global
or geophysical research letters estimated in 1997 that if the
Earth, that is all of the nations, lived up to the United
Nation's Kyoto protocol on global warming, that we would
prevent no more than 0.1 to 6 degrees Fahrenheit of warming in
50 years. That says that you are talking about some pretty
strong actions that are going to have to be taken. I think this
makes fixing Social Security look easy by comparison. And I
guess I am wondering, you talk about the fact that we have got
the highest level of CO2 in 650,000 years. I guess
my question is, how was it that Greenland was harvesting corn
in the year, what, 900 or 1000 if the CO2 was so
high? Or was there something else making the world warm? And is
it so bad if it gets warmer?
Speaker Pelosi. Well, that is a very good question. About
19 or 18 years ago, early in my term in Congress, I had a piece
of legislation that was called the International Banking
Environmental Protection Act, and it goes right to your final
question. That was a bill that said--that talked about the
International Bank, the World Bank, the Interamerican Bank, the
Asian--all of the multi-development banks. It was a piece of
legislation that I introduced on the Banking Committee. And at
the time, I had opposition from my fellow Democrats on the
legislation because it called for an environmental impact
statement to be made on any projects that the United States
would vote on and that the results of that impact statement
would be made known to the indigenous people of the region as
well as internationally. So that is the bottom line of it.
At the very same time--now this had to be--President Bush
was President, so it was after President Reagan, so it was,
say, 1990, something like that. At that time, the President of
the World Bank said, a very distinguished gentleman, but this
is what he said. He said, ``What difference does it make if
there is global warming, if there is climate change? We can
just go develop those countries where the snow--those areas
where the snow is melting.'' It wasn't really a very informed
statement, and that was, again, like 1990, and it did more to
pass my bill than anything I could do, even getting past the
Democrats on the Committee who were not particularly well
inclined, and President Bush signed it into law.
Mr. Akin. I guess----
Speaker Pelosi. But there was a reality at the time, and
there are serious consequences to global warming, and we have
to face that reality.
Chairman Gordon. The gentleman's time is up. I would----
Mr. Akin. Thank you, Mr. Chairman.
Chairman Gordon.--suggest that it may not matter to
Missouri about global warming, but if Greenland loses all of
its ice and snow, then our friends around the coast are going
to be concerned about it, because there will be an enormous
amount of flooding. I recognize----
Mr. Hall. Mr. Chairman, would you yield?
Chairman Gordon. Yes, Mr. Hall.
Mr. Hall. I think what you are really saying is if we
really want to alter the warming trend significantly, we are
going to have to cut emissions by a very large amount, even
beyond Kyoto. And the question is, that I think the gentleman
is asking down there, is do we currently have affordable
technologies for significantly reducing greenhouse gas
emissions, and is there any estimate of cost, and who pays? I
think that is the major question. That is the reason the
gentleman from----
Speaker Pelosi. That is a good answer.
Chairman Gordon. That is a good----
Mr. Hall. The U.S. Chamber did not want to come on such
short notice.
Chairman Gordon. Well, I have a high regard for the Chamber
and their intelligence and their ability, and I think that they
could have made a good statement, but you have raised a good
question. The good news is we have a panel of scientists that
just got through working on a report with 113 nations, I think
6,000 scientists, approved by this country and this President,
and we are going to hear from them with those very specific
answers, and I am glad we are going to be able to do that.
Mr. Costello.
Question and Answer Session: Congressional Customs
Mr. Costello. Mr. Chairman, thank you.
Mr. Chairman, I do not have any questions for the
distinguished Speaker, but let me say that I am very
disappointed and very surprised that we have not extended to
this witness, to the Speaker of the House, the same courtesy
that we have extended to many Members of the House of
Representatives since I have served on this committee.
I have served on the Science Committee for 18 years. As I
recall under the leadership, I think the record will reflect,
under the distinguished Chairman Sherry Boehlert, under Mr.
Sensenbrenner, under every Chairman of this committee since I
have been there serving on this committee, I can recall many
Members of Congress testifying, presenting their statement
before this committee, and we extended the courtesy to them
because of demanding schedules, let alone the Speaker of the
House of Representatives, allowed them to submit their
testimony and to leave without going through the long ordeal of
questions.
I serve on the Transportation and Infrastructure Committee,
as Mr. Boehlert did in his service in the Congress. We extended
the same courtesy there to countless Members of Congress, and I
just have to tell you that I am extremely surprised. This is
the first, but it won't be the last time that we are going to
debate this issue in this committee and a whole host of other
committees. So I just have to tell you, I am very disappointed
and very surprised.
Mr. Rohrabacher. Would the gentleman yield?
Mr. Costello. We are--I will in just one second. That we
are subjecting the Speaker of the House of Representatives to a
higher standard than we have extended the courtesy to other
Members. Again, I----
Mr. Rohrabacher. Would the gentleman yield?
Mr. Costello. Yes, I will.
Mr. Rohrabacher. I agree with you.
Speaker Pelosi. Thank you, Dana.
Chairman Gordon. Well, the good news is that we have a
great Speaker who can handle herself very well.
Speaker Pelosi. I do have to leave.
Chairman Gordon.We have to reset our timer, and so as we do
that, I am going to recess this committee.
Speaker Pelosi. And may I just--may I thank you, Mr.
Chairman?
Chairman Gordon. Yes, you may.
Speaker Pelosi. May I thank the distinguished Chairman and
Ranking Member, Members of the Committee. It is the first
committee that I have testified before as Speaker of the House.
And because you are a committee about the future, I think that
is perfectly appropriate. I wish you much success in your
deliberations.
Thank you, Mr. Chairman.
Chairman Gordon. You made this a better hearing. Thank you.
Speaker Pelosi. Thank you.
Chairman Gordon. And we are in recess.
[Recess.]
Chairman Gordon. Thank you all. We have our clocks working
again. And now that we have our equipment back in shape, we
will recommence. And I will call this committee back to order,
and I would like to call our panel of witnesses to the table.
Thank you.
We are very pleased to have this distinguished panel of
climate scientists here for this morning. All of our four
witnesses have just returned from Paris where they have
participated in the preparation of the Summary for Policy-
makers release by the IPCC last Friday.
I will begin by introducing Mr. Richard Alley. Mr. Alley is
a Professor of geosciences and an associate of Earth and
Environmental Systems Institute at the Pennsylvania State
University. Mr. Alley is an expert in the area of glaciers and
ice sheets and their potential to cause changes in the sea
level. He serves on the National Academy of Sciences' Polar
Research Board and chaired the NAS Panel on Abrupt Climate
Change. Mr. Alley was a Lead Author of Chapter 4 of the IPCC
Report dealing with changes in snow, ice, and frozen ground.
I will now yield to Representative Udall, if Mr. Udall is
here, yes, to introduce the remaining three panelists who are
members and constituents from his district.
Mr. Udall.
Mr. Udall. Thank you, Mr. Chairman. And many of you on the
Committee know that Boulder is home to many outstanding climate
science facilities, including NOAA's Earth System Research
Laboratory and the National Center for Atmospheric Research.
And I want to start with Dr. Susan Solomon. She serves as
the Co-Chair of Working Group I of the IPCC, and she provided
overall coordination for the report. Dr. Solomon received her
Ph.D. in chemistry from the University of California at
Berkeley in 1981 and currently is a senior scientist at NOAA's
Earth System Research Laboratory. A couple of interesting
background facts about Dr. Solomon, she has a glacier named
after her in the Antarctic because of her work on the causes of
the ozone hole. She is a member of the National Academy of
Sciences. And in March of 2000, she received the National Medal
of Science, the United States' highest scientific honor, for
her ``Key on Insights in Explaining the Cause of the Antarctic
Ozone Hole.'' She has also written a book, which is of great
interest to me as an aging mountaineer, called ``The Coldest
March,'' which covers the tragic story of Captain Robert Falcon
Scott and his British team, who in November 1911, began a trek
across the snows of the Antarctic, striving to be the first to
reach the South Pole. And Dr. Solomon, I can't help but wonder
if the lessons learned from Scott's and Amundsen's expeditions
to the South Pole could be applied to this similarly long,
challenging, and crucial journey to stabilize and reduce
greenhouse gases.
Next to Dr. Solomon is Dr. Kevin Trenberth. Dr. Trenberth
served as a Coordinating Lead Author for Chapter 3 of the
report, ``Observations, Surface, and Atmospheric Climate
Change.'' Currently, he is the head of the climate analysis
section at the National Center for Atmospheric Research (NCAR),
originally from New Zealand, who obtained his doctorate in
meteorology in 1972 from MIT. He was named a fellow of the
American Meteorological Society in 1985 and the American
Association for the Advancement of Science in 1994. He has
published over 400 scientific articles or papers, including 40
books or book chapters and over 175 referee journal articles,
and he is listed among the top 20 authors in Hyatt citations
and all of geophysics. He has also recently served as a member
of the National Oceanic and Atmospheric Administration Climate
Working Group from 1987 to 2006 and is a member of NOAA's
Climate Observing System Council and NOAA's Advisory Panel for
Climate Change Data and Detection.
At the end of the table is Dr. Gerald Meehl. Dr. Meehl is
the Coordinating Lead Author for Chapter 10 of the report,
``Global Climate Projections.'' Dr. Meehl received his Ph.D. in
climate dynamics from the University of Colorado in 1987. His
expertise is in the field of climate modeling. He has been a
scientist on staff at NCAR since 1979. Dr. Meehl has long been
involved with the IPCC, having been a member of the Working
Group I Report group since 1989 and has participated in the
development of several IPCC assessment reports. He is the
author of more than 140 scientific papers and peer-review
journals. He has also, since 1979, as a scientist in the
Climate and Global Dynamics Division, studied the interactions
between El Nino, the Southern Oscillation, and the Indian
monsoon, analyzed the results from global-coupled ocean
atmosphere general circulation models at NCAR, and examined the
possible effects of increased carbon dioxide, sulfate,
aerosols, and other forcings on global climate.
We are really proud to have you three here today. Thank you
for taking your valuable time to share your conclusions and
your observations.
Thank you, Mr. Chairman.
Chairman Gordon. Thank you, Mr. Udall.
This is a very, very distinguished panel, and we know this
has been a hectic period for you, and we do appreciate you
being here. Each of you will be allowed five minutes, but in
the spirit of our former Chairman, I don't know whether he was
embarrassed and left, but Sherry Boehlert was here earlier, he
would say to witnesses of your nature that 300 seconds is not
very much to talk about these very serious problems, so we hope
you will be quick, because we want to have questions, but we
want you to take the time that you need to make the points that
need to be.
So Dr. Solomon, please begin.
Panel II:
STATEMENT OF DR. SUSAN SOLOMON, CO-CHAIR, IPCC, WORKING GROUP
I: THE PHYSICAL BASIS OF CLIMATE CHANGE; SENIOR SCIENTIST,
EARTH SYSTEM RESEARCH LABORATORY, OFFICE OF OCEANIC AND
ATMOSPHERIC RESEARCH, NATIONAL OCEANIC AND ATMOSPHERIC
ADMINISTRATION, U.S. DEPARTMENT OF COMMERCE
Dr. Solomon. Thank you. I would like to thank Chairperson
Gordon, Ranking Member Hall, and the other Members of the
Committee for the opportunity to talk with you today on the
Working Group I Report of the IPCC. I appreciate very much the
generous introduction by Mr. Udall. I would just like to add
that I have served as an author on various reports of the IPCC
beginning in 1992.
In 2002, I was greatly honored to be formally nominated by
the United States of America to Co-Chair the Fourth Assessment
of Working Group I, the part that deals with physical climate
science.
The IPCC was established under the World Meteorological
Organization and the United Nations Environment Program to
provide regular assessments for policy-makers on the
scientific, technical, and socio-economic aspects of climate
change. Today, we will be talking about the scientific aspects
of climate change, the physical science basis. IPCC does not
do, nor does it manage, research. It provides assessment
reports covering the state of scientific understanding based
upon the scientific literature. Each report is written by
international experts on a volunteer basis. IPCC's past reports
have been highly praised by many organizations, such as
scientific academies around the world, including our own U.S.
National Academy of Sciences.
The 152 primary authors of the Working Group I's Fourth
Assessment Report come from every inhabited continent in the
world. About 75 percent of those authors did not work on the
Third Assessment Report, the last previous report, guaranteeing
a fresh look. About a quarter of the authors are young, in the
professional sense, having had their highest degree for less
than 10 years at the time that we started our work. Over 600
experts participated in two rounds of open review. And in
addition to the experts, dozens of governments also provided
formal coordinated reviews, including our own government. In
total, the Working Group I scientific assessment received over
30,000 comments. To put those numbers in perspective, a typical
research paper published in a scientific journal is subject to
review by two or three experts. It may receive a few dozen
comments. A distinguished team of 27 review editors, who are
independent of the author teams, played an oversight role,
ensuring that all substantive review comments were given
appropriate consideration. It took over two years to write,
review, revise and finalize the document, giving us a product
that we believe is unique in many ways; not least the fact that
it is not the view of any one scientist or a few scientists but
rather reflects an extremely broad-ranging synthesis of
scientific viewpoints. It indicates what is known, and also
what is not known, and remaining uncertainties.
A different Working Group covers impacts and adaptation and
another covers mitigation and policy options. The reports of
these other two groups will be delivered later this spring.
And now I would like to briefly turn to some key highlights
of our own Report, the key messages of this document.
Greenhouse gases have increased markedly since 1750 and are
now at levels unprecedented in many thousands of years. The
warming is unequivocal. Our planet is warming. That is evident
in many different types of observations. Most of the warming of
the past 50 years is very likely due to greenhouse gas
increases. We believe that has a 9-out-of-10 chance based on a
very careful detailed assessment that accounts for solar and
volcanic effects, that takes into account many factors,
including the simple fact that the recent years have been
remarkably warm, and the chances of that happening at random
are quite small.
We are already committed to further warming. Even if we
were to stabilize all greenhouse gases now, instead of having
continuing increases. And in that regard, the rate of increase
of carbon dioxide of the past 10 years was the largest since
direct measurements began in 1960.
Continued emissions at or above current rates will very
likely lead to larger changes in the 21st century than those of
the 20th. The effects expected include: more heavy rain, more
drought, more heat waves, and more sea level rise. How much
depends on how much we choose to emit on a global basis.
Sea level rise is expected to increase due to expansion of
water in a warmer world. Changes in ice sheets are currently
contributing about 12 percent to the total sea level rise of
the past decade. That could grow or it could decrease in the
future. And I will leave it to Dr. Alley to talk more about
that.
And thank you very, very much for the invitation and for
your attention.
[The prepared statement of Dr. Solomon follows:]
Prepared Statement of Susan Solomon
I thank Chairperson Gordon, Ranking Member Hall, and the other
Members of the Committee for the opportunity to speak with you today on
the Working Group I report of the Intergovernmental Panel on Climate
Change 2007 Report (IPCC, 2007). My name is Susan Solomon and I am a
Senior Scientist at NOAA's Earth System Research Laboratory in Boulder,
Colorado. I've been a scientist at NOAA for more than 26 years. Much of
my work over that time has focused on understanding the cause of ozone
depletion. In 2000, I received this nation's highest scientific award,
the National Medal of Science, in recognition of that work. I've also
been honored with membership in the U.S. National Academy of Sciences
and I am a foreign associate of the French Academy of Sciences and the
Acadamiae Europaea. In addition to my research on ozone depletion, I
also do personal research on climate change, in particular on the range
of chemicals that contribute to climate change. I'm the author or co-
author of more than 150 scientific publications, and I've served as an
author on various reports of the Intergovernmental Panel on Climate
Change beginning in 1992.
In 2002, I had the honor of being formally nominated by the United
States of America to co-chair Working Group I, the part of the IPCC
that deals with physical climate science. I was selected by the IPCC
Panel of governments to serve in that role, and for almost the past
five years have accordingly co-chaired the process that resulted in the
2007 Working Group I Assessment Report, together with Dr. Qin Dahe of
China. We are assisted by six able vice-chairs from around the world
and by a technical support unit that provides logistical and related
functions.
The Intergovernmental Panel on Climate Change was established under
the auspices of the World Meteorological Organization and the United
Nations Environment Program to provide regular assessments for policy-
makers of the scientific, technical and socio-economic aspects climate
change. IPCC does not do or manage research. It provides assessment
reports covering the state of scientific understanding based upon the
scientific literature. Each report is written by international experts
on a volunteer basis. IPCC has produced its major assessments every
five to six years since 1990, and the 2007 report is the fourth in that
series. The Working Group Co-Chairs and Vice-Chairs select authors on
the basis of their scientific publications and products from among
nominees proposed by governments, with due regard for geographic
balance. IPCC's reports have been highly praised by many organizations
such as scientific academies around the world including our own U.S.
National Academy of Sciences.
The 152 authors of the Working Group I Fourth Assessment Report
hail from every inhabited continent in the world. About 75 percent of
these authors did not work on the previous 2001 report. About a quarter
of the authors are young in the professional sense, having had their
highest degree for less than 10 years at the time we began our work.
Over 400 other scientists have served as contributing authors. Over 600
experts participated in two rounds of open review. In addition to the
experts, dozens of governments also provided formal coordinated
reviews. In total, the Working Group I assessment received over 30,000
comments. To put these numbers in perspective, a typical research paper
published in a scientific journal is subject to review by two or three
experts. It may receive a few dozen comments. A distinguished team of
27 review editors, who are independent of the author teams, played an
oversight role ensuring that all substantive review comments were given
appropriate consideration. It took over two years to write, review,
revise and finalize the document. The product is unique in many ways,
not least the fact that it is not the view of any one scientist or a
few scientists but rather reflects an extremely broad-ranging synthesis
of scientific viewpoints.
A different Working Group (Working Group II), covers impacts and
adaptation and another (Working Group III) covers mitigation and policy
options. The reports of these other two groups are due to be released
later this spring. There will also be a Synthesis Report released in
November, 2007, which endeavors to provide a synthesis of all three
Working Group reports.
The Summary for Policy-makers of the Working Group I was approved
by the governments of the IPCC Panel in Paris last week. That document
is appended here as the scientific basis of my testimony.
Biography for Susan Solomon
Susan Solomon is widely recognized as one of the leaders in the
field of atmospheric science. Since receiving her Ph.D. degree in
chemistry from the University of California at Berkeley in l98l, she
has been employed by the National Oceanic and Atmospheric
Administration as a research scientist. Her scientific papers have
provided not only key measurements but also theoretical understanding
regarding ozone destruction, especially the role of surface chemistry.
In l986 and l987, she served as the Head Project Scientist of the
National Ozone Expedition at McMurdo Station, Antarctica and made some
of the first measurements there that pointed towards
chlorofluorocarbons as the cause of the ozone hole. In l994, an
Antarctic glacier was named in her honor in recognition of that work.
In March of 2000, she received the National Medal of Science, the
United States' highest scientific honor, for ``key insights in
explaining the cause of the Antarctic ozone hole.'' In 2004 she
received the prestigious Blue Planet Prize for ``pioneering research
identifying the causative mechanisms producing the Antarctic ozone
hole.''
She is the recipient of many other honors and awards, including the
J.B. MacElwane award of the American Geophysical Union, the Department
of Commerce Gold Medal for Exceptional Service, the Henry G. Houghton
and Carl-Gustaf Rossby awards of the American Meteorological Society
for excellence in research, the Arthur S. Flemming Award for
exceptional government service, the Common Wealth Award of the Common
Wealth Trust, and the ozone award from the United Nations Environment
Programme. In l992, R&D Magazine honored her as its ``scientist of the
year.'' She is a recipient of honorary doctoral degrees from Tulane
University, Williams College, the State University of New York at Stony
Brook, the Illinois Institute of Technology, the University of Miami,
the University of Colorado, and the University of East Anglia in the
UK. She is a member of the U.S. National Academy of Sciences and a
Foreign Associate of both the French Academy of Sciences and the
European Academy of Sciences. Her current research includes climate
change and ozone depletion, and she serves as Co-Chair of Working Group
I of the Intergovernmental Panel on Climate Change (IPCC), providing
scientific information to the United Nations Framework Convention on
Climate Change.
Chairman Gordon. Thank you, Doctor. And now Dr. Trenberth.
STATEMENT OF DR. KEVIN E. TRENBERTH, COORDINATING LEAD AUTHOR,
IPCC, WORKING GROUP I, CHAPTER 3: OBSERVATIONS: SURFACE AND
ATMOSPHERIC CLIMATE CHANGE; HEAD, CLIMATE ANALYSIS SECTION,
NATIONAL CENTER FOR ATMOSPHERIC RESEARCH
Dr. Trenberth. Thank you, Mr. Chairman. I thank
Representative Udall for introducing me, and as he said, I am
the Coordinating Lead Author of Chapter 3 of the IPCC Report,
which Susan has introduced, and that deals with the
observations in the atmosphere and at the surface and also does
a synthesis across all observations, and that is what I am
going to focus on here.
And essentially, what we have done in the IPCC, perhaps as
a medical analogy, is to do a diagnosis of the vital signs of
the planet Earth. And what we have found, then, is that the
planet is running a fever, so to speak, and the prognosis is
that it is apt to become much worse.
Now to paraphrase the Report, ``Warming of the climate
system is unequivocal.'' That is actually a quote, and it is
very likely due to human activities.
In my written testimony, a summary is given of the main
findings for Chapter 3, and it is linked to the other
observational chapters. And the overall summary statement of
one of the highlight points in the policy-maker's summary is,
to quote, ``Warming of the climate system is unequivocal, as is
now evident from observations of increases in global-averaged
air and ocean temperatures, widespread melting of snow and ice,
and rising global mean sea level.'' And then there is another
item, which goes on to elaborate on more regional aspects and
other variables as well. And that is what I am going to focus
on in my following remarks.
And so we say that the warming of the climate system is
unequivocal because it is now clear from an increasing body of
evidence showing discernable, physically-consistent changes. In
other words, we can relate all of these changes to warming. And
there are many more variables listed than in the brief IPCC
statement. Now these include, firstly, global average air
temperature, and I am going to come back to that.
If I could have the first slide, if I might, please.
This just shows you global warming is unequivocal, and what
I have done here is to put the main bullets that I am going to
talk about on here, the different variables and the items.
And so as well as global surface air temperature, there are
the air temperatures above the surface, and this refers to what
is called often the satellite temperatures. Sea surface
temperatures are also increasing, and they are very important
for things like storms over the oceans and hurricanes.
Subsurface ocean water temperatures are increasing, below the
surface. We can measure those, and that leads to expansion of
the ocean, contributing to sea level. There is widespread
melting of snow in the Northern Hemisphere. There are decreases
in Arctic sea ice extent and thickness. There are decreases in
glacier and small ice cap extent and mass. And as a result,
there is a global mean sea level rise at a rate in the last 12
years of more than a foot a century, and that is contributed to
by the expansion of the ocean and the melting of land ice.
The observed surface warming at both global and continental
scales is also consistent with the reduced duration of freeze
seasons, less frost, increases in heat waves, and increased
atmospheric water vapor in the atmosphere, and this is very
important, because it feeds into heavier precipitation events,
and this includes, ironically, perhaps, heavier snowfall
events, because the atmosphere can hold more water vapor when
it is warmer.
There are also changes in precipitation around the world,
and part of that leads to increases in drought, especially in
the tropics, and this is already evident in the observational
record. Increases in the intensity of hurricane activity are
also evident, and there are changes in the large-scale patterns
of atmospheric winds, changes in where storms are actually
going in middle latitudes.
So if I can look at the second--or the next slide, here it
is here.
This is the global average temperatures, the time series
from 1850 up until 2006. The dots are the annual values. The
heavy blue curve is the decadal smooth values, and the yellow
is the sort of uncertainty around that. And what we frequently
do with a curve like this is to put a straight line through it.
And if we do that, you get this line here for the last 150
years, and on the bottom right, I don't know if you can see the
numbers here, there is actually--the rate of change is given.
