♪ ♪ NARRATOR:
What happens when a frozen world
locked away for millennia starts to thaw? In 2014, a helicopter crew
flying over Siberia discovers something mysterious: a crater more than 80 feet wide and deeper than a 15-story
building. Sinkholes are nothing new, but this is no ordinary
sinkhole. SUSAN NATALI:
The ground has exploded. There's no way--
this is not real. NARRATOR:
More Siberian craters
have since been discovered. There's even evidence
they may be appearing in Alaska. TAYLOR SULLIVAN:
The lake bottom went from being flat, flat, flat,
and then it just dropped out. NARRATOR:
And they show no sign
of stopping. Now, scientists from around
the globe race to understand a hidden world: permafrost,
a layer of frozen earth spanning a quarter of the
Northern Hemisphere's land mass. This ancient freezer
is beginning to thaw, revealing its deepest secrets... Pretty exciting, this is a
mammoth bone right here. NARRATOR:
...releasing over half a billion
tons of carbon every year... JANELLE SHARP:
It was just insane,
like, the water is boiling around you. NARRATOR:
...and threatening local
communities. LARS NELSON:
Houses need to be torn down. We're in the middle
of a housing crisis. ♪ ♪ NARRATOR:
Are the craters warning shots
for our climate future? KATEY WALTER ANTHONY:
That is not included
in climate models. That's a scary wildcard
in the climate change story. NARRATOR:
What new dangers lurk beneath this vast frozen landscape? And could they warm our planet
even further? "Arctic Sinkholes." Right now, on "NOVA." ♪ ♪ ANNOUNCER:
Major funding for "NOVA"
is provided by the following: (wildlife chirping, chittering) NARRATOR:
The Yamal peninsula, Siberia. 47,000 square miles
of freezing tundra. ♪ ♪ Located in Northern Russia, the Yamal lies well above
the Arctic Circle. It's home to around 10,000
Indigenous Nenet people, most living as nomadic
reindeer herders. ♪ ♪ In their language,
Yamal means "end of the land." It's now beginning
to look like it. ♪ ♪ Giant craters were spotted
in the North of Russia. They popped up out of nowhere
in the Yamal peninsula. NATALI:
When I first heard about
the crater, I didn't believe it. I actually thought it was
a made-up story. ♪ ♪ MARINA LEIBMAN:
Believe me, I remember this
date, and I will remember it forever, because it was
absolutely exciting, something I have never
seen before. NARRATOR:
The mysterious crater
is 150 feet deep. Filled up with rainwater, its volume is greater than
ten Olympic swimming pools. The striking images go viral
worldwide because no one can answer,
what caused it? ♪ ♪ Vasily Bogoyavlensky
is an expert on the geology of the Yamal. With other scientists,
he choppers out to the scene. ♪ ♪ BOGOYAVLENSKY:
When we just came to
this crater, of course, we didn't know for sure
what was there. We never saw something
like that, never. ♪ ♪ NARRATOR:
This isn't the first massive pit
to open up. (people crying out) ♪ ♪ Across the world,
gaping sinkholes have appeared due to water or erosion weakening the ground
beneath, swallowing cars whole and wreaking havoc in towns
and cities. But while the Yamal crater
looks at first like an ordinary sinkhole, there's something unusual
visible around the edges. (Bogoyavlensky speaking Russian) ♪ ♪ NARRATOR:
Most sinkholes have a rim
that is flat, not raised. And while sinkholes
collapse inwards, the team discovers debris
spread far outside the crater. Pieces of rocks and ice
are flying, sometimes in quite
long distance, from 200 meters to 500 meters. And in one case,
it was distance to 900 meters. NARRATOR:
Debris like this can be thrown out by the impact
of an asteroid. But there are no other signs
of a massive object striking Earth. For the scientists,
that leaves only one reasonable explanation. A gigantic natural explosion. NATALI:
I don't know if there are many Earth system processes
that have never occurred-- I mean, in my lifetime, or at least to scientific
understanding-- that have never occurred
and that we're starting to see as a new process. NARRATOR:
So what could have provided the
power for such a massive blast? There is no sign of lava
or volcanic rock, so this clearly isn't a volcano. But exploring inside the crater, sampling the air and water
at the bottom, the scientists do discover
an intriguing clue: unusually high levels
of a single gas, methane. ♪ ♪ Used for cooking and heating, methane is a flammable gas
made from carbon and hydrogen. (exploding) When combined with air,
it ignites easily. ♪ ♪ BOGOYAVLENSKY:
