Sharon April 17th, 2008
“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.”
And for good measure:
“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.”
An older report on the potential problem reports:
“But calculations by Dr Sitch and his colleagues show that even if methane seeped from the permafrost over the next 100 years, it would add around 700m tonnes of carbon into the atmosphere each year, roughly the same amount that is released annually from the world’s wetlands and agriculture.
It would effectively double atmospheric levels of the gas, leading to a 10% to 25% increase in global warming, he said.”
There is, of course, no evidence whatsoever that the release couldn’t take place quite rapidly - over years or decades. BTW, the last time the methane was released, half the life on earth died.
Of course, the odds can’t be more than 50-50 that’ll happen this time, so why worry?