March 12, 2012

Greenland Ice Sheet Nearing Point Of No Return, Scientists Warn

German and Spanish researchers have discovered that the Greenland ice sheet may be more vulnerable to the effects of global climate change than initially thought, and that temperatures may not have to rise much more before it could be lost for good.

According to Bloomberg reporter Alex Morales, scientists at the Complutense University in Madrid (UCM) and the Potsdam Institute for Climate Impact Research (PIK) are reporting that the ice sheet could lose its ability to grow if the global warming level reaches 1.6 degrees Celsius -- far less than the previous estimate of 3.1 degrees.

In a press release, the PIK reports that the threshold for complete melting of the ice sheet is in the 0.8 to 3.2 degree global warming range, with 1.6 degrees above pre-industrial temperature levels being the "best estimate." Currently, the planet has warmed an estimated 0.8 degrees over pre-industrial levels, they added, and the faster the world's temperature rises, the less time it will take before the ice in Greenland is lost forever.

"The more we exceed the threshold, the faster it melts," Alexander Robinson, a researcher affiliated with both institutions and the lead author of the study, which has been published in the journal Nature Climate Change, said in a statement Sunday. "This is not what one would call a rapid collapse. However, compared to what has happened in our planet's history, it is fast. And we might already be approaching the critical threshold."

"Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice sheet is a tipping element in the Earth system," added PIK's Andrey Ganopolski, head of the joint research team. "If the global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow -- even if the climate would, after many thousand years, return to its preindustrial state."

The scientists report that it would take 50,000 years to melt the sheet with 2 degrees of warming, according to Morales. At 4 degrees, the period required for it to disappear for be reduced to 8,000, and at 8 degrees, it would melt completely in just 2,000 years, he added.


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