Study Warning of Massive Release of Methane From Melting Ice Not Without Critics
Controversy has erupted over a recent study examining the greenhouse gases emitted through the melting of Arctic ice.
Published in the journal Nature, the report warned that the estimated 50 gigatons of methane trapped inside the East Siberian Arctic Shelf is likely to be released within the next several decades as it thaws, causing an estimated $60 trillion in costs to countries everywhere due to resulting extreme weather.
The authors of the study, which included Chris Hope and Peter Wadhams of the University of Cambridge and Gail Whiteman of Erasmus University, reported using the well established PAGE09 model developed to calculate the impacts of climate change and the costs of mitigation and adaptation measures.
All told, the model was run 10,000 times in an effort to minimize room for error as much as possible, the scientists said.
However, NASA's Gavin Schmidt of the Goddard Institute for Space Studies says he's not convinced.
"The paper says that their scenario is 'likely,'" he told LiveScience. "I strongly disagree."
Schmidt argues that evidence points to two periods -- one 8,000 years ago and the other 125,000 years ago -- during which summer sea ice was reduced, suggesting that the methane-release mechanism could have happened then. However, missing from ice core records dating back to both of these periods is evidence of any such an event.
"It might be a small thing that we can't detect, but if it was large enough to have a big climate impact, we would see it," he said.
David Archer, a climate scientist at the University of Chicago, is another critic of the study who argues such a mechanism by which large quantities of methane gas are released from seafloor sediments into the atmosphere has yet to be proposed.
"It has to be released within a few years to have much impact on climate, but the mechanisms for release operate on time scales of centuries and longer," he told LiveScience in an email.
Standing up for the study is Wadhams who wrote on his university's site that the "mechanism which is causing the observed mass of rising methane plumes in the Eastern Siberian Sea is itself unprecedented, and the scientists who dismiss the idea of extensive methane release in earlier research were simply not aware of the new mechanisms causing it."
With the ice disappearing and the temperature of the water rising, Wadhams argues that "the heat content reaching the seabed can melt the frozen sediments at a rate that was never before possible."