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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 112,
D20103,
doi:10.1029/2007JD008753,
2007
Climate response to projected changes in short-lived species under an A1B scenario from 2000–2050 in the GISS climate model
Drew T. Shindell
NASA Goddard Institute for Space Studies, New York, New York, USA
Center for Climate Systems Research, Columbia University, New York, New York, USA
Greg Faluvegi
NASA Goddard Institute for Space Studies, New York, New York, USA
Center for Climate Systems Research, Columbia University, New York, New York, USA
Susanne E. Bauer
NASA Goddard Institute for Space Studies, New York, New York, USA
Center for Climate Systems Research, Columbia University, New York, New York, USA
Dorothy M. Koch
NASA Goddard Institute for Space Studies, New York, New York, USA
Center for Climate Systems Research, Columbia University, New York, New York, USA
Nadine Unger
Department of Atmospheric Sciences, University of Vermont, Burlington, Vermont, USA
Surabi Menon
Lawrence Berkeley Laboratory, Berkeley, California, USA
Ron L. Miller
NASA Goddard Institute for Space Studies, New York, New York, USA
Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, USA
Gavin A. Schmidt
NASA Goddard Institute for Space Studies, New York, New York, USA
Center for Climate Systems Research, Columbia University, New York, New York, USA
David G. Streets
Argonne National Laboratory, Argonne, Illinois, USA
Abstract
We investigate the climate forcing from and response to projected changes in short-lived species and methane under an A1B
scenario from 2000-2050 in the GISS climate model. We present a meta-analysis of new simulations of the full evolution of
gas and aerosol species and other existing experiments with variations of the same model. The comparison highlights the importance
of several physical processes in determining radiative forcing, especially the effect of climate change on stratosphere-troposphere
exchange, heterogeneous sulfate-nitrate-dust chemistry, and changes in methane oxidation and natural emissions. However, the
impact of these fairly uncertain physical effects is substantially less than the difference between alternative emission scenarios
for all short-lived species. The net global mean annual average direct radiative forcing from the short-lived species is .02
W/m2 or less in our projections, as substantial positive ozone forcing is largely offset by negative aerosol direct forcing. Since
aerosol reductions also lead to a reduced indirect effect, the global mean surface temperature warms by ∼0.07°C by 2030 and
∼0.13°C by 2050, adding 19% and 17%, respectively, to the warming induced by long-lived greenhouse gases. Regional direct
forcings are large, up to 3.8 W/m2. The ensemble-mean climate response shows little regional correlation with the spatial pattern of the forcing, however, suggesting
that oceanic and atmospheric mixing generally overwhelms the effect of even large localized forcings. Exceptions are the polar
regions, where ozone and aerosols may induce substantial seasonal climate changes.
Received 2
April
2007;
accepted 7
August
2007;
published 16
October
2007.
Keywords: Climate;
aerosols;
ozone.
Index Terms: 1610 Global Change: Atmosphere (0315, 0325); 1637 Global Change: Regional climate change; 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906); 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513).
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Citation: Shindell, D. T., G. Faluvegi, S. E. Bauer, D. M. Koch, N. Unger, S. Menon, R. L. Miller, G. A. Schmidt, and D. G. Streets
(2007),
Climate response to projected changes in short-lived species under an A1B scenario from 2000–2050 in the GISS climate model,
J. Geophys. Res.,
112,
D20103,
doi:10.1029/2007JD008753.
Copyright 2007 by the American Geophysical Union.
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