Plateau uplift and climatic change

It is suggested that a spasm of geologic upheaval that resulted in the development of huge elevated plateaus in several regions, particularly southern Asia and western North America, may be responsible for the cooling and diversification of climate and vegetation into a variety of regionally distinctive types over the past 40 million years. Several computer experiments that model the atmospheric circulation physics were performed to investigate the apparent link between plateau uplift and climatic change in the Northern Hemisphere. The experiments showed that elevated plateaus affect atmospheric circulation in a number of significant ways. The results of the computer simulations were compared to climatic histories found in the geologic records. It is noted that, in addition to causing physical changes in circulation, plateau uplift may alter climate by increasing chemical weathering of rocks, thereby reducing atmospheric carbon dioxide concentrations. It is concluded that, in the world's present climate which represents the warm extreme of a cycle of glaciation, the uplifted plateaus that have set off the recent ice ages are still in place.