December 1, 2011
Melting Permafrost Amplifies Global Warming Effect
According to a survey published in the November 30 issue of the journal Nature, melting permafrost in the northern climes is releasing large amounts of methane and carbon, amplifying the global warming effect.
When permafrost melts, long dormant microbes come alive and break down the organic matter underneath the layers of frozen soil creating methane. Methane gas has 2.5 times the effect on the atmosphere than carbon dioxide, creating a greater warming effect.
The survey, led by Edward Schuur from the University of Florida and graduate student Benjamin Abbott from the University of Alaska Fairbanks asked climate scientists what percentage of the permafrost will thaw, how much carbon will be emitted and how much of that carbon is methane. The researchers estimate by 2100 that the amount of carbon released from these largely untapped stores of carbon will be 1.7 to 5.2 times larger than recent modeling studies show.
According to Abbott, “The larger estimate is due to the inclusion of processes missing from current models and new estimates of the amount of organic carbon stored deep in frozen soils. There´s more organic carbon in northern soils than there is in all living things combined; it´s kind of mind boggling.”
According to estimates there are 1,700 gigatons of organic carbon stored within the northern soils, four times more than all the carbon ever emitted by modern human activity and twice that currently being held in the atmosphere.
Current models of permafrost melting assume the air above the ground will cause the soil to melt, but the models miss processes where abrupt thawing melts an underground ice wedge that causes the ground to collapse, creating thermokarsts and accelerating the thawing of the ice in the ground.
Schuur says, “This survey is part of the scientific process, what we think is going to happen in the future, and how we come up with testable hypotheses for future research. Our survey outlines the additional risk to society caused by thawing of the frozen North and the need to reduce fossil fuel use and deforestation.”
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