Glacier melt causes large fraction of sea level rise

Melting glaciers around the world, discrete from the polar ice sheets, accounted for 29 percent of sea level rise from 2003 to 2009, scientists report in the May 17 Science. That’s almost as much sea level rise as the ice sheets themselves contributed during that time.

Glaciers, including those in Greenland and Antarctica that aren’t part of the ice sheets, lost 259 billion tons of ice per year, raising sea level 0.71 millimeters annually. Alex Gardner of Clark University in Worcester, Mass., and colleagues calculated the ice losses using satellite data and ground measurements of glaciers. Most of the melting occurred in Alaska, the Canadian Arctic, Greenland, the southern Andes and the Himalayas and other high mountains of Asia.

The team estimates that, together, the glacier and ice sheet losses explain 60 percent of sea level rise from 2003 to 2009. Other sources include expansion of the ocean as its waters warm.