Ninth Community Climate System Model Workshop

Summary

The ninth Community Climate System Model (CCSM) Workshop was held July 7-9, 2004, at Santa Fe, New Mexico. The CCSM WS followed the June 23 release of CCSM3.0, the most recent version of the global coupled climate model. CCSM3.0 marks a significant milestone in the development of climate models that now incorporate phenomena ranging from the effect that volcanic eruptions have on temperature patterns to the impact of shifting sea ice on sunlight absorbed by the oceans. The CCSM effort is funded primarily by NSF and DOE. The model was developed at National Center for Atmospheric Research in collaboration with researchers at universities and DOE-lab scientists, with major funding from the National Science Foundation and the Department of Energy. Model results and the underlying computer codes have been released to atmospheric researchers and other users worldwide. Because a single day of simulated climate requires about 3 trillion computer calculations, the project has already consumed more than 7.5 million hours nearly 1,000 years of concurrent computer processor time. Scientists will contribute results from the new system to the next assessment by the Intergovernmental Panel on Climate Change, an international research body that advises policymakers on the likely impacts of climate change. Preliminary results using CCSM3.0 indicate global temperatures could rise by 2.6 degrees Celsius (4.7 degrees Fahrenheit) in a hypothetical scenario in which atmospheric levels of carbon dioxide are suddenly doubled. That is significantly more than the 2° Celsius (3.6° Fahrenheit) increase that had been indicated by the preceding version of the model. In addition to simulating temperatures over the next century, scientists will use the model to study climate patterns of the past, such as the peak of the last ice age 21,000 years ago. They will also use it to probe chemical processes and the cycling of carbon between the atmosphere, ocean, and land, as well as the localized impacts of sulfates and other pollutants on climate.