on the rocks

Over half of Greenland’s ice sheet is in danger of melting.

New research in the journal Geophysical Research Letters confirms that 139 glaciers are exposed to the melting influence of ocean water, many of those reaching deep below sea level where the water is warmer.

Using a combination of satellite radar, aerial imagery, and sonar data, researchers carefully mapped the topography — the intricate landscape of canyons and crevices on the ocean floor — below the ice itself. The results illustrate two major issues behind the accelerated melting of Greenland’s glaciers: warmer-than-normal ocean water and the shape of the bedrock itself.

Geophysical Research Letters

The contours of the rock that the glaciers sits on top of determine how that ice melts, by changing the amount of ice exposed to melt-inducing seawater. For example, a glacier embedded on a downward slope melts faster as the grounding line retreats and more and more ice is exposed to warm water.

Plus, the new research indicates that the Greenland ice sheet is almost three inches thicker than previous research suggested, which means the ice sheet could raise global sea levels by about 24.3 feet if it melted entirely. Yikes!