And what we can also do is then put a line through it for the
last 100 years, and it looks like this. And you can see that it
is considerably steeper. And then for the last 50 years, it
looks like this. And then for the last 25 years, it looks like
this. And listed at the top there is a list of the last 12
years. Indeed, 11 out of the last 12 years are the warmest on
record.
And so the rate of warming has increased over time, and
indeed, this is the direction we are going in the immediate
future.
And so the Fourth Assessment Report of IPCC finds that the
Earth is warming and that the major components of the Earth's
climate system are already responding to that warming.
Now the wide variety of observations gives a very high
degree of confidence in the overall findings, and moreover,
these changes are now simulated in climate models for the past
100 years to a reasonable degree, as my colleague Jerry Meehl
is likely to talk about, and this adds confidence to the future
projections.
Mr. Chairman, one interpretation of this is that, you know,
as with a fiscal budget, we are running a deficit and building
a debt for the future generations. And our current generation
is now running what we might refer to as an environmental
deficit, and it will, indeed, be paid for by the future
generations.
I appreciate the opportunity to address the Committee
concerning the science of global climate change, and I look
forward to answering any questions.
Thank you.
[The prepared statement of Dr. Trenberth follows:]
Prepared Statement of Kevin E. Trenberth
Observations of climate change:
The 2007 IPCC Assessment
Summary
Following a detailed diagnosis of the vital signs of the planet
Earth, it has become evident that the planet is running a ``fever'' and
the prognosis is that it is apt to get much worse. ``Warming of the
climate system is unequivocal'' and it is ``very likely'' due to human
activities. This is the verdict of the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC), known as AR4. In the
following, I provide a brief introduction to the IPCC and its
processes. A summary is then given of the main findings from the AR4
for Chapter 3, ``Observations: Surface and Atmospheric Climate
Change,'' and its links to other observational chapters. Warming of the
climate system is unequivocal as is now clear from an increasing body
of evidence showing discernible physically consistent changes. These
include increases in global average air temperature; atmospheric
temperatures above the surface, surface and sub-surface ocean water
temperature; widespread melting of snow; decreases in Arctic sea-ice
extent and thickness; decreases in glacier and small ice cap extent and
mass; and rising global mean sea level. The observed surface warming at
global and continental scales is also consistent with reduced duration
of freeze seasons; increased heat waves; increased atmospheric water
vapor content and heavier precipitation events; changes in patterns of
precipitation; increased drought; increases in intensity of hurricane
activity, and changes in atmospheric winds. That is, the IPCC Fourth
Assessment finds that the Earth is warming, and that major components
of the Earth's climate system are already responding to that warming.
This wide variety of observations gives a very high degree of
confidence to the overall findings. Moreover these changes are now
simulated in climate models for the past 100 years to a reasonable
degree, adding confidence to future projections. The summary is
followed by a few personal remarks about the meaning of these findings.
Introduction
My name is Kevin Trenberth.\1\ I am a senior scientist and the Head
of the Climate Analysis Section at NCAR, the National Center for
Atmospheric Research.\2\ I have authored over 400 publications in the
area of climate, and given hundreds of talks on the subject. I am among
the most highly cited researchers in all of geophysics. I am especially
interested in global-scale climate dynamics; the observations,
processes and modeling of climate changes from inter-annual to
centennial time scales. I have particular expertise in El Nino, the
hydrological and energy cycles, and hurricanes and climate change. I
have served on many national and international committees including
National Research Council/National Academy of Science committees,
panels and/or boards. I co-chaired the international Climate
Variability and Predictability (CLIVAR) Scientific Steering Group of
the World Climate Research Programme (WCRP) from 1996 to 1999 and I
have served as a member and officer of the Joint Scientific Committee
that oversees the WCRP as a whole from 1998 to 2006. I chair the WCRP
Observations and Assimilation Panel. I have been involved in global
warming science and I have been extensively involved in the
Intergovernmental Panel on Climate Change (IPCC) scientific assessment
activity as a Lead Author of individual chapters, the Technical
Summary, and Summary for Policy-makers (SPM) of Working Group (WG) I
for both the Second and Third Assessment Reports (SAR and TAR; IPCC
1996, 2001). I am a Coordinating Lead Author of Chapter 3 of the Fourth
IPCC Assessment (AR4) that deals with observations of the surface and
atmospheric climate change.
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\1\ Any opinions, findings, conclusions, or recommendations
expressed in this publication are those of the author and do not
necessarily reflect those of the National Science Foundation.
\2\ The National Center for Atmospheric Research (NCAR) is
sponsored by the National Science Foundation.
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The IPCC is a body of scientists from around the world convened by
the United Nations jointly under the United Nations Environment
Programme (UNEP) and the World Meteorological Organization (WMO) and
initiated in 1988. Its mandate is to provide policy-makers with an
objective assessment of the scientific and technical information
available about climate change, its environmental and socio-economic
impacts, and possible response options. The IPCC reports on the science
of global climate and the effects of human activities on climate in
particular. Major assessments were made in 1990, 1995, 2001, and now
2007. Each new IPCC report reviews all the published literature over
the previous five to seven years, and assesses the state of knowledge,
while trying to reconcile disparate claims and resolve discrepancies,
and document uncertainties.
WG I deals with how the climate has changed and the possible
causes. It considers how the climate system responds to various agents
of change and our ability to model the processes involved as well as
the performance of the whole system. It further seeks to attribute
recent changes to the possible various causes, including the human
influences, and thus it goes on to make projections for the future. WG
II deals with impacts of climate change, vulnerability, and options for
adaptation to such changes, and WG III deals with options for
mitigating and slowing the climate change, including possible policy
options. Each WG is made up of participants from the United Nations
countries, and for the 2007 assessment there are over 450 Lead Authors,
800 contributing authors, and over 2,500 reviewers from over 130
countries. In my chapter, as well as the two Coordinating Lead Authors,
we have 10 Lead Authors, 66 contributing authors, about 100 pages of
text, 126 figure panels in 47 figures, and 863 references. The IPCC
process is very open. Two major reviews were carried out in producing
the report, and climate ``skeptics'' can and do participate, some as
authors. For our chapter we received over 2230 comments on the expert
review and 1270 on the governmental review, all of which were responded
to in writing and by changing the report. The process is overseen by
two Review Editors. The strength is that it is a consensus report. The
SPM was approved line by line by governments in a major meeting in
Paris from 29 January to 1 February, 2007. The rationale is that the
scientists determine what can be said, but the governments help
determine how it can best be said. Negotiations occur over wording to
ensure accuracy, balance, clarity of message, and relevance to
understanding and policy. The latest report (IPCC 2007) reaffirms in
much stronger language that the climate is changing in ways that cannot
be accounted for by natural variability and that ``global warming'' is
happening.
Observed Climate Change
The iconic summary statement of the observations section of the
IPCC (2007) report is ``Warming of the climate system is unequivocal,
as is now evident from observations of increases in global average air
and ocean temperatures, widespread melting of snow and ice, and rising
global mean sea level.'' The language here is carefully chosen to
reinforce the view that
1) There are multiple lines of evidence from many variables
2) There is a wide body of evidence and multiple analyses of
each variable
3) The variables and evidence are physically consistent with
warming
4) The human signal has clearly emerged from noise of natural
variability, i.e., it is large.
Since the TAR, progress in understanding how the current climate is
changing in space and in time has been gained through improvements and
extensions of numerous data sets and data analyses, broader
geographical coverage, better understanding of uncertainties, and a
wider variety of measurements. Increasingly comprehensive observations
are available for glaciers and snow cover since the 1960s, and for sea
level and ice sheets since about the past decade. Numerous changes in
climate have been observed at the scales of continents or ocean basins.
These include wind patterns, precipitation, ocean salinity, sea ice,
ice sheets, and aspects of extreme weather.
a. Temperature and related
Instrumental observations over the past 157 years show that
temperatures at the surface (Fig. 1) have risen globally, with
important regional variations. For the global average, warming in the
last century has occurred in two phases, from the 1910s to the 1940s
(0.35+C or 0.63+F), and more strongly from the
1970s to the present (0.55+C or 1.0+F) at a rate
of about 0.16+C (0.3+F) per decade. An increasing
rate of warming has taken place over the last 25 years, and 11 of the
12 warmest years on record have occurred in the past 12 years. Indeed,
the six years since the TAR are among the seven warmest years on
record. The total warming since the 1800s is about 0.76+C
(1.4+F). Globally, 2006 ranks sixth and it was the warmest
on record in the United States. Sea surface temperatures (SSTs) are
also increasing, however land areas are warming much faster than the
oceans since 1970.
Two possible issues with the surface temperature record--urban heat
island effects, and discrepancies with balloon-based and satellite
measurements--have been extensively studied in the 2007 IPCC report.
The urban heat island effects are real but local, and have been found
to have a negligible influence on the overall surface temperature
record. New analyses of balloon-borne and satellite measurements of
lower- and mid-tropospheric temperature show warming rates that are
similar to the surface temperature record and consistent within their
respective uncertainties, largely reconciling a discrepancy noted in
the TAR. The 2007 IPCC report essentially removes these two issues as
serious sources of uncertainty for the global surface temperature
record.
Regional temperature observations do not always track the global
average warming because of atmospheric wave patterns, as well as
increased natural variability at smaller geographic scales. For
example, the eastern half of the United States has not warmed as much
as other areas, especially during the daytime, owing to increases in
cloud and precipitation associated with changes in atmospheric
circulation as the climate changes. On the other hand, average Arctic
temperatures increased at almost twice the global average rate in the
past 100 years and also since 1960. However, Arctic temperatures have
high decadal variability and a warm period was observed from 1925 to
1945, but that was focused in the North Atlantic and not global as in
the recent warming.
Since 1950, the number of heat waves globally has increased and
widespread increases have occurred in the numbers of warm nights. Cold
days, cold nights and frost have generally become rarer.
Decreases are found in the length of the freeze season of river and
lake ice. Temperature at the top of the permafrost layer has increased
by up to 3+C since the 1980s in the Arctic. The maximum area
covered by seasonally frozen ground has decreased by about seven
percent in the Northern Hemisphere since 1900 and this value is up to
15 percent in spring.
The average temperature of global ocean water from the surface to a
depth of 700m increased significantly from 1961 to 2003, indicating
that the ocean is absorbing most of the heat being added to the climate
system. This causes seawater to expand and is estimated to have
contributed 0.42mm per year to the average sea level rise from 1961 to
2003, and 1.8mm per year from 1993 to 2003.
Sea-ice extents have decreased in the Arctic since 1978,
particularly in spring and summer (7.4 percent per decade), and
patterns of the changes are consistent with regions showing a
temperature increase, although changes in winds are also a major
factor. Sea-ice extents were at record low values in 2005, which was
also the warmest year since records began in 1850 for the Arctic north
of 65 N. There have also been decreases in sea-ice thickness. In
contrast to the Arctic, Antarctic sea ice does not exhibit any
significant trend since the end of the 1970s, which is consistent with
the lack of trend in surface temperature south of 65 S over that
period. However, along the Antarctic Peninsula, where significant
warming has occurred, progressive break up of ice shelves has occurred
beginning in the late 1980s, culminating in the break up of the Larsen-
B ice shelf in 2002.
The observed surface temperature increases are consistent with the
observed nearly worldwide reduction in glacier and small ice cap mass
and extent in the 20th century. In addition, flow speed has recently
increased for some Greenland and Antarctic outlet glaciers, which drain
ice from the interior, and melting of Greenland has increased after
about 2000. Glaciers and ice caps respond not only to temperatures but
also to changes in precipitation, and both winter accumulation and
summer melting have increased over the last half century in association
with temperature increases. In some regions moderately increased
accumulation observed in recent decades is consistent with changes in
atmospheric circulation and associated increases in winter
precipitation (e.g., southwestern Norway, parts of coastal Alaska,
Patagonia, and the South Island of New Zealand) even though increased
ablation has led to marked declines in mass balances in Alaska and
Patagonia. Tropical glacier changes are synchronous with higher
latitude ones and all have shown declines in recent decades. Decreases
in glaciers and ice caps contributed to sea level rise by 0.5mm per
year from 1961 to 2003 and 0.8mm per year from 1993 to 2003. Taken
together, shrinkage of the ice sheets of Greenland and Antarctica has
contributed 0.4mm per year to sea level rise over 1993 to 2003.
Global average sea level rose at an average rate of 1.8mm per year
over 1961 to 2003. The rate was faster during 1993-2003, when truly
global values have been measured from altimeters in space, at about
3.1mm per year. Hence about 60 percent of this is from ocean warming
and expansion, and 40 percent is from melting land ice, adding to the
ocean volume. The observation of consistent sea level rise over several
decades, and also an increasing rate of sea level rise in the last
decade or so, is probably the single best metric of the cumulative
global warming that we have experienced to date. There is really no
explanation other than global warming for the observed sea level rise.
The average atmospheric water vapor content has increased over land
and ocean as well as in the upper troposphere, and over the global
oceans this is estimated to be four percent since 1970. The increase is
broadly consistent with the extra water that warmer air can hold and
amounts to a fairly constant relative humidity. The added water vapor
also adds to the greenhouse effect and roughly doubles that due to
carbon dioxide, providing a powerful positive feedback to climate
change.
The observed surface warming at global and continental scales is
consistent with observed changes in sub-surface ocean water
temperature; decreases in sea-ice extent and thickness; decreases in
glacier and small ice cap extent and mass; sea-level rise; reduced
duration of freeze seasons, increased heat waves; and increased
atmospheric water vapor content. That is, the IPCC Fourth Assessment
finds that the Earth is warming, and that major components of the
Earth's climate system are already responding to that warming. This
wide variety of observations gives a very high degree of confidence to
the overall findings.
b. Precipitation and related
The 2007 IPCC report finds that changes are occurring in the
amount, intensity, frequency, and type of precipitation in ways that
are also consistent with a warming planet. These aspects of
precipitation generally exhibit large natural variability (compared to
temperature trends), and El Nino and changes in atmospheric circulation
patterns have a substantial influence, making it harder to detect
trends in the observational record.
A key ingredient in changes in character of precipitation is the
observed increase in water vapor and thus the supply of atmospheric
moisture to all storms, increasing the intensity of precipitation
events. Indeed, widespread increases in heavy precipitation events and
risk of flooding have been observed, even in places where total amounts
have decreased. Hence the frequency of heavy rain events has increased
in most places but so too has episodic heavy snowfall events that are
thus associated with warming. Snow cover has decreased in many Northern
Hemisphere regions, particularly in spring, and more precipitation is
falling as rain instead of snow. These changes are consistent with
changes in permafrost, noted above.
Long-term trends from 1900 to 2005 have been observed in total
precipitation amounts over many large regions. Significantly increased
precipitation has been observed in eastern parts of North and South
America, northern Europe and northern and central Asia. Drying has been
observed in the Sahel, the Mediterranean, southern Africa and parts of
southern Asia. Precipitation is highly variable spatially and
temporally. Robust long-term trends have not been observed for other
large regions. The pattern of precipitation change is one of increases
generally at higher northern latitudes (because as the atmosphere warms
it holds more moisture) and drying in the tropics and subtropics over
land. Basin-scale changes in ocean salinity provide further evidence of
changes in the Earth's water cycle, with freshening at high latitudes
and increased salinity in the subtropics.
More intense and longer droughts have been observed over wider
areas since the 1970s, particularly in the tropics and subtropics.
Increased drying due to higher temperatures and decreased precipitation
have contributed to these changes, with the latter the dominant factor.
The regions where droughts have occurred are determined largely by
changes in sea surface temperature (SST), especially in the tropics
(such as during El Nino), through changes in the atmospheric
circulation and precipitation. In the western United States,
diminishing snow pack and subsequent summer soil moisture reductions
have also been a factor. In Australia and Europe, direct links to
warming have been inferred through the extreme nature of high
temperatures and heat waves accompanying drought.
Satellite records suggest a global trend towards more intense and
longer lasting tropical cyclones (including hurricanes and typhoons)
since about 1970, correlated with observed warming of tropical SSTs.
There is no clear trend in the annual number of tropical cyclones
globally although a substantial increase has occurred in the North
Atlantic after 1994. There are concerns about the quality of tropical
cyclone data, particularly before the satellite era. Further, strong
multi-decadal variability is observed and complicates detection of
long-term trends in tropical cyclone activity.
c. Synthesis across variables
In summary, global mean temperatures have increased since the 19th
century, especially since the mid-1970s. Temperatures have increased
nearly everywhere over land, and SSTs have also increased, reinforcing
the evidence from land. However, global warming does not mean that
temperatures increase steadily or uniformly, indeed temperatures have
increased neither monotonically, nor in a spatially uniform manner,
especially over shorter time intervals. The atmospheric circulation has
also changed: in particular increasing westerly wind flow is observed
in most seasons in both hemispheres. In the Northern Hemisphere this
brought milder maritime air into Europe and much of high-latitude Asia
from the North Atlantic in winter, enhancing warming there. In the
Southern Hemisphere, where the ozone hole has played a role, it has
resulted in cooling over 1971-2000 for parts of the interior of
Antarctica but large warming in the Antarctic Peninsula region and
Patagonia. Temperatures generally have risen more than average where
flow has become more poleward, and less than average or even cooled
where flow has become more equatorward, reflecting atmospheric patterns
of variability.
Over land in low latitudes and in summer more generally, there is a
strong tendency for either hot and dry or cool and wet. Hence areas
that have become wetter, such as the eastern United States and
Argentina, have not warmed as much as other land areas. Increased
precipitation is associated with increases in cloud and surface
wetness. Thus more heat goes into increased evapotranspiration and less
into raising temperature at the surface in wetter conditions.
The three main ocean basins are unique and contain very different
wind systems, SST patterns and ocean currents, leading to vastly
different variability associated, for instance, with El Nino in the
Pacific, and the ocean currents including the Gulf Stream in the
Atlantic. Consequently the oceans have not warmed uniformly, especially
at depth. SSTs in the tropics have warmed at different rates and help
drive, through coupling with tropical convection and winds, distinctive
wave patterns known as teleconnections around the world. This has
changed the atmospheric circulation and the monsoons. Changes in
precipitation and storm tracks are not as well documented but clearly
respond to these changes on inter-annual and decadal timescales. When
precipitation increases over the ocean, as it has in recent years in
the tropics, it decreases over land, although it has increased over
land at higher latitudes. Droughts have increased over many tropical
and mid-latitude land areas, in part because of decreased precipitation
over land since the 1970s but also from increased drying arising from
increased atmospheric demand associated with warming.
Many of these observed changes are now simulated in climate models
run for the past 100 years, adding confidence to understanding of the
relationship with the agents that alter the climate, and human-induced
changes in atmospheric composition, in particular, as is documented in
other IPCC chapters.
Some implications
The scientific understanding of climate change is now sufficiently
clear to show that specific global and regional changes resulting from
global warming are already upon us. Uncertainties remain, and new
efforts at reprocessing past satellite records for phenomena such as
hurricanes are required, but the 2007 IPCC report definitively shows
that the climate is changing. ``Warming is unequivocal'' and it is
``very likely'' caused by human activities.
In my personal opinion as a climate scientist, the IPCC report
strongly implies the need for a three pronged approach of mitigation,
adaptation, and maintaining and improving climate observing and
information systems.
While there are uncertainties (although these cut both ways) and
some changes arising from global warming may be benign or even
beneficial, at least in some places and in the short run, the IPCC
report shows that the rate of change as projected exceeds anything seen
in nature in the past 10,000 years. Moreover, the inertia of the
climate system and the long life of carbon dioxide in the atmosphere
mean that we are already committed to a significant level of climate
change. I believe that mitigation actions are certainly needed to
significantly reduce the build-up of greenhouse gases in the atmosphere
and lessen the magnitude and rate of climate change.
At the same time, the 2007 IPCC report makes clear that even
aggressive mitigation would yield benefits many decades in the future,
and that no amount of mitigation can avoid significant climate change.
I believe it is apt to be disruptive in many ways. Hence it is also
vital to plan to cope with the changes, such as enhanced droughts, heat
waves and wild fires, and stronger downpours and risk of flooding.
Managing water resources will be a major challenge in the future.
Adapting to climate change and reducing vulnerability is essential.
This means that we should adapt to climate change by planning for it
and making better predictions of likely outcomes on several time
horizons.
Finally, although not reported by the IPCC, my experience in
working with observations of climate change has led me to urge the
Committee to address the considerable shortcomings in our observing
systems. Weather observing systems are continually used for climate
purposes for which they were not designed. Moreover, weather stations
come and go and changes are made without regard to the effect on the
climate record. Changes in observing systems, especially from
satellites, as new satellites and instruments are launched, create
artifacts in the climate record. Loss of Earth observing satellites is
also of concern, as documented in the recent National Research Council
(2007) decadal survey. Ground based observations are not being
adequately kept up in many countries. Calibration of climate records is
critical. Small changes over long times are characteristic of climate
change but they occur in the midst of large variations associated with
weather and natural climate variations such as El Nino. Yet the climate
is changing and an imperative is to track the changes and the causes as
they occur. We need to build a system based on these observations to
inform decision-makers on what is happening, and why, and what the
predictions are for the future on several time horizons.
I appreciate the opportunity to address the Committee concerning
the science of global climate change, and look forward to answering any
questions you may have today or in the future.
References and some bibliography
IPCC, 1996: Climate Change 1995: The Science of Climate Change. Eds.
J.T. Houghton et al., Cambridge University Press, Cambridge,
U.K. 572 pp.
IPCC, 2001: Climate Change 2001: The Scientific Basis. Eds. J.T.
Houghton, et al., Cambridge University Press, Cambridge, U.K.
881 pp.
IPCC, 2007: Climate Change 2007: The Scientific Basis. Eds. S. Solomon,
et al., Cambridge University Press, Cambridge, U.K. (in press).
Karl, T.R., and K.E. Trenberth, 2003: Modern global climate change.
Science, 302, 1719-1723.
Karl, T.R., and K.E. Trenberth, 2006: Modern global climate change.
Science Magazine's State of the Planet, Donald Kennedy and the
editors of Science magazine, Eds., Island Press, 88-98.
National Research Council, 2007: Earth Science and Applications from
Space: National Imperatives for the Next Decade and Beyond. The
National Academies Press.
Trenberth, K.E., 2001: Stronger evidence for human influences on
climate: The 2001 IPCC Assessment. Environment, 43, 4(May), 8-
19.
Trenberth, K.E., T.R. Karl and T.W. Spence, 2002: The need for a
systems approach to climate observations. Bull. Amer. Meteor.
Soc., 83, 1593-1602.
Trenberth, K.E., 2005: Uncertainty in hurricanes and global warming.
Science, 308, 1753-1754.
Trenberth, K.E., and D.J. Shea, 2006: Atlantic hurricanes and natural
variability in 2005. Geophys. Res. Lett., 33, L12704,
doi:10.1029/2006GL026894.
Biography for Kevin E. Trenberth
Dr. Kevin Trenberth is Head of the Climate Analysis Section at the
National Center for Atmospheric Research (NCAR) in Boulder, CO. From
New Zealand, he completed a first class honors degree in mathematics at
the University of Canterbury, Christchurch, New Zealand, and obtained
his Sc.D. in meteorology in 1972 from Massachusetts Institute of
Technology, Cambridge, Massachusetts. He was previously employed as a
research scientist in the New Zealand Meteorological Service and was a
Professor at the University of Illinois for nearly seven years prior to
joining NCAR in 1984.
He was named a Fellow of the American Meteorological Society (AMS)
in 1985, the American Association for Advancement of Science (AAAS) in
1994, the American Geophysical Union in 2006 and an Honorary Fellow of
the New Zealand Royal Society in 1995. In 2000 he received the Jule G.
Charney award from the AMS and in 2003 he was given the NCAR
Distinguished Achievement Award. He has served as an editor and
associate editor for several professional journals. He edited a 788
page book, Climate System Modeling (1992). He has published over 400
scientific articles or papers, including 40 books or book chapters, and
over 175 refereed journal articles and has given many invited
scientific talks as well as appearing in a number of television, radio
programs and newspaper articles. He is listed among the top 20 authors
in highest citations in all of geophysics.
