One quarter of Alaska permafrost could melt by 2100 – US Geological Survey
Source: The Guardian
One quarter of Alaska permafrost could melt by 2100 – US Geological Survey
Oliver Milman
Wednesday 9 December 2015 18.23 GMT
Up to a quarter of the permafrost that lies underneath the surface of Alaska could melt by the end of the century, spewing long-held carbon into the atmosphere and helping accelerate climate change, US government scientists have predicted.
The US Geological Survey used satellite and on-ground data to estimate that 38% of mainland Alaska has permafrost, a band of soil, rock or sediment that is frozen underground for at least two consecutive years. In Fairbanks, Alaska, the soil has been frozen for several thousand years at just 30 to 40cm underground, with only the upper level of soil thawing every summer before freezing again in winter.
But this icy mass is now under threat from warming temperatures. Under scenarios calculated by USGS, 16% to 24% of Alaska’s permafrost will disappear by the end of the century under varying climate change outcomes. The declines are expected to be sharper in the heavily forested central areas of Alaska, rather than the state’s north.
“Increasing air temperatures have led to widespread thawing and degradation of permafrost, which in turn has affected ecosystems, socioeconomics, and the carbon cycle of high latitudes,” the USGS study states. “Taken together, these results have obvious implications for potential remobilization of frozen soil carbon pools under warmer temperatures.”
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Read more: http://www.theguardian.com/us-news/2015/dec/09/alaska-permafrost-melting-us-geological-survey-study