Climate Sensitivity: Analysis of Feedback Mechanisms

We study climate sensitivity and feedback processes in three independent ways : (1) by using a three dimensional (3-D) global cli- mate model for experiments in which solar irra- diance So is increased 2 percent or C02 is doubled, (2) by using the CLIMAP climate boun- dary conditions to analyze the contributions of different physical processes to the cooling of the last ice age (18K years ago), and (3) by using estimated changes in global temperature and the abundance of atmospheric greenhouse gases to deduce an empirical climate sensitivity for the period 1850-1980. Our 3-D global climate model yields a warming of -4OC for either a 2 percent increase of So or doubled C02. This indicates a net feedback fac- tor of f = 3-4, because either of these forcings would cause the earth's surface temperature to warm 1.2-1.3OC to restore radiative balance with space, if other factors remained unchanged. Principal positive feedback processes in the model are changes in atmospheric water vapor, clouds and snow lice cover. Feedback factors calculated for these processes, with atmospheric dynamical feedbacks implicitly incorporated, are respectively fwater va or - 1.6. fclouds - 1.3 and fsnqw/ice - 1.1, wiph the latter mainly caused by sea ice changes. A number of potential feed- backs, such as land ice cover, vegetation cover and ocean heat transport were held fixed in these experiments. We calculate land ice, sea ice and vegetation feedback 1.2-1.3, 1.05-1

[1]  H. Craig,et al.  Methane: The record in polar ice cores , 1982 .

[2]  Roger G. Barry,et al.  Simulation of the Atmospheric Circulation Using the NCAR Global Circulation Model with Ice Age Boundary Conditions , 1974 .

[3]  S. Manabe,et al.  SIMULATED CLIMATOLOGY OF A GENERAL CIRCULATION MODEL WITH A HYDROLOGIC CYCLE , 1965 .

[4]  G. Russell,et al.  Annual oceanic heat transports computed from an atmospheric model , 1983 .

[5]  K. Bryan,et al.  The Ocean's Transient Response to Global Surface Temperature Anomalies , 2013 .

[6]  M. Ferguson,et al.  GEOSECS Atlantic radiocarbon and tritium results (Miami). Data report , 1976 .

[7]  André Berger,et al.  Long-term variations of daily insolation and Quaternary climatic changes , 1978 .

[8]  Robert D. Cess,et al.  Radiative transfer due to atmospheric water vapor: Global considerations of the earth's energy balance , 1974 .

[9]  Robert E. Dickinson,et al.  Vegetation‐Albedo Feedbacks , 2013 .

[10]  A. Robock.  El Chinchón eruption: The dust cloud of the century , 1983, Nature.

[11]  S. Levitus.  Climatological Atlas of the World Ocean , 1982 .

[12]  Peter H. Stone,et al.  Efficient Three-Dimensional Global Models for Climate Studies: Models I and II , 1983 .

[13]  Robert D. Cess,et al.  Biosphere-Albedo Feedback and Climate Modeling , 1978 .

[14]  P. Stone.  Feedbacks between Dynamical Heat Fluxes and Temperature Structure in the Atmosphere , 2013 .

[15]  Syukuro Manabe,et al.  Carbon Dioxide and Climatic Change , 1983 .

[16]  H. W. Bode,et al.  Network analysis and feedback amplifier design , 1945 .

[17]  Syukuro Manabe,et al.  The Effects of Changing the Solar Constant on the Climate of a General Circulation Model , 1975 .

[18]  W. Köppen.  Das geographische System der Klimate , 1936 .

[19]  H. Oeschger,et al.  Ice core sample measurements give atmospheric CO2 content during the past 40,000 yr , 1982, Nature.

[20]  M. Maccracken.  Climatic effects of atmospheric carbon dioxide. , 1983, Science.

[21]  N. J. Shackleton,et al.  Carbon isotope data in core V19-30 confirm reduced carbon dioxide concentration in the ice age atmosphere , 1983, Nature.

