http://grist.org/briefly/over-half-of-greenlands-ice-sheet-is-in-danger-of-melting/
[images in on-line article]
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.
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!
