Emerging patterns of simulated regional climatic changes for the 21st century due to anthropogenic forcings

We analyse temperature and precipitation changes for the late decades of th e 21st century (with respect to present day conditions) over 23 land region s of the world from 18 recent transient climate change experiments with cou pled atmosphere-ocean General Circulation Models (AOGCMs). The analysis inv olves two different forcing scenarios and nine models, and it focuses on mo del agreement in the simulated regional changes for the summer and winter s easons. While to date very few conclusions have been presented on regional climatic changes, mostly limited to some broad latitudinal bands, our analy sis shows that a number of consistent patterns of regional change across mo dels and scenarios are now emerging. For temperature, in addition to maximu m winter warming in northern high latitudes, warming much greater than the global average is found over Central Asia, Tibet and the Mediterranean regi on in summer. Consistent warming lower than the global average is found in some seasons over Southern South America, Southeast Asia and South Asia, wh ile cases of inconsistent warming amplification compared to the global aver age occur mostly in some tropical and southern sub-tropical regions. Consis tent increase in winter precipitation is found in northern high latitude re gions, as well as Central Asia, Tibet, Western and Eastern North America, a nd "Western and Eastern Africa regions. The experiments also indicate an in crease in South Asia and East Asia summer monsoon precipitation. A number o f regions show a consistent decrease in precipitation, such as Southern Afr ica and Australia in winter, the Mediterranean region in summer and Central America in both seasons. Possible physical mechanisms that lead to the sim ulated changes are discussed.