Global Warming

Greenland’s Ice Melting from Below

The massive Greenland ice sheet is being melted as a result of heat emitted from within the Earth, rather than rising atmospheric temperatures, a new NASA study has claimed.

The US space agency, which uses satellites orbiting the earth to monitor the environment and study climate change, looked at how much the the huge ice sheet was still attached to bed rock underneath.

For the first time, the agency obtained a series of temperatures from the base of the sheet - the second biggest in the world after that in the Antarctic - and found it was up to tens of degrees warmer at the base than the surface. The Greenland ice sheet is around 1,500 miles north to south and up to 680 miles across.

Scientists found alarmingly high areas of ice at the base of the sheet had melted and come free from the bedrock below. But they also said it was heat coming out of the bedrock itself which was causing the melting. This means the ice sheet would melt from below anyway even if global warming was not taking place.

Knowing whether Greenland’s ice lies on wet, slippery ground or is anchored to dry, frozen bedrock is essential for predicting how this ice will flow in the future, but scientists have very few direct observations of the thermal conditions beneath the ice sheet, obtained through fewer than two dozen boreholes that have reached the bottom.

The map shows parts of the ice sheet that are likely thawed (red), frozen (blue) or uncertain (grey)