Global cooling, rise of Himalayas helped stir up South Asian monsoon
The mighty monsoon winds that periodically bring rains that drench India first billowed around 12.9 million years ago, new research shows. The work provides the best look yet at the conditions that fostered the modern monsoon.
By examining sediments piled up around Indian Ocean islands, researchers uncovered a geologic history of the South Asian monsoon stretching back tens of millions of years. The monsoon winds began abruptly, researchers report online July 20 in Scientific Reports. That speedy start-up suggests that factors such as global cooling were at play in addition to the rise of the Himalayan mountain range, which scientists typically blame for the monsoon’s inception.
The monsoon “came on really fast, and it came on because the whole system went over a threshold, not just the Himalayas,” says study coauthor Gregor Eberli, a marine geoscientist at the University of Miami in