Reuters Jan 24, 2018 11:05 AM IST
Researchers have found that the loss of heat that comes up from the interior of the Earth melts Greenland's ice sheet from below and triggers the sliding of glaciers towards the sea.
Greenland's ice sheet is becoming smaller and smaller. The melting is taking place with an increased strength and at a speed that no models have previously predicted.
As a result, the deep bottom water of north-eastern Greenland's fjords is also warming up, the research showed.
"North-East Greenland has several hot springs where the water becomes up to 60 degrees warm and, like Iceland, the area has abundant underground geothermal activity," said Soren Rysgaard, Professor at the Aarhus University in Denmark.
In the study, appearing in the journal Scientific Reports, the team focussed on an isolated basin in the fjord with a depth range between 200 and 340 metre and measured how the deep water is heated over a 10-year period.
Based on the data, researchers estimated that the loss of heat from the Earth's interior to the fjord is about 100 MW m-2 (milliWatt per square metre).
This corresponds to a 2-megawatt wind turbine sending electricity to a large heater at the bottom of the fjord all year round.
If the Earth releases heat to a fjord, heat also seeps up to the bottom part of the glaciers. This means that the glaciers melt from below and thus slide more easily over the terrain on which they sit when moving to the sea, the researchers said.
"There is no doubt that the heat from the Earth's interior affects the movement of the ice, and we expect that a similar heat seepage takes place below a major part of the ice cap in the north-eastern corner of Greenland," explained Soren Rysgaard from the varsity.
The findings may help improve the models of ice sheet dynamics, allowing better predictions of the stability of the Greenland ice sheet, its melting and the resulting global water rise.