The disappearing Greenland Ice Sheet continues to thin along its edges, and could soon open up in the north, according to the latest results of satellite and aerial studies presented here today at the annual meeting of the American Geophysical Union.
The broad view is that the entire Greenland ice sheet
is thinning, and has done so for 20 years, researchers reported at the
meeting. But regionally, Greenland presents a more complicated story.
Portions of the giant ice cap, one of the biggest blocks of ice on
Earth, are melting faster than others, but a few places also seem to be
getting thicker, scientists said.
Greenland is now losing about 22 gigatons (22 cubic kilometers) of ice a
year, said Beata Csatho, a professor at the University of Buffalo in
New York. All of that melting ice adds to rising global sea levels, and
future melting is expected to further contribute to that rise.
The north of the ice sheet in particular presents a possible future
hazard should rapid thinning there continue. The northeast edge is
thinning rapidly, with potential for opening up the rest of the northern
portion of the ice to melt, Csatho said. The ice sheet could start
flowing like a river out to the north if the edges thin rapidly enough.
The southeast part of the ice sheet is also melting at increasing
rates, Csatho reported. The data comes from satellites and NASA's
IceBridge campaign, which flies planes laden with instruments over both
the Arctic and Antarctic to fill a gap between the retirement of one
ice-monitoring satellite and the launch of another. (Dazzling Images from NASA's IceBridge)
While the southwest's famous Jakobshavn glacier
seems stable, researchers at the University of Texas at Dallas found
the Jakobshavn was rapidly thinning. The elevation change was 0.17
inches (4.34 millimeters) a year at the outlet glacier from IceBridge
data, which covers the past four years, said doctoral student Wenlu Qi.
Laser altimetry data indicates that the entire ice sheet continues to
thin even though snowfall over Greenland increased after the year 2000,
said Bill Krabill, principal investigator for NASA's Airborne
Topographic Mapper and a scientist at NASA's Wallops Flight Facility in
Wallops Island, Va.
"It's a consistent story. There are a few areas of thickening that are
taking place, but anytime you get to the edge of Greenland, you are
seeing thinning," he said.
Krabill, who works with NASA's IceBridge campaign,
said the space agency just agreed to "re-wing" or replace the wings on
the sturdy P-3 aircraft that flies for IceBridge. The IceBridge mission
will "keep on to an extent" after the launch of ICESAT-2 for specific
data collection and ICESat-2 data validation, NASA told OurAmazingPlanet
in a tweet.Themodified P-3 flies daily missions through mid-May out of
Thule and Kangerlussuaq, Greenland to measure sea and land ice.
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