Some very frightening news from the world of climate science, as an international scientific team discovers that the Arctic permafrost in Siberia may be starting to leak huge amounts of methane into the atmosphere.

And if this proves to be true, my friends, it will put every other concern of human beings on the back burner.

One of the greatest concerns and large unknowns in climate science has been the potential impact of methane trapped and frozen in the polar regions of the planet, particularly in the Arctic permafrost. If climate change causes the methane to be released, the gas could start a positive feedback reaction that could trigger abrupt climate warming.

Until now no evidence of such a mechanism has been seen, but an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov say this change is under way—in a little-studied area under the sea, the East Siberian Arctic Shelf, west of the Bering Strait.

The East Siberian Arctic Shelf, a methane-rich area that encompasses more than 2 million square kilometers of seafloor, was long thought to be an impermeable barrier sealing in the methane, but Shakhova and Semiletov team states that it is in fact perforated and starting to leak large amounts of methane into the atmosphere.

“The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world’s oceans,” said Shakhova, a researcher at UAF’s International Arctic Research Center. “Subsea permafrost is losing its ability to be an impermeable cap.”

Methane is more than 30 times more potent than carbon dioxide as a greenhouse gas. It is released from previously frozen soils in two ways. When the organic material (which contains carbon) stored in permafrost thaws, it begins to decompose and, under anaerobic conditions, gradually releases methane. Methane can also be stored in the seabed as methane gas or methane hydrates and then released as subsea permafrost thaws. These releases can be larger and more abrupt than those that result from decomposition.

The East Siberian Arctic Shelf is more than three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. Shakhova’s research results show that the East Siberian Arctic Shelf is already a significant methane source, releasing 7 teragrams of methane yearly, which is as much as is emitted from the rest of the ocean. A teragram is equal to about 1.1 million tons.

“Our concern is that the subsea permafrost has been showing signs of destabilization already,” she said. “If it further destabilizes, the methane emissions may not be teragrams, it would be significantly larger.”

UPDATE at 4/8/10 6:54:12 pm:

RealClimate says it’s not time to get frightened. Yet. RealClimate: Arctic Methane on the Move?