Snowfall making Greenland darker, warmer

Washington: Greenland is becoming darker and warmer due to a weather pattern that is pushing fresh snowfall away from its ice sheet, a study said on Tuesday.

A reduction in the amount of fresh, light-colored snow leaves more old and dark snow exposed on the surface -- which in turn causes the ice sheet to absorb more heat and melt faster. "As snow ages, even over hours to a few days, you get this reduction in reflectivity, and that’s why the fresh snow is so important," said Erich Osterberg, an associate professor of earth sciences at Dartmouth College and co-author of the paper in Geophysical Research Letters.

Osterberg and colleagues attributed the decrease in snowfall to a weather phenomenon called "atmospheric blocking" -- in which persistent high-pressure systems hover over the ice sheet for weeks at a time.

These systems, which have become more prevalent in the region since the 1990s, hold warmer air over western Greenland, reduce light-blocking cloud cover, and push snowstorms to the north.

The result is a "triple whammy," said Osterberg. "This all contributes to Greenland melting faster and faster."