Dangerous Arctic Ocean methane leak found

FAIRBANKS, Alaska, March 4 (UPI) -- U.S.-led scientists say part of the Arctic Ocean seafloor that holds vast stores of frozen methane has started leaking the gas into the Earth's atmosphere.

The international team of researchers warns the release of just a fraction of the methane stored in the shelf could trigger abrupt climate warming.

The scientists led by the University of Alaska-Fairbanks Assistant Professor Natalia Shakhova and Associate Professor Igor Semiletov say the frozen methane is becoming unstable because of the melting of permafrost under the East Siberian Arctic Shelf.

The scientists said their study suggests the permafrost that had long been thought to be an impermeable barrier has become perforated.

"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. "Subsea permafrost is losing its ability to be an impermeable cap."

Methane is a greenhouse gas more than 30 times more potent than carbon dioxide.

The East Siberian Arctic Shelf is a methane-rich area that encompasses more than 772,000 square miles of seafloor in the Arctic Ocean, more than three times as large as the Siberian wetlands that have been considered the primary Northern Hemisphere source of atmospheric methane.

"The climatic consequences of this are hard to predict," Shakhova said.

The research is reported in the journal Science.