Thawing Permafrost — Changing Planet


ANNE THOMPSON, reporting: You can’t see it, but it’s here. In Alaska,
in Greenland, and in Siberia. Permafrost: frozen ground that’s so cold, it stays frozen
even during the summer. Dr. VLADIMIR ROMANOVSKY (University of Alaska
Fairbanks): Permafrost is any earth material under ground surface, which at or below zero
degrees Celsius for two or more consecutive years. JOHN DANCY (in 1975 NBC News Clip): Approximately
fifty percent of the Soviet Union is on permafrost, ground that never thaws completely. THOMPSON: Some permafrost has been frozen
solid for thousands of years. But not anymore. Because of a warming climate, permafrost is
warming, too, challenging the people who build on it and live on it, and accelerating global
warming even more. [MAP] Permafrost makes up nearly a quarter
of all the land in the northern hemisphere, about 8.8 million square miles. In some places,
like Siberia, the ground is frozen a thousand feet deep or more. In Interior Alaska, the
permafrost dates back to the last glacial cycle. Dr. MATTHEW STURM (U.S. Army Corps of Engineers
Cold Regions Research and Engineering Laboratory, Alaska): Were at least 30,000 years here. THOMPSON: Ten miles north of Fairbanks, the
U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Lab operates a tunnel
where scientists can research permafrost: its geological properties and the fossils
frozen in its walls. Dr. Matthew Sturm is their chief scientist in Alaska. STURM: The permafrost tunnel was built in
the 1960s. The reasons at the time were to see how do you dig permafrost? But with time,
the tunnel I like to think of it as a phoenix, it keeps rejuvenating itself. There’s other
new questions we can investigate. So modern questions now have to do with climate change,
changes in environmental systems. But we’re also interested in how to deal with permafrost,
cause it’s still a big issue in Alaska. THOMPSON: Alaskans have known for years all
about the shifting nature of permafrost. Large parts of the Trans-Alaska Pipeline had to
be built above ground on stilts, to prevent the permafrost below from thawing. And Fairbanks,
Alaska’s second-largest city, is dotted with pockets of permafrost. The sinkholes, collapsed
roads and tipping houses are clues to places where it has warmed. But now measurements
around Fairbanks show that in many places, permafrost temperatures have risen so much
that it is only one degree below freezing. At the University of Alaska’s main campus,
geophysics professor Vladimir Romanovsky runs the permafrost laboratory. He uses a Russian
word to describe thawing permafrost: Talik. ROMANOVSKY: And talik, it means not frozen
in Russian, just simply not frozen. So it’s very important now, because these taliks start
to develop because of warming in climate, and the development and growing of taliks
is really an indication of permafrost degradation. THOMPSON: Romanovsky has planted forty-five
boreholes deep in the permafrost all over Alaska. The results show that permafrost temperatures
have warmed as much as two degrees Celsius in the last 20 to 30 years. [GRAPHIC] Normally, because of the heat emanating
from the center of the Earth, permafrost should be warm at the bottom, and get colder as it
reaches the surface. But exactly the opposite is happening. Romanovsky’s data show that
since the mid-1980s, the temperatures in permafrost have gotten warmer as they creep towards the
surface. ROMANOVSKY: And this warming is a hundred
percent effect of changing climate, warming in air temperature. THOMPSON: Thawing permafrost can take a toll
on buildings and even force entire communities to relocate. But an even bigger cause for
concern is the powerful greenhouse gas that gets released from thawing permafrost. Katey
Walter Anthony was a young assistant professor when she made the discovery that permafrost
thawing under lakes in Siberia and Alaska releases high levels of methane into the air.
Methane is a greenhouse gas that’s 25 times stronger than carbon dioxide. KATEY WALTER ANTHONY (University of Alaska
Fairbanks): 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.
Then the forest falls in, and the organic, matter dead plant and animal remains that
were in the permafrost thaw 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. CLIP: Katey Walter Anthony sets methane on
fire, she and students cry, Whoa! THOMPSON: Katie’s dramatic videos of methane
being released from frozen lakes have gotten her and methane a lot of attention. WALTER ANTHONY: So I have seen now hundreds
of lakes, thousands of lakes. And some lakes can release hundreds to thousands of times
more methane than other lakes. And the most important factor is permafrost. If permafrost
is around the lake and thawing beneath the lake, the lake will emit a lot of methane. THOMPSON: Even small releases of methane from
the soil under these frozen lakes can make permafrost thaw more. That can help form more
lakes that will release more methane, and so on and so on. Back in Vladimir Romanovsky’s
lab, his models predict permafrost warming all over Alaska in the near future. ROMANOVSKY: By the end of the century, only
the permafrost on the North Slope and maybe in Brooks Range will be stable. Rest of it
will be pretty much thawing by the end of the century. THOMPSON: Scientists at the National Snow
and Ice Data Center in Colorado estimate that if global warming continues at current rates,
up to two-thirds of the earth’s permafrost could be gone by the year 2200, vastly increasing
the amount of greenhouse gases in the atmosphere. There’s little chance that all the world’s
permafrost will thaw at once, and an even smaller chance that deep permafrost can thaw
rapidly. But just ask someone living in the far north if permafrost is warming, and they’ll
show you. All they have to do is look down.

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