Methane Hydrate Feedbacks Chapter in WWF International Arctic Programme Report

Wed, 11/04/2009 - 13:00
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In a recent report produced by the WWF International Arctic Programme, IARC scientists Natalia Shakhova and Igor Semiletov published key findings of their research on the powerful greenhouse effects of methane released into the atmosphere from destabilized ocean sediments and permafrost.

"Methane Hydrate Feedbacks" by Shakhova and Semiletov is chapter 6 of Arctic Climate Feedbacks: Global Implications, which documents the worldwide consequences of accelerated warming in the Arctic. "Acting as the Northern Hemisphere's refrigerator," the report's Executive Summary states," a frozen Arctic plays a central role in regulating Earth's climate system. A number of critical Arctic climate feedbacks affect the global climate system, and many of these are now being altered in a rapidly warming Arctic.

" Among the most significant of those feedbacks, as Shakhova and Semiletov report, is the release of methane, which contains more carbon than all the proven reserves of coal, oil, and natural gas in the world. Methane lies frozen in sediments and permafrost stored in Arctic continental shelf deposits. However, current temperatures are causing Arctic sub-sea permafrost to thaw. It then fails to seal off the hydrates, and methane, about 25 times more potent than carbon dioxide as a greenhouse gas, is released into the ocean waters. Because of the shallow depth of Arctic shelves, methane reaches the atmosphere un-oxidized (not changed into carbon dioxide).

The largest and shallowest percentage of methane deposits occurs on the East Siberian Shelf. Increased methane emissions have been observed there, but it is not yet known whether recent Arctic warming is responsible for the increase or how much the release of Arctic methane contributes to global atmospheric methane concentrations.

Arctic Climate Feedbacks: Global Implications is aimed principally at policy makers. The WWF International Arctic Programme web site is http://www.panda.org/arctic, and the Arctic climate feedbacks page is http://www.panda.org/arctic/climatefeedbacks.