It's always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor -- hard clumps of ice and methane, conserved by freezing temperatures and high pressure -- could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will.
Russian polar scientists have strong evidence that the first stages of melting are underway. They've studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.
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The permafrost has grown porous, says Shakhova, and already the shelf sea has become "a source of methane passing into the atmosphere."
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Data from offshore drilling in the region, studied by experts at the Alfred Wegener Institute for Polar and Marine Research (AWI), also suggest that the situation has grown critical. AWI's results show that permafrost in the flat shelf is perilously close to thawing. Three to 12 kilometers from the coast, the temperature of sea sediment was -1 to -1.5 degrees Celsius, just below freezing. Permafrost on land, though, was as cold as -12.4 degrees Celsius. "That's a drastic difference and the best proof of a critical thermal status of the submarine permafrost," said Shakhova.
Paul Overduin, a geophysicist at AWI, agreed. "She's right," he said. "Changes are far more likely to occur on the sea shelf than on land."
I look forward to reading this research when published. It certainly makes intuitive sense that given the recent loss of sea ice north of Siberia that this relatively shallow shelf would be thawing. Given methane's powerful greenhouse effect, this is disturbing.