So this is huge bomb. Methane bomb. NARRATOR:
But before scientists
can determine where the methane came from... ...more giant craters
are discovered. Investigating, scientists find
new evidence of methane. Since 2014,
at least eight confirmed craters have been found on or close to
the Yamal. But the growing number
of craters isn't the scientists'
only concern. They notice a climate
connection. (birds twittering) 2014,
when the first crater appears, followed one of the hottest
years on record in Russia. And all the craters are
discovered during a period of uncharacteristically
warm weather in Siberia. Since the late 19th century,
the average global temperature has risen around two degrees
Fahrenheit. But the Arctic
is warming faster. It's currently heating up
around twice as fast as the rest of the planet. ♪ ♪ The scientists begin to ask: could the explosive craters
be connected to climate change? If so, what might they be
telling us about Earth's climate future? ♪ ♪ While scientists on the Yamal
study the crater, elsewhere in the Arctic, another
team is about to discover new pieces of the puzzle. This time, in Alaska. ♪ ♪ Kotzebue,
near Alaska's northwest coast. In 2017, a local pilot reports
a lake that's behaving oddly. Now, a team of scientists that had been investigating
returns to the site to continue its work. PHIL HANKE:
So we just left Kotzebue, and then we crossed
the Kotzebue Sound, and into the mouth
of the Noatak, which was this, like,
beautiful, sweeping landscape. SHARP:
Look, there's the lake
right there! Man, that's exciting! ♪ ♪ NARRATOR:
Far from the nearest town
lies Esieh Lake. Field technician Phil Hanke
proceeds cautiously, hoping to avoid surprises. Hey, bear! SHARP:
Hey, bear! HANKE:
Hey, bear! Bear scat. Well, there's, uh, definitely bears around here, so we're going to have to
take that into account when setting up camp. ♪ ♪ NARRATOR:
Esieh Lake is located
on the lands of the Indigenous Inupiat people. The state is home to over
13,000 Inupiaq people, whose traditional lands
stretch across Northern Alaska. One of the scientists
on the team has special ties to this community. My name is Janelle Sharp,
my Inupiaq name is Anausuk. My mom is originally
from Kotzebue. My family is from this region. And so this project is really special to me, because it's
kind of, like, me coming back to my roots. ♪ ♪ NARRATOR:
In 2017, Sharp and other
scientists asked the local community
to help them identify unusual features
in the wilderness. A pilot named Eric Sieh
told them that while flying over the area,
he'd spotted something unusual. ♪ ♪ SHARP:
If you fly low enough,
even from the air, you can see the bubbling. ♪ ♪ HANKE:
It's just mysterious. It looks like a Jacuzzi. And so you, you get up to it,
and you can hear this... (imitates bubbling) Like, the water is boiling
around you. (water bubbling loudly) ♪ ♪ NARRATOR:
On their first visit,
the team wanted to investigate, what's causing the bubbles? SHARP:
We took gas samples, and then those were sent to
the lab for analysis, and they found that it is
a super-high amount of methane. NARRATOR:
Methane leaks, known as seeps, have been found elsewhere
in the Arctic. But they're usually
much smaller. The team's measurements reveal
that Esieh Lake is belching out over ten tons of methane
every day. SULLIVAN:
This is the highest flux methane seep that humans
have discovered in the Arctic. The amount of methane you see
is staggering. ♪ ♪ NARRATOR:
From the shore,
it's difficult to see where the methane
is coming from. So the team decides
to get closer to the source. SULLIVAN:
Hypothermia is obviously
the main danger. Second is me getting air. I'm very curious about
what's down there. ♪ ♪ NARRATOR:
Sullivan finds that the lake is
shallow-- just a few feet deep. But then,
he follows the lake floor towards the source
of the bubbles. SULLIVAN:
I was kicking really hard to stay down along the bottom, and I was moving my hands
along it. And it went from this mushy
lake bottom that was flat, flat, flat, and then it just dropped out. ♪ ♪ SULLIVAN:
That gets deep so quickly. HANKE: Yeah. It's like you're on
the bottom, you're on the bottom,
bottom's gone. NARRATOR:
Sullivan finds the
methane bubbles are streaming up from the hole in the lake floor. SULLIVAN:
The bubbling, it, it sounded like seeping gas, as if it was even from
a propane tank. ♪ ♪ HANKE:
How'd it go? SULLIVAN:
Still going down! SHARP: Wow. (breathing heavily) NARRATOR:
With the lake bottom
