Permafrost Thaw Will Cause Faster Warming than Previous Estimates

A survey of 41 international experts on permafrost shows that the amount of greenhouse gases released as frozen soils melt in a warming world will be 1.7 to 5.2 times larger than previous estimates. In the survey, published in the journal Nature, the scientists significantly raised their estimates of the impact of melting permafrost because recent studies have shown that permafrost in Arctic and sub-Arctic regions holds far more organic carbon, and at greater depths, than previously thought. As these frozen soils melt, they will release large quantities of methane, a far more potent greenhouse gas than carbon dioxide. University of Florida scientist Edward Schuur, lead author on the paper, said that northern soils store more organic carbon than all living things combined and hold four times more carbon than all the carbon ever released by modern human activity. Thawing permafrost will release about as many greenhouse gases as those caused by deforestation, which accounts for about 15 percent of human-caused carbon emissions.