Greenland’s big melt

Greenland’s massive ice sheet may be melting in a more complex fashion than scientists had realized. It’s known that meltwater atop the ice percolates down and lubricates glaciers’ advance, thus hastening ice loss into the ocean. But a team led by scientists at the University of Leeds in England suggests in the Jan. 27 Nature that this is not the whole story. Their studies of six glaciers in western Greenland show that drainage at the glaciers’ bottoms becomes more efficient as summer advances, helping offset melt-induced ice acceleration. The work could improve predictions of how much sea level rise to expect as Greenland thaws. s