Committed warming and its implications for climate change

• Published in: Geophysical research letters Vol. 28; no. 8; pp. 1535 - 1538
• Main Authors: Wetherald, Richard T., Stouffer, Ronald J., Dixon, Keith W.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 15.04.2001; American Geophysical Union
• Subjects: Climatology. Bioclimatology. Climate change; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; Physics of the oceans; Sea-air exchange processes; Warming; Atmospheric temperature; General circulation models; Radiative properties; Soil moisture; Numerical simulation; Surface temperature; Forcing; Climate modification; Ocean atmosphere interaction
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2000GL011786

Time lags between changes in radiative forcing and the resulting simulated climate responses are investigated in a set of transient climate change experiments. Both surface air temperature (SAT) and soil moisture responses are examined. Results suggest that if the radiative forcing is held fixed at today's levels, the global mean SAT will rise an additional 1.0K before equilibrating. This unrealized warming commitment is larger than the 0.6K warming observed since 1900. The coupled atmosphere‐ocean GCM's transient SAT response for the year 2000 is estimated to be similar to its equilibration response to 1980 radiative forcings—a lag of ∼20 years. Both the time lag and the warming commitment are projected to increase in the future, and depend on the model‧s climate sensitivity, oceanic heat uptake, and the forcing scenario. These results imply that much of the warming due to current greenhouse gas levels is yet to be realized.