Glaciers on the Tibetan Plateau contain the largest ice mass outside the polar regions, yet those ice stores are at risk: Over the past decade the glaciers have been melting at an accelerating rate. Moreover, the plateau has seen its mean temperature rise twice as rapidly as the global average. Both trends suggest that in addition to warming due to greenhouse gases, some other mechanism is at work.
New studies of five Tibetan ice cores by researchers at the Chinese Academy of Sciences and the NASA Goddard Institute for Space Studies confirm black soot as the likely culprit. Formed in the incomplete combustion of carbon-based fuels, black soot is known to contribute to the warming of the lower atmosphere. Incorporated into snowfall it darkens the glaciers’ surface, which can dramatically increase the absorption of radiation and the rate of melting. The ice-core samples show a marked rise in black-soot concentrations...
