Thawing permafrost has released so much methane into Esieh Lake near Fairbanks, Alaska that the air above it is flammable.
Credit: Katey Walter Anthony/ University of Alaska Fairbanks
Credit: Katey Walter Anthony/ University of Alaska Fairbanks
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TechTranscript
00:00We're out standing on a frozen lake in interior Alaska, outside of the University of Alaska Fairbanks campus,
00:07and this ice is already about 20 centimeters thick.
00:12So as it's been freezing up, methane gas has been coming out of the bottom of the lake and getting trapped in the lake ice.
00:19If you look at the shore, you can see that there are lots of trees that are falling in the lake and they're dying.
00:24What's happening is the permafrost is thawing,
00:27and the ice that was in the ground, when it melts, causes the ground surface to collapse.
00:32When the forest falls in and any organic matter, dead plant and animal remains that were in the permafrost,
00:39thaw out in the bottom of the lake, microbes decompose it and it generates methane.
00:45And methane doesn't like to stay in water and solution.
00:49It forms bubbles and those bubbles make their way to the surface.
00:53In the summertime, the bubbles pop and they enter the atmosphere.
00:56In the winter, however, this ice forms a cover on the surface of the lake.
01:01Bubbles get trapped right under the ice and then the ice thickens and freezes around them.
01:06So what we have out here is like a time-lapse photograph of methane emissions from the lakes.
01:12Methane is a very potent greenhouse gas.
01:16A molecule of methane is 25 times stronger than carbon dioxide.
01:21Methane is formed in millions of lakes around the Arctic where permafrost is thawing.
01:28And each year, these lakes are emitting already tremendous amounts of methane.
01:32But when we look at how much carbon is in permafrost still frozen,
01:36and the potential for that permafrost to thaw in the future,
01:39we estimate that more than 10 times the amount of methane that's right now in the atmosphere will come out of these lakes.
01:50NASA Jet Propulsion Laboratory, California Institute of Technology