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SOURCE: New York Times

DATE: August 23, 2017

SNIP: In Alaska, nowhere is permafrost more vulnerable than here, 350 miles south of the Arctic Circle, in a vast, largely treeless landscape formed from sediment brought down by two of the state’s biggest rivers, the Yukon and the Kuskokwim. Temperatures three feet down into the frozen ground are less than half a degree below freezing. This area could lose much of its permafrost by midcentury.

That, said Max Holmes, senior scientist and deputy director of the research center, “has all kinds of consequences both locally for this region, for the animals and the people who live here, as well as globally.”

Even in colder northern Alaska, where permafrost in some parts of the North Slope extends more than 2,100 feet below the surface, scientists are seeing stark changes. Vladimir E. Romanovsky, a permafrost researcher at the University of Alaska, Fairbanks, said that temperatures at a depth of 65 feet have risen by 3 degrees Celsius (about 5.5 degrees Fahrenheit) over decades.

Near-surface changes have been even greater. At one northern site, he said, permafrost temperatures at shallow depths have climbed from minus 8 degrees Celsius to minus 3.

But Dr. Romanovsky said that his and others’ work shows that permafrost “is not as stable as people thought.”

Already, thawing permafrost and warmer temperatures are being blamed for rising carbon emissions in the Alaskan tundra, both here and farther north. In a study earlier this year, researchers found that bacterial decomposition of thawed permafrost, as well as carbon dioxide produced by living vegetation, continues later into the fall because freezing of the surface is delayed.

The rise in emissions has been so significant, the researchers found, that Alaska may be shifting from a sink, or storehouse, of carbon, to a net source.