SENSITIVITY OF EURASIAN CLIMATE TO SURFACE UPLIFT OF THE TIBETAN PLATEAU

Experiments with climate models are used to illustrate how earth's climate could be expected to change if surface uplift occurred. The experiments contrast two climate simulations: one with all continents at sea level and one with present-day mountains and plateaus. The simulations in the Eurasia sector show that surface uplift (increased elevation) produces marked increases in the intensity of summer and winter monsoons of Asia, with development of wetter climates to the south and east of the Tibetan plateau and drier climates to the north and west of the plateau; there is a general cooling in northern polar latitudes. Comparison of simulations from two different models shows that the magnitude of the simulated changes depends upon how the models calculate the land surface hydrology and the ocean temperature. The simulated changes produced by surface uplift agree in a general way with many geologic indicators of late Cenozoic climate change. The results suggest that surface uplift of mountains and plateaus has contributed significantly to late Cenozoic climate change but that some other mechanism, perhaps decreasing levels of atmospheric carbon dioxide, is needed to explain the full range of observed trends.