Space lasers track ice sheet thinning

CAMBRIDGE, England, Sept. 28 (UPI) -- British scientists say they've used NASA's satellite-based lasers to conduct the most comprehensive study to date of the Antarctic and Greenland ice sheets.

The British Antarctic Survey and University of Bristol researchers say their findings show the most profound ice loss in both ice sheets is a result of glaciers speeding up where they flow into the sea.

The researchers say such "dynamic thinning" of glaciers now reaches all latitudes in Greenland, has intensified on key Antarctic coastlines, is penetrating far into the ice sheets' interior and is spreading as ice shelves thin by ocean-driven melt. Ice shelf collapse has triggered particularly strong thinning that has endured for decades.

"We were surprised to see such a strong pattern of thinning glaciers across such large areas of coastline -- it's widespread and in some cases thinning extends hundreds of kilometers inland," said Hamish Pritchard of the British Antarctic Survey. "We think that warm ocean currents reaching the coast and melting the glacier front is the most likely cause of faster glacier flow. This kind of ice loss is so poorly understood that it remains the most unpredictable part of future sea level rise."

The scientists said they discovered the ice loss from many glaciers in both Antarctica and Greenland is greater than the rate of snowfall further inland.

The research is reported in the journal Nature.