Word: permafrost
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...examined the financial consequences. The research team looked at the rate at which surfaces change from white ice and snow to ocean or exposed tundra, since darker surfaces absorb, rather than reflect, solar heat. According to the report, this shift and the increased methane emissions linked with melting permafrost currently slap us with annual losses in the range of $61 billion to $371 "resulting from such changes as heat waves and flooding." But the anticipated monetary fallout described in the study, expected to run deep into the trillions over the coming decades, may actually be conservative, as it does...
...calculations, points to the difficulty of coming up with accurate figures while climate science is still evolving. "It's a slow process," he says, noting that while there is documentation on rising sea levels, there are little data on such factors as methane release from melting permafrost, the impacts of ocean acidification, and the timing of the potential disintegration of the West Antarctic Ice Sheet. "We as social scientists can't [offer precise financial estimates] until we have reliable information from natural scientists. We will probably get better resolution over the next two decades." (See pictures of the effects...
...permafrost is on dry land either. The East Siberian Arctic Shelf, a vast expanse of shallow seafloor off Russia's northeast coast, was once wetland as well. It was submerged as melting glaciers drove sea level up at the end of the last ice age, but it still contains methane-rich permafrost, which Shakhova believes may now be becoming unstable. The numbers are not alarmingly large, she agrees, but what is worrisome is that no leakage was expected here. (See TIME's special report on the environment...
...changed, she thinks, may be that warmer water pouring into the sea from Siberia's north-flowing rivers have raised the sea-bottom temperature to the point where the methane, much of it stored under pressure in the form of methane hydrates, can begin to break free. Unlike the permafrost on land, says Shakhova, soil under the sea floor is always hovering at close to the melting point because of its proximity to unfrozen seawater. Anthropogenic (that is, human-caused) warming may be the last straw...
...undersea permafrost really is destabilizing rapidly, it could in principle lead to a catastrophic burp that would release a massive amount of methane in a short time. That's a big if. The problem is that nobody has ever taken such careful measurements in this part of the world before, says Heimann. We have satellites that do a remarkable job of observing methane emissions from land, he says, but they're not very accurate over water. So while he considers Shakhova's data absolutely convincing, he's less convinced that these emissions are necessarily new. "In the context...