[22]  Syukuro Manabe,et al.  Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity , 1967 .

[23]  K. Bryan,et al.  Transient Climate Response to Increasing Atmospheric Carbon Dioxide , 1982, Science.

[24]  G. North.  Theory of Energy-Balance Climate Models. , 1975 .

[25]  S. Manabe,et al.  On the Distribution of Climate Change Resulting from an Increase in CO2 Content of the Atmosphere , 1980 .

[26]  P. Stone,et al.  Effect of Ice-Albedo Feedback on Global Sensitivity in a One-Dimensional Radiative-Convective Climate Model , 1980 .

[27]  T. van der Hammen,et al.  The Equatorial Rain Forest: A Geological History. , 1981 .

[28]  R. Cess,et al.  The effect of ocean heat capacity upon global warming due to increasing atmospheric carbon dioxide , 1981 .

[29]  R. Weiss.  The temporal and spatial distribution of tropospheric nitrous oxide , 1981 .

[30]  J. Hansen,et al.  Climatic effects of atmospheric carbon dioxide. , 1983, Science.

[31]  Syukuro Manabe,et al.  Sensitivity of a global climate model to an increase of CO2 concentration in the atmosphere , 1980 .

[32]  J. Hansen,et al.  Greenhouse effect of trace gases, 1970‐1980 , 1981 .

[33]  J. W. Dini.  Carbon dioxide and climate change , 2005 .

[34]  M. Budyko.  The Effects of Changing the Solar Constant on the Climate of a General Circulation Model , 2008 .

[35]  J. Hansen,et al.  Climate Impact of Increasing Atmospheric Carbon Dioxide , 1981, Science.

[36]  R. Mobley,et al.  Monthly Average SeaSurface Temperatures and IcePack Limits on a 1 Global Grid , 1976 .

[37]  William D. Sellers,et al.  A Global Climatic Model Based on the Energy Balance of the Earth-Atmosphere System. , 1969 .

[38]  B. Hunt,et al.  An assessment of the possible future climatic impact of carbon dioxide increases based on a coupled one‐dimensional atmospheric‐oceanic model , 1979 .

[39]  D. Robinson,et al.  Reappraisal of sea-ice distribution in Atlantic and Pacific sectors of the Southern Ocean at 18,000 yr BP , 1982, Nature.

[40]  S. Manabe,et al.  The Effects of Doubling the CO2 Concentration on the climate of a General Circulation Model , 1975 .

[41]  W L Gates,et al.  Modeling the Ice-Age Climate , 1976, Science.

[42]  R. Cess,et al.  Energy Balance Climate Models: A Reappraisal of Ice-Albedo Feedback , 1977 .

[43]  Beryl S. Vuilleumier.  Pleistocene Changes in the Fauna and Flora of South America , 1971, Science.

[44]  J. Hansen,et al.  Climate Sensitivity to Increasing Greenhouse Gases , 1999 .

[45]  D. Ehhalt,et al.  On the temporal increase of tropospheric CH4 , 1983 .

[46]  Stephen H. Schneider,et al.  Atmospheric CO2 and climate: Importance of the transient response , 1981 .

[47]  J. Walsh,et al.  An Analysis of Arctic Sea Ice Fluctuations, 1953–77 , 1979 .

[48]  A. Callegari,et al.  The role of deep sea heat storage in the secular response to climatic forcing , 1980 .

[49]  S. Schneider,et al.  Climate stabilization: for better or for worse? , 1974, Science.

[50]  Wallace S. Broecker,et al.  Modeling the Carbon System , 1980, Radiocarbon.

[51]  P. Webster,et al.  Late Quaternary Ice Age Climates of Tropical Australasia: Interpretations and Reconstructions , 1978, Quaternary Research.

[52]  M. Sarnthein.  Sand deserts during glacial maximum and climatic optimum , 1978, Nature.

[53]  A. T. Grove,et al.  Global Maps of Lake-Level Fluctuations since 30,000 yr B.P. , 1979, Quaternary Research.