Trenberth has served on a number of national and international
advisory committees and panels including many panels, committees and a
board of the National Academy of Sciences. Trenberth has been prominent
in the Intergovernmental Panel on Climate Change (IPCC) Scientific
Assessment activities, was a Convening Lead Author for the 1995
Scientific Assessment and Lead Author for the 2001 assessment
(including for the Technical Summary and Summary for Policy-makers) and
is a Coordinating Lead Author of the 2007 assessment. He has recently
served as a member of the National Oceanic and Atmospheric
Administration (NOAA) Climate Working Group (from 1987 to 2006), and is
a member of NOAA's Climate Observing System Council, and NOAA's
Advisory Panel for Climate Change Data and Detection. He also recently
served on the Joint Scientific Committee of the World Climate Research
Programme (WCRP) from 1999 to 2006 and was an officer from 2003 to
2006, and he chairs the WCRP Observations and Assimilation Panel. He
served on the Scientific Steering Group for the WCRP Climate
Variability and Predictability (CLIVAR) program and was Co-Chair from
1995 to 1999.
See http://www.cgd.ucar.edu/cas/trenbert.html
Chairman Gordon. Dr. Alley.
STATEMENT OF DR. RICHARD B. ALLEY, LEAD AUTHOR, IPCC, WORKING
GROUP I, CHAPTER 4: OBSERVATIONS: CHANGES IN SNOW, ICE AND
FROZEN GROUND; EVAN PUGH PROFESSOR OF GEOSCIENCES AND ASSOCIATE
OF THE EARTH AND ENVIRONMENTAL SYSTEMS INSTITUTE, PENNSYLVANIA
STATE UNIVERSITY
Dr. Alley. Thank you, Mr. Chairman, honored Members.
As Dr. Trenberth pointed out, observations of snow and ice
show that melting is now widespread. We see this in snow cover
in the north. We see this in the Arctic sea ice. We see it in
most of the glaciers of the world. We see it in frozen ground
and permafrost. We see it in the great ice sheets of Greenland
and Antarctica. And we see it even where there is more snow
falling. And so it is really hard to blame a loss of ice on
loss of snow if there is more snow in some places, and yet it
is melting faster. And so it is very clear that warming is
implicated in this.
I would like to focus especially on the large ice sheets of
Greenland and Antarctica, because they have great potential to
change sea level. Snow falls on top, melting happens around the
side, especially in Greenland, and our understanding of those
processes has gotten a lot better. However, we have observed
surprising changes in the flow of the ice sheets around their
edges that we didn't really expect.
If I may, for a moment, an ice sheet is just a two-mile-
thick, continent-wide pile of snow that has been squeezed to
ice under its own weight. And like any pile, it spreads under
its own weight. If I were to pour pancake batter on a griddle
in front of us here, you would see it spread and thin and drip
off the edge. The same thing happens to an ice sheet. It
spreads and thins and it drips icebergs off of the edge.
If I were to grease that pancake griddle, you would see the
batter spread faster. Ice sheets have exactly the same problem.
In Greenland, observations show that when the melt water starts
on the edge, it goes through great holes in the ice to the
bottom, and water makes things slippery. And so the ice
actually spreads faster because of this melt water that
amplifies the effects of it. And so in the same way that you
can grease a pancake griddle, the ice sheet is greasing its own
bed to spread faster.
If I were holding the pancake batter in with a spatula and
I removed it, of course, the batter would spread faster, and
ice sheets have this same problem, as well. When the ice gets
down to the ocean, it usually does not immediately break off to
make an iceberg. It spreads over the ocean in something we call
an ice shelf, and that will run aground on an island, or it
will sheer past the rocky sides of a fjord, and those hold back
in the same way that your spatula holds back the spreading
pancake batter.
Now in a warming world, those are very low in elevation.
They can be warmed easily. They are in contact with the ocean
already. They are at the melting point underneath, and so they
can melt very easily underneath. We have seen where warming has
attacked these spatulas, these ice shelves, and when they have
been pulled out of the way, the ice behind is gone faster by as
much as eight-fold. So we know these things are out there, and
we know that we don't have a really good scientific
understanding of all of these aspects. And when we look to the
future, we expect sea level to rise, as ocean water warms and
expands, as the mountain glaciers melt, and with effects from
changing snowfall and melting on the big ice sheets.
And there is a greatly increased confidence in that. If you
compare the projections of sea level rise that were just now
made in the new Report to those that were made in the previous
report, we have a better understanding of certain things. The
numbers have looked slightly different. Had we treated
uncertainties in exactly the same way, you would have had very
similar projections. They have not changed much. But we have
this additional uncertainty that we just don't know whether
these changes in the spreading of that giant pile in Antarctica
or that giant pile in Greenland will slow down, whether they
will stay constant, whether they will speed up. It is just this
big uncertainty that is sitting out there.
We do not have any credible scientific models of which I
personally am aware that would dump an ice sheet into the ocean
over decades. However, it is possible that we will reach
temperatures over decades that, if sustained, would lose an ice
sheet over centuries to millennia. As someone who works for a
land grant institution, which tries to provide useful advice to
you, I am distressed that I cannot tell you more accurately
what the future might hold. As someone who gets paid to do
research, I am really excited. I am going to go home and have
fun.
So to summarize, we have much scientific confidence that
warming-induced ice loss is now widespread in the climate
system, that it is contributing to sea level rise and other
changes. Improved understanding of many aspects of this is
reflected in the new Report, and it is really wonderful, but
there are unexpected changes in ice flow that have occurred for
which we lack a scientific basis to provide accurate estimates.
Thank you.
[The prepared statement of Dr. Alley follows:]
Prepared Statement of Richard B. Alley
Changes in Ice:
The 2007 IPCC Assessment
Introduction
My name is Richard Alley.\1\ I am Evan Pugh Professor of
Geosciences and Associate of the Earth and Environmental Systems
Institute at the Pennsylvania State University. I have authored over
170 refereed scientific publications in the areas of ice and climate,
which are ``highly cited'' according to a prominent indexing service,
and I have given hundreds of presentations concerning my areas of
expertise. My research interests focus especially on glaciers and ice
sheets, their potential for causing major changes in sea level, and the
climate records they contain. I have been a member of many national and
international committees, including chairing the National Research
Council's Panel on Abrupt Climate Change and serving on their Polar
Research Board. I have contributed to the efforts of the
Intergovernmental Panel on Climate Change (IPCC) in various ways, and
serve as a Lead Author on Chapter 4 (the Cryosphere), and on the
Technical Summary and the Summary for Policy-makers of Working Group I
of the Fourth Assessment Report. A brief description of the IPCC
process as it applies to this testimony is appended, for your
information.
---------------------------------------------------------------------------
\1\ Any opinions, findings, conclusions, or recommendations
expressed in this publication are those of the author and do not
necessarily reflect those of the Pennsylvania State University, the
Intergovernmental Panel on Climate Change, or other organizations.
---------------------------------------------------------------------------
Changes in Ice
The newly released report reaffirms the strong scientific evidence
that human activities are changing the composition of the planet's
atmosphere, and that this is warming the climate and affecting it in
other ways. In particular, our chapter documents the increasingly
strong evidence for widespread reductions in the Earth's ice, including
snow, river and lake ice, sea ice, permafrost and seasonally frozen
ground, mountain glaciers, and the great ice sheets of Greenland and
Antarctica. Our chapter and others highlight the strong evidence for
the dominant role of warming, which is primarily being caused by human
activities, in this loss of ice.
I will briefly summarize some of these many aspects, especially
focusing my attention on the issue of ice-sheet shrinkage and its
possible effect on sea-level rise. I will rely on the recent IPCC
report, as well as other materials as needed.
Snow cover has decreased in most regions, as shown by satellite
data tied to limited surface observations. Snow melt is shifting
earlier into the spring. Declines in April 1 snowpack have been
measured in 75 percent of western North American sites monitored.
Impacts of climate change on people will be covered in the WGII report,
coming soon, but other sources express great concern about earlier
snowmelt in the U.S. West, because the snow pack in many regions is a
dominant source of summertime water. Trends in snow cover cannot be
explained by changing precipitation (and indeed, in some very cold
places snow depth has increased with increasing precipitation), but the
overall shrinkage of snow cover can be explained by rising temperature.
Freezing of rivers and lakes generally has been occurring later in
the fall, with thawing earlier in the spring, giving longer intervals
of open water. Coordinated data collection is scarce, however, and the
data set not extensive.
Arctic sea ice, formed by freezing of ocean water, has decreased in
area and thickness. The change in the summer has been especially large,
with ice lost from an area twice the size of Texas between 1979 and
2005 (decreasing trend in ice area of seven percent per decade over
that interval). Data sets from satellites, tied to observations from
ships submarines, have been especially important in documenting these
changes. Although shifts in circulation of the ocean and atmosphere may
have contributed to the ice loss, greenhouse-gas warming is likely to
have been important. (Any Antarctic sea-ice changes fall within natural
variability; cooling associated with the ozone hole may be affecting
Antarctic climate, a complex subject beyond the scope of these brief
remarks.)
Permanently frozen ground (permafrost) and seasonally frozen ground
are not readily monitored globally. However, available reports point to
overall warming and thawing of this ice in the ground, in response to
rising air temperatures and changes in snow cover.
Glaciers and ice caps occur primarily in mountainous areas, and
near but distinct from the Greenland and Antarctic ice sheets. On
average, the world's glaciers were not changing much around 1960 but
have lost mass since, generally with faster mass loss more recently.
Glacier melting contributed almost an inch to sea-level rise during
1961-2003 (about 0.50 mm/year, and a faster rate of 0.88 mm/year during
1993-2003). Glaciers experience numerous intriguing ice-flow processes
(surges, kinematic waves, tidewater instabilities), allowing a single
glacier over a short time to behave in ways that are not controlled by
climate. Care is thus required when interpreting the behavior of a
particular iconic glacier (and especially the coldest tropical
glaciers). But, ice-flow processes and regional effects average out if
enough glaciers are studied for a long enough time, allowing glaciers
to be quite good indicators of climate change. Furthermore, for a
typical mountain glacier, a small warming will increase the mass loss
by melting roughly five times more than the increase in precipitation
from the ability of the warmer air to hold more moisture. Thus,
glaciers respond primarily to temperature changes during the summer
melt season. Indeed, the observed shrinkage of glaciers, contributing
to sea-level rise, has occurred despite a general increase in
wintertime snowfall.
Ice-sheet Changes
The large ice sheets of Greenland and Antarctica are of special
interest, because they are so big and thus could affect sea level so
much. Melting of all of the world's mountain glaciers and small ice
caps might raise sea level by about one foot (0.3m), but melting of the
great ice sheets would raise sea level by just over 200 feet (more than
60m). We do not expect to see melting of most of that ice, but even a
relatively small change in the ice sheets could matter to the world's
coasts.
A paper published in the journal Science last week (Rahmstorf et
al., 2007) compared the projections made in the 2001 IPCC Third
Assessment Report to changes that have occurred. The carbon dioxide in
the atmosphere has followed expectations closely. Temperature has
increased just slightly faster than projected, but well within the
stated uncertainties. Sea level is following near the upper edge of the
stated uncertainties, however, well above the central estimate. Changes
in the ice sheets help explain this.
The 2001 IPCC report noted large uncertainties, but presented a
central estimate that the combined response of the ice sheets to
warming would be net growth, lowering the sea-level rise from other
sources averaged over the 21st century, with increase in snowfall on
the ice sheets exceeding increase in melting and with little change in
ice flow. Data collected recently show that the ice sheets very likely
have been shrinking and contributing to sea level rise over 1993-2003
and with even larger loss by 2005, as noted in the IPCC report and
elsewhere (e.g., Alley et al., in press; Cazenave, 2006). Thickening in
central Greenland from increased snowfall has been more than offset by
increased melting in coastal regions. Many of the fast-moving ice
streams that drain Greenland (see the Figure, below) and parts of
Antarctica have accelerated, transferring mass to the ocean and further
contributing to sea-level rise. The total contribution to sea-level
rise from the ice sheets remains smaller than the contribution from
mountain-glacier melting or from the expansion of ocean water as it
warms. However, the existence of the ice-sheet contribution, its
important ice-flow source, and the large potential sea-level rise from
such mechanisms in the future motivate careful consideration.
An ice-sheet is a two-mile-thick, continent-wide pile of snow that
has been squeezed to ice. All piles tend to spread under their own
weight, restrained by their own strength (which is why spilled coffee
spreads on a table top but the stronger table beneath does not spread),
by friction beneath (so pancake batter spreads faster on a greased
griddle than on a dry waffle iron), or by ``buttressing'' from the
sides (so a spatula will slow the spreading of the pancake batter).
Observations at a site in Greenland have shown that meltwater on top of
the ice sheet flows through the ice to the bottom and reduces friction
there. More melting in the future thus may reduce friction further,
speeding the production of icebergs and the increase in sea level.
Some early gothic cathedrals suffered from the ``spreading-pile''
problem, the sides tending to bulge out while the roof sagged down,
with potentially unpleasant consequences. The beautiful solution was
the flying buttress, which transfers some of the spreading tendency to
the strong Earth beyond the cathedral. Ice sheets also have flying
buttresses, called ice shelves. The ice reaching the ocean usually does
not immediately break off to form icebergs, but remains attached to the
ice sheet while spreading over the ocean. The friction of these ice
shelves with islands, or with the sides of embayments, helps restrain
the spreading of the ice sheet much as a flying buttress supports a
cathedral. The ice shelves are at the melting point where they contact
water below, and are relatively low in elevation hence warm above. Ice
shelves thus are much more easily affected by climatic warming than are
the thick, cold central regions of ice sheets. Rapid melting or
collapse of several ice shelves has occurred recently, allowing the
``gothic cathedrals'' behind to spread faster, contributing to sea-
level rise.
Although science has succeeded in generating useful understanding
and models of numerous aspects of the climate, similar success is not
yet available for ice-sheet projections, for reasons that I would be
happy to explore with the Committee. We do not expect ice sheets to
collapse so rapidly that they could raise sea level by meters over
decades; simple arguments point to at least centuries. However, the
IPCC report is quite clear on the lack of scientific knowledge to make
confident projections.
Synopsis
In summary, with high scientific confidence, changes are occurring
in much of the world's ice. These are being caused primarily by
warming. That warming is largely being caused by greenhouse gases being
released to the atmosphere by human activities. Shrinkage of the large
ice sheets was unexpected to many observers but appears to be
occurring, and the poor understanding of these changes prevents
reliable projections of future sea-level rise over long times.
Recently published estimates of the mass balance of the Greenland ice
sheet through time (Alley et al., in press)
A Total Mass Balance of 0 indicates neither growth nor shrinkage,
and -180 Gt yr-1 indicates ice-sheet shrinkage contributing to sea-
level rise of 0.5 mm/year (one inch in about 50 years), as indicated.
Each box extends from the beginning to the end of the time interval
covered by the estimate, with the upper and lower lines indicating the
uncertainties in the estimates. A given color is associated with a
particular technique, and the different letters identify different
studies. Two estimates have arrows attached, because those authors
indicated that the change is probably larger than shown. The dotted box
in the upper right is a frequently-cited study that applies only to the
central part of the ice sheet, which is thickening, and misses the
faster thinning in the margins.
References Cited
Alley, R.B., M.K. Spencer and S. Anandakrishnan. Ice-sheet mass
balance: Assessment, attribution and prognosis. In press.
Annals of Glaciology.
Cazenave, A. 2006. How fast are the ice sheets melting? Science 314,
1250-1252.
Rahmstorf, S., A. Cazenave, J.A. Church, J.E. Hansen, R.F. Keeling,
D.E. Parker and R.C.J. Somerville. 2007. Recent observations
compared to projections. Science, Sciencexpress, 10.1126/
science.1136843.
The Intergovernmental Panel on Climate Change (IPCC) Assessment
The IPCC was founded by the United Nations Environment Programme
and the World Meteorological Organization in 1988 (this information is
summarized from the publications of the IPCC, which are widely
available including at www.ipcc.ch). The Panel is charged to assess the
best scientific information on climate change, in a comprehensive,
objective, open and transparent way. The panel is divided into three
working groups. Working Group I assesses the scientific aspects of the
climate system and climate change. Working Group II assesses the
vulnerability of socio-economic and natural systems to climate change,
negative and positive consequences of climate change, and options for
adapting to it. Working Group III assesses options for limiting
greenhouse gas emissions and otherwise mitigating climate change.
The IPCC reports are written by teams of authors, who are nominated
by governments and international organizations. Author selection is
based on expertise relative to the specific task. Experts come from
universities, research centers, business and environmental
associations, and other organizations from more than 130 countries.
Procedures are enforced to ensure that the results of the IPCC process
are policy-relevant. A rigorous review process is used throughout the
process. Specialists review a first draft of the report, and
governments, authors and independent experts review a second draft,
with special review editors for each chapter ensuring that balance is
maintained and that all review comments are properly addressed. For our
chapter, Chapter 4 (the Cryosphere) of Working Group I of the Fourth
Assessment Report, which in near-final draft had 47 pages, 255
references, and 23 figures involving 41 panels, the two Coordinating
Lead Authors, nine Lead Authors (informed by 44 contributing authors),
and two review editors addressed over 1,000 comments from the expert
review alone. As one of the shorter chapters, we were not the busiest.
The Third Assessment Report in total involves more than 2,500 expert
reviewers, 800 contributing authors, and 450 Lead Authors.
The report from Working Group I was condensed into a Technical
Summary, and then into a Summary for Policy-makers. The Summary for
Policy-makers was approved line-by-line by governments in plenary from
January 29 to February 1 in Paris, and was released to the public on
February 2, 2007. The Technical Summary and the full report will follow
later in the spring, as will reports from Working Groups II and III.
The approximately 1,000-page main report from Working Group I is being
copy-edited and formatted for publication, with a limited number of
small changes in specific wording for clarity based on the results of
the Paris plenary.
Biography for Richard B. Alley
Dr. Richard Alley is Evan Pugh Professor of Geosciences and
Associate of the Earth and Environmental Systems Institute at The
Pennsylvania State University, University Park, where he has worked
since 1988. He was graduated with the Ph.D. in 1987 from the University
of Wisconsin-Madison and with M.Sc. (1983) and B.Sc. (1980) degrees
from The Ohio State University-Columbus, all in Geology. Dr. Alley
teaches, and conducts research on the climatic records, flow behavior,
and sedimentary deposits of large ice sheets, to aid in prediction of
future changes in climate and sea level. His experience includes three
field seasons in Antarctica, eight in Greenland, and three in Alaska.
His awards include the Seligman Crystal of the International
Glaciological Society, the first Agassiz Medal of the European
Geosciences Union Cryospheric Section, a Presidential Young
Investigator Award, the Horton Award of the American Geophysical Union
Hydrology Section and Fellowship in the Union, the Wilson Teaching
Award and the Mitchell Innovative Teaching Award of the College of
Earth and Mineral Sciences and the Faculty Scholar Medal in Science at
Penn State. Dr. Alley has served on a variety of advisory panels and
steering committees, including chairing the National Research Council's
Panel on Abrupt Climate Change, and has provided requested advice to
numerous government officials in multiple administrations including a
U.S. Vice President, the President's Science Advisor, and a Senate
Committee. He has published over 170 refereed papers, and is a ``highly
cited'' scientist as indexed by ISI. His popular account of climate
change and ice cores, The Two-Mile Time Machine, was chosen science
book of the year by Phi Beta Kappa in 2001. Dr. Alley is happily
married with two children, two cats, and two bicycles, and resides in
State College, PA, where he coaches recreational soccer and
occasionally plays some.
Chairman Gordon. Thank you, Dr. Alley.
I just received a message here that the International House
of Pancakes wanted to offer you an evening job if you need to
supplement. I know that land grant institutions don't pay that
well.
Dr. Meehl.
STATEMENT OF DR. GERALD A. MEEHL, COORDINATING LEAD AUTHOR,
IPCC, WORKING GROUP I, CHAPTER 10: GLOBAL CLIMATE PROJECTIONS;
SENIOR SCIENTIST, NATIONAL CENTER FOR ATMOSPHERIC RESEARCH
Dr. Meehl. Yes. Dr. Alley's enthusiasm is, indeed,
contagious. I think we would all like to run back to our labs
and get back to work on science after doing a lot of this kind
of assessment work.
But I want to thank the Chairman and Members of the
Committee for the opportunity to communicate to you some of the
findings from the IPCC AR4.
The thing I wanted to stress, the first thing, is that a
significant new aspect regarding projections of future climate
change has involved an unprecedented coordinated international
effort to perform a set of climate change experiments. These
were done with high-end computer climate modeling tools we use
to quantify possible future climate change. These are called
Global-Coupled Ocean and Atmosphere Climate Models, or we just
call them AOGCMs for short, and a total of 16 modeling groups
from around the world from 11 countries, and this includes
three groups in the United States, use 23 of these high-end
models, AOGCMs, to perform coordinated climate-change
experiments. These include simulations of 20th century climate
with both natural and anthropogenic forcings, three possible
outcomes for the 21st century based on low, medium, and high
emission scenarios and three idealized stabilization
experiments.
These data were then collected and made openly available
for analysis, and this is really the first time we have been
able to do something on this scale. And to date, over 950
scientists from around the world have accessed these model
data. And the many papers that have been written were assessed
by us in the process of coming up with the AR4. These analyses
provide an improved quantification of likelihoods and many
aspects of future climate change.
And a little more on the models, the amount of detail and
realism in the climate models we use has increased in recent
years. This is partly because of our increase in understanding
of the processes in the climate system and also in part because
the calculations provided by newer supercomputers has
increased.
For future climate, this now allows us to provide more
detailed information on aspects of the climate system, such as
possible future changes of weather and climate extremes.
Regarding near-term climate change, warming of about two-
tenths of a degree centigrade per decade over the next couple
of decades is projected across the range of scenarios
considered. And this actually continues about the same rate we
have observed in observations over the past few decades.
Hypothetically, if concentrations of greenhouse gases had
been held constant at year 2000 values, we are already
committed to about a tenth of a degree C per decade, mainly due
to the slow response of the ocean. By the 2020s, most of the
United States is projected to warm by about an additional one
degree centigrade, and this is larger than warming we observed
during the 20th century and very likely larger than estimates
of natural variability during the 20th century.
As we approach the middle part of the 21st century and
beyond, it is clear that it makes a difference regarding what
emission scenario we choose to follow now. By 2100, there is a
spread of globally-averaged surface air temperature increase
among the six scenarios considered. Best estimates for this
global warming range from about 1.8 degrees centigrade for the
lowest scenario with a likely range of 1.1 to 2.9 degrees C and
four degrees C for the highest scenario with a likely range of
2.4 degrees to 6.4 degrees centigrade.
Now these scenarios are constructed based on various
assumptions of future population growth, economic activity, and
energy usage, but no climate initiatives were considered in
these scenarios.
So based on the existing models available for assessment,
the central values for projection of sea level rise by 2100 are
similar to previous estimates. These range from about 20 to 40
centimeters, depending on scenario, with the upper end of the
range for the highest scenario of about 60 centimeters. These
ranges of sea level rise are narrower than previous estimates,
mainly because of reduced uncertainties in some of the
components that contribute to sea level rise.
However, a large unquantified uncertainty arises from
processes we don't yet fully understand and have only recently
been able to observe, such as potential ice sheet instability
that Dr. Alley was alluding to.
For example, additional sea level rise from this source by
the end of the 21st century could add another 10 to 20
centimeters to the upper ranges and higher future sea level
rise values cannot be excluded. This is an area of great
concern and active ongoing research given the potential
consequences.
As seen in recent trends and observations, the future
pattern for temperature change is characterized by greater
warming over land compared to oceans and more warming at high
northern latitudes. Associated with these temperature changes
there are projected decreases of snow cover, decreases in thaw
depth over most permafrost regions and other changes.
