Fears that the thawing of Arctic permafrost from global warming could release climate-tipping volumes of methane into the atmosphere may be unfounded, a new study suggests.
Canadian scientists say the vast areas of frozen soil lying beneath the surface of Canada, Siberia, Alaska and Greenland appear to have survived significant temperature swings before. After studying the soils in Canada’s Yukon they say that over the past three-quarters of a million years surface temperatures have at times risen to high levels without the tundra below thawing.
The world’s permafrost layer holds up to 950 billion tonnes of methane, a greenhouse gas which has 23 times the
global warming potential of carbon dioxide if release into the atmosphere. At this volume, it would dwarf the impact of burning the entire known reserves of coal, oil and gas if released.
Scientists are concerned that if the global warming already occurring triggered such an event, the world could be subjected to runaway climate change that could not be stopped.
But Duane Froese, leading a team from the University of Alberta, says their study to published in the journal Science this week “highlights the resilience” of the tundra. “Permafrost and associated carbon reservoirs that are more than a few meters below the surface may be more stable than previously thought,” they conclude.
Bloomberg 18/9/08
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