[tw]

From ABC News:

Global Warming: Bubbling Up From Below dated 6 Sept 2006
What they found, and report in this week's issue of NATURE, worries them.

... Katey Walter and colleagues from the University of Alaska, Fairbanks, have been studying lakes in Siberia, which, historically, have spent much of the year frozen over.

When the lakes are not frozen, methane bubbles up from the bottom. Methane, you'll recall, is created as organic material decays. There's less methane than carbon dioxide--but molecule for molecule, methane is about 20 times more effective at trapping heat in the atmosphere.

Here's the problem Walter and her colleagues found: the amount of methane blubbling from those lakes may be five times as much as existing estimates--and there's likely to be more of it as the climate warms. ...

And Siberian lakes are only part of the problem. There's permafrost all over northern Canada, the northern reaches of Europe, etc., that's not so permanently frosty anymore. The northern tundra may be less diverse than, say, tropical rainforests, but scientists say there's about as much organic material there.