Permafrost GHG emission slow, prolonged

A team of scientists has evaluated research into the emission of greenhouse gases from thawing Arctic and sub-Arctic permafrost and has concluded that the emission will be slow and prolonged, rather than taking place suddenly, as a “carbon bomb,” as thought a couple of decades ago, according to a paper published in the journal Nature on April 8. According to a U.S. Geological Survey press release, permafrost soils contain twice as much carbon as exists in the atmosphere, thus raising the possibility of elevating carbon dioxide and methane levels in the air as microbes act on organic material when the frozen soil thaws. The release of carbon in this way can lead to what is referred to as a positive feedback loop, an acceleration in global warming as the warming expels increased amounts of warming gas.

Vladimir Romansky, a permafrost expert from the University of Alaska Fairbanks Geophysical Institute and a co-author of the Nature paper, has said that the average temperature of permafrost in Alaska, Russia and other Arctic regions has increased from almost 18 F to just over 28 F in the last 30 years. But, although the eventual melting of the permafrost will release carbon, that release will be relatively gradual, the Nature paper says.

“Twenty years ago there was very little research about the possible rate of permafrost carbon release,” said co-author A. David McGuire, a senior scientist with the U.S. Geological Survey’s Alaska Cooperative Fish and Wildlife Research Unit and a climate modeling expert with the Institute of Arctic Biology at the University of Alaska Fairbanks. “In 2011, we assembled an international team of scientists into the Permafrost Carbon Network to synthesize existing research and answer the questions of how much permafrost carbon is out there, how vulnerable to decomposition it is once it’s thawed, and what are the forms in which it’s released into the atmosphere.”

- Alan Bailey