Reductions in sea ice, of course, go along with increased
temperatures with a late summer sea ice free Arctic by the end
of the 21st century in the high forcing scenario in some
models. The pattern of future precipitation change indicates
increases at higher latitudes, such as the northern tier of
states during winter and decreases over subtropical land areas,
such as the Southwest United States.
Though the picture of a future warming world appears bleak,
it is not yet hopeless. The six different mission scenarios
considered in the AR4 show that the longer we wait to do
something, the worse the problem gets. These scenarios also
illustrate that what we do now can make a difference for the
future.
Thank you very much for your invitation to address the
Committee.
[The prepared statement of Dr. Meehl follows:]
Prepared Statement of Gerald A. Meehl
Global Climate Projections:
The 2007 IPCC Assessment
Introduction
I thank the Chairman and other Members of the Committee for the
opportunity to communicate to you today some of the recent findings
from the IPCC Fourth Assessment Report (AR4). My name is Gerald Meehl,
Senior Scientist at the National Center for Atmospheric Research (NCAR)
in Boulder, Colorado. My research interests include tropical climate
involving the monsoons and El Nino Southern Oscillation, climate
variability and climate change. I have authored or co-authored more
than 145 peer-reviewed scientific journal articles and book chapters. I
have been involved with the Intergovernmental Panel on Climate Change
(IPCC) assessments since the first one that was published in 1990. I
was a Contributing Author on that first assessment and its update in
1992, a Lead Author for the 1995 Assessment, and a Coordinating Lead
Author for the 2001 and the present 2007 assessments. I have been
involved with committees of the World Climate Research Program (WCRP)
on Climate Variability and Predictability (CLIVAR), and am currently
Co-Chair of the WCRP/CLIVAR Working Group on Coupled Models (WGCM).
This committee organized and coordinated the international modeling
groups in performing climate model experiments for assessment in the
AR4, and in the collection and analysis of data from those model
experiments. Through the efforts of that committee, this extensive
multi-model data set on climate change has been made openly available
for analysis, and over 950 scientists from around the world have been
able to access and analyze these data. The resulting papers have
contributed extensively to the IPCC AR4. I have served on several
National Research Council (NRC) panels, and am currently a member of
the NRC Climate Research Committee. I was a Lead Author on the U.S.
Climate Change Science Program (CCSP) Report 1.1 on temperature trends
in the atmosphere, and am currently co-coordinator for the CCSP report
on weather and climate extremes in a changing climate.
In my capacity as a Coordinating Lead Author for the chapter on
climate change projections for the IPCC AR4, I was in Paris last week
attending the Plenary of the IPCC where the IPCC Fourth Assessment
Report was accepted and approved by the roughly 180 governments that
make up the IPCC. Thus, the IPCC is a group of governments, not a group
of scientists, which is a common misconception. The IPCC commissions
assessments to be performed roughly every five or six years, and they
are prepared through the efforts of hundreds of scientists from around
the world who are actively involved in state-of-the-art research in
climate science. The IPCC assessments provide a comprehensive view of
the current state of human understanding of climate science and climate
change. My testimony today will summarize some of the main findings of
the IPCC AR4 with regards to projections of future climate change.
A much larger group of climate models have contributed to the IPCC AR4
A major international effort to perform a set of coordinated
climate change experiments was organized by the WCRP/CLIVAR WGCM. A
total of 16 modeling groups from 11 countries (three groups from the
U.S.) used 23 global coupled climate models to perform these
coordinated climate change experiments that involved simulations of the
20th century climate, three possible outcomes for the 21st century
(based on low, medium and high emission scenarios), and three idealized
stabilization experiments. In addition there were idealized carbon
dioxide increase experiments, and associated stabilization experiments
with doubled and quadrupled CO2 amounts. These data were
then collected, and over 31 Terabytes of model data were archived at
the DOE-sponsored Program for Climate Model Diagnosis and
Intercomparison (PCMDI) at Lawrence Livermore National Lab (LLNL) in
Livermore, CA. WGCM then coordinated the analysis of this multi-model
data set. This unprecedented effort has involved over 950 scientists
who have accessed these model data and wrote many papers that were
assessed in the AR4. This massive effort was the first time the
international climate modeling community has performed such an
extensive set of climate change experiments, with the output from those
experiments openly available for analysis.
Climate change commitment and near-term warming
Several of the experiments run with the most recent global climate
models explored the concept of climate change commitment. That is, if
concentrations of greenhouse gases are stabilized at various levels,
how much more warming would occur due to the emissions already in the
system. Such committed climate change is due to the time lag introduced
by the oceans because it takes longer for water to warm. If
concentrations of greenhouse gases could have been stabilized in the
year 2000, a committed warming of about 0.1C per decade averaged over
the period 2000 to 2020 would occur, with smaller warming continuing
after that. Of course there are ongoing increases of greenhouse gases,
so the models project that no matter what emissions scenario is
followed (not taking into account possible large volcanic eruptions
that we are not able to forecast but would produce temporary cooling a
year or two after the eruption), the combination of climate change
commitment and additional warming from increasing greenhouse gases
would result in a warming of about 0.2C per decade over the next two
decades.
The sea level rise commitment is much longer-term. This is due to
the effects of thermal expansion on sea level. That is, since water has
the physical property of expanding as it heats up, as the warming
penetrates deeper into the ocean, an ever increasing volume of water
expands and contributes to ongoing sea level rise. Since it would take
centuries for the entire volume of the ocean to warm in response to the
effects of the greenhouse gases we have already put into the air, we
are committed right now to further sea level rise that would continue
for centuries.
Previous IPCC assessments starting in 1990 used global climate
models to project global warming of between about 0.15C and 0.3C per
decade for 1990 to 2005. The actual observed values of global warming
for that time period are about 0.2C per decade. This increases our
confidence in the climate model projections for future climate change,
since previous generations of models were able to project warming rates
similar to those subsequently observed.
Climate change later in the 21st century
As we approach the middle part of the 21st century and beyond, it
makes a difference regarding what emissions scenario we choose to
follow now. By 2100 there is a spread of globally averaged surface air
temperature increase among the six scenarios considered, with best
estimates ranging from nearly 2C for a lowest scenario (B1) and about
4C for the highest scenario (A1FI). Likely ranges for warming at the
end of the 21st century are also now provided. For example, for a low
scenario (B1), the warming averaged for 2090-99 relative to 1980-99 has
a best estimate of 1.8C with a likely range of 1.1C to 2.9C. For a
medium scenario (A1B), the best estimate is 3.4C with a likely range of
2.0C to 5.4C, and for the highest scenario (A1FI), the best estimate is
4.0C with a likely range from 2.4C to 6.4C. There are greater values at
the higher end of the ranges due to relatively new understanding
regarding the nature of the feedbacks from the carbon cycle (i.e., how
the oceans and land absorb and emit carbon dioxide). Though only
relatively few global coupled climate models include the complex
processes involved with modeling the carbon cycle, this feedback is
positive (i.e., adding to more warming) in all models so far
considered. Therefore, the addition of carbon cycle feedbacks provides
higher values on the warm end of the uncertainty ranges.
Rising global temperatures are very likely to raise sea level by
expanding ocean water and melting mountain ice caps and glaciers.
Recently observed ice sheet dynamical processes that could produce
potentially larger contributions to sea level rise than accounted for
in the present estimates are not fully included in existing models of
the Greenland and Antarctic ice sheets assessed for the AR4. Therefore
larger increases in sea level rise than the present projections cannot
be excluded. Consequently, the AR4 cannot quantify a full uncertainty
range of sea level rise at the end of the 21st century. Based on the
existing models available for assessment, the central values for
projections of sea level rise by 2100 are similar to previous
estimates, ranging from about 30 to 40 cm. About 60 percent to 70
percent of this increase is due to thermal expansion of sea water
(i.e., as water warms, it expands) and is thus connected to the more
certain estimates of warming of surface air temperatures. There is less
certainty with regards to the other components of sea level rise
(contributions from melting land glaciers and small ice caps, the net
balance between snow accumulation and melting ice for Greenland and
Antarctica, and the dynamic ice flow contributions from Greenland and
Antarctica). This is reflected in the ranges of sea level rise that
differ from previous estimates, due in part to the way the uncertainty
of these contributions is taken into account. This is an area of great
concern and active ongoing research given the potential consequences.
The projected globally averaged temperature increase is also
reflected by patterns of regional climate changes. As noted in previous
assessments, this pattern for temperature change is characterized by
greater warming over land compared to oceans, and more warming at the
high northern latitudes. Associated with these temperature changes,
there are projected decreases of snow cover, and increases in thaw
depth over most permafrost regions. Reductions in sea ice go along with
the increased temperatures, with a sea-ice free Arctic by the end of
the 21st century in the high forcing scenario in some models. The
pattern of future precipitation change indicates likely increases at
higher latitudes, such as the northern tier of states, and decreases
over subtropical land areas such as the Southwest U.S.
It would seem that the relatively small increases in average
temperature amounting to a few degrees may not make that much
difference. However, such small changes in average values can lead to
much larger changes of extreme weather and climate events. For example,
it is very likely that heat waves will increase in intensity, frequency
and duration, with heavy precipitation events also increasing. These
projected changes in extremes continue trends we have already observed.
Though present-day global climate models used for the climate
change projections discussed above have inherent limitations in
simulating hurricanes, new types of specialized models have been
formulated to study such possible future changes. From a range of
models, it is likely that future tropical cyclones (typhoons and
hurricanes) will become more intense with larger peak wind speeds and
more intense precipitation. This is physically consistent with ongoing
increases of sea surface temperature since there is a well-established
link between warmer water and hurricane intensity. There is less
confidence in projections of a global decrease in numbers of hurricanes
since the model results are not as consistent.
There has been some interest in the media and in Hollywood
regarding the possibility of an abrupt shutdown of the Atlantic Ocean
meridional overturning circulation (MOC). This large-scale ocean
circulation system, sometimes called the ``ocean conveyor belt,''
transports heat northwards, in part via the Gulf Stream, to the North
Atlantic. A warming of the North Atlantic from increasing greenhouse
gases could produce more precipitation and warmer water that would
stabilize this overturning circulation and consequently reduce the
amount of northward heat transport. Using this line of reasoning, if
the MOC suddenly shut down, there could be a sudden decrease in
northward heat transport and possibly a large cooling of the North
Atlantic region. Research assessed in the IPCC AR4 indicates that it is
very likely that the MOC will indeed slow down during the 21st century.
With the weakening of this circulation, there is somewhat less heat
transported northward. But there is still a future net increase of
surface air temperatures over the North Atlantic since the warming from
the increased greenhouse gases overwhelms any cooling from the MOC
slowdown. Additionally, it is very unlikely that the MOC will undergo a
large abrupt shut-down during the 21st century, with an associated
cooling from such a sudden shut-down also very unlikely. No global
coupled climate model simulation assessed in the AR4 produces such an
abrupt change, even if Greenland ice melt is taken into account.
However, changes in the MOC in the 22nd century and beyond cannot be
assessed with confidence at this time.
Summary
The IPCC AR4 represents the current state of human understanding of
climate science and climate change. Projected changes of future climate
have relied on an unprecedented set of coordinated climate change
experiments undertaken by the international climate modeling community,
and the U.S. modeling groups have played a prominent role in this
process. The projections of future climate are consistent with earlier
IPCC assessments in terms of the magnitude of global changes. This is
reassuring since successive generations of climate models are now
producing comparable results from assessment to assessment. But there
are now many more details as well as increased certainty regarding
quantifications of regional climate change, extremes, hurricanes,
climate change commitment, ocean circulation changes, and better
information regarding both near-term and longer-term climate change.
Biography for Gerald A. Meehl
Gerald Meehl received his Bachelor's (1974), Master's (1978), and
Ph.D. (1987) degrees in climate dynamics from the University of
Colorado in Boulder. Since 1973, he has worked at the National Center
for Atmospheric Research (NCAR) in various capacities, including
participating in the Tropical Wind Energetics Reference Level
Experiment (TWERLE) in Pago Pago, American Samoa, and Christchurch, New
Zealand (1975-76), in the Monsoon Experiment (MONEX) in Bintulu,
Sarawak, Malaysia, and Kathmandu, Nepal (1978-79), and in the Tropical
Ocean Global Atmosphere (TOGA) Coupled Ocean Atmosphere Response
Experiment (COARE) in Townsville, Australia, Kapingamarangi, FSM,
Pohnpei, FSM, and Republic of Nauru (1992-93). Since 1979, as a
scientist in the Climate and Global Dynamics Division, he has studied
the interactions between El Nino/Southern Oscillation (ENSO) and the
Indian monsoon, analyzed the results from global coupled ocean-
atmosphere general circulation models at NCAR, and examined the
possible effects of increased carbon dioxide, sulfate aerosols, and
other forcings on global climate. He is the author of more than 140
scientific papers in peer-reviewed journals, and has contributed
chapters to several textbooks. He was a contributing author for the
Intergovernmental Panel on Climate Change (IPCC) 1990 and 1992
assessments, a Lead Author for the chapter on climate model projections
of future climate change for the 1995 IPCC assessment, a Coordinating
Lead Author for the chapter on climate model projections of future
climate change for the IPCC Third Assessment Report published in 2001,
and a Coordinating Lead Author for the chapter on global climate change
projections for the 2007 IPCC Fourth Assessment Report. Among his
current committee appointments, he is a member of National Research
Council Climate Research Committee, Co-Chair of the Community Climate
System Model Climate Change Working Group, Co-Chair of the World
Climate Research Programme CLIVAR Working Group on Coupled Models
(WGCM), and Chairman of the WGCM Climate Simulation Panel which has
coordinated analyses of global coupled climate model simulations for
the IPCC Fourth Assessment Report.
Discussion
The IPCC Process
Chairman Gordon. Thank you, Dr. Meehl.
Now, Dr. Solomon, the message I am taking away from this
Report is that the climate is changing, the Earth is getting
warmer, human activities have started and continue to drive
this change. Have I gotten that message right?
Dr. Solomon. Basically, yes. I would put some ``very
likely''s in there, but I would agree with you.
Chairman Gordon. Thank you. And Dr. Solomon, I understand
that all 113 nations had to agree on that. This had to be a
unanimous Report, is that correct?
Dr. Solomon. All of the nations present in Paris, including
the United States, were in agreement with the final document.
That is correct. It was a consensus document.
Chairman Gordon. And by virtue of that, does that mean that
this would be on the conservative side of a report?
Dr. Solomon. I would actually say that the point of this
kind of a report is to say what we know, what we don't know,
and what the remaining uncertainties are. I don't think that a
report, such as ours, if it is intended to be the sort of
global consensus statement that it is could go any farther than
we have gone. I think we have done a very fair job in reporting
what is known and what is not known. I would not call it
conservative, personally.
Glacier Melt Accelerations
Chairman Gordon. And Dr. Alley, I understand that the
research had to be cut off by the end of 2005, and so
additional information that came from Greenland with the ice
floats and things of this nature were not a part of this
information. Is that correct?
Dr. Alley. Some of the information on acceleration in
Greenland did come in time to be assessed properly and a couple
of recent papers are not included. That is correct.
Chairman Gordon. And from press reports that I have seen,
it indicated that in terms of the rise in sea level, you were
somewhat limited to the change of temperature. As the water got
warmer, obviously, it would expand. How limited were you in the
discussions and the new information concerning Greenland and
elsewhere where glaciers were melting?
Dr. Alley. The melting of mountain glaciers, in the Alps,
for example, or in the Rockies, is taken account of, and--with
improved accuracy, so I think we understand better. The changes
in snowfall and melting on top of Greenland and on top of
Antarctica are also taken into account and somewhat better than
it had been. The----
Chairman Gordon. But was it taken into account in terms of
the rise in the sea level?
Dr. Alley. It is taken into account in terms of rise in sea
level. What is missing is an accurate assessment of these
changes in the spreading, the changes in the flow, how much the
self-lubrication of the ice or the loss of the spatulas would
contribute to accelerated flow in a warmer world. And we simply
don't have the scientific understanding to provide an accurate
assessment of that.
Chairman Gordon. But we know it is not going to get slower.
It is only going to get faster. The question is just how much
faster.
Dr. Alley. But we don't even really know that, because that
sort of implies a knowledge that we are trying rather
desperately to build for you right now. Certainly, we have seen
glacier accelerations, and we have seen those accelerations in
response to warming. We have fairly high confidence in that. If
you see future warming, it, perhaps, would not be surprising
that if warming causes mass loss that more warming would cause
more mass loss, but we are still fighting on that. This
document works very, very hard to be an assessment of what is
known scientifically, what is well founded in the refereed
literature, and when we come up to that cliff and look over and
say we don't have a foundation right now, we have to tell you
that. And on this particular issue, the trend of acceleration
of this flow with warming, we don't have a good assessed
scientific foundation right now.
Chairman Gordon. How long would you expect that that would
be before you will?
Dr. Alley. I don't know. I am very optimistic that we will
be better in five years. I am doubtful that we will have as
good an understanding of that as we do of, say, mean global
surface temperature that Dr. Meehl was talking about.
Chairman Gordon. Thank you, Dr. Alley.
Mr. Rohrabacher.
Mr. Rohrabacher. Thank you very much, and thank you very
much, Dr. Alley, for your honesty and your candor, considering
that people obviously wanted you to say something else than
what you have just told us, that they would like to have
certainty. For the record, Mr. Chairman, I would like to put in
the record a list of a number of scientists and statements by
scientists, very well respected statements and very well
respected scientists, who are not part of this so-called
consensus that any climate change is being caused by human
activity. If I could submit those for the record at this point.
Chairman Gordon. Certainly, Mr. Rohrabacher, and I will
also point out that the Minority had the opportunity to call
any of these witnesses and have them be part of this panel----
Mr. Rohrabacher. I appreciate that----
Chairman Gordon.--and had quite a bit of time to be able to
do that. But certainly this will add to our report. And without
any objection, they will be made a part of the record.
[The information follows:]
Information to be placed in the record relating to the House Science &
Technology Committee hearing on The State of Climate Change Science
2007 on February 8, 2007 by Congressman Dana Rohrabacher
Timothy Ball
``Believe it or not, Global Warming is not due to human
contribution of Carbon Dioxide (CO2). This in fact is the
greatest deception in the history of science. We are wasting time,
energy and trillions of dollars while creating unnecessary fear and
consternation over an issue with no scientific justification.''
Monday, February 5, 2007
Open News web site
http://www.opednews.com/articles/
opedne-daniel-g-070207-globa
l-warming- 3a-the-.htm
Dr. Tim Ball, Chairman of the Natural Resources Stewardship Project
(www.nrsp.com), is a Victoria-based environmental consultant and former
climatology Professor at the University of Winnipeg. He can be reached
at: [email protected]
Fred Singer
``Crucially, greenhouse models cannot explain the observed patterns
of warming--temperature trends at different latitudes and altitudes.
These data, published in a U.S. Government scientific report in May
2006, lead us to conclude that the human contribution is not
significant. Most of current warming must therefore stem from natural
causes. It may well be part of an unstoppable solar-driven 1,500-year
cycle of warming and cooling that's been documented in ice cores, ocean
sediments, stalagmites, and so forth--going back a million years.
``If indeed most of current warming is natural rather than from
greenhouse gases, there is little point in reducing carbon dioxide
emissions. Further, carbon dioxide is not an atmospheric pollutant.
Programs and policies for carbon dioxide control should therefore be
scrapped--including uneconomic alternative energy sources, carbon-
sequestration efforts, and costly emission-trading schemes. All of
these waste money and squander scarce resources, without in any way
affecting the atmosphere or climate. Humans have adapted to major
climate changes in the past, and we should have no problem doing so in
the future.''
The Science and Environmental Policy Project's The Week That Was
newsletter (2/3/07)
http://www.sepp.org/Archive/weekwas/2007/February%203.htm
S. Fred Singer, an atmospheric physicist, is Professor Emeritus of
environmental sciences at the University of Virginia, adjunct scholar
at the National Center for Policy Analysis, and former Director of the
U.S. Weather Satellite Service. He is also a research fellow at the
Independent Institute and author of Hot Talk, Cold Science: Global
Warming's Unfinished Debate (The Independent Institute, 1997).
Bill Gray
``I think we're coming out of the little ice age, and warming is
due to changes to ocean circulation patterns due to salinity
variations.''
Quote from an article in the Daily Reporter-Herald (9/19/06)
Dr. William M. Gray is a world famous hurricane expert and Emeritus
Professor of Atmospheric Science, Colorado State University.
From an interview with Dr. William M. Gray in Discover Magazine,
September 2005, Title: ``Weather Seer: `We're Lucky' ''
A few years ago, you almost called it quits because you'd lost so much
funding. What made you continue?
G: I don't have the budget that I had, so I have to cut back my project
way back. I am in retirement. I'm still working everyday, but I don't
teach and don't have as many graduate students and as much financial
need. I've got a little money from Lexington Insurance out of Boston,
and I have some National Science Foundation money. For years haven't
had any NOAA, NASA, or Navy money. But I'm having more fun. Right now
I'm trying to work on this human-induced global warming thing that I
think is grossly exaggerated.
You don't believe global warming is causing climate change?
G: No. If it is, it is causing such a small part that is negligible.
I'm not disputing that there has been global warming. There was a lot
of global warming in the 1930's and '40s, and then there was a slight
global cooling from the middle '40s to the early '70s. And there has
been warming since the middle '70s, especially in the last 10 years.
But this is natural, due to ocean circulation changes and other
factors. It is not human induced.
That must be a controversial position among hurricane researchers.
G: Nearly all of my colleagues who have been around 40 or 50 years are
skeptical as hell about this whole global warming thing. But no one
asks us. If you don't know anything about how the atmosphere functions,
you will of course say, ``Look, greenhouse gases are going up, the
globe is warming, they must be related.'' Well, just because there are
two associations, changing with the same sign, doesn't mean that one is
causing the other.
With last year's hurricane season so active, and this year's looking
like it will be, won't people say it's evidence of global warming?
G: The Atlantic has had more of these storms in the least 10 years or
so, but in other ocean basins, activity is slightly down. Why would
that be so if this is climate change? The Atlantic is a special basin?
The number of major storms in the Atlantic also went way down from the
middle 1960s to the middle '90s, when greenhouse gases were going up.
Why is there scientific support for the idea?
G: So many people have a vested interest in this global warming thing.
. .all these big labs and research and stuff. The idea is to frighten
the public, to get money to study it more. Now that the cold war is
over, we have to generate a common enemy to support science, and what
better common enemy for the glove than greenhouse gases?
Are your funding problems due in part to your views?
G: I can't be sure, but I think that's a lot of the reason. I have been
around 50 years, so my views on this are well known. I had NOAA money
for 30 some years, and then when the Clinton Administration came in and
Gore started directing some of the environmental stuff, I was cut off.
I couldn't get any NOAA money. They turned down 13 straight proposals
from me.
Global Warming Trends
Mr. Rohrabacher. Thank you.
My question--well, first of all, Dr. Solomon, is a glacier
named after you?
Dr. Solomon. Yeah, I am afraid so.
Mr. Rohrabacher. Is it melting? I am serious about that. Is
the glacier named after you melting?
Dr. Solomon. Well, that particular one is at 78 degrees
south, sir. It is at such a high latitude in the Antarctic
that----
Mr. Rohrabacher. So it is not melting?
Dr. Solomon.--it is out of reach of global warming.
Mr. Rohrabacher. It is out--it is not melting. Thank you
very much.
Let me--I am not a scientist. Look, I am a former
journalist and a writer, and so I have to really, you know,
look down and see what is being said, condense things into the
real meaning. Let me ask you just a couple fundamental
questions.
I saw on the History Channel a whole big special on the
mini ice age. Was there a mini ice age, and did it end at about
the middle of the 19th century? Or you know, were there really
Vikings that were living at a much higher temperature on
Greenland 1,000 years ago, or are we being--is the History
Channel just telling us, you know, a myth?
