Greenland Ice Melting Due to Heat from Below, Study Finds

High heat flow from the mantle to the lithosphere is increasing the rate of ice melt in Greenland. Researchers said that although the rate isn't high, this process must be considered during calculations of ice-loss in the region.

Scientists from IceGeoHeat found the association between geothermal heating and Greenland ice sheet melting at an exceptionally thin lithosphere in Greenland. They said that coupling ice/climate models with those that explain the flow of heat in the region is a better way to look at the mechanism responsible for ice sheet loss in Greenland.

The Greenland Ice Sheet is about 1,500 miles long and 680 miles wide, which makes it second largest ice sheet in the world. If all this ice were to melt entirely in a day, the global sea-levels would rise by 24 feet. The ice-sheet at Central Greenland is exceptionally thin; only about 43 to 49 miles thick.

This ice-sheet currently loses about 227 gigatonnes of ice per year, which accounts for 0.7 millimeters rise of sea level, about 3 mm per year.

The current models that describe the ice-melt in this region don't consider the lithosphere to be a contributor in the ice melt.

In the present study, Alexey Petrunin and Irina Rogozhina from GFZ German Research Centre for Geosciences combined data from "ice/climate model with a thermo-mechanical model for the Greenland lithosphere."

"We have run the model over a simulated period of three million years, and taken into account measurements from ice cores and independent magnetic and seismic data", said Petrunin. "Our model calculations are in good agreement with the measurements. Both the thickness of the ice sheet as well as the temperature at its base are depicted very accurately. "

The new model can explain the difference in ice-melt at two adjacent drill holes.           

"The temperature at the base of the ice, and therefore the current dynamics of the Greenland ice sheet is the result of the interaction between the heat flow from the earth's interior and the temperature changes associated with glacial cycles," said Rogozhina in a news release. "We found areas where the ice melts at the base next to other areas where the base is extremely cold."

The study is published in the journal Nature Geoscience.