For the last 10,000 years, the Greenland Ice Sheet has been quite stable. Since 1990, it has been melting and shrinking and in the last decade its rate of decline has accelerated. Why?

Warmer air temperatures are increasing rate of surface melting Meltwater percolates downward, lubricating base and causing ice sheet to move faster Three largest outlet glaciers which flow into Greenland’s fjords – and extend several hundred meters beneath sea level – are moving faster than other parts of ice sheet. Outlet glaciers which shed icebergs into the surrounding seas, are the largest conduit for annual loss of mass that, until recently, has maintained a balance in Greenland’s ice sheet. NY Times June 8, 2004

Is the ocean playing an active role in the ice sheet’s decline?

Ocean basins surrounding Greenland – which are alternately flushed with cold Arctic and warm subtropical waters – are presently the warmest on record. Heat storage anomaly (1020 Joules) The recent flush of warmer waters through the seas around the southern half of Greenland coincided perfectly with the observed surge in the its outlet glaciers. They originated in lower latitudes where greenhouse warming has created a recognizable signature

This summer, WHOI scientists Fiamma Straneo and Ruth Curry obtained the first measurements in three E. Greenland fjords, and found that those warm Atlantic waters are being funneled right up to the base of the outlet glaciers.

Temperature (deg C) outflow inflow inflow Map shows Sermilik fjord and locations of measurements acquired using boats and a helicopter to get up to the base of Helheim glacier. The temperature section along the fjord shows the warm Atlantic waters flowing in beneath 200 m and cold meltwater flowing out at the surface.

“Warm enough to melt ice …” Sermilik Fjord Helheim Glacier Kangerdlugssuaq Fjord/Glacier 79º N Fjord/Glacier “Warm enough to melt ice …” Nine moorings are now sitting in Sermilik and Kangerdlugssuaq Fjords obtaining the first ever measurements of year-round temperatures and currents. These will help determine what controls the flow of warm waters deep into the fjords and how ocean-ice sheet interactions may affect the rate of sea level rise.