Dr. Trenberth. Mr. Rohrabacher, if I can have a crack at
that. There was a period called the little ice age----
Mr. Rohrabacher. Okay.
Dr. Trenberth.--that, indeed, occurred around about that
time up until about the end of, say, the 19th century, which
was----
Mr. Rohrabacher. All right.
Dr. Trenberth.--clearly cooler. It is a little bit of a
Eurocentric view of the world, though, because a lot of it was
certainly focused in the North Atlantic European region where,
you know----
Mr. Rohrabacher. Well, that, of course, is where we had all
of the statistics being kept, and so at that time period, of
course it would be Eurocentric, because they didn't keep all of
those temperature records in other places in the world. So
there was a mini ice age, and it went down to about the middle
of the 19th century. I couldn't help but notice that the chart
that was presented started the low point of this mini ice age.
It started there to prove that there was a global warming
trend.
Now if you start at the bottom of something that is
recognized as a time of cooling on the Earth, isn't it going to
go up naturally if there is a natural cycle going on?
Dr. Trenberth. The instrumental record, we have been able
to push it back to 1850, and that is the reason it starts then.
And the way we would characterize it is that there is really
not much change up until about 1920. There is a warming that
goes on from about 1920 to 1940, and we believe that some of
that--the work that the models have done and the instruments
and what has happened with the sun is that a part of that is
natural and associated with changes in the sun. It is really
only in the last 35 years, since about 1970, that the global
warming aspect has clearly emerged above these levels of
natural variability. So----
Mr. Rohrabacher. And we are only talking about one degree,
a one degree change, right? And in fact, over these last 20
years, you are talking about it is less than one degree,
because your one degree started back in the middle of the 19th
century.
Dr. Trenberth. Well, one degree Celsius. Over one degree
Fahrenheit since 1970.
Mr. Rohrabacher. Okay. One degree since 1970. Now is it
possible that there is a natural cycle going on here? Is that a
possibility?
Dr. Trenberth. This is one of the things that we can do
now. Natural cycles also have causes. They--you know, they come
from somewhere.
Mr. Rohrabacher. Like sunspots.
Dr. Trenberth. Sunspots or----
Mr. Rohrabacher. Okay.
Dr. Trenberth.--changes in the heat of the ocean or----
Mr. Rohrabacher. I have only got a little bit of time left.
Let me ask you--I am sorry, because you know, we are only given
a very short period of time to ask. What percentage of what are
called greenhouse gases are created by nature or--and that is
even leaving the sunspot issue out, as compared to humankind?
All of humankind produces what, 10 percent of the greenhouse
gases, five percent?
Dr. Solomon. Well, this is in my area of research, Mr.
Rohrabacher, so I would like to respond. On the issue of solar
activity, we have direct measurements in how the sun has varied
since 1970. They show very clearly that the solar, in radians,
changes since 1970 have been very small, much less than the
changes in the energy budget due to greenhouse gases. You will
find that figure to----
Mr. Rohrabacher. Okay. So the greenhouse gases are what
percentage again?
Dr. Solomon. Well, greenhouse gas contribution to warming
far outstrips the solar brightness changes. That is a figure--
--
Mr. Rohrabacher. Okay. But what percentage of greenhouse--
--
Dr. Solomon. May I continue----
Mr. Rohrabacher. No, no, because I have only got a little
bit of time. I am sorry----
Dr. Solomon.--because you have asked----
Mr. Rohrabacher.--I control this time. You don't. I am
asking what percentage of the greenhouse gases are created by
human beings?
Dr. Solomon. Yeah. That is what I was just about to get
to----
Mr. Rohrabacher. Okay.
Dr. Solomon.--actually. Thank you. If you look at Figure 1
of our Summary for Policy-makers, it actually shows you the
time series of carbon dioxide, for example, and you will see it
has increased markedly since 1750----
Mr. Rohrabacher. I am not asking about that.
Dr. Solomon. It is almost entirely due to human activities.
Mr. Rohrabacher. Listen. Listen. Hold on. Excuse me. But
unless you are going to be honest about this, we are not going
to have an honest discussion. At least Mr. Alley was being
honest about it, saying we don't know. If I ask you a direct
question, what percentage of the greenhouse gases are caused
naturally rather than by human beings, can't anybody answer
that directly?
Dr. Solomon. The CO2 increase is caused almost
entirely----
Mr. Rohrabacher. I didn't ask that.
Dr. Solomon.--by human beings.
Mr. Rohrabacher. I didn't--listen. I am asking you a direct
question, what percentage of the greenhouse gases are made by
human beings and what percentage are made by nature?
Dr. Solomon. I would say a fair number regarding the
increase since 1750 is that greater than 90 percent of the
increase has been caused by human activities.
Mr. Rohrabacher. That wasn't the question, was it? Why
can't you--listen, this is very dishonest. You are supposed to
be a scientist. I have asked you a direct question. Can anybody
else in the panel be honest about the answer?
Dr. Solomon. Sir, I am really trying to be honest.
Mr. Rohrabacher. What percentage of the greenhouse gases in
our atmosphere and created in our atmosphere are being created
by nature versus humankind? I have asked you that four times
now and have been dodged four times.
Dr. Solomon. No, sir, I am not dodging your question. I am
sorry.
Mr. Rohrabacher. Does someone else--I didn't say the
increase.
Dr. Solomon. There is a baseline.
Mr. Rohrabacher. I didn't say increase.
Dr. Solomon. There is, indeed, a baseline.
Mr. Rohrabacher. What is the baseline?
Dr. Solomon. The baseline for carbon dioxide is 270 parts
per million. What we are now at is about 380 parts per million.
Mr. Rohrabacher. Excuse me, I am asking--Mr. Chairman----
Dr. Solomon. That increase is due to human activity.
Mr. Rohrabacher. Mr. Chairman, I don't--I would like my
time not to be spent by witnesses not----
Dr. Solomon. 270 out of 380. I can----
Chairman Gordon. Well, your time has been up for quite some
time.
Mr. Rohrabacher. Well, I wish we could have this--is
everyone else afraid to answer that question as well?
Mr. Baird. Would the gentleman from California yield for
one second?
Mr. Rohrabacher. Sure.
Mr. Baird. My belief is that the answer resides in what the
gentlelady just said in the following sense. If you take a
baseline, one might presume that the baseline is the natural
prevalence of CO2, because----
Mr. Rohrabacher. That is not my question.
Mr. Baird. No, I understand that, but I am going to get to
your question----
Mr. Rohrabacher. I have been trying to get an honest----
Mr. Baird. Stay with me. I am going to get to your--I am
going to get to it.
Mr. Rohrabacher. All right.
Mr. Baird. And then if you look at where we are now----
Mr. Rohrabacher. Yes.
Mr. Baird.--that difference between baseline and where we
are now would presumably yield the information you are asking
for, which is what percentage of the carbon is caused by----
Mr. Rohrabacher. No, no, no. That is not the suggestion at
all--I mean, that is not the way. I mean, it is a simple
question, and every scientist that I have asked has said it is
less than 10 percent of any of the greenhouse gases are caused
by human activity. And I was just trying to find out whether
these scientists agreed with the assessment that I have heard
from all of the other scientists----
Chairman Gordon. The gentleman's time has expired, but let
me suggest that if you will put those questions in writing----
Mr. Rohrabacher. Okay.
Chairman Gordon.--that the panel will have an opportunity
to give you the best answer that they can.
Mr. Baird.
More on the IPCC Process
Mr. Baird. I thank the gentleman.
I thank the expert testimony.
Is it correct that there were 450 Lead Authors, 800
contributing authors and over 2,500 reviewing authors who
participated in this study or this Report? Is that an
accurate----
Dr. Solomon. That is the number across all three Working
Groups, sir. For Working Group I, the numbers are in my
testimony, 152 Lead Authors, 400 contributing authors, 600
expert reviewers.
Mr. Baird. Was there a----
Dr. Solomon. The numbers that you quoted are for group I,
II, and III that you were----
Mr. Baird. Okay.
Dr. Solomon.--talking about. We are Group I only.
Mr. Baird. Thank you. Was there an effort to intentionally
exclude people who might have a different opinion about global
warming, or were people allowed to participate and offer
comments if they disagreed with global warming hypotheses?
Dr. Solomon. The review process was entirely open.
Scientists could register on the web. They only had to say who
they were. They weren't asked anything else, and they were sent
whatever materials they wanted to review. So it was totally
open to anyone who wished to review it.
Mr. Baird. So presumably, if they had had compelling
arguments and data to persuade their colleagues to reach
contrary conclusions, they had ample opportunity to do that?
Dr. Solomon. They had ample opportunity to express their
views, indeed.
Mr. Baird. Dr. Trenberth, you seem to want to comment.
Dr. Trenberth. In my chapter, yes, there were many well-
known, so-called skeptics that participated as reviewers, and
their comments were all addressed.
Mr. Baird. So it would not be accurate to suggest that this
was somehow a biased report, and one could actually see if
there were--some of my colleagues are raising questions that
they have heard from so-called skeptics, one could see those
answers to the skeptics in the Report or presumably in the web
dialogue that led to the Report?
Dr. Trenberth. The Report is changed, of course, in
response to comments, but there are many comments. And in
addition, all of the comments are responded to in writing, and
there is a file, there is a great big file at the technical
support unit, which has the responses to every comment and how
they were addressed.
More on Global Warming Trends
Mr. Baird. I appreciate that.
So what you are saying is there is a baseline level of
CO2 produced by agricultural processes, sea changes,
et cetera, the normal kind of fluctuations? But beyond that
baseline, we have seen a substantial increase in CO2
that correlates quite closely to the production of CO2
by human-related activity, i.e., predominantly the consumption
of fossil fuels. Would that be a fair statement?
Dr. Solomon. Indeed. Figure 1 of the Summary for Policy-
makers shows a constant CO2 for 9.9 thousand years,
approximately, followed by a dramatic increase in the last
century, which is essentially entirely attributable to human
activities.
Mr. Baird. So to sum--while it is an intriguing question to
ask, what percentage of the total CO2 budget is
produced by human activity in terms of gauging changes in the
CO2 budget, which may correlate to changes in
temperature. It may, in fact, be the change that is of most
significance and importance for understanding here, not just
the base level--the differential percentages, because prior to
that, presumably, the CO2 production of humankind
was background, a rounding error, possibly.
Dr. Solomon. I am afraid I don't know the number exactly,
but again, in terms of concentrations, 270 parts per million by
volume in, say 1700, 270 parts per million 1,000 years before
that, today, 380 parts per million, sir, so----
Mr. Baird. So could we not assume that is 110 parts per
million?
Dr. Solomon. 110-part-per-million increase due essentially
entirely to human activity. That is what I am trying to say.
Mr. Baird. So 110 parts per million is what----
Dr. Solomon. Out of 270.
Mr. Baird. Correct. So that is about, what----
Dr. Solomon. A third.
Mr. Baird.--30 percent. So that may answer the gentleman
from California's question, I think, and that is what I was
trying to get to earlier.
But more importantly, in terms of the global warming
debate, if you have got that increase presumably in, I think--
we cannot dispute that we produce more CO2. I mean,
that would be pretty hard to dispute on any credible scientific
grounds. We also seem to have pretty clear evidence from this
Report of the increase in temperature. While correlation is not
causation, correlation can give us some pretty good insights.
One final question. Skeptics may ask you to prove beyond a
shadow of a doubt that this global warming, which we are
observing, is caused by human consumption--production of
CO2. I don't think that is scientifically possible.
I used to teach scientific method. I hold a doctorate in the
scientific field. You can't do it. But that doesn't mean one
does not act on the best available scientific information. Will
you care to comment on that?
Dr. Meehl. Yeah, maybe I can comment on that.
The real big advance we have seen in the last five years
with trying to address this question of attribution, that is
basically your question, you know, how can we attribute, how
can we be sure that humans are causing this warming, are these
computer climate models we use, and they have been improved
quite a bit. We have been putting in single factors that we
think affected climate over the 20th century, natural and
human-produced. So we can put in solar variability by itself in
the model, run it for the 20th century, see how the climate
system responds. We can put volcanic activity in. We get a big
volcano going off that cools off the climate for a couple of
years and see how that responds. We can put in other forms of
air pollution, sulfate aerosols, which are small particles that
reflect sunlight, so that is a cooling effect. We can put that
in separately and see how it affects the climate. We can put in
increases of greenhouse gases produced by human activity and
see how that affects the climate. So we can deconstruct the
20th century climate in a way that we just couldn't do taking
observations, because the observations you are seeing out the
window are a combination of all of these factors wrapped up
together. There is a great use of these models as tools, so we
can actually look at each of these things separately and in
combination to see how they contributed to what we observed
over the 20th century. And as was alluded to earlier, the
results from these studies, the first started to be done about
five years ago, and we have many more now that we assessed,
show that most of the warming that we observed in the first
part of the 20th century was natural. Not many volcanoes were
going off. We had an increase of solar output. Then we had the
level period from the 1940s to the 1970s when the big increase
in industrial activity after World War II produced a lot more
air pollution. That was a cooling effect, but the increase in
greenhouse gases were still going up. That was warming, but
they about balanced until about the mid-1970s. Then the ongoing
increases of greenhouse gases plus some efforts by
industrialized countries to reduce visible air pollution then
produced the big warming we have seen since the 1970s.
So I think by being able to do these kinds of studies with
these calibrated models, we can make this statement that it is
very likely that most of the warming we have seen in the last
half-century or so is due to human activities. That is where
that comes from.
Mr. Baird. I appreciate that and yield back.
Chairman Gordon. Thank you, Dr. Meehl.
Mr. Sensenbrenner is recognized for five minutes.
Mr. Sensenbrenner. Yes. Thank you very much.
I would like to ask members of the panel to rank the three
big greenhouse gases, CO2, methane, and NOX as to
which is the biggest culprit, which is the second biggest, and
which is the third biggest.
Dr. Solomon. Figure 2 of the summary shows that explicitly,
so what you can see there is that carbon dioxide is the largest
contributor. Methane is the second. Nitrous oxide is also
significant, and that is shown in the middle of the second
column. And the halocarbons also contribute. Tropospheric ozone
does as well.
Mr. Sensenbrenner. Okay. Now----
Dr. Solomon. You can see the ranking, sir.
Mr. Sensenbrenner.--by looking at your Figure 1, Dr.
Solomon, CO2 has gone up about 40 percent since 1750
whereas methane has gone up, by my rough figures, about 130
percent. What is causing the difference between the increase of
human activity is the culprit on all of that?
Dr. Solomon. The sources are different. In the case of
methane, the primary sources are agricultural, whereas in the
case of carbon dioxide, the primary sources are fossil fuel, so
they are coming from different things.
Mr. Sensenbrenner. Does that mean that to stop this huge
growth of methane, we better put catalytic converters on the
back of cows?
Dr. Solomon. Certainly, animals are one contributor to the
increases in methane. You are quite right. There are----
Mr. Sensenbrenner. Now you are hitting the Wisconsin
economy right between the horns.
Dr. Solomon. I can always tell you I love your cheese, sir.
I don't know what else to say.
Mr. Sensenbrenner. Well, we better make sure that there are
cows there to produce it, and we appreciate your patronage.
Dr. Trenberth.
Dr. Trenberth. Yes. I am from New Zealand, and it turns out
New Zealand is pretty unique in that it emits more methane than
carbon dioxide because of all of the sheep and cows in New
Zealand, and there is a tremendous amount of research going on
on exactly that topic and how to change feed in order to reduce
methane coming out of the mouths and the other end of animals.
Greenhouse Gas Production: Country Comparisons
Mr. Sensenbrenner. Okay. Have you done any figures or any
calculations as to which particular countries are culprits in
emitting more or less CO2 and methane relatively?
Meaning, do you see more methane in Europe and more CO2
in North America, or don't you know?
Dr. Trenberth. There are charts on those. I don't have
those numbers at my fingertips. And the other revealing factor,
which you may want to look into, is the amount per capita, and
I do know that the United States leads the world in both
categories. And that per capita, the United States emits about
two and a half times more carbon dioxide than in Europe, for
instance, and about 10 times more than China and about 20 times
more than India, but of course, the per capita aspect and the
number of people then makes a very big difference, and so that
is another important----
Mr. Sensenbrenner. Well, now, you know, I was the head of
the Congressional Observer Delegation to Kyoto, so I went and
watched all of that stuff. One of the meetings that my
bipartisan delegation had was with the Chinese delegation. And
they told Mr. Dingell that they weren't going to cut down on
their greenhouse gas emissions, no way, no how. Mr. Dingell
kept on going forward for 20 years, seeing if they would change
their mind, and if I didn't tell him to stop, he would still be
there, and we would probably be up to the year about 15,000.
The Chinese Government, last week, when your report was coming
out, reiterated the fact that it was going to stonewall dealing
with this issue because it needed to burn more hydrocarbons in
order to develop its economy. If you have the world's biggest
country and the world's most rapidly developing economy not
participating in this and the United States, for example, doing
what has been suggested here, have you thought about the
economic impact on where jobs go, meaning to China and away
from the United States?
Dr. Trenberth. It is not for me to really say that, but I
would emphasize, indeed, that this is a global problem, and so
whereas other countries are concerned about the United States'
emissions, indeed, I think we need to be concerned about other
countries' emissions and therefore the international
negotiations are an important part of this problem.
Mr. Sensenbrenner. But with all due----
Chairman Gordon. The gentleman's time has expired.
Mr. Udall.
Climate Research
Mr. Udall. Thank you, Mr. Chairman.
I would note for my colleague from Wisconsin that Dr.
Bartlett, who has just recently traveled to China, had some
very interesting discussions with the Chinese, and I am going
to maintain my own time, but I am hoping to cue Dr. Bartlett,
and perhaps when he has some questions, to talk about what the
Chinese are doing. So their actions are speaking, certainly, as
loud as their words. They understand that the present path
cannot be maintained in any sustainable fashion.
Dr. Trenberth, I want to turn to your testimony. You
restate the Report's findings that we're already committed to a
significant level of climate change in that you believe we need
to mitigate the effects of the coming changes. And I might like
to, in that spirit, note that yesterday I introduced H.R. 906,
the Global Change Research and Data Management Act of 2007,
along with my good friend and colleague from South Carolina,
Mr. Inglis. And this bill updates the existing law that
formally established the U.S. Global Change Research Program in
1990, and it would help reorient the research program to be
more user-driven, which would help local and state and regional
and national policy-makers make more informed decisions.
Would you speak to that from your point of view? Do you
believe that improving these regional models would enable us to
produce these vulnerability assessments that you reference in
your document?
Dr. Trenberth. One of the things that we struggled with in
our chapter in dealing with observations is that in a number of
countries, in fact, observations, especially the surface
observations, are decaying over time. And as a recent National
Academy of Sciences report has stated, there are real risks in
losing a lot of space-based observations in the future. Space-
based observations are very difficult to deal with, as well,
because every time you put a new satellite up with a new
instrument, it is very hard to know exactly how those
measurements relate to the previous set of measurements. And so
it depends on whether these satellites have been launched for
climate purposes and whether the observations are adequately
calibrated or whether they are launched for other purposes,
such as weather, where those issues are not so great. And what
the science community is certainly urging is that we pay more
attention to these kinds of issues and the degradation that is
going on in the observing system, because this builds the
information base as to what is going on and also why. So in
this case, we are not just talking about observations of
temperature and precipitation, and so on, but also the
observations on why the climate is changing, what is happening
to the composition of the atmosphere, what is happening to the
sun, and so on, and I think there is a very compelling case
that we need to do more in this area to track why this winter
in the East Coast was so warm up until recently, why there has
been no snow and it has been very warm in Europe, and they are
having trouble with the World Cup Skiing, what the role of El
Nino is in this, which is playing a role, understanding the
variability and the climate change aspects and tracking what is
going on. This relates to natural variability as well. If it is
natural variability playing a role, we should be able to
measure it and account for it. So if the ocean currents are
changing, the Gulf Stream is changing, we should be able to
measure that and assess its impact and whether or not there is
going to be a shut down in the Gulf Stream and so on. So I
think a compelling part of what we need to do, also, is to
build an information base and a climate service that addresses
these kinds of concerns.
Mr. Udall. Doctor, is it fair to say what you are proposing
and suggesting we could do is gathering and assessing and
concluding about the data, it is--you are not involved in the
processing, okay, what do we do about carbon emissions? And the
reason I am asking you that is to promote the idea behind this
legislation I proposed, which is to make better use of our
resources, be more efficient in this whole area of research,
and then we can continue to have the debate that we are having
here and all over the world.
Dr. Trenberth. Yeah, the mitigation aspects are dealt with
in Working Group III, and I would urge you to wait for their
report in May of this year. It is not an area where I am an
expert. All I can say is, for myself, I have put solar panels
on the roof of my house.
Mr. Udall. Thank you.
Dr. Solomon, somebody suggested that--particularly on the
heels of Mr. Sensenbrenner's comments about methane, that
humans are actually temporary carbon sinks and that we could
think about ourselves in that regard, but I have never seen a
study on the balance between humans as carbon sinks and the
methane that we may or may not emit. Be that as it may, what
surprised you of the IPCC process?
Dr. Solomon. That is an interesting question. I knew pretty
well what to expect, having been involved in it for a very long
time. I think what surprised me the most was actually how much
progress we have, in fact, made from remarkable new databases,
from satellites on issues, such as the effects of aerosols, as
Kevin was saying, the improvements in observations. Indeed,
there is more to be done there, but we just have so much better
information now. The advances in modeling, I was very
impressed, actually, by the degree of progress we were able to
make in this assessment compared to the past one. It surprised
me.
Chairman Gordon. Thank you, Mr. Udall. Your time is
expired.
Mr. Calvert, you are recognized for five minutes.
Carbon Sequestration
Mr. Calvert. Thank you, Mr. Chairman.
I am going to go at this in a different direction. I think
that there is pretty much unanimity that there is climate
change taking place, global warming taking place, and this
committee is gathering information, scientific information
within our jurisdiction. And I assume that information will be
shared with other committees that will have the jurisdiction to
regulate certain industries, such as the coal industry, the
automobile industry, the hydrocarbon-fired energy sources
within the United States. And so it is important that we try to
get it right, because the unintended consequences of taking bad
information and trying to make policy is going to have dramatic
effects on the economy of this country and certainly for the
rest of the world. And so when Mr. Rohrabacher, for instance,
is asking the question how much of a percentage, for us laymen,
is greenhouse gases relative to natural sources, that is an
important question, because--and also, the question of what
countries and what regions have an increase relative to natural
sources for--we have a better understanding of how we go about
that problem. But it has been said that the United States
produces 25 percent--or uses 25 percent of the energy in the
world, and it is about four percent of the world's population.
So you know, you could say that the United States,
overwhelmingly, has the most responsibility to regulate its
economy in order to meet its responsibilities, especially under
the Kyoto accord, which I went to with Mr. Sensenbrenner a
number of years ago. So we have got to get it right, because I
would suspect the four of you all agree that with the summary
of the report, 90 percent confidence that human activity is the
cause of global warming. Would you say that all four of you
agree to that basic concept, since you are here, obviously,
testifying for the majority? And so if, in fact, that is
correct, how do we go about tackling this problem? And I think
that that is really what this Congress is going to be trying to
answer, whether we go into mandatory caps, which was mentioned
by the Speaker, or, as I believe, incentives in the economy to
bring on new industries that I think will have the same result
in the long-term and in the short-term of having--the result of
having less greenhouse gases. In that, China--the issue of
China has been brought up. I believe China, right now, is
opening a new coal-powered plant once a week. And is that
approximately correct?
Dr. Trenberth. It is less than every three days.
Mr. Calvert. Less than every three days. The United
States--the largest energy source within the United States is
still coal, based on our base load power. And I know we are
trying to get the clean coal technology. Doctor, do you think
that that is possible, that we can sequester the CO2
that is put out by the coal industry? Do you think that is a
possibility and continue to use coal?
