| ||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page R1
Carbon Dioxide and Climate: A Scientific Assessment
Carbon Dioxide and Climate: A Scientific Assessment
Report of an Ad Hoc Study Group on Carbon Dioxide and Climate
Woods Hole, Massachusetts
July 23–27, 1979
to the
Climate Research Board
Assembly of Mathematical and Physical Sciences
National Research Council
NATIONAL ACADEMY OF SCIENCES
Washington, D.C.
1979
OCR for page R2
Carbon Dioxide and Climate: A Scientific Assessment
NOTICE The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the Councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the Committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
Available from
Climate Research Board
2101 Constitution Avenue
Washington, D.C. 20418
OCR for page R3
Carbon Dioxide and Climate: A Scientific Assessment
Climate Research Board
Verner E.Suomi,
University of Wisconsin-Madison,
Chairman
Francis P.Bretherton,
National Center for Atmospheric Research
Dayton H.Clewell,
Mobil Oil Corporation (retired)
Thomas Donahue,
University of Michigan
Herbert Friedman,
Naval Research Laboratory
J.Herbert Hollomon,
Massachusetts Institute of Technology
Charles W.Howe,
University of Colorado
John Imbrie,
Brown University
Robert W.Kates,
Clark University
John E.Kutzbach,
University of Wisconsin-Madison
Cecil E.Leith,
National Center for Atmospheric Research
William A.Nierenberg,
Scripps Institution of Oceanography
Roger R.Revelle,
University of California, San Diego
Joseph Smagorinsky,
National Oceanic and Atmospheric Administration
Frederick E.Smith,
Harvard University
Karl K.Turekian,
Yale University
John Waelti,
University of Minnesota
Sylvan H.Wittwer,
Michigan State University
Warren Wooster,
University of Washington
LIAISON WITH FEDERAL AGENCIES
Eugene W.Bierly,
National Science Foundation
John G.Dardis,
Department of State
Edward Epstein,
National Climate Program Office, National Oceanic and Atmospheric Administration
OCR for page R4
Carbon Dioxide and Climate: A Scientific Assessment
Steven Flajser,
Committee on Commerce, Science and Transportation, U.S. Senate
Elbert W.Friday,
Department of Defense
Lawrence R.Greenwood,
National Aeronautics and Space Administration
Galen Hart,
Department of Agriculture
Keith Howard,
Department of the Interior
Gerald J.Kovach,
Committee on Commerce, Science and Transportation, U.S. Senate
Ian Marceau,
Subcommittee on Natural Resources and Environment, U.S. House of Representatives
Lloyd J.Money,
Department of Transportation
Douglas H.Sargeant,
National Oceanic and Atmospheric Administration
David Slade,
Department of Energy
Herbert L.Wiser,
Environmental Protection Agency
STAFF
John S.Perry,
National Research Council,
Executive Secretary
Robert S.Chen,
National Academy of Sciences,
Resident Fellow
OCR for page R5
Carbon Dioxide and Climate: A Scientific Assessment
Ad Hoc Study Group on Carbon Dioxide and Climate
Jule G.Charney,
Massachusetts Institute of Technology,
Chairman
Akio Arakawa,
University of California, Los Angeles
D.James Baker,
University of Washington
Bert Bolin,
University of Stockholm
Robert E.Dickinson,
National Center for Atmospheric Research
Richard M.Goody,
Harvard University
Cecil E.Leith,
National Center for Atmospheric Research
Henry M.Stommel,
Woods Hole Oceanographic Institution
Carl I.Wunsch,
Massachusetts Institute of Technology
STAFF
John S.Perry
Robert S.Chen
Doris Bouadjemi
Theresa Fisher
OCR for page R6
Carbon Dioxide and Climate: A Scientific Assessment
ERRATUM
p. 9, Section 3.2, 3d paragraph, line 6 should read as follows:
“atmosphere-earth system would absorb about 0.9 W m−2 less solar radiation”
OCR for page R7
Carbon Dioxide and Climate: A Scientific Assessment
Foreword
Each of our sun’s planets has its own climate, determined in large measure by the planet’s separation from its mother star and the nature of its atmospheric blanket. Life on our own earth is possible only because of its equable climate, and the distribution of climatic regimes over the globe has profoundly shaped the evolution of man and his society.
For more than a century, we have been aware that changes in the composition of the atmosphere could affect its ability to trap the sun’s energy for our benefit. We now have incontrovertible evidence that the atmosphere is indeed changing and that we ourselves contribute to that change. Atmospheric concentrations of carbon dioxide are steadily increasing, and these changes are linked with man’s use of fossil fuels and exploitation of the land. Since carbon dioxide plays a significant role in the heat budget of the atmosphere, it is reasonable to suppose that continued increases would affect climate.
These concerns have prompted a number of investigations of the implications of increasing carbon dioxide. Their consensus has been that increasing carbon dioxide will lead to a warmer earth with a different distribution of climatic regimes. In view of the implications of this issue for national and international policy planning, the Office of Science and Technology Policy requested the National Academy of Sciences to undertake an independent critical assessment of the scientific basis of these studies and the degree of certainty that could be attached to their results.