too dark to see, the team deploys a sonar scan. Most of this bed is around
three feet deep. But beneath the streams
of bubbles, the ground abruptly falls away, at its deepest reaching 50 feet. Why does a lake floor otherwise flat and shallow
contain such a massive hole? (rotor blades whirring) On the Yamal, scientists believe
a methane leak blew out a huge crater. Esieh Lake is another sign
within the Arctic that beneath the surface,
methane is stirring. So could more craters-- and more methane--
be on the way? ♪ ♪ As well as methane,
there's one more clue that links Esieh Lake
and the Yamal craters. (birds twittering) Both are located on the same
type of frozen terrain: permafrost. ♪ ♪ Most permafrost is found
in the land masses of high northern latitudes, including Russia, Canada,
and most of Alaska, Covering an area almost as large
as the U.S. and Canada combined. Permafrost can stretch almost
a mile beneath Earth's surface. It's defined as any ground
whose temperature remains at or below 32 degrees Fahrenheit for two or more
consecutive years. But it can remain frozen
for millennia. ♪ ♪ Recently, rising Arctic
temperatures have meant that in some regions, the permafrost
has started to thaw. (birds twittering) Just how fast and the danger this may pose
to our climate is revealed 450 miles
from Esieh Lake. Near the town of Fox,
in Interior Alaska, something strange is happening
in the woods. (birds twittering,
branches rustling) ♪ ♪ TOM DOUGLAS:
This is what people refer to as this drunken forest. You can see a bunch of these
have kind of started to go. They're just having a hard time
getting enough rooting in to grow straight. NARRATOR:
This forest sits on top of
permafrost. Scientist Tom Douglas has been
tracking some surprising changes taking place as the permafrost starts
to thaw. DOUGLAS:
I mean, look at those
huge birch trees. They're literally just riding down those slopes
as it's all degrading. ♪ ♪ I mean, this goes a good
20 or so meters below us. This is a giant hole. You can hear water in there. (water rushing) This whole landscape
is just very slowly sliding downhill with gravity. ♪ ♪ This is a very dramatic and very rapid change
in the landscape here that, again, we're seeing
in a matter of years. Not decades, not 20 years,
not by 2100. Since 2018. It's pretty dramatic. ♪ ♪ NARRATOR:
This rapid thaw is also
affecting human settlements. Like Utqiagvik,
the most northern city in the United States. ♪ ♪ This entire community sits on
top of the Alaskan permafrost. Locals call it
"the top of the world." ♪ ♪ GORDON BROWER:
If you point that way, that's Greenland over there. Canada is over here. And that way is, guess what. (laughing):
Russia. NARRATOR:
Gordon Brower is a Native Alaskan Inupiaq
whaling captain. His people have lived in this
region for thousands of years. BROWER:
Communities like these,
they're special. A lot of the cultures
in the world are assimilated,
and we're assimilated here, but we brought our culture
and our ways to the future with us. And you can come here and still
see the same celebration that took place
10,000 years ago. ♪ ♪ NARRATOR:
For five decades, Brower has
been hunting in these waters, part of an ancient Inupiaq
tradition of living off the land and the sea. We don't have Walmart or we
don't have McDonald's up here. We have other small restaurants and other things to do
like that. But the majority of
food resources are still hunted today:
seals, whales, belugas, ducks, geese, caribou, wolves... All of those
are still traded and used. NARRATOR:
With little fresh food available in winter, generations of
Native Alaskans have depended on cellars carved out
of the permafrost. BROWER:
Well, we're in an ice cellar. My folks used this ice cellar
for years and years. This is where I put a whale and store it in trust
for the community. NARRATOR:
But thawing permafrost means
this natural deep freeze isn't as cold as it used to be. As Brower discovered. BROWER:
I had checked on the meat
and told my brothers, you know, "We got to pull that
meat out. It's draining,
and we don't want that." I've resorted to pulling
a whole whale out of there and putting it into
walk-in freezers. ♪ ♪ NARRATOR:
Thawing ice cellars aren't the
only threat rising temperatures pose to this community. Recently, sea ice that used to
protect the shore from storms has begun to melt. BROWER:
Storm surge is pretty dramatic. And it's going to wreak havoc on your coastline
here. And the thing about is,
