More carbon in the Arctic than previously thought 1

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   econdemocracy Posted 3:44 pm
   09 Jun 2008

   Disturbing discoveries in Russia, redux"It's always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor -- hard clumps of ice and methane, conserved by freezing temperatures and high pressure -- could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will."
   ">In the permafrost bottom of the
   
   200-meter-deep sea, enormous stores of gas hydrates lie dormant in
   
   mighty frozen layers of sediment. The carbon content of the
   
   ice-and-methane mixture here is estimated at 540 billion tons."
   "This submarine hydrate was considered stable until now," says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.
   The permafrost has grown porous, says Shakhova, and already the shelf sea has become "a source of methane passing into the atmosphere." The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet's atmosphere would increase twelvefold. "The result would be catastrophic global warming," say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.
   "hakhova and her colleagues gathered evidence for the loss of rigor in the frozen sea floor in a measuring campaign during the Siberian summer. The seawater proved to be "highly oversaturated with solute methane," reports Shakhova. In the air over the sea, greenhouse-gas content was measured in some places at five times normal values. "In helicopter flights over the delta of the Lena River, higher methane concentrations have been measured at altitudes as high as 1,800 meters," she says.
   The methane climate bomb is also ticking on land: A few years ago researchers noticed higher concentrations of methane in northern Siberia. "
   ..No one can say right now whether that will take years, decades or hundreds of years," she said. But one cannot rule out sudden methane emissions. They could happen at "any time."
   One thing is clear, though: The thawing of the Arctic sea floor will create "new potential sources for methane ... which no one had reckoned with until now," said Laurence Smith, a professor for geography at the University of California in Los Angeles.."
   http://www.spiegel.de/international/world/0,1518,547976,0 ...
   
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