We employ new observationally-based datasets of Antarctic near-surface air temperature and snowfall accumulation to evaluate 20th century simulations from five representative global climate models (GCMs) that support the Intergovernmental Panel on Climate Change Fourth Assessment Report. Annual Antarctic snowfall accumulation trends in the GCMs agree with observations during 1960-1999, and the sensitivity of snowfall accumulation to near-surface air temperature fluctuations is approximately the same as observed, about 5 %/K , suggesting that if Antarctic temperatures rise as projected, snowfall increases may partially offset ice sheet mass loss by mitigating an additional 1 mm/y of global sea level rise by 2100. However, 20th century annual Antarctic near-surface air temperature trends in the GCMs are about 2.5-to-5 times larger-than-observed, raising questions about the robustness of the 21st century projections. Resolving the relative contributions of dynamic and radiative forcing on Antarctic temperature variability will be an important step toward improving GCM projections.

Full Article: http://polarmet.mps.ohio-state.edu/PolarMet/PMGFulldocs/monaghan_bromwich_grl_2008.pdf

Last Updated: 2008-08-21