Methane is a potent greenhouse gas; its heat-trapping effect is more than 30 times that of carbon dioxide. In the seabed, it’s often stored as gas or as methane hydrates, and is kept contained by the sub-sea permafrost. However, when this permafrost thaws, it can allow the methane to escape.
A team led by Natalia Shakhova of the University of Alaska Fairbanks has been making twice-yearly expeditions to the Arctic to monitor the state of the sub-sea permafrost and the amount of methane being released. Their results indicate that the permafrost on the East Siberian Arctic Shelf has thawed more than previously thought, in part due to warming water near the sea floor. This has allowed more methane to escape than models had estimated. The shelf is venting at least 17 million tonnes of methane into the atmosphere each year, they found.
‘It’s now on a par with the methane being released from the Arctic tundra, which is considered to be one of the major sources of methane in the Northern Hemisphere,’ Shakhova said. ‘We believe that the release of methane from the Arctic, and in particular this part of the Arctic, could affect the entire globe.’
This story was published in the January 2014 edition of Geographical Magazine