Dr. Trenberth. This is not an area where I am an expert. It
is certainly an area where that potential is, I believe,
growing. And there is, of course, some cost to that, but it
needs to be balanced against the cost of not doing it as well.
But----
Mr. Calvert. Well, right now, the renewable energy sources
in the United States are approximately less than five percent.
Ninety-five percent of all energy source in the United States
is hydrocarbon-based or nuclear-power-based. Twenty percent of
the base load in the United States is nuclear. The rest of it
is either coal or gas-powered plants. And so in order for us to
really meet the goals that are outlined within the scientific
information that is being represented to us, without coal or
nuclear power, is that possible? I mean, can we have a
sustainable economy without coal or nuclear power?
Dr. Solomon. You know, I would just like to emphasize, sir,
that this group are physical scientists. That is all we are. We
are not economists and----
Mr. Calvert. No, and I understand that. And you are
providing the information that we, as policy-makers ultimately
have to make a determination. Because you know, the automobile
industry, the coal industry, the manufacturing industry in this
country are really depending upon getting it right, getting the
right science to us. You know, something was talked about El
Nino earlier this year. We were supposed to have an El Nino
effect in southern California this year. Unfortunately, it
didn't happen, and we are having one of the largest droughts we
have ever had. So sometimes, we just don't get it right. And so
hopefully we get it right when we make these types of policy
decisions.
With that, I yield back the balance of my time.
Chairman Gordon. The gentleman's time is expired.
Ms. Hooley is recognized for five minutes.
Advancements in Climate Research
Ms. Hooley. Thank you, Mr. Chair. I want to thank all of
the panelists for being here today.
Dr. Solomon, I have a question. There seems to be a big
change in the certainty assigned to this Report compared to the
2001. Was that because of modeling or was that because of data
collection and observation? And was there----
Dr. Solomon. Certainly in both areas. We have really seen
advances with, by far, more models, models with better physics
in them, models with improved representation of processes, such
as sea ice and the carbon cycle. We made advances in those
areas. In terms of observations, there have also been many,
many advances in observations. A lot of satellite information
has become available that we just didn't have before. We now
have satellite measurements of sea level rise, for example, for
the last 10 years. We also have satellite data that allows us
to say things about the ice sheets, as Dr. Alley was talking
about. And you know, we have also had more warm years, as I
tried to emphasize in the testimony. And Dr. Trenberth also has
emphasized. So the fact that 11 out of 12 of the last years
have been among the warmest is a remarkable and very
interesting bit of information.
Cooling in Antarctica
Ms. Hooley. Thank you.
Dr. Trenberth, you say the planet is ``running a fever.''
Are there any areas that can get colder instead of warmer as a
result of climate change?
Dr. Trenberth. In the interior part of Antarctica, it seems
as though it may have even cooled slightly, and we believe that
that is a unique part of the globe because of the ozone hole
that occurs over Antarctica. And so it has created some changes
in the atmospheric circulation there that has led to quite warm
conditions in the Antarctic peninsula and the southern part of
South America, the decay of the ice shelf occurred in that
region, but at the same time, perhaps even slightly cooler
conditions on the interior part of Antarctica. So that is one
unique area.
Impact on the Western United States
Ms. Hooley. Okay. And Dr. Alley, in your testimony, you
described the effect of loss of snow pack and--that it will
have on the wintertime water supplies in the west. And since I
am from the West, can you elaborate the impact on our Western
states?
Dr. Alley. I really can't, because I am a physical
scientist as opposed to an impacts person. What we do observe
is that there has been a shift to earlier snowmelt, and what
one sees in projections of the future is if that continues so
that you lose more and more of your snow pack. And you well
know, as a Representative of a Western state, that the snow
pack has been important in maintaining stream flow. Now in
terms of what that means for the salmon versus the farm or
versus the irrigation versus drinking water versus recreation,
that is clearly for someone who is wiser than me. But I think
you are well aware, and you are probably wiser than me on these
issues.
Ms. Hooley. I don't know about that.
Thermal Expansion of Seawater
Dr. Meehl, would you talk a little bit about the thermal
expansion of seawater and the effect it has on global sea
levels?
Dr. Meehl. Yes, water has this interesting property that as
it warms up, it expands. And so as the warming that is taking
place in the climate system penetrates into the ocean, you get
ever-increasing layers of ocean water expanding. And as this
warming works its way down into the ocean into a deeper and
deeper layer, you get more and more thermal expansion. So when
we talk about the commitment of climate change, committed
warming, it is on the order of centuries. In other words, we
have already committed ourselves to centuries more sea level
rise from what we have already put into the system just because
it is going to take centuries for that warming to work its way
all of the way down through the depth of the ocean. And as long
as you still have warming that is working its way down, you are
going to have an ever-increasing volume of ocean warming up and
expanding. So I think that is an important and probably one of
the best things we can quantify in terms of sea level rise is
thermal expansion. These other aspects related to ice sheets
and things like that we have less confidence in.
Mitigating Climate Change
Ms. Hooley. How much time do we have to turn back the clock
or do something about it?
Dr. Meehl. Again, that is kind of a mitigation question,
and that is, frankly, out of my area of expertise, but I think
just what we can say from the scenarios we have looked at for
the 21st century where we see that what we do makes a
difference. If we go on a low-emission track, we get less
warming. If we go on a high-emission track, we get more
warming. And the longer we wait to do something, the worse the
problem gets, the harder it is to try to do something about it.
So I think those kind of very general conclusions you can draw
from the projections chapter in the AR4. In terms of details on
exactly how to mitigate the problem, this combination
mitigation and adaptation, that is out of our area of our
expertise.
Ms. Hooley. I would like to ask the other panelists if you
can, what do you think about how much time we have to turn this
around or change things or try to lower those emissions
significantly?
Dr. Trenberth. Let me comment. As is clear from the
observations, there are already changes underway. I mean, they
are already with us, and some of those changes are really,
perhaps, already having devastating effects. We mentioned
drought, and drought has become widespread in the subtropics in
particular, and parts of Africa have suffered greatly from that
and our understanding is building now that a component of this
is very likely associated with the global warming that is going
on. So from the standpoint of Africa, maybe it is already too
late.
Chairman Gordon. The gentlelady's time has expired.
Ms. Hooley. Thank you.
Chairman Gordon. Dr. Bartlett is recognized for five
minutes.
Ocean Circulation Changes
Mr. Bartlett. Thank you very much.
Mr. Udall mentioned my recent trip to China. I was very
surprised and pleased when they began their discussion of
energy and talking about post-oil. They get it. Somehow, we
don't in this country. I would suggest that there ought to be
enormous common cause between those of us who are concerned
that there will not be a limitless supply of oil in the world
and those of us, and I am in both categories, who are concerned
that we are involved in global warming. And I would think that
we can harness our joint energies and get more attention to
this.
My colleague, Mr. Rohrabacher, is somehow concerned, I
believe, that because humans produce only about 10 percent of
the greenhouse gases that what we do, maybe, doesn't matter
much. And I have a little illustration that may help us to
understand that the total amount of gases up there may be
somewhat irrelevant relative to what we can do to change that.
If you have a seesaw with 100 pounds on each end and you put
another 100 pounds on one end, that is really going down, isn't
it? If you put 1,000 pounds on each end as the seesaw and you
put another 100 pounds on one end, it is still going down,
isn't it? So the total amount of greenhouse gases that are up
there may be somewhat irrelevant as to our contribution.
Obviously, where our Earth's temperature is, it is a balance
between the heat we gain from the sun and the heat we lose. And
you know, a very small change can produce enormous effects. I
was stunned the other day when I read, and I would ask you if
this is true, that in the last ice age the world was five
degrees centigrade, that is nine degrees Fahrenheit, cooler
than it is today. That is correct? And for those that think,
gee, a degree or two, my living room goes up and down three or
four degrees. That doesn't matter much. Three or four degrees
in the world may not matter much. But nine degrees cooler
Fahrenheit, and we were in an ice age. With ice sheets coming
down to southeast Ohio, you can see the terminal there from
those, someone was asking about where it is warmer and where it
is cooler. There is an ironic thing that could happen as the
result of global warming, that is that the British Isles and
northern Europe could become very much colder because we have a
big conveyor belt called the Gulf Stream, which carries heat
from the tropics up there. And obviously, water is not piling
up up there, so it has to come back. And it comes back, because
it gets more dense and it drops down. And one of the things
that is happening up there may prohibit this increase in
density and that is the melting of ice up there, which produces
fresh water, which is very much lighter than the salty water.
And so if we have a little bit more global warming, we could
shut down the Gulf Stream. And if you look at where England is
on the globe, it is up about central Canada. I had to stop for
refueling in the Emerald Isle. And that really is incredibly
green and warm there in Ireland compared to what it would be if
it weren't for the Gulf Stream. So we can have enormous changes
in climate in certain parts of the world from relatively small
changes in temperature.
I was in Antarctica. I have been to the South Pole twice,
and of course 90 percent of the world's ice is found there and
70 percent of the world's fresh water is found there in
Antarctica. We have a circumpolar stream there, a current, that
kind of keeps the warm waters from the north, well, it is north
down there, from coming in. Are there any hints that the global
warming may interfere with that circumpolar current down there?
And if that is true and warmer northern waters could come down,
is it possible that we could see very much accelerated changes
in temperatures down there? And by the way, if that ice pack
melted with all of the others, the ocean levels would rise
about 200 feet is my understanding. But 60 percent of the
world's population lives within 200 feet of sea level. Is there
a potential that global warming could somewhat interfere with
that circumpolar current down there, which is keeping the warm
waters out and keeping Antarctica the refrigerator it is?
Dr. Meehl. Maybe I could try taking a crack at this. All of
these ocean circulation changes you mentioned, and you have a
real good knowledge of it, obviously, are things that we are
really concerned about, obviously, as scientists. And one of
the things that is really getting a lot of attention, due to a
certain Hollywood movie that we all really like, was this
sudden shutdown of this overturning circulation in the Atlantic
that you mentioned that the Gulf Stream is a part of. And if it
suddenly shut down, the idea was that you would suddenly get a
lot more colder in the North Atlantic, because you wouldn't be
carrying all of that heat up into the North Atlantic that the
conveyor belt transfers. So we have looked at that in all of
the models that we have run so far. No model that we have run
yet, for the 21st century, for the present century, shows a
sudden shutdown of this overturning circulation, this conveyor
belt. They all show a slowing down of the conveyor belt for the
reasons--exactly the reasons you mentioned. It gets warmer and
less dense in the high-latitude North Atlantic, therefore you
don't get as much sinking, and you just kind of slow down this
conveyor belt circulation. But, of course, then that would
contribute to less heat transport to the North Atlantic. You
think, well, maybe that would give a cooling. When it turns
out, to get that slow down, you have to have so much of an
increase of greenhouse gases in the atmosphere that the warming
itself from those greenhouse gases just swamps, it overwhelms
any small decrease of northward heat transport you get from the
slowdown of this overturning circulation. So we say, in fact,
it is very likely that the overturning would slow down. It is
very unlikely that it would suddenly seize up and stop, at
least in the 21st century. And that is even taking into account
possible contributions from melt water from Greenland and other
things that would add to this decrease in density.
Chairman Gordon. The gentleman's time has expired--oh, I am
sorry.
Dr. Meehl. I was just going to say, beyond 2100, we are not
as sure, because there may be odd things in the system we
haven't anticipated, but for the time periods we looked at,
especially to 2100, we don't see that.
Mr. Bartlett. Thank you.
Chairman Gordon. The gentleman's time has expired.
Chairman Miller is recognized for five minutes.
Tropical Storms
Mr. Miller. Thank you, Mr. Chairman.
Dr. Trenberth, the IPCC Report and your testimony both
referred to one result of global climate change, global
warming, as being the intensity of tropical storms. In the fall
of 2005, after the hurricane season that we had that included
Katrina, of course, and several other catastrophic storms,
Category 4 and Category 5, I can't recall how many, but
several, and they were stunning to look at in the satellite
view of how large and perfectly symmetrical they were. The
press wondered whether there was a relationship between global
climate change or global warming and that hurricane season. And
many made many requests of NOAA and NOAA produced a hurricane
scientist named Chris Landsea, who treated those questions as
if they were an urban legend and was very dismissive of that
possibility. And as a result, the press kind of went away on
that topic and concluded that was not serious science that
anyone had that question. In fact, there were others within
NOAA, other scientists, who said that yes, the formation of the
tropical storms may be cyclical, as Dr. Landsea had said, but
the intensification is very much related to temperature. What
was the state of the science in the fall of 2005 and what is it
now on the relationship between the intensity of tropical
storms and water temperature?
Dr. Trenberth. Indeed, the 2005 season, in fact, it began a
little before that, even with the 2004 season where four
hurricanes hit Florida and there were ten typhoons that ended
up hitting Japan, have raised this question, and there has been
a great deal of research that has gone on even after our
report, although our report, I think, is still a fair
assessment of the current situation. And we had a breakout
group that dealt with this in Paris, and the statement on page
8 of the SPM is fully consistent with all of the literature
that we have reviewed in our report. And maybe I should read
it. It says, ``There is observational evidence for an increase
in intense tropical cyclone activity in the North Atlantic
since about 1970, correlating with increases in tropical sea
surface temperatures.'' This is one thing where there is
widespread agreement that if the sea temperatures go up, you
get more activity. And we are seeing that in the North
Atlantic. And then the second question is why are the sea
temperatures going up. And certainly, on a global basis, we
know that there is a component of that. We believe it is close
to about one degree Fahrenheit now associated with the
increases in greenhouse gases. And then you can argue about how
much of that is occurring in the hurricane regions and so on.
There is some natural variability.
Another key part of our statement also recognizes that
``multi-decadal variability and the quality of tropical cyclone
records prior to routine satellite observations in about 1970
complicate the detection of long-term trends in tropical
cyclone activity.'' And so this is saying that, indeed, a lot
of natural variability as well as the greenhouse gas-induced
trends that are playing a role, and in addition, the database
that we have is not as good as we would like. And so there are
some uncertainties there. But nonetheless, there has been an
increase in activity.
Now the theoretical understanding suggests that, indeed,
there will be an increase in activity of some sort, and that
can be manifested in a number of ways. You can have increased
numbers, increased intensity, increases in size, increases in
duration. And we don't have measures of all of those. They are
not in the historical record. We don't have measures of size
adequately. And so this is a very important question, but there
are a number of uncertainties that remain.
Social and Economic Impacts of Climate Change
Mr. Miller. Okay. One more question for any of you who wish
to answer.
There have been several references to economic consequences
dealing with greenhouse gases in opening statements and in some
of the questions that were propounded to all of you. Last fall,
the British government released an economic report by Sir
Nicholas Stern, who is a former World Bank economist, a 600-
page report that I admit to not having read. But it concluded
that global warming could leave millions homeless and result in
as much as a $7 trillion, or 20 percent diminution in the size
of the world's economy and cause the greatest market failure--
greatest economic failure in the world's history comparable to
the Great Depression and worse than the Great Depression, worse
than the world wars. Knowing what you know about the
consequences of global warming of the forecast, does that sound
right?
Dr. Solomon. I would really urge you to wait for the
Working Group III assessment. Those are the people who would be
qualified to make that kind of statement. Also, Working Group
II, I believe, will be dealing with that. This is simply not
something that is covered in the Working Group I reports. Sir,
I am sorry, but we don't have the expertise to respond to this
question.
Chairman Gordon. The gentleman's time has expired. Dr.
Ehlers is recognized for five minutes.
More on the IPCC Process
Mr. Ehlers. Thank you, Mr. Chairman, and first of all, just
a little housekeeping. I did a quick calculation on the
question Mr. Rohrabacher asked, and my estimate is that 35
percent is the answer.
The other comment I wanted to make, Mr. Chairman, is that I
personally appreciate the fact that the Speaker of the House
appeared before this committee and made some comments. First of
all, this is an extremely important issue, but also I think
that any time the leadership pays any attention to this
committee is good because sometimes--personally, not publicly--
this is the first time I said it publicly, but sometimes I
think this is the Rodney Dangerfield Committee. We do
incredibly good work here and don't get the respect we should.
So I hope this is a sign----
Chairman Gordon. We had a lot of bills on the Floor today--
--
Mr. Ehlers. I know.
Chairman Gordon.--yesterday, and previously that I think
will demonstrate that Rodney is out of town.
Mr. Ehlers. I hope that he has moved out permanently.
Having said all of that, just first of all, I want to thank
you for being here. A quick question anyone could answer: this
is of course a summary that you have prepared. When will the
full report be published? Do you know? Dr. Solomon?
Dr. Solomon. The full report is being copy-edited and laid
out. It will be available probably around May.
Global Impacts of Climate Change
Mr. Ehlers. All right. Thank you.
Just a few quick comments. First of all, I think it is very
clear that global warming is occurring, and we can argue about
how much and the causes and so forth, but it is occurring. The
next question is it anthropogenic? It definitely seems to be,
either through industrialization or through farming, as we have
heard.
A couple of questions: what about global climate change, by
which I mean the whole picture? We seem to be obsessed here
this morning about global warming, but I am much more worried
about climate change. For example, I am from Michigan. We would
certainly welcome a bit of global warming in Michigan,
especially this past weekend when I got up Monday morning and
it was nine-below with a wind chill of 21-below. But I wouldn't
want global warming at the expense of losing rainfall in
Michigan and having it turn into a place like Kansas or--I
guess I can say Texas since our Ranking Member isn't here.
That really points to the political difficultly we have. We
have two political problems. One is, if we are talking just
about global warming, which is related to human activity,
industrialization particularly, that is an immense political
problem, globally, to try to get people to cut back. And I was
opposed to the Kyoto Agreement because it gave a free card to
China, and I knew China was going to be one of the biggest
contributors. So that is one political problem. The other one
is that global climate change is going to be good for some
areas of the planet and bad for other areas of the planet.
Now, how far along are you in determining the effects of
global climate change and the impact that it is likely to have
on different parts of the globe? How far along are the models
in determining that and with what accuracy?
Dr. Meehl. This is sometimes referred to as the winners and
losers issues. We didn't really address that in the Working
Group I Report. That is really a Working Group II impacts
question. But when I get asked this question--you know, we have
said a lot about changes in weather and climate extremes. And
one of the changes we have seen in extremes lately is a
decrease in the number of frost days, in other words, nighttime
temperatures going below freezing. This is something we have
already observed, and in the models, we project this to
increase in the future, that you will have warmer nights, and
less nights below freezing.
So you can say, well, maybe that is a good thing because
maybe that will expand the growing season length, and we do
show in the report that the growing season gets longer because
of that. You have later frost in the fall and then earlier
warming up in the spring. But then there are things like insect
infestations that are affected because, if it doesn't get as
cold in the winter, you don't kill off as many of the bugs in
the wintertime. They live though the winter, and then you have
severe problems with insect infestation. Out in Colorado, we
have seen a lot of problems with that with pine beetle kill.
So it is kind of a mixed bag, a lot of times. There are
some things that may be better, but then there are other
unforeseen consequences, and I think that is what makes me,
personally, nervous because when we are moving into a new
regime, which we are, which we have never really observed
before, there are things that we can anticipate that could have
good consequences, but other things that have bad consequences.
And that is the part, at least, that hopefully Working Group II
will address in more detail.
Mr. Ehlers. Well, that is precisely my concern because in
our arena--now, I am a scientist, but I ended up in this arena.
That is where the decisions are made in those issues, and we
need the information to make intelligent decisions, and the
sooner you can develop comprehensive models that can deal with
those issues, the better off we will be in this arena.
Chairman Gordon. Thank you, Dr. Ehlers. You got bonus time
for nice comments. Mr. Lipinski is recognized for five minutes.
Managing Water Resources
Mr. Lipinski. Thank you Mr. Chairman. Thank you for holding
this hearing on this very important topic that I am very
hopeful will move forward in this Congress in a bipartisan
fashion. I am working on this issue, and I appreciate the
testimony that all of you have given. I understand that your
role here is to talk about the science behind what is going on.
In the future I am sure we will have many panels where we will
talk about what can be done to mitigate this, but than you for
bringing you expertise to us today.
I want to ask--I am from the Chicago area, and I represent
part of Chicago, and I want to ask Dr. Trenberth: you talked
about managing water resources in the future as climate change
progresses. Now, I am just wondering if there is anything you
can tell us, perhaps not, but I was wondering if there was
anything you could tell us about how these atmospheric changes
may effect Chicago and other areas like that. I mean Chicago
uses about two billion gallons of water per day, from Lake
Michigan. Is there anything you can tell us about that?
Dr. Trenberth. As the climate warms, the water-holding
capacity of the atmosphere goes up about four percent per
degree Fahrenheit, and we find from the observations that this
is actually happening over the ocean. Over the land, it is
happening at a slightly less rate. But it means that there is
more water vapor in the atmosphere. Now when you have a storm,
the storm reaches out and grabs the available water vapor,
concentrates it and dumps it down in the form of rainfall. So
with more water vapor in the atmosphere, you expect that when
it rains, it is going to rain harder, or even when it snows, it
can snow harder, and that is what we are actually seeing. And
so you get heavier rainfall events. This is what is also
predicted in the models. However, when that happens, you also
deplete the water vapor in the atmosphere, so you change the
frequency of these events, and it may be that they are more
intense but they may be a little bit fewer and farther in
between, and so you have a greater risk of drought in between.
There is a little bit of extra heat available, so the drying
effects of that exacerbate drought.
Ironically, then you get both extremes of what we call the
water cycle that are affected by global warming, and it means
that the challenge of water resource management is that they
have times when they have got too much of a good thing, too
much rainfall, a risk of flooding, and then there are times in
between when they don't have enough. This is particularly what
that comment refers to: the changing character of
precipitation, the changes in snow to rain, it also means that
you have less snow pack going into the spring and summer, which
is when you most need the water, so that aspect of management
is another key part of it. And so these are the factors that
play into the water management challenge.
More on Climate Research
Mr. Lipinski. Thank you, and I want to ask Dr. Alley, you
mentioned that the apparent shrinking of the large ice sheets
was an unexpected finding. Why was this unexpected and can you
point out any other findings that came out as a big surprise to
you?
Dr. Alley. We had a longstanding debate in the community.
How fast can ice sheets do interesting things? They are very
large; they look sluggish. And yet you look back at the history
of the climate, back to the Ice Age, and most of the time ice
sheets were boring, and occasionally they were really
interesting. And so we have had this longstanding debate in the
community are the ice sheets going to be boring or they going
to be interesting, and the assessed science of the report said
the most likely outcome is boring, and they have been
interesting, and that, probably, for me was the most surprising
thing that came out of it.
The other thing that I see, looking at the report, is how
good the science has become on so many things. So the early
IPCC reports picked out sensitivity. You are at double
CO2. How much does the climate warm? And it was
based on moderately weak evidence. It was good science, but
there just wasn't a lot of it. And as the amount of science has
been produced, as more research has been done, more models,
more observations, the quality of the support, the strength of
the conclusions has just become tremendously greater. So there
are a few, you know, gaping holes that we would love to fill,
but primarily the quality of the science is just superb. It is
just outstanding, and results are getting to the sort of pound-
on-the-table-this-is-right stage. Thank you.
Chairman Gordon. The gentleman's time has expired. I am
told that the gentleman from South Carolina, Mr. Inlgis is next
and recognized for five minutes.
Opposition to Climate Change
Mr. Inglis. Thank you, Mr. Chairman. I am one of those
people that used to poo-poo global warming. It seems to me it
is hard not to be persuaded with the evidence that you have
been talking about. There is always the question of causation,
so I would make the analogy to the doctor who determines it is
genetics that determines longevity. Doctor, would it hurt us to
diet and exercise? Not likely to hurt us. So it is not likely
to hurt us to take some action, as long as we can do that in a
way that maintains balance with other things that we have got
to do in life, like make a living and provide for our families
and all of those kinds of things. So it seems to me the key is
to work cooperatively to solve some of these challenges.
It is going to be hard, though. I read yesterday, Mr.
