Are Alaska’s wildfires accelerating global warming?

From Alaska Dispatch, Sunday, December 12, 2010:

A series of warmer summers and drier springs in Interior Alaska has forced wildfires to burn deeper into the region’s ancient peat, releasing far more carbon dioxide into the air than previously thought, according to a new study by a team of scientists.

The longer-burning fires, and longer burn season, has dramatically increased the release into the atmosphere of carbons stored over eons by Alaska’s black spruce ecosystem, a dynamic that threatens to accelerate global warming even more.

The result may be a climate game-changer.

Alaska’s boreal forests — long thought to be one of the Arctic’s main carbon sinks and a stabilizing influence against global warming — have begun to spew out more greenhouse gas than they take in, according to a study by University of Guelph plant biologist Merritt Turetsky, of Ontario, Canada, and six other researchers.

“Essentially this could represent a runaway climate change scenario in which warming is leading to larger and more intense fires, releasing more greenhouse gases and resulting in more warming,” said lead author Turetsky, in a release about the study, to be published in Nature Geoscience. “This cycle can be broken for a number of reasons, but likely not without dramatic changes to the boreal forest as we currently know it.”

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