UAF – 2010 – Hunting for methane with Katey Walter Anthony

We’re out standing on a
frozen lake in interior Alaska outside of the University
of Alaska, Fairbanks campus. And this ice is already
about 20 centimeters thick, so 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. If you look at
the shore, you can see that there are lots of trees
that are falling in the lake and they’re dying. What’s happening is the
permafrost is thawing, and the ice that was in
the ground when it melts, causes the ground
surface to collapse. When the forest falls in and
any organic matter, dead plant and animal remains that
were in the permafrost, fall out in the
bottom of the lake, microbes decompose it
and it generates methane. And methane doesn’t like to
stay in the water in solution. It forms bubbles
and those bubbles make their way to the surface. In the summertime,
the bubbles pop and they enter the atmosphere. In the winter,
however, this ice forms a cover on the
surface of the lake and the bubbles get trapped
right under the ice. And the ice thickens
and freezes around them. So what we have out here is
like a time lapse photograph of methane emissions
from the lakes. Methane is a very
potent greenhouse gas. A molecule of methane
is 25 times stronger than carbon dioxide. Whoa! Methane is formed in millions
of lakes around the Arctic where permafrost is thawing,
and each year these lakes are emitting already
tremendous amounts of methane. But when we look
at how much carbon is in permafrost still
frozen and the potential for that permafrost
to thaw in the future, we estimate that more than 10
times the amount of methane that’s right now
in the atmosphere will come out of these lakes.

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