This image is from the Univ. of Alaska presentation excerpted below:
UPDATE JANUARY 21, 2012: Arctic Methane Release - now described as a "known UnKnown" by John Mason of Skeptical Science.  See Dr. Natalia Shakova's latest paper HERE - Large episodic Arctic methane loss continues to threaten life as we know it as part of a positive feedback system!  This paper is reviewed and many helpful comments are to be found at Skeptical Science - Part One, and a recent email interview with Dr. Shakova by Skeptical Science - Part 2

Before reading any further download James Hansen's new paper: http://www.columbia.edu/~jeh1/mailings/2011/20110505_CaseForYoungPeople.pdf, or get it from the list at the end of this page "The Case for Young People" dated May 5, 2011.

Alan Page is not a climate change scientist.  But the following details of recent extensive study of the Siberian Sea and the permafrost around it are a cause for extreme unease!

A few notes about methane:  The methane atmospheric residence time is around twelve years due to systematic UV conversion of methane to CO2 in the upper atmosphere.  This conversion changes methane (CH4) into one molecule of carbon dioxide and two water molecules.  Over a hundred year period at average methane release rates the average methane green house gas (ghg) effect is about 25 times that of carbon dioxide.  However, the short term green house gas effect is ~100 times that of carbon dioxide.  If the methane release is in a positive feed back loop as described below, there are significant questions raised about how long we have before the relative methane ghg effects surpass those of carbon dioxide.  Satellite based atmosphere analysis suggests that atmospheric methane concentration is growing at 7% per year (or doubling every ten years) while the CO2 concentration is growing at 0.7% per year.  The major question posed here is: If the ghg effects of methane are rising very fast, once this crossover of relative effects occurs, what good will attempts at containment or reduction of carbon dioxide have?  Is it possible that we have a very short period to get control of methane releases before whatever we do will no longer matter?  This is a question we can only pose, but the past history of correct impressions does not bode well for the future.

The following is an excerpt from a report issued by the University of Alaska (the full text is available in the file 20100303192545.html below.

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Shakhova notes that Earth's geological record indicates that atmospheric methane concentrations have varied between about .3 to .4 parts per million during cold periods to .6 to .7 parts per million during warm periods. Current average methane concentrations in the Arctic average about 1.85 parts per million, the highest in 400,000 years, she said. Concentrations above the East Siberian Arctic Shelf are even higher.

The East Siberian Arctic Shelf is a relative frontier in methane studies. The shelf is shallow, 50 meters or less in depth, which means it has been alternately submerged or terrestrial, depending on sea levels throughout Earth’s history. During Earth's coldest periods, it is a frozen arctic coastal plain, and does not release methane. As the planet warms and sea levels rise, it is inundated with seawater, which is 12-15 degrees warmer than the average air temperature.

"It was thought that seawater kept the East Siberian Arctic Shelf permafrost frozen," Shakhova said. "Nobody considered this huge area."

Earlier studies in Siberia focused on methane escaping from thawing terrestrial permafrost. Semiletov's work during the 1990s showed, among other things, that the amount of methane being emitted from terrestrial sources decreased at higher latitudes. But those studies stopped at the coast. Starting in the fall of 2003, Shakhova, Semiletov and the rest of their team took the studies offshore. From 2003 through 2008, they took annual research cruises throughout the shelf and sampled seawater at various depths and the air 10 meters above the ocean. In September 2006, they flew a helicopter over the same area, taking air samples at up to 2,000 meters in the atmosphere. In April 2007, they conducted a winter expedition on the sea ice.

They found that more than 80 percent of the deep water and greater than half of surface water had methane levels more than eight times that of normal seawater. In some areas, the saturation levels reached at least 250 times that of background levels in the summer and 1,400 times higher in the winter. They found corresponding results in the air directly above the ocean surface. Methane levels were elevated overall and the seascape was dotted with more than 100 hotspots. This, combined with winter expedition results that found methane gas trapped under and in the sea ice, showed the team that the methane was not only being dissolved in the water, it was bubbling out into the atmosphere.

These findings were further confirmed when Dr. Shakhova and her colleagues sampled methane levels at higher elevations. Methane levels throughout the Arctic are usually 8 to 10 percent higher than the global baseline. When they flew over the shelf, they found methane at levels another 5 to 10 percent higher than the already elevated arctic levels.

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