Warming Arctic Permafrost Fuels Climate Change Worries - NYTimes.com
This haunts my thoughts:
Thawing has been most notable at the southern margins. Across huge areas, including much of central Alaska, permafrost is hovering just below the freezing point, and is expected to start thawing in earnest as soon as the 2020s. In northern Alaska and northern Siberia, where permafrost is at least 12 degrees Fahrenheit below freezing, experts say it should take longer.
“Even in a greenhouse-warmed world, it will still get cold and dark in the Arctic in the winter,” said Mark Serreze, director of the snow and ice data center in Boulder.
Scientists need better inventories of the ancient carbon. The best estimate so far was published in 2009 by a Canadian scientist, Charles Tarnocai, and some colleagues. They calculated that there was about 1.7 trillion tons of carbon in soils of the northern regions, about 88 percent of it locked in permafrost. That is about two and a half times the amount of carbon in the atmosphere.
Philippe Ciais, a leading French scientist, wrote at the time that he was “stunned” by the estimate, a large upward revision from previous calculations.
“If, in a warmer world, bacteria decompose organic soil matter faster, releasing carbon dioxide,” Dr. Ciais wrote, “this will set up a positive feedback loop, speeding up global warming.”
