Saturday, February 23, 2013

Siberia could experience widespread permafrost thaw due to global warming

Lee Rannals in RedOrbit: More evidence is pointing to the nightmare scenario that global warming is taking a toll on our planet. Oxford University scientists say that a global temperature rise of 2.7 degrees Fahrenheit could thaw the ground over a large area of Siberia, threatening the release of carbon from soil.

If the thawing of Siberia’s permafrost occurs, it could see that over 1,000 gigatons of the greenhouse gases carbon dioxide and methane are dished out into the atmosphere, adding an even larger global warming threat.

The scientists studied stalactites and stalagmites from caves located along the permafrost frontier in Siberia, where the ground stays permanently frozen in a layer of tens to hundreds of feet thick. Because these cave features only grow when liquid rainwater and snow melt drips into the caves, these formations record 500,00 years of changing permafrost conditions.

Records from 400,000 years ago show that a global warming of 2.7 degrees Fahrenheit is enough to cause substantial thawing of permafrost far north from its present-day southern limit.

“The stalactites and stalagmites from these caves are a way of looking back in time to see how warm periods similar to our modern climate affect how far permafrost extends across Siberia,” lead author Dr Anton Vaks of Oxford University’s Department of Earth Sciences, said in a statement. “As permafrost covers 24 percent of the land surface of the Northern hemisphere significant thawing could affect vast areas and release gigatonnes of carbon.”...

Permafrost in South Gydan, Siberia, shot by Skonstantinov09, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license 

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