NEW YORK: A 700 square kilometer ice sheet in Amundsen Sea Embayment in Antarctica has thinned over the last few decades, mostly on account of global warming and contributing to sea level rise, climate scientists and polar experts said at a recent meeting.
Experts from various disciplines from the United States and Britain met at the Jackson School of Geosciences in Austin, Texas, to discuss the fate of the world's largest fresh water reservoir, the West Antarctic Ice Sheet, and concluded that there is evidence to show "surprisingly rapid changes" occurring in Amundsen Sea Embayment, which is the size of Texas, and felt more studies are required to know how fast the ice sheet is melting and to what extent the seal levels would rise.
In a statement at the end of the meeting, the scientists said the melting of ice could be the result of changing winds in the region, which is leading to flow of warmer waters underneath the ice shelves.
The wind change, they said, appeared to be the result of several factors, including global warming, ozone depletion in the atmosphere and natural variability.
The Antarctic Ice Sheet is two miles thick and spreads under its own weight, flowing down to the sea with icebergs breaking from the edges of the shelves. The thinning of the ice shelf has been noticed in satellite pictures, but it is not clear how much ice has been lost.
The scientists say ice concentration in Amundsen Sea Embayment is enough to raise world sea levels by six meters.
The scientists specifically noted that:
-- while average warming of the global ocean has not yet notably affected the waters reaching the base of the ice shelves, recent changes in winds around Antarctica, caused by human influence and/or natural variability, could be the cause for changing ocean currents, which moves warmer waters under the ice shelves.
-- too much melting beneath the ice shelves may lead to “runaway” thinning of the grounded ice sheet. While it is not possible to know when and how rapidly this will happen with the current understanding of the phenomenon, there is possibility that sea level could rise several feet over a few centuries.
-- new satellite, ground, and ship-based observations, along with improved models of the ice-ocean-atmosphere system, will be needed to reduce the very large uncertainties concerning the behavior of the Antarctic ice in the Amundsen Sea Embayment.
