Is Permafrost Really Permanent?

Despite its name, permafrost doesn't necessarily last forever -- and when it melts, it can have a negative effect on the environment. Learn how permafrost works (and how it preserves long-dead creatures so well) in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio, Hey, brain Stuff,
lor and Vogel Bomb here in. A wally mammoth carcass
was discovered in Siberia near the coast of the Left
of Sea. Nicknamed Yucca, this specimen of the long extinct
beast died around twenty eight thousand years ago, yet her
body was astonishingly well preserved, complete with patches of reddened

(00:25):
for a brain that was largely intact and nucleus like
cell structures. So how did her body last so long
without rotting away? The short answer is Yuka was frozen,
but not inside some glacier or iceberg. After death, Yuca
became encased in a layer of what's known as permafrost.
Let's break down what that is. As we know, water

(00:46):
freezes at thirty two degrees fahrenheit or zero degrees celsius.
Permafrost is any ground materials such as soil, sediment, and rock,
that remains at or below freezing temperatures for at least
two consecutive years. About scent of all the land area
in the Northern Hemisphere is known to contain permafrost. It
was American paleontologist Simon W. Mueller who originally coined the

(01:09):
term permafrost, a portmanteau of the words permanent and frost.
Despite that name, permafrost doesn't last forever. Thanks to climate change,
it's been thawing in large quantities. This has serious ramifications
for both the environment and the economy. Generally speaking, permafrost
tends to occur in places where the average air temperature

(01:29):
is zero degrees celsius or lower every year. According to
the National Snow and Ice Data Center, most of the
northern hemispheres, permafrost sits between the high latitudes of sixty
and sixty degrees north Siberia, Canada, Alaska, and parts of
Scandinavia are loaded with this frigid turf. Further south, permafrost
tends to be found in high elevation areas like the

(01:52):
Tibetan Plateau and this was Alps. Permafrost isn't as widespread
below the equator, but it does underlie parts of New Zealand,
the and Mountains, and Antarctica. Just as its locations vary,
so does its composition. It's not uniform. Some sections are
ice free while others are made up of more than
thirty ice. Likewise, the depth, age and extent of permafrost

(02:15):
can vary widely. Oftentimes, permafrost sits beneath an active layer
of ground, that is, a layer that thaws and refreezes seasonally.
The permafrost itself can measure anywhere from less than three
feet that's one meter thick to more than five thousand
feet or fift thick, and it can get patchy. Northern
Alaska occupies a continuous permafrost zone that means permafrost underlies

(02:40):
more of the local terrain, but at lower latitudes it's
a different story. Pretty Much everything south of the Brooks
Mountain Range sits in a discontinuous permafrost zone. Here, permafrost
resides under a smaller percentage of the land's surface. That's
partially because, as counterintuitive is it may sound, snow is
a really good insult, so when thick blankets of snow

(03:02):
stick around all year long, they might keep the ground
too warm for permafrost. Likewise, in spots where permafrost already exists,
insulating layers of surface level snow are liable to heat
it up. But while snow is an impediment, Pete is
a boon wide spread in and around the southern Arctic
pete is a kind of ground material that's made up

(03:23):
of partially decayed organic matter like mosses or swamp plants.
By and large, the ground beneath it is kept cool
shielded from solar heat. Thus pete safeguards permafrost. Evergreen forests
lend a helping hand too. With their thickly needled branches.
Pine trees limit the amount of sunlight and snow that
hits the surface. In the process, the evergreens help keep

(03:45):
permafrost from thawing, so permafrost is common below the clustered
pines and high elevation and high altitude areas. The arrangement
is mutually beneficial. Since liquid water can't seep through hard permafrost,
it acts like a drainage barrier. Unfrozen water that's absorbed
into the active layer gets trapped there, barred from traveling

(04:05):
deeper into the earth. This water sustained some of the
plants that live at the surface. Although not all permafrost
sticks around more than a couple of years, some is
quite old. At minimum, the permafrost in Prudo Bay, Alaska
is thought to be five hundred thousand years of age,
and some of the permafrost beneath the Canadians Yukon territory
could be more than seven hundred thousand years old. Inside

(04:27):
the ladder, scientists found an ancient horse leg complete with
DNA samples. Permafrost can keep all kinds of organic matter
preserved over long periods of time. In Russian scientists regenerated
live hunter plants from ice age fruits that have been
encased in permafrost for about thirty thousand years. Unfortunately, as
permafrost thaws, the trapped organic material decomposes, releasing carbon and

(04:51):
methane into the atmosphere. Those gases exacerbate climate change, and
the bad news is According to a twenty nineteen study
published in Nature, Community Patians, various permafrost deposits around the
world have warmed up by a couple degrees between the
years two thousand seven and two thousand sixteen. Right now,
approximately one point seven billion tons of carbon is trapped

(05:12):
in permafrost. Scientists don't know how much of this will
be released into the atmosphere if current thawing trends continue,
or how quickly it will escape, but some projections are
not encouraging. To make matters worse. When permafrost thaws, it
can destabilize the landscape. In the city of Norlis, Russia alone,
more than one hundred residential buildings have been damaged because

(05:34):
the once solid permafrost beneath them is softening. The warming
of permafrost has also triggered landslides, drained lakes, and torn
roads apart, it's yet another reason to be concerned about
our contributions to climate change. But to end on a
positive note, remember the wooly mammoth Yucca found in Siberian permafrost.
She was so well preserved that in early twenty nineteen,

(05:56):
scientists were able to extract eighty eight nucleus like structures
from her cells an attempt to coax them back to life.
The team injected the nuclei into mouse ovarian cells, and
while the cells never fully divided, they did complete the
process called spindle assembly, which is a step where chromosomes
attached to spindle structures before the parents cell breaks into

(06:16):
two daughter cells. Perhaps, as genetics progresses will be able
to help the process along. Today's episode was written by
Mark Mancini and produced by Tyler Clang. Brain Stuff is
a production of I Heart Radio's How Stuff Works. For
more in this and lots of other cool topics, visit
our home planet, how Stuff Works dot com and for

(06:38):
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