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Friday, February 01, 2013

Even in Winter, the Arctic Heats Up

Why worry about methane?

Seeping methane is worrisome because it is a potent greenhouse gas. Melanie Engram, a researcher at the University of Alaska and a colleague of Walter Anthony’s said, “Methane is twenty-five to twenty-eight times more effective at retaining heat as carbon dioxide.” Engram is one of the researchers working with Walter Anthony to figure out how to measure the amount of methane now seeping out. When scientists model the effects of greenhouse gases, they need to account for as many sources of a gas as possible, now including these seeps. “Currently there is no quantification for these lakes in the methane budget,” Engram said. “One of the most exciting aspects of this project is investigating the use of synthetic aperture radar (SAR) satellite imagery, provided by NASA through the Alaska Satellite Facility, to quantify methane bubbles trapped by lake ice.” SAR remote sensing, which can image through clouds and at night, is a tool well-suited for monitoring northern landscapes during dark Arctic winters. Satellite remote sensing is valuable for providing images of remote Arctic regions that would otherwise be too logistically difficult or expensive to observe.

And as permafrost warms and glaciers recede across the Arctic, the frozen cap locking methane underground will continue to thaw. Scientists are still trying to understand the extent of seeping methane. If thawing continues, Walter Anthony estimates that more than ten times the amount of methane currently in the atmosphere may bubble up out of the lakes. More methane could fuel the feedback loop that further warms the Arctic and the global atmosphere.

Reference

Walter Anthony, K. 2009. Methane: A menace surfaces. Scientific American 301: 68-75
doi:10.1038/scientificamerican1209-68