Samuelson's piece, Mr. Chairman, that I asked to insert in the
record. It is Robert J. Samuelson, ``Global Warming and Hot
Air.'' And basically describes just how difficult it is going
to be and address the challenges at hand. But there are some
real opportunities, for example, reinventing the car so that it
runs ultimately on hydrogen, let us say, or batteries, or
something that doesn't emit CO2. What an exciting
opportunity for us to make money, which is great thing too, and
to clean the air, and to improve the national security of the
United States. But it is going to be hard.
I think we made progress here, today, Mr. Chairman, with
the Speaker's open-mindedness to looking at nuclear power. That
is a very significant development here today, I think. And it
shows a level of cooperation I think we all need to have: come
with open minds about how to solve this challenge.
Part of the change in my thinking came from a wonderful
trip to Antarctica about this time last year with a number of
Members who are here today, led by Sherwood Boehlert, and
perhaps one of you can help me relearn what I think I learned
there about the methodology of the ice cores, the drillings,
and what we found there. Can somebody describe that so I can
relearn, and maybe, I can just learn?
Dr. Alley. Happily. I have worked on ice cores in many
places, Antarctica and Greenland, and essentially an ice core
is like a really fancy drill. If you were going to put a knob
in your door, you would just take a pipe with teeth on the end,
you would spin it, you would run it down, you pull out a piece
of ice, and you would do that until you have two miles of it.
And if you break the bubbles, that is a little bottled sample
of old air. You can find out whether carbon dioxide was higher
or lower in the past. Very high confidence that this works. It
matches the instrumental record over recent times, different
cores from different places with different temperatures and
different snowfall rates give the same answers. And so what
shows is that the level of carbon dioxide, the level of
greenhouse gasses that we have in the atmosphere, are
unprecedented, at least for the last 650,000 years.
Mr. Inglis. And going back to some earlier questions. What
is the chance of that happening as a result of natural
phenomena, that significant increase?
Dr. Alley. If one looks at a long record like that and
says, well, it surely looks now like we are above what nature
has done for the last 650,000 years, and it happened in the
last 1000, that would seem unlikely. In addition, we very
clearly--oil companies are quite good; they know how to find
oil. Coal companies are quite good; they know how to find coal.
And we know how much they found, so we know how much is being
burned. We know how much carbon dioxide is going into the air,
and we know where it is going, and sort of our fingerprint is
on this with very high confidence.
Mr. Inglis. For those who dispute that, what is their best
argument? Where can they find some data besides what you just
reported on?
Dr. Alley. I truly don't know what a really good argument
is against this. There are a number--we have the budget. We
know what is going up, what is going down. But then you can
ask, well, is there evidence of that? Maybe your budgeting is
wrong. And then you say--but carbon isotopic composition of
fossil fuels is different than the carbon isotopic composition
that was in the air. And we can see the change over time as
humans are putting fossil fuel CO2 up. That applies
both to the stable carbon and to the radioactive carbon. We are
diluting the natural radiocarbon in the atmosphere by putting
old carbon up from below. One can see the very, very tiny
change in oxygen composition that goes with burning the fossil
fuels. So once you say, well, we know the budget, then, someone
will say, well, are you are right about that. Then, you say,
well, if we are right, then you should say this in the stable
carbon, you should see that in the radioactive carbon, you
should see the others in the oxygen, and you see all of those.
Chairman Gordon. The gentleman's time has expired. The
Gentleman from Kentucky.
Mr. Inglis. Mr. Chairman, a reminder to insert that in the
record, the Samuelson piece, without objection?
Chairman Gordon. Without objection.
[The information follows:]
Information for the Record
Global Warming and Hot Air
By Robert J. Samuelson
Washington Post
Wednesday, February 7, 2007; A17
You could be excused for thinking that we'll soon do something
serious about global warming. Last Friday, the Intergovernmental Panel
on Climate Change (IPCC)--an international group of scientists--
concluded that, to a 90 percent probability, human activity is warming
the Earth. Earlier, Democratic congressional leaders made global
warming legislation a top priority; and 10 big U.S. companies
(including General Electric and DuPont) endorsed federal regulation.
Strong action seems at hand.
Don't be fooled. The dirty secret about global warming is this: We
have no solution. About 80 percent of the world's energy comes from
fossil fuels (coal, oil, natural gas), the main sources of man-made
greenhouse gases. Energy use sustains economic growth, which--in all
modern societies--buttresses political and social stability. Until we
can replace fossil fuels or find practical ways to capture their
emissions, governments will not sanction the deep energy cuts that
would truly affect global warming.
Considering this reality, you should treat the pious exhortations
to ``do something'' with skepticism, disbelief or contempt. These
pronouncements are (take your pick) naive, self-interested,
misinformed, stupid or dishonest. Politicians mainly want to be seen as
reducing global warming. Companies want to polish their images and
exploit markets created by new environmental regulations. As for
editorialists and pundits, there's no explanation except superficiality
or herd behavior.
Anyone who honestly examines global energy trends must reach these
harsh conclusions. In 2004, world emissions of carbon dioxide
(CO2, the main greenhouse gas) totaled 26 billion metric
tons. Under plausible economic and population assumptions, CO2
emissions will grow to 40 billion tons by 2030, projects the
International Energy Agency. About three-quarters of the increase is
forecast to come from developing countries, two-fifths from China
alone. The IEA expects China to pass the United States as the largest
source of carbon dioxide by 2009.
Poor countries won't sacrifice economic growth--lowering poverty,
fostering political stability--to placate the rich world's global
warming fears. Why should they? On a per-person basis, their carbon
dioxide emissions are only about one-fifth the level of rich countries.
In Africa, less than 40 percent of the population even has electricity.
Nor will existing technologies, aggressively deployed, rescue us.
The IEA studied an ``alternative scenario'' that simulated the effect
of 1,400 policies to reduce fossil fuel use. Fuel economy for new U.S.
vehicles was assumed to increase 30 percent by 2030; the global share
of energy from ``renewables'' (solar, wind, hydropower, biomass) would
quadruple, to eight percent. The result: by 2030, annual carbon dioxide
emissions would rise 31 percent instead of 55 percent. The
concentration levels of emissions in the atmosphere (which presumably
cause warming) would rise.
Since 1850, global temperatures have increased almost one degree
Celsius. Sea level has risen about seven inches, though the connection
is unclear. So far, global warming has been a change, not a calamity.
The IPCC projects wide ranges for the next century: temperature
increases from 1.1 degrees Celsius to 6.4 degrees; sea level rises from
seven inches to almost two feet. People might easily adapt; or there
might be costly disruptions (say, frequent flooding of coastal cities
resulting from melting polar ice caps).
I do not say we should do nothing, but we should not delude
ourselves. In the United States, the favored remedy is ``cap and
trade.'' It's environmental grandstanding--politicians pretending
they're doing something.
Companies would receive or buy quotas (``caps'') to emit carbon
dioxide. To exceed the limits, they'd acquire some other company's
unused quotas (``trade''). How simple. Just order companies to cut
emissions. Businesses absorb all the costs.
But in practice, no plausible ``cap and trade'' program would
significantly curb global warming. To do that, quotas would have to be
set so low as to shut down the economy. Or the cost of scarce quotas
would skyrocket and be passed along to consumers through much higher
energy prices. Neither outcome seems likely. Quotas would be lax. The
program would be a regulatory burden with little benefit. It would also
be a bonanza for lobbyists, lawyers and consultants, as industries and
localities besieged Washington for exceptions and special treatment.
Hello, influence-peddling and sleaze.
What we really need is a more urgent program of research and
development, focusing on nuclear power, electric batteries, alternative
fuels and the capture of carbon dioxide. Naturally, there's no
guarantee that socially acceptable and cost-competitive technologies
will result. But without them, global warming is more or less on
automatic pilot. Only new technologies would enable countries--rich and
poor--to reconcile the immediate imperative of economic growth with the
potential hazards of climate change.
Meanwhile, we could temper our energy appetite. I've argued before
for a high oil tax to prod Americans to buy more fuel-efficient
vehicles. The main aim would be to limit insecure oil imports, but it
would also check CO2 emissions. Similarly, we might be
better off shifting some of the tax burden from wages and profits to a
broader tax on energy or carbon. That would favor more fuel-efficient
light bulbs, appliances and industrial processes.
It's a debate we ought to have--but probably won't. Any realistic
response would be costly, uncertain and no doubt unpopular. That's one
truth too inconvenient for almost anyone to admit.
2007 The Washington Post Company
Mr. Inglis. Thank you, sir.
Chairman Gordon. Mr. Chandler from Kentucky is recognized
for five minutes.
Climate Change Scenarios
Mr. Chandler. Thank you, Mr. Chairman. I do not need to be
persuaded. I think I can see facts rather clearly when they are
presented. I had the opportunity, along with the gentleman from
South Carolina, to go on that Congressional Antarctic sojourn
last year, and it was a truly eye-opening experience. We saw a
lot and, I think, got a pretty clear picture of what the
science--at least the science that people were working on down
there--showed. One thing that is abundantly clear is what the
graphs show in the last handful of years, and that is shocking,
truly shocking, to see the change in terms of warmth in the
atmosphere in a really surprisingly short period of time. And
frankly, it is just hard for me to imagine that fossil fuels
can be deposited in the Earth over hundreds of millions of
years and can be released in the amounts that they have been
released in, in a very short period of time, without having
some dramatic effect on the atmosphere. It just goes against
any sort of reasonable thinking.
And I would like to know, can you give us any idea about
how quickly you feel this process is going to speed up in the
near-term, this warming process? It has been quite dramatic in
the last decade or two. Do you look for that speed, that sort
of dramatic uptake to continue in the next couple of years? Do
you think it will speed up exponentially?
Dr. Meehl. Well, I think what we have seen from the
scenarios we have run with the models is that pretty much no
matter scenario we are on, the next 20 or 30 years, the warming
is going to be about two-tenths of a degree centigrade, per
decade. And of course, that is barring any huge volcanic
eruption that would cool it down for a year or two. But from
the anthropogenic or human-caused part, we are on a track now
for another, for about two-tenth of a degree C warming over the
next few decades. But having said that, when you get past about
the 20s, 30s, then you will start seeing the scenarios really
starting to spread.
Mr. Chandler. You mean a big spike?
Dr. Meehl. A spreading out. The high emissions give you
more warming and the low emissions give you less warming. So we
kind of have this very consistent warming no matter what
scenario we are on for the next 30 years, and then you start
seeing the spread. But having said that, it does make a
difference what track we are on because we are setting
ourselves on a course now to follow one of these outcomes and
depending on if we are on a high-emissions outcome, we are
going to get a lot more warming. If we are on a low-emissions
outcome, we are going to get less warming. So I think what we
do now does make a difference for the future.
More Climate Change Scenarios
Mr. Chandler. Now, I would like to ask a question about the
ice. Dr Alley, you have mentioned something on ice sheets being
boring. The same, certainly, cannot be said about you. I can't
help but ask, what do you think is going to happen? I heard
predictions of dire results in the Arctic, among other places,
largely because, as I understand it, because there is no land
up there, and that makes a big difference in all of the forces
that are involved there. Can you make some kind of a prediction
about what you think is going to happen to the Arctic and how
quick you feel that result will occur if we do nothing?
Dr. Alley. There are a number of assessed-model results in
the report looking at the sea ice of the Arctic Ocean, which is
the frozen ocean water, and I don't have the quota in front of
me, but some of the extreme warming scenarios in some of the
models get to a no-sea-ice in the summer in the Arctic at the
end of this century, so fairly large changes showing up in the
frozen ocean water.
Mr. Chandler. All gone?
Dr. Alley. For the late summer, in the more extreme warming
scenarios, in some of the models, and it would grow back in the
winter in those models. So that is the floating part. Then, the
part that is not yet floating, up on Greenland, almost
certainly is there yet in the end of the century, but in the
larger warming is melting fairly rapidly at that point.
Mr. Chandler. Which would almost certainly have an impact
on things like the Gulf Stream. A kind of huge impact, wouldn't
it?
Dr. Meehl. Not so much on the Gulf Stream. I think it is
more on sea level raise. Because in the projections, where
models have included melt from the Greenland ice sheet, like I
was explaining before, it does contribute to slowing down this
overturning circulation, but it doesn't ever actually stop it.
But I think the biggest concern, and something Dr. Alley
alluded to, is how unstable something like the Greenland ice
sheet is. And this again is in this category as we are moving
into an era where we are starting to observe things we have
never seen before in recorded human history. Glaciologists have
talked about the possibility of rapid ice-sheet destabilization
as a possibility. They have talked about a possible mechanism.
In the last ten years, they started to make observations that
maybe this mechanism actually is working. But because we have a
very short time period when we have actually observed this kind
of possible instability, we don't know what to make of it. Like
Dr. Alley said, is it a temporary thing? Would it be sustained
or accelerated more in the future? And we just don't know. And
I think that falls under the category of things that we can
with certainty and other things that we just don't know about
right now. This is obviously being researched, and a lot of
scrutiny is being put on this now, so we will have better
answers in the next few years, but right now, we just don't
know.
Chairman Gordon. The gentleman's time has expired, but I
would assume that there is no good news. It is only bad news
that will be coming from this. The Gentleman from Florida?
Scientific Consensus
Mr. Diaz-Balart. Thank you, Mr. Chairman. First, I want to
thank you for putting this hearing together. I think you
brought some great witnesses. I also want to thank the Speaker.
It is always good to bring attention to issues, so obviously,
she honored us this morning.
You know, I am pretty much like Mr. Inglis is, like
Congressman Inglis. I have gone from not knowing much about it,
just because you know, you see Hollywood movies, and that kind
of scares me. The more you read--and being one that always has
to--I think we all have to--obviously, since we aren't all
scientists, we have to rely on the real science as much as
possible, so what I keep hearing more of is that that is where
real science is certainly going.
I am asking for some reassurance to make sure that I am
leaning in the right direction. I tell you that before, for
example, the more I read--let me just quote this one thing from
the press, ``As for the present trend, a number of leading
climatologists have concluded that it is very unpleasant news,
indeed.'' They say that it is the root cause of a lot of the
unpleasant weather around the world, and they warn that it
carries potential for human disasters of unprecedented
magnitude. I keep hearing about this possibility because of
global warming.
What scares me sometimes is that that is not about global
warming. That is an article in Fortune magazine from 1974 about
climatologists now blame those droughts and floods on global
cooling trends. I also have, then, from the Washington, January
1970. ``Is mankind manufacturing a new Ice Age for itself?''
And it quotes a number of prestigious scientists who, now, are
some of the ones who believe that they were wrong then and now
that we are going to global warming. ``Winter held dawn of new
Ice Age,'' this is from the Washington Post. Science Digest,
``Brace yourself for an Ice Age.''
If we would have obviously gone ahead and acted because of
what a number of very prestigious scientists would have said
then, we would have been dead wrong--because I have to believe
you all. I really do. I happen to believe you all. So what I am
asking for is reassure me that in 1970 we were still looking at
science that the world was flat and that prestigious scientists
were dead wrong, because that is what I believe because that is
what I hear. And now science has changed dramatically and
technology, which is what I think I have heard today--and that
therefore that is wrong, and that the new consensus that we are
in a warming trend is correct, and that therefore I can feel
comfortable with that point of view.
Dr. Alley. I will try first, and then maybe my colleagues
will help a little bit.
Mr. Diaz-Balart. And if I may interrupt you, Mr. Alley, I
am also resentful of the fact that you made me very hungry this
morning with your pancake analogies. It is 12:30, and I think
that is unfair.
Dr. Alley. I apologize for that, yes. We are with you on
that one, actually.
As scientists, you know, our job is to push the limits. I
teach at a very large school, and I can assure you that there
are a lot of very bright students there that are pushing the
limits. They are coming up with new ideas that are going to
help us and save us, and some of it is totally off the wall.
And so as scientists, we bubble up all of these interesting
ideas, and then you have built mechanisms, we have built
mechanisms, the world has built mechanisms, to distill all of
these ideas into something which is policy-relevant for you.
And so this global cooling, which some of it came from us
learning to understand the Ice Age, and some it came from a lot
of aerosols coming out off smokestacks, blocking the sun, was
something that was bubbled up in a little bit of discussion and
huge amount of press interest. But if you go back and ask if
the National Academy actually come out with a global-cooling
warning, you won't find it. You know, when you get to the point
of asking was the assessed knowledge that was pulled together
policy relevant for you? Was that warning about this? Was that
the big issue? I don't believe you will find it. And so the
IPCC here exists as a mechanism, as does the National Academy.
It exists as a mechanism to take all of these wonderful ideas,
this ferment and froth that is out there in the scientist
community, and say what stands up, what is reliable, and to
give it to you. And we are here to tell you that the assessed
science of the world is pointing to human activities, changing
the atmosphere in a way that is causing warming.
Mr. Diaz-Balart. And I appreciate that.
Mr. Gilchrest. Will the gentleman from Florida yield just
for two seconds on this time?
Mr. Diaz-Balart. Of course.
Mr. Gilchrest. Having lived through that period of time,
and having read a number of articles and books, born in the
1970s, Dr. Alley is correct, there was not a consensus that we
were cooling. There was some suggestion, for a variety of
reasons--the consensus was are we cooling or warming. We don't
know yet. So at that point, there was no consensus.
Chairman Gordon. The gentleman's time has expired.
Mr. Diaz-Balart. Could I have a ten-second comment?
Chairman Gordon. With unanimous--we will see if I can get
this unanimous consent. I wasn't able to get one earlier.
Mr. Diaz-Balart. Mr. Chairman, I just learned--is it
possible that the press exaggerates on issues? I am just
shocked at what I learned today in this committee. I can't
believe that. I am sorry. I just can't believe that.
Chairman Gordon. Okay. Thank you, Professor--or Doctor, was
it? I guess it was Inspector Reneau. And a very patient
gentlelady from Arizona, Ms. Giffords, is recognized for five
minutes and ten seconds extra if she needs it.
Impact on the Southwestern United States
Ms. Giffords. Thank you Mr. Chairman. First of all, I want
to thank all of you for coming. It is important that you are
here. We appreciate that you are here. The American people are
glad you are here, and frankly, the world is. This is an area
that I so passionately believe that we need to lead in. And I
look around at all of the portraits behind you, particularly
that depict America's mission to go to the Moon and to explore
space and where we lead. And that Apollo mission of the future,
I believe, is in energy and climate change. And this is just a
first start. Mr. Chairman, thank you for bringing such
distinguished speakers here today, and we appreciate your
science. We may all not agree, but this is a process where we
deliberate, and I just certainly appreciate being here.
My question reflects my district, which is Southern
Arizona, the most extraordinary district. If you can, imagine
Tucson going all of the way to New Mexico. And this is an
area--we are not sure quite, but eight or nine years of a
drought we are experiencing. We are also seeing some other
strange changes that we have just not seen before. We had a
very strange storm happen about a year-and-a-half ago that
produced some rockslides in our mountains that we are not
familiar with. We also had some wildfires in Arizona,
particularly in the Catalina mountain range, that burned very
hot, we understand, that because of the weevil infestation that
has been allowed to build up, because of it not freezing, and
the trees then weakening. So I am just curious and as a former
legislator, I tried to establish a climate-change study group
in the Arizona legislature. We brought some distinguished
scientists from the University of Arizona, where they have a
global climate center, and frankly, my colleagues on both sides
of the aisle were not polite to the scientists. And even one of
my colleagues said well, heck, hot is hot. What is the
difference between 115 degrees or 120 degrees? So I ask you,
and I am not sure which scientist to address this to, if you
could explain in real terms, for the citizens of southern
Arizona, the difference between 115, 116 degrees, 120 degrees.
What does that really mean in the next five years, the ten
years, and 50 years for the people of Arizona?
Dr. Trenberth. Well, let me have a crack at this there.
Indeed, the drought in the southwestern parts of the United
States from 1999 to 2004 is one of the things which we think
may be, indeed, symptomatic of the climate changes that are
underway related to global warming. In the winter of 2004-2005,
we had weak to moderate El Nino, so there was maybe temporary
relief. We are not quite sure. Certainly, the droughty regions
have continued since then. But your concern about temperature,
there are a number of analogs, and perhaps one of the best
analogs is the year 2002 which is when the drought in the West
and in the Southwest was most extensive. And one of the things
that goes along with the drought is higher temperatures and
heat waves, and in particular, one of the consequences is
wildfires. And the risk of wildfires went up in 2002, there
were a very large number of wildfires. In fact, I don't know
what the cost of those was; I do know there was over a quarter
of a billion dollars spent just in fighting the wildfires
alone. And so that is one of the risks that goes along with the
increases in drought and increases in heat waves.
Dr. Meehl. Let me just add that the Southwest U.S. is
actually an area that we saw some interesting results when we
looked the model projections for extreme events, and you
mentioned rainfall. That's an area that shows that when it does
rain, in future projections, it rains harder, but there are
actually more days in between rainfall events. So the dry
spells in between rainfall events increases, but when it does
rain, it rains really hard. But when you average those changes
over a season, the average rainfall is still less in the future
projection. So in that area, in the Southwestern U.S., is one
area that is most consistent for this kind of result where you
just see a change in the nature of the precipitation, how it
falls, and how intense it is when it does rain.
Regional vs. Global Modeling
Ms. Giffords. Dr. Meehl, if I can follow up with you
concerning the difference between regional modeling and global
modeling. Can you talk a little bit about the regional models
and how long it is going to take them to catch up, globally?
Dr. Meehl. Yes, there is whole class of models that we can
imbed, various high resolution regional models in the global
models, so we have better representation of the mountain ranges
and things like that. This can be very important in regions
where, like in Colorado where I am from, where you have big
mountains, or in Arizona, you see the mountain ranges and where
you get almost locally specific rainfall regimes depending on
how the mountain ranges are. We can imbed these models in the
global models and get more information on smaller space scales.
But those regional models really depend on good global models
to drive them. And it is kind of the old garbage-in, garbage-
out adage for computing. So if your global model is bad, your
regional model is not going to do much better. But if the
global model is improved it can drive the imbedded regional
model in a more credible way. So that is one of the tools that
we can use to get more regionally specific climate-change
information, but it is still just a tool. It is not an end in
itself.
Chairman Gordon. The lady's time has expired. I will say
that my grandfather used to tell me that the most important
road in the county is the one in front of your house. You have
learned that lesson also.
Ms. Giffords. And Mr. Chairman, can I just say that if
every kid growing up had Dr. Alley as a science teacher, we
would have more kids going into science because of your
passions, so thank you, Dr. Alley.
Chairman Gordon. So that is why we all want to sponsor and
be part of our competitiveness agenda. We are going to do that
with more scholarships for more science and math and physical
science teachers.
Again, the patient gentleman from Georgia, Mr. Gingrey,
thank you for sticking with us.
U.S. Leadership in Mitigating Climate Change
Mr. Gingrey. Mr. Chairman, thank you so much. It has not
been difficult sticking with you for almost three hours. I am,
as you know, returning to the Science Committee, and so it puts
me down in the bottom row.
But Dr. Alley, you had commented that those ice sheets are
sometimes--well, most of the time are boring and are
occasionally exciting, and I think you might could say the same
thing about the Science Committee, those of you have been here
this morning. And I think under Chairman Gordon's leadership,
it is going to be mostly exciting on the Science Committee. I
agree with my colleague who just said in complimenting Dr.
Alley and the other panelists who testified on the panel this
morning. If you could take the tape of this hearing and play it
to the middle school class, I guarantee there would be more
young people going into science because this has indeed been
very exciting.
Chairman, I think you said there wasn't a lot of good news
here. I would say that although it is pretty frightening, the
global warming and the sea level and the ultimate outcome of
what that might be, well, the good news is it looks like God
has given us a lot more time than he gave Noah. Now, Dr.
Solomon, that is not your NOAA. That is N-o-a-h.
