Modeling abrupt climate changes

Lawrence Berkeley National Lab Newscenter: Abrupt climate change is a potential menace that hasn’t received much attention. That’s about to change. Through its Climate Change Prediction Program, the U.S. Department of Energy’s Office of Biological and Environmental Research (OBER) recently launched IMPACTS – Investigation of the Magnitudes and Probabilities of Abrupt Climate Transitions – a program led by William Collins of Berkeley Lab’s Earth Sciences Division (ESD) that brings together six national laboratories to attack the problem of abrupt climate change, or ACC.

Sparked by the 2007 Nobel Peace Prize that was shared by Al Gore and the Intergovernmental Panel on Climate Change (IPCC), the reality of global warming finally got through to the majority of the world’s population. Most people think of climate change as something that occurs only gradually, however, with average temperature changing two or three degrees Celsius over a century or more; this is the rate at which ‘forcing’ mechanisms operate, such as the accumulation of carbon dioxide in the atmosphere due to the burning of fossil fuels or widespread changes in land use.

…Collins, who heads the Climate Science Department in ESD, is the principal investigator for IMPACTS, which will bring together the work of experts in physical, chemical, and biogeochemical climate processes and in computer simulations of the whole Earth system. Argonne, Los Alamos, Lawrence Berkeley, Lawrence Livermore, Oak Ridge, and Pacific Northwest are the participating national laboratories.

…Collins coordinated the development of the most recent version of the Community Climate System Model (CCSM), one of the leading models underpinning the physical science basis of the IPCC’s 2007 climate change assessment; the IMPACTS program will be based on CCSM and will add new capabilities and new diagnostics for processes that could initiate abrupt climate change. CCSM, called by Science magazine “the nation’s foremost academic global climate model,” has long been supported by both DOE and the National Science Foundation.

…The IMPACTS team will initially focus on four types of ACC:

1) instability among marine ice sheets, particularly the West Antarctic ice sheet;

2) positive feedback mechanisms in subarctic forests and arctic ecosystems, leading to rapid methane release or large-scale changes in the surface energy balance;

3) destabilization of methane hydrates (vast deposits of methane gas caged in water ice), particularly in the Arctic Ocean; and

4) feedback between biosphere and atmosphere that could lead to megadroughts in North America….

Better science, more sophisticated models, and more powerful computers like those at DOE’s National Energy Research Scientific Computing Center (NERSC) have only recently made it possible to build comprehensive climate models. Image from the Berkeley Lab website