The PhysOrg version of the story has more detail, including this somewhat worrying conclusion:A wide expanse of Arctic Ocean seabed is bubbling methane into the atmosphere. This is the first time that the ocean has been found to be releasing this powerful greenhouse gas into the atmosphere on this scale.
The discovery will rekindle fears that global warming might be on the verge of unlocking billions of tonnes of methane from beneath the oceans, which could trigger runaway climate change. The trouble is, nobody knows if the Arctic emissions are new, or indeed anything to do with global warming.
The East Siberian Arctic Shelf, in addition to holding large stores of frozen methane, is more of a concern because it is so shallow. In deep water, methane gas oxidizes into carbon dioxide before it reaches the surface. In the shallows of the East Siberian Arctic Shelf, methane simply doesn’t have enough time to oxidize, which means more of it escapes into the atmosphere. That, combined with the sheer amount of methane in the region, could add a previously uncalculated variable to climate models.
"The release to the atmosphere of only one percent of the methane assumed to be stored in shallow hydrate deposits might alter the current atmospheric burden of methane up to 3 to 4 times,” Shakhova said. “The climatic consequences of this are hard to predict.”
Update: On the other hand, the Christian Science Monitor's take on the story indicates that the current level of emissions is not so large on the global scale:
They are estimated at nearly 8 million metric tons a year, making them roughly equal to the amount that, until now, scientists had attributed to emissions from all the world's oceans combined, the researchers calculate. Still, the emissions represent no more than about 1 percent of total global emissions.I guess the worry is whether it is currently coming from thawing shallow hydrate deposits or not, and if it is, whether that will increase dramatically.
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