Word: shakhova
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...data, it isn't always clear what it means. That's very much the case with a new paper about methane emissions, published Thursday in Science. Based on a series of expeditions to the margins of the Arctic Ocean by ship and helicopter, University of Alaska researcher Natalia Shakhova and her colleagues report that methane, a greenhouse gas that is 30 times more effective in trapping heat in the atmosphere than carbon dioxide, is bubbling up from the continental shelf and leaking into the atmosphere. The estimated total: 8 teragrams - that's 8 trillion grams - per year. (See pictures...
...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...
...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...
...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 of the global methane cycle, has this been accelerating recently, or has it been going on for some time?" Heimann says. "It may be related to recent Arctic warming, but I don't know...
| 1 |