when it's reaching the edge, a lot of the banks
are permafrost-rich, and it undercuts them. NARRATOR:
Exposed by the storms, permafrost is thawing
and crumbling away. Now communities like Utqiagvik are trying to protect
their homes. BROWER:
These are all our local efforts to stop
the storm surge. This is our way of trying to
save the town. NARRATOR:
With a retreating coastline and warming ice cellars, local communities are hit twice
by thawing permafrost. But the big thaw
is an Arctic-wide problem. NATALI:
Through the next decades
and century, we expect anywhere,
across the Arctic, between 30% and 70%
of near-surface permafrost will be lost. That range partly has to do with
just some uncertainty in the science,
but largely has to do with how much warming will happen
in the future. NARRATOR:
Arctic communities are facing
the immediate effects now. But scientists are concerned
this loss has implications for the entire planet. So why is permafrost thaw
so dangerous? And what is the link to methane? (birds twittering) Back near Fox
in Interior Alaska, Tom Douglas is about to do
something only possible in a few places on Earth-- walk deep down into
the permafrost itself. The Fox permafrost tunnel
reveals there's more to permafrost than frozen earth. DOUGLAS:
That's a horn. That's from the longhorn
steppe bison. And they are extinct now, but back 18,000
to 40,000 years ago, you know, there were
steppe bison here. Pretty exciting, this is a mammoth bone
right here. You can just see kind of the piece of it sticking out
right there. It's pretty big. NARRATOR:
The tunnel reveals
that permafrost contains vast quantities
of organic matter. DOUGLAS:
So these are, these are sedges,
kind of like grass. And you can see that they,
they're green. They still have their
chlorophyll in 'em. They're also upside down. This block fell into
a water feature that then froze, probably 20,000 or so
years ago. ♪ ♪ NARRATOR:
This ancient organic matter, like all life on our planet,
contains carbon. (birds twittering) And is part of a vital
Earth system called the carbon cycle. ♪ ♪ As they grow,
plants absorb carbon dioxide. When they die, they, or the
animals that have eaten them, decompose, releasing some of this carbon
back into the atmosphere. But in the freezing Arctic, decomposition happens slowly. So over millennia, a huge amount of organic matter
became permafrost before it could decompose, its carbon frozen in time. DOUGLAS:
In the late '90s into the 2000s, people start to look at the
stocks of carbon in permafrost. And it's, it's a lot, it's about
1,400 billion metric tons. It's almost twice as much carbon as is currently in Earth's
atmosphere. When we walked in,
we noted that smell, right? You're smelling ancient bacteria
and carbon being oxidized. It's almost like a, well,
I've heard anything from, like, a French cheese, to barnyard, but it's kind of that organic,
almost a late fall, wet leaf kind of organic smell. You are smelling permafrost
carbon being oxidized. And so the big question is, that carbon that we smell,
that's all over this tunnel walls, what's its ultimate fate? And there's a lot of people
working on that. NARRATOR:
In other words,
how much of this carbon will end up in the atmosphere? And most importantly, how fast? ♪ ♪ Falmouth, Massachusetts. 3,000 miles from the ice tunnel. Arctic ecologist Susan Natali
investigates samples of permafrost to find out what happens
when it thaws. NATALI:
So these are permafrost cores
that were collected from different locations
across Alaska. Some of these are really dark,
like particularly this one. And that dark color means that that has
a lot of carbon in it. ♪ ♪ NARRATOR:
As permafrost warms,
its carbon thaws. And the carbon cycle starts up
once again. So that carbon then is available
for microbes to break down. And they use it for energy
and they decompose it. And in that process,
they're releasing carbon dioxide or methane. ♪ ♪ NARRATOR:
Carbon dioxide and methane
are both greenhouse gases. As Earth's surface absorbs
energy from the sun, it radiates some of it
back out as heat. In the atmosphere, greenhouse
gases absorb this heat, radiating part of its energy
back at Earth and heating up our planet. NATALI:
Greenhouse gases are a concern
because they trap heat. They're helpful to us because they, they make this
habitable planet, but because there's too much
in the atmosphere, they're now making this
an unhabitable planet, or less habitable planet. ♪ ♪ NARRATOR:
It's estimated that