I wanted to point out, and it is been said by some of my
colleagues, that a number of us, actually six on this
committee, had an opportunity to go to Antarctica, and that is
because of the Science Committee. And I was one of those six, I
am very grateful. And it was mentioned today, something, a
policy, that when we were on the ice, that we couldn't use
aerosols. I now know why. I didn't ask the questions, then. But
this has been an outstanding hearing. I am grateful to the
panel. I am grateful for the Speaker. It is an historic
opportunity for the Speaker of House to come before the
Committee and testify. I appreciate her comments, particularly
in regard to nuclear power. I do have an answer for one of her
concerns and that is where would we store the waste? I would
suggest that maybe there is place out in Nevada called Yucca
Mountain, but that is an argument for another day.
I do have a question, believe it or not, and Dr. Meehl, I
am going to address it to you. There is going to be an upcoming
article in Newsweek magazine by George Will. We have talked
about this, and I know this is a question that you scientists
maybe don't want to address and are maybe not necessarily the
experts, and that is for us to do, but basically this is what
he says in this article ``Inconvenient Kyoto Truth: the United
States is able to drastically regulate our manmade, greenhouse
gas emissions,'' 35 percent, as was stated by Dr. Ehlers, ``but
other large industrial countries like China, Israel and Brazil,
do not.'' Will the United States efforts still achieve a
positive effect? Take, for example, that China is set to
construct all of those new coal-powered plants by 2030, and
they have stated that they have no interest, they aren't going
to do anything to regulate their emissions. What will the
United States' restrictions do to stem the climate change
trends that you outline in the IPCC AR-4 report? And that is my
question.
Dr. Meehl. And again, I am going to have to apologize
because I am not an expert in this area, so I really can't give
you a good answer for that.
Mr. Gingrey. Well, any one of the four would be grateful.
Dr. Trenberth. It will set a good example. I mean I think I
think it is a global problem, and U.S. leadership plays a key
role, and it does relate then to international pressures to
bring everyone in line, I think.
Mr. Gingrey. Anyone else? Dr. Trenberth, I think that is a
darn good answer, and I appreciate it, and I too have learned a
lot here today and changed my attitude. I began to change that
attitude when I went to the ice about a year ago, and that was
a great opportunity. I thank you, Mr. Chairman, and I yield
back.
Chairman Gordon. Thank you, Dr. Gingrey. In response to
your suggestion that we should be able to watch this for
children, we can. Compliments of the Science Committee, if you
will go to www.science.house.gov, you can get the web cast of
this hearing, the witnesses' statements, Leader Pelosi's
statement, and the Chair and Ranking Member's statement, so
that is, once again--get your pencil--www.science.house.gov.
I was two out of three today, Mr. Gilchrest, on unanimous
consent. The first unanimous consent was to allow you as a
former Member of this committee to sit in and ask questions, so
we will conclude with those statements or questions with you,
sir.
More on Climate Science
Mr. Gilchrest. Thank you very much, Mr. Chairman. I am very
happy to see that none of my Republican colleagues objected to
that. I have been on the Science Committee a couple of times in
the past, and like many of my colleagues, I have been to the
ice, the dry valleys and the magnificent spots down there in
the Antarctica, so maybe after this hearing, I might ask my
side for a waiver to get on the Science Committee again. It
looks like it is going to be a pretty exciting year.
I want to take a few seconds to talk about the economic
impact of pursuing a program to reduce greenhouse gases and
what that would do. To my colleagues remaining here, we have
worked with about a dozen Fortune 500 companies, including
DuPont, General Electric, Caterpillar, Lehman Brothers, and so
on to work this issue through. Their suggestion, their strong
suggestion, is based on the risk factor of investment of doing
something and what could happen economically if we don't do
something. Their suggestion is that the Federal Government
create a goal of reducing greenhouse gases by the year 2050 by
70 percent below 1990 levels and then set up a regulatory
structure in which there is a cap-and-trade program and tax
incentives. And they say through that structure, they can meet
that goal by the year 2050--not only meet that goal, but excel
at it based on propensity and ingenuity of the United States
technology and efficiency, and improve economic viability by
improving situations as far as dependence on foreign oil is
concerned and a whole range of other things. So there is a
pretty good structure out there to do that.
I have four questions that I would like to ask right up
front in case I run out of time. The first one is, you have
mentioned, let us say, 10,000 years ago that CO2
concentrations in the atmosphere was about 180 parts per
million. Fast forward about 10,000 years, and you have it at
280 per million. And then you come up to the present day, and
it is about 380 parts per million. Now, the most recent
introduction of increases from a variety of sources is the
burning of fossil fuel. Like one of our colleagues said, we
have put in the atmosphere in just a few decades, that it took
the natural sources to lock up in the form of fossil fuel over
millions of years. Can you make a distinction between the kind
of carbon that you get from a volcano or other natural sources
and the kind of carbon that you get from burning fossil fuel?
Is there a marker that you can see, and do you use that in your
equation to determine what it man-induced and what not man-
induced?
The second question is can you over, let us say, the last
20 years, maybe the last 30 years, determine the cubic miles,
the volume of water, coming off the Greenland ices, and has
that accelerated in the last 20, 10, five years.
Chairman Gordon. In all due respect, let us see if we are
going to have time to get through those two before we go on any
further.
Dr. Solomon. On the first one, if I may, the numbers you
gave were more or less right, except for the time scales. The
time when very much lower concentration of CO2 were
observed is really quite a bit earlier. You have to go back to,
really, the ice ages.
Mr. Gilchrest. About 10,000 what were the concentrations?
Dr. Solomon. You have to go a little bit farther back, more
like 20.
Mr. Gilchrest. 20,000, it was about 180 parts per million.
Dr. Solomon. And then when we came out of the Ice Age, it
went to about 270. As it said earlier, it stayed at 270 for
almost 9.9 thousand years.
Mr. Gilchrest. Really, that is even more incredible.
Dr. Solomon. Yeah, you can see that in Figure 1. And then,
in the last 100, it went dramatically up to about 380, which is
where it is now, and it has not been at levels that high in at
least 650,000 as Dr. Alley said.
Your question about a marker is also a very good one. As we
talked about earlier, the kind of carbon that you get when you
burn a fossil fuel is different in terms of its isotopes than
what you get from, you know, say trees or other sources of
carbon. So the changes in isotopes are a very key element in
demonstrating the human influence. Also, the north-south
gradient, we see a difference between the northern hemisphere
and the southern hemisphere which is also indicative of the
human source in the northern hemisphere.
Dr. Alley. And then for the Greenland ice sheet, we have
watched some of the glaciers speed up with satellite data and
put more icebergs into the ocean, and the Atmospheric Surface
Mass Balance Community has been reconstructing snowfall and
melting on the ice sheet and has seen a rise in snowfall but a
faster rise in melting so that it is losing mass that way. You
also see that from satellite.
Chairman Gordon. Excuse me. The gentleman's time has
expired. In respect to this committee, this panel has been here
for three hours. I know you have another briefing to go to and
then you have a hearing in the Senate. The Minority had more
than due notice to find someone to rebut you. They were not
able to do that either through the scientific community or
through the Chamber of Commerce. However, Mr. Rohrabacher has
been very studious these last three hours in preparing a
rebuttal, and I think it is only fair that we allow him that
opportunity.
Mr. Rohrabacher. Thank you much, Mr. Chairman. First, of
all, let me compliment you on putting together a fine panel of
experts for us, and I apologize for us in the Science Committee
along with the many scientists, who disagree with them and have
honest disagreement on this issue. And in fact, I will be
placing in the record the names of hundreds of those scientists
who disagree with this concept that climate change is caused by
human activities. Not that there is climate change, but that it
is caused by human activity. And we could have had any number
of those scientists, and it was remiss on our part not to have
someone here representing a scientific--there are people from
MIT and Harvard and many, many respected scientists who
disagree with this theory. They should have been here. It is
our fault for not getting them here.
Let me compliment you as far as a good panel. I think it is
great that Speaker Pelosi was here, and I apologize if I do not
believe that the objection that was made reflects in any way
the attitude of the other Members of this committee, the
Republican Members of this committee. I thought it was fine
that she spoke, and we paid her the same respect that paid Newt
Gingrich and others who have spoken before this panel in the
past.
With that said, I do have very serious disagreement with
some of the ideas presented today. And look, the reason I have
to push for an answer, and I shouldn't have to actually ask
five times before I get an answer on certain questions, that it
is important to know how much of the greenhouse gases that
exist in our atmosphere were caused by natural occurrences. And
that is an important thing because in terms of the weight that
you put on the changes that need to be made it makes all of the
difference in the world. A small change--and if you believe
that, as I do, and I remember Dr. Bartlett, who is also a Ph.D.
I might add, and has many credentials on this, nor did he
believe was 10 percent. Vern Ehlers said 35. I have heard other
science panels who really struggled to say that it was between
five and ten percent. With that noted, there is a huge
disproportion of natural causes of greenhouse gas. Which means
that a small change in the natural causes of greenhouse gases,
like volcanoes, would have a much bigger impact than a change
of human activity, if we could, indeed, create human-activity
change on such a broad scale.
So scientists disagree. I am submitting for the record
their names. Also, let me note that many scientists are
complaining that their research money has been cut off because
they disagreed with global warming concepts, and I will be
submitting their names for the record as well.
But there is no doubt that global climate change is
happening. The only question is why is this cycle of global
climate change, and we have gone through dozen of cycles of
global climate change, why is it any different than all the
other cycles? I noted during the testimony that was presented,
the chart that shows that we are now in a cycle when
temperature is going up, that it started at the very end of the
mini Ice Age which was a very low point, where temperature had
been declining for hundreds of years. So whether or not how
dramatic this change will be or what it is caused by, are
things that honest people, I think, can disagree with. And I
really, personally, having been a journalist, the first thing I
was cautioned by is when someone was claiming, ``well everybody
is on my side or everybody says this or there is a total
consensus.'' Most always when people said that to me during my
years as a journalist, it wasn't true. It was that there were
honest people who disagreed and there was significant
disagreement on such issues, and we don't know what those other
cycles were caused by in the past. It could be dinosaur
flatulence or--who knows? But we do know the CO2 in
the past had its time when it was greater as well. And what
happened when the CO2 was greater than now? There is
been many cycles of up-and-down warming.
So with that said, I think that we have had a great
discussion today. We need this discussion because the idea, Mr.
Chairman, of having some sort of initiative so that our country
creates new energy sources to make ourselves independent and
making sure that those energy sources are clean is a totally
bipartisan goal. It is. There is no doubt that all of us should
want to make sure that America isn't held hostage to foreign
energy sources and that when we do develop new energy sources
that they are clean. But the question that comes to the heart
of the matter is this--I am sorry for pontificating too long in
this--when we make that decision as a Congress as to what those
energy alternatives will be, we shouldn't be basing on science,
if it is wrong science that suggests that global climate change
is as big an issue as human health. I would prefer to make sure
that when we are becoming energy independent and that we
develop new energy sources, that we focus our science on making
sure that we take the bad stuff out of the atmosphere that
hurts human beings, rather than the stuff that may or may not
create a cycle that would make us two or three degrees warmer
or less in the future.
So with that, I have had my say. I appreciate the privilege
of having a closing statement. I appreciate your leadership on
this. You held a great discussion today.
Chairman Gordon. Thank you, Mr. Rohrabacher. I hope you
feel better. I think the panel has addressed Mr. Rohrabacher's
concern on a variety of occasions, so I won't take your time
any more, but I do want to very sincerely thank you for the
Herculean effort that you put into this product and for
allowing the United States Congress Science and Technology
Committee to be your first forum today
I think one of the lessons learned today is something that
we all should already know which is sometimes it is tough to be
a messenger, but you have a very important message. We are glad
you came. The message that needs to go out from this hearing is
that 113 nations concurred, including this country, that with
100 percent certainty, there is global warming and with 90
percent certainty it is a result, to a great extent, from human
activities.
Thank you very much for being here, and all of the
witnesses are dismissed, and the meeting is adjourned.
[Whereupon, at 1:05 p.m., the Committee was adjourned.]
Appendix:
----------
Answers to Post-Hearing Questions
Answers to Post-Hearing Questions
Responses by Susan Solomon, Co-Chair, IPCC, Working Group I: The
Physical Basis of Climate Change; Senior Scientist, Earth
System Research Laboratory, Office of Oceanic and Atmospheric
Research, National Oceanic and Atmospheric Administration, U.S.
Department of Commerce
Questions submitted by Representative Ralph M. Hall
Q1. How did you develop the Summary for Policy-makers? For example,
did you ask policy-makers what scientific information would be most
useful to them and structure the Summary around that information? If
not, how did you determine which findings to include in the Summary for
Policy-makers?
A1. First and subsequent drafts of the Summary for Policy-makers (SPM)
were prepared and revised by a sub-group of authors of the IPCC (2007)
Working Group I Report and reflect their joint selection of material
that they felt should be presented in order to best summarize the full
report.
The list of those scientists is given on the front page of the
Summary and includes 33 primary authors (collectively representing each
of the 11 chapters of the full report), along with 18 contributing
authors.
Drafts of the SPM were also discussed with the entire Working Group
I author team during author team meetings. All of the 152 authors of
the full report were also invited to provide written comments. Comments
were also invited from over 600 experts who had reviewed the rest of
the full report. Comments were also invited from governments. The SPM
draft was revised by the listed subgroup of authors based upon their
evaluation of all comments received.
In the course of the IPCC Working Group I Tenth Session held in
Paris from January 29 to February 1, 2007, delegates from 113 countries
approved the final SPM on a line-by-line basis. Authors were present
throughout this session and were charged with ensuring that all
proposed changes to wording in the SPM remained fully consistent with
the full report. During this final approval process the Lead Authors
also identified a small number of changes to the underlying report that
will ensure consistency with the language used in the final SPM or
provide additional clarity for policy-makers on matters discussed
during the session. None of these changes alter the substantive
findings of the report and the list of such changes was made available
from the IPCC Working Group I web site after the conclusion of the WG I
session (http://ipcc-wg1.ucar.edu/).
Q2. It is my understanding that in this IPCC report you associated
terms such as ``very likely'' with numerical confidence levels such as
``90 percent probability of occurrence;'' but that in previous IPCC
reports you did not associate numerical confidence levels with terms
such as ``very likely.'' Why did you add in the numerical confidence
levels in this IPCC report?
A2. Addressed in joint response.
Answers to Post-Hearing Questions
Responses jointly by Richard B. Alley, Lead Author, IPCC, Working Group
I, Chapter 4: Observations: Changes in Snow, Ice and Frozen
Ground; Evan Pugh Professor of Geosciences and Associate of the
Earth and Environmental Systems Institute, Pennsylvania State
University; Kevin E. Trenberth, Coordinating Lead Author, IPCC,
Working Group I, Chapter 3: Observations: Surface and
Atmospheric Climate Change; Head, Climate Analysis Section,
National Center for Atmospheric Research; Gerald A. Meehl,
Coordinating Lead Author, IPCC, Working Group I, Chapter 10:
Global Climate Projections; Senior Scientist, National Center
for Atmospheric Research; and Susan Solomon, Co-Chair, IPCC,
Working Group I: The Physical Basis of Climate Change; Senior
Scientist, Earth System Research Laboratory, Office of Oceanic
and Atmospheric Research, National Oceanic and Atmospheric
Administration, U.S. Department of Commerce
Question submitted by Representative Ralph M. Hall
Q1. It is my understanding that in this IPCC report you associated
terms such as ``very likely'' with numerical confidence levels such as
``90 percent probability of occurrence;'' but that in previous IPCC
reports you did not associate numerical confidence levels with terms
such as ``very likely.'' Why did you add in the numerical confidence
levels in this IPCC report?
A1. It is not the case that numerical confidence levels were introduced
for the first time in this report as suggested in the question. IPCC
has carefully developed the numerical confidence levels used, and they
were also used in the previous IPCC report in 2001 (see footnote 7 of
the 2001 Summary for Policy-makers, page 2 of the report). The terms
``likely'' and ``very likely'' were used in the 2001 report where each
was deemed appropriate by the authors, and the terms ``likely'' and
``very likely'' are used in exactly the same way in the new IPCC (2007)
report. This was introduced in the 2001 report to avoid the problem
that the confidence, uncertainty and likelihood of certain things can
be interpreted differently by different readers of the report, so a
clearly defined scale aids communication and understanding.
Questions submitted by Representative Jo Bonner
Q1. A Wall Street Journal article dated Feb. 5, 2007 says that data
from the U.S. National Climate Data Center showed that in 2006 the
world was only 0.03 degrees Celsius warmer than it was in 2001. This
difference is in the range of measurement error and is thus not
statistically significant. This data might suggest that the world is
not warming as fast as first thought. How do you respond to this data
report?
A1. These data do not indicate any weakness in scientific observations
of warming to date or projections of further temperature increase
described in the Working Group I report. Natural fluctuations
associated with weather and phenomena like El Nino mean that warming
trends are only reliably seen over decades, not year to year. The
recent history of temperature change includes a general warming trend,
most of which is very likely due to the increase in greenhouse gas
concentrations, overlaid with year-to-year variability arising from
other features of the climate system. The effects of this short-term
variability must be separated from the longer-term trend to allow
estimation of the size of the trend; the comparison between single-year
numbers for 2001 and 2006 does not do so, and so does not produce a
scientifically valid estimation of the warming trend. Over the past 25
years the trend is 0.18+C per decade, and the statistical
uncertainty puts the value from 0.13 to 0.23+C per decade
with 90 percent confidence.
Q2. A report published by the Center for Science and Public Policy and
authored by Lord Christopher Monckton shows that a 2001 U.N. assessment
has over-estimated the human influence on climate change by at least
one-third. Lord Monckton also says that in a 2001 report the U.N.
estimated that sea levels would rise three feet by 2100, but in reality
he notes that sea levels will rise only seventeen inches. This is a big
difference. What do you think this difference shows?
A2. We presume that the reports referenced are the ``IPCC Fourth
Assessment Report 2007: Analysis and Summary'' and the corresponding
IPCC Third Assessment Report from 2001. Further, we presume that the
claimed ``over-estimate'' of human influence refers to this statement
in Lord Monckton's document: ``The U.N.'s 2001 report showed that our
greenhouse gas emissions since 1750 had caused a ``radiative forcing''
of 2.43 watts per square meter. Our other effects on climate were shown
as broadly self-canceling. In the current draft, the U.N. has cut its
estimate of our net effect on climate by more than a third, to 1.6
watts per square meter. It now thinks pollutant particles reflecting
sunlight back to space have a very strong cooling effect.''
The values in the 2007 IPCC report actually are very consistent
with and thus increase confidence in those from the earlier IPCC
report, and show that the previous report did not ``over-estimate the
human influence on climate change by at least one-third.'' Primarily
because of continuing emissions, the best estimate of radiative forcing
of long-lived greenhouse gases has increased from 2.43 watts per square
meter in the 2001 report to 2.64 watts per square meter in the 2007
report (obtained by summing the central estimates of the effects from
carbon dioxide, methane, nitrous oxide and halocarbons from Table SPM-2
of the 2007 report, corresponding directly to the sum from the 2001
report). This long-lived greenhouse gas forcing is not the total
forcing, however, and the effects of ozone and the cooling effects of
aerosols must be properly included. The 2001 report did discuss the
aerosol effects (in Lord Monckton's words, the ``cooling effect'' of
``pollutant particles''), including direct effects on radiation and
indirect effects through induced changes in clouds, but the 2001 report
noted that no best estimate could be given for some of these effects
owing to large uncertainties. The improved ability to include these
effects in the 2007 report represents a scientific advance that more
accurately quantifies the human effect on climate, and does not in any
way represent a prior overestimate of human influence.
Regarding sea-level rise, the Summary for Policy-makers of the IPCC
Fourth Assessment Report states (p. 14) that, if considered for the
same time interval and emission scenario, the midpoint of the projected
sea-level rise from the Third Assessment Report is within 10 percent of
that for the Fourth Assessment Report, and that, had uncertainties been
treated in the same way, the ranges in those projections would have
been similar. Thus, there is not a big difference. Furthermore, as
noted in our response to Question 5, below, any additional contribution
to sea-level change from additional changes in the dynamical behavior
of the large ice sheets cannot be assessed accurately and was therefore
omitted from the quantitative estimates.
Q3. Do you think that more emphasis needs to be placed on the
population increases in China and India and the vast migration from
rural areas to cities? This increase creates demand for property and
increases pollution in the cities. Why do we not focus more on these
areas to reduce pollution and stop what you consider global warming?
A3. Our testimony concerned the findings of Working Group I of the
Fourth Assessment Report of the Intergovernmental Panel on Climate
Change, on the physical science basis of climate change. Impacts and
adaptation will be considered by Working Group II, and mitigation by
Working Group III. The question here goes beyond the scope of our
Working Group I report, and beyond our individual scientific expertise.
However, different possible future population levels, patterns of
development, and energy sources and conversion technologies, among
other factors, are considered in the Special Report on Emissions
Scenarios (SRES). The SRES scenarios in turn underlie the projections
of future climate change discussed in the Working Group I report. The
different scenarios, e.g., in Table SPM-2 and Figure SPM-7, therefore
provide considerable information on the importance of the factors
mentioned in the question.
Q4. A.R. Ravishankara with the National Oceanic and Atmospheric
Administration said that if you remove pollutants from the air that act
as a cooling mechanism, then the heating effect would be intensified.
How do you suggest that we find a medium to which pollutants could be
reduced to an extent without harming the cooling effect that they have?
A4. Dr. Ravishankara's statement is fully consistent with the IPCC
(2007) report. For a given atmospheric concentration of anthropogenic
greenhouse gases, lowering the level of anthropogenic aerosols would
produce an additional heating effect. (We interpret ``pollutants'' in
the question to refer to anthropogenic aerosols.) As a corollary to
this, the ``cooling'' effect of current levels of aerosols can be seen
in estimates of global-average radiative forcing. As shown in Figure
SPM-2 of the Summary for Policy-makers of the Fourth Assessment Report
of Working Group I of the Intergovernmental Panel on Climate Change,
there is a negative radiative forcing from anthropogenic aerosols,
partially offsetting the warming effect of anthropogenic greenhouse
gases.
The appropriate policy response to this observation is beyond the
scope of our report, and beyond our individual scientific expertise.
Climate science and the Working Group I Report can inform policy
choices by describing how the climate will respond to given levels of
aerosols and greenhouse gases. However, there is nothing inherent to
the Earth's physical climate that prevents both anthropogenic aerosols
and anthropogenic greenhouse gases being reduced to whatever levels are
deemed societally desirable. For instance, by increasing energy
efficiency and cutting down on fossil fuel burning, both greenhouse gas
and aerosol emissions could be reduced.
Q5. The U.N. Climate Panel estimates that Antarctica will actually
increase its snow mass this century. Would this not go against the
argument that scientists are making saying that glaciers and polar ice
caps are melting as a result of global warming?
A5. We presume that ``The U.N. Climate Panel'' refers to Working Group
I of the Intergovernmental Panel on Climate Change, in which we
participated. Our report notes that data show that mountain glaciers
have declined on average in both hemispheres, and that losses from the
ice sheets of Greenland and Antarctica have very likely contributed to
sea level rise over 1993 to 2003. The report states ``Current global
model studies project that the Antarctic ice sheet will remain too cold
for widespread surface melting and is expected to gain in mass due to
increased snowfall. However, net loss of ice mass could occur if
dynamical ice discharge dominates the ice sheet mass balance'' (p. 17)
and, with reference to the dynamical ice discharge, ``understanding of
these effects is too limited to assess their likelihood or provide a
best estimate or an upper bound for sea level rise.'' (p. 17) Thus,
increased snowfall is expected in Antarctica, but the trend in overall
mass of the ice sheet (including loss by ice flow feeding iceberg
calving) is not known. More generally, all glaciers respond to the
balance between accumulation of snow and loss by melting or iceberg
calving. With warming, the atmosphere can hold more water vapor and
thus precipitation is apt to increase. In some areas, a resulting
increase in accumulation wins out. However, for most glaciers, in spite
of increased accumulation, the melt wins out, but this can vary
enormously over short distances depending on the local features.