Using data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite system and continuous GPS measurements from long-term sites on the bedrock on the margins of the ice sheet, a team led by scientists at the Denmark Technical University in Copenhagen measured the uplift of the crust caused by the loss of ice. ‘Our results show that the ice loss, which has been well documented over southern portions of Greenland, is now spreading up along the northwest coast,’ said Shfaqat Abbas Khan, the lead author of the study, which will appear in Geophysical Research Letters.

The team found that near the Thule Air Base on Greenland’s northwest coast, the crust rose by about four centimetres between October 2005 and August last year. Because the resolution of the GRACE measurements is relatively poor, the researchers weren’t able to pinpoint the source of the ice loss. However, they say that the fact that ice loss is occurring near the edges of the ice sheet suggests that flows of outlet glaciers are increasing in velocity.

‘If this activity in northwest Greenland continues and really accelerates some of the major glaciers in the area, such as the Humboldt Glacier and the Peterman Glacier, Greenland’s total ice loss could easily be increased by an additional 50–100 cubic kilometres within a few years,’ Khan said.

May 2010