In order to address this question in its entirety, one would have to peer into the world of our grandchildren, the world of the twenty-first century. Between now and then, how much fuel will we burn, how many trees will we
OCR for page R8
Carbon Dioxide and Climate: A Scientific Assessment
cut? How will the carbon thus released be distributed between the earth, ocean, and atmosphere? How would a changed climate affect the world society of a generation yet unborn? A complete assessment of all the issues will be a long and difficult task.
It seemed feasible, however, to start with a single basic question: If we were indeed certain that atmospheric carbon dioxide would increase on a known schedule, how well could we project the climatic consequences? We were fortunate in securing the cooperation of an outstanding group of distinguished scientists to study this question. By reaching outside the membership of the Climate Research Board, we hoped to find unbiased viewpoints on this important and much studied issue.
The conclusions of this brief but intense investigation may be comforting to scientists but disturbing to policymakers. If carbon dioxide continues to increase, the study group finds no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible. The conclusions of prior studies have been generally reaffirmed. However, the study group points out that the ocean, the great and ponderous flywheel of the global climate system, may be expected to slow the course of observable climatic change. A wait-and-see policy may mean waiting until it is too late.
In cooperation with other units of the National Research Council, the Climate Research Board expects to continue review and assessment of this important issue in order to clarify further the scientific questions involved and the range of uncertainty in the principal conclusions. We hope that this preliminary report covering but one aspect of this many-faceted issue will prove to be a constructive contribution to the formulation of national and international policies.
We are grateful to Jule Charney and to the members of the study group for agreeing to undertake this task. Their diligence, expertise, and critical judgment has yielded a report that has significantly sharpened our perception of the implications of the carbon dioxide issue and of the use of climate models in their consideration.
Verner E.Suomi, Chairman
Climate Research Board
OCR for page R9
Carbon Dioxide and Climate: A Scientific Assessment
Preface
In response to a request from the Director of the Office of Science and Technology Policy, the President of the National Academy of Sciences convened a study group under the auspices of the Climate Research Board of the National Research Council to assess the scientific basis for projection of possible future climatic changes resulting from man-made releases of carbon dioxide into the atmosphere. Specifically, our charge was
To identify the principal premises on which our current understanding of the question is based,
To assess quantitatively the adequacy and uncertainty of our knowledge of these factors and processes, and
To summarize in concise and objective terms our best present understanding of the carbon dioxide/climate issue for the benefit of policy-makers.
The Study Group met at the NAS Summer Studies Center at Woods Hole, Massachusetts, on July 23–27, 1979, and additional consultations between various members of the group took place in subsequent weeks. We recognized from the outset that estimates of future concentrations of atmospheric carbon dioxide are necessarily uncertain because of our imperfect ability to project the future workings of both human society and the biosphere. We did not consider ourselves competent to address the former and recognized that the latter group of problems had recently been reviewed in considerable detail by the Scientific Committee on Problems of the Environment (SCOPE) of the
OCR for page R10
Carbon Dioxide and Climate: A Scientific Assessment
International Council of Scientific Unions. We therefore focused our attention on the climate system itself and our ability to foretell its response to changing levels of carbon dioxide. We hope that the results of our study will contribute to a better understanding of the implications of this issue for future climate and human welfare.
In our review, we had access not only to the principal published studies relating to carbon dioxide and climate but also to additional unpublished results. For these contributions, we gratefully acknowledge the assistance of the following scientists:
A.Gilchrist, British Meteorological Office
J.Hansen, Goddard Institute for Space Studies, NASA
S.Manabe, R.T.Wetherald, and K.Bryan, Geophysical Fluid Dynamics Laboratory, NOAA
We also had the benefit of discussions with a number of other scientists in the course of the review. We wish to thank the following individuals for their helpful comments:
R.S.Lindzen, Harvard University
C.G.Rooth, University of Miami
R.J.Reed, University of Washington
G.W.Paltridge, Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia
W.L.Gates, Oregon State University
Finally, I wish to express my appreciation to the members of the Study Group for their contributions. In particular, the report benefited greatly from Akio Arakawa’s careful examination of the results of general circulation model studies. Our group is also grateful to the staff of the Climate Research Board for their support.
Jule G.Charney, Chairman
Ad Hoc Study Group on Carbon Dioxide and Climate
OCR for page R11
Carbon Dioxide and Climate: A Scientific Assessment
Contents
1
SUMMARY AND CONCLUSIONS
1
2
CARBON IN THE ATMOSPHERE
4
3
PHYSICAL PROCESSES IMPORTANT FOR CLIMATE AND CLIMATE MODELING
7
3.1 Radiative Heating
7
3.2 Cloud Effects
9
3.3 Oceans
10
4
MODELS AND THEIR VALIDITY
12
4.1 Three-Dimensional General Circulation Models
13
REFERENCES
18
BIBLIOGRAPHY
20
APPENDIX: Comparison of Snow-Ice Effects in the Models Examined
21
OCR for page R12
Carbon Dioxide and Climate: A Scientific Assessment
This page intentionally left blank.
Items in cart [0]
