Dr. Sellers will carry out detailed numerical experiments based on doubled carbon dioxide loading of the atmosphere, using the University of Arizona's climate model. This model-type falls between the full general circulation model (GCM) and a simple energy balance model and thus facilitates rapid model integrations for long time periods while retaining some of the important features of a more complex model. Focus of the numerical work will be on systematic investigation of the CO2 - doubling sensitivity of the model to all of the parameterizations in the model. This would aid in our understanding of factors that contribute to the global temperature sensitivity, which for GCMs may range from 2.8C to 5.2C depending upon the model. The results of this work would help pin down those processes that need to be very accurately modeled or parametarized.