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
00:01We're out standing on a frozen lake in interior Alaska, outside of the University of Alaska
00:06Fairbanks campus, and this ice is already about 20 centimeters thick, so as it's been
00:14freezing up, methane gas has been coming out of the bottom of the lake and getting trapped
00:18in the lake ice.
00:19If you look at the shore, you can see that there are lots of trees that are falling in
00:23the lake and they're dying.
00:24What's happening is the permafrost is thawing, and the ice that was in the ground, when it
00:29melts, causes the ground surface to collapse.
00:31When the forest falls in and any organic matter, dead plant and animal remains that were in
00:38the permafrost, thaw out in the bottom of the lake, microbes decompose it and it generates
00:44methane.
00:45And methane doesn't like to stay in water, in solution.
00:49It forms bubbles, and those bubbles make their way to the surface.
00:52In 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, and the bubbles
01:01get 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.
01:13Methane is a very potent greenhouse gas.
01:15A molecule of methane is 25 times stronger than carbon dioxide.
01:19Methane 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, and the potential for that permafrost
01:37to thaw in the future, we estimate that more than 10 times the amount of methane that's right
01:42now in the atmosphere will come out of these lakes.
01:49So let's see if we want to see that more of these lakes.