Global warming isn't the only problem for glaciers.

Layered-on soot is increasing the rate that glaciers in the Himalayan plateau are melting, according to a new NASA study released at the American Geophysical Union taking place this week in San Francisco. Clouds of soot and particles that cling to glaciers in the region trap heat and thereby accelerate melting. Since the 1960s, the acreage covered by Himalayan glaciers has shrunk by 20 percent.

One of the persistent worries in Asia remains a deepening water crisis as high mountain glaciers shrink. Three nothern states in India have lost 17.7 cubic kilometers a year for the past decade. Typically, the glaciers act to refill water supplies in lowlying regions.