|Manu||Date: Thursday, 15-December-2016, 5:26 PM | Message # 1|
|Mysterious 'crater' on Antarctica indication of vulnerable ice sheet (Update)|
December 12, 2016 by Marlowe Hood
East Antarctica's massive ice sheet may be more exposed to global warming than long assumed, according to a study Monday that shows how strong winds can erode ice shelves that help hold it in place.
There is enough frozen water sitting on top of the world's polar continent to raise sea level by dozens of metres and redraw the world map if it melts.
But understanding the dynamics of the region—which includes the much smaller West Antarctica ice sheet—has proven difficult.
Up to now, scientists have focused on the threat of West Antarctica.
Recent studies have suggested that climate change may already have condemned large chunks of its ice sheet to disintegration, whether on a time scale of centuries or millennia.
In contrast, ice covering East Antarctica was seen as far more stable, even gaining mass.
The floating, cliff-like ice shelves straddling land and ocean that prevent inland ice from slipping into the sea, it was thought, were solidly anchored.
That remains largely true. But a mysterious crater on the King Baudoin ice shelf, due south from the tip of Africa, prompted a team of researchers from the Netherlands, Belgium and Germany to challenge that assumption.
"Our research has shown that East Antarctica is also vulnerable to climate change," said Jan Lenaerts, lead author of the study and a researcher at Utrecht University in the Netherlands.
The findings were published in the journal Nature Climate Change.
Some reports had attributed the crater to a meteorite impact, but when Lenaerts and his team arrived in January they realised the water-filled cavity had other origins.
Combining climate models, satellite data and on-site measurements, they concluded that strong winds carrying warm air were blowing away reflective snow, allowing the Sun's rays to be absorbed into the darker ice rather than bounced back into space.
Read more/fullarticle/source - http://phys.org/news....le.html