From: Editor, ENN
Published October 24, 2012 03:15 PM
Melting Greenland
The Greenland ice sheet is a vast body of ice covering 660,235 square
miles, roughly 80% of the surface of Greenland. It is the second largest
ice body in the world, after the Antarctic Ice Sheet. The ice sheet is
almost 1,500 miles long in a north-south direction, and its greatest
width is 680 miles. The mean altitude of the ice is 7,005 feet. And it
is all melting. Freshwater losses in Greenland have accelerated since
the early 1990s, with the south-east of the island seeing losses rise by
50 per cent in less than 20 years, according to new research from the
University of Bristol.
"Greenland has been losing increasing amounts of mass. What had been
unclear was how much of that was due to losing water to the ocean, as
opposed to factors like reduced snowfall." stated Professor Jonathan
Bamber from the School of Geographical Sciences.
Such an increase in the volume of fresh water flowing into the Atlantic
could interfere with the Atlantic Meridional Overturning Circulation
(AMOC), the current that carries warm tropical water to northern
Europe. It could also reduce the ocean's ability to store carbon.
The Greenland Ice Sheet has experienced record melting in recent years
and is also likely to contribute substantially to sea level rise.
If the entire ice sheet were to melt, global sea levels would rise 23.6
feet. Recently, fears have grown that continued climate change will make
the Greenland Ice Sheet cross a threshold where long-term melting of the
ice sheet is inevitable. Climate models project that local warming in
Greenland will be 3 °C (5.4 °F) to 9 °C (16.2 °F) during this century.
Such a rise would inundate almost every major coastal city in the world.
Dumping fresh water into the North Atlantic could weaken the Atlantic
Meridional Overturning Circulation (AMOC), the vast "conveyor belt"
current that carries warm tropical water to northern Europe. It has been
suggested that Europe will get colder as a result, but that is unlikely
to happen, at least in the next few decades. "That was all blown out of
proportion," says Ruth Curry of the Woods Hole Oceanographic Institution
in Massachusetts.
The polar oceans are among the world's most important carbon sinks,
taking in carbon dioxide from the air and trapping it in their depths —
and that could change as a result of the freshwater flux. Curry says
Greenland's fresh water will remain at the surface, since the weakened
AMOC will be slow to carry it to the bottom. That also means that once
this fresh water has absorbed as much carbon dioxide as it can hold, it
will not be replaced at the surface by carbon-dioxide-free water that
could absorb more of the gas.
For further information see
Greenland Ice
Sheet.
Greenland image via Wikipedia.
©2012. Copyright Environmental News Network To
subscribe or visit go to: http://www.enn.com
|