By Sid Perkins
The Tibetan Plateau, an area in central Asia half the size of the United States and with an average altitude of more than 5 kilometers, has a powerful effect on climates in surrounding regions. Now, scientists have used computer models to show that both the onset of Asian monsoons and their strengthening over millions of years are strongly linked to various stages in the uplift of the plateau.
Sediments drilled from beneath the Arabian Sea show that the summertime onshore winds in the region gained strength between 8 million and 9 million years ago, says John E. Kutzbach, a climatologist at the University of Wisconsin-Madison. This airflow, the Indian monsoon, brings heavy rains to the Indian subcontinent.