in the mid-18th century, there were over 2,000 gigatons
of naturally occurring carbon-based greenhouse gases
in the atmosphere. With industrialization, human-made greenhouse
gas emissions began to add to this amount. By 2019, it's estimated
the total had risen to over 3,000 gigatons. Over the last century
and a half, Earth's average temperature
increased around two degrees Fahrenheit. ♪ ♪ Scientists agree human emissions
caused this warming. But recently,
they've become concerned greenhouse gases
being released by permafrost might be driving
temperatures higher, too. As the name suggests, permafrost
is permanently frozen ground. So we thought, "Okay, this carbon is very stable, so
nothing is going to happen." But as permafrost
starts to thaw, this carbon
becomes vulnerable. NARRATOR:
Since the mid-'70s, carbon dioxide emissions from the
North Alaskan wilderness have spiked by more
than 70%. But while we know a lot
about carbon dioxide, the impact of
another greenhouse gas coming out of the permafrost
is less widely known-- the very one escaping
from the Yamal and Esieh Lake, methane. Methane is really important, because it's much more potent in terms of
its ability to trap heat. So it's about 30 times more
powerful than carbon dioxide. ♪ ♪ NARRATOR:
Luckily, while carbon dioxide lasts centuries or longer
in our atmosphere, methane only lasts
around 12 years. But as a far more potent
greenhouse gas, any large-scale increases
in methane emissions have climate scientists
seriously concerned. ♪ ♪ For now, more than half of
methane emissions come from human sources like
fossil fuels and agriculture, sources well understood
by climate experts. But scientists
are increasingly worried about methane emissions
from permafrost. So far,
they don't know how much methane
the permafrost is releasing. And that's a big problem. In order to
control our temperature, we have a certain
amount of carbon that humans can release--
that's our carbon budget. NARRATOR:
In 2015, the international
Paris Agreement set a target
for limiting global warming. Its goal was
to keep the temperature rise to well below two, preferably
to 1.5 degrees Celsius. To stand a good chance of remaining below
the 1.5-degree mark, one estimate states that humans
could release a maximum of around 460 gigatons more
carbon dioxide. But recent climate calculations
are based on computer models with incomplete information. LEE:
Unfortunately, a lot of these
Earth system models that contribute to such goals do not take into account CO2
and methane emissions from permafrost. NARRATOR:
The most recent carbon budgets have started to
include permafrost carbon. But some scientists believe
they still underestimate the amount of carbon
the warming Arctic will release, making temperature goals
harder to meet and putting more pressure
on societies to dramatically cut
their emissions to compensate. NATALI:
So we think we have a certain amount
of greenhouse gases that humans can release, but our target
is wrong right now, because we're not
accounting for potential
permafrost emissions of methane
and carbon dioxide. NARRATOR:
Understanding the dynamics
of thawing permafrost is now critical to
predicting our climate future. So how much methane is
permafrost emitting each year? And is this annual amount
going to increase? (dogs yapping) HANKE:
Good dogs! Straight ahead,
on by, on by, on by. NARRATOR:
Fairbanks, Interior Alaska. Ecologist
Katey Walter Anthony is heading out
onto the frozen terrain. HANKE:
Haw! Haw! Come on, Biggy, come on. (dogs whining) NARRATOR:
Walter Anthony was among the first
to study Esieh Lake. She's found
concerning evidence it's not the only lake
in the permafrost region that's releasing methane. ♪ ♪ WALTER ANTHONY:
So when you spear the spot, if I hear gas coming out, I'm going to
try to ignite it. And if there's fire, we both
need to get out of the way. Okay. Ready? Yep. Whoa... (flames roaring) That got me. Oh, shoot. Am I on fire? No-- I was wondering. (both chuckle) What's smoking? (laughing) You okay? (laughing):
Yeah, I'm fine. (laughing) That was a good one. That was a good one. All right. NARRATOR:
The methane comes from organic matter in permafrost
thawing and decomposing at the bottom of the lake, then rising in
methane bubbles to the surface. Across the Arctic,
permafrost thaw is generating
vast numbers of new lakes. As the soil warms, ice beneath the surface melts, causing the ground to
slump and fill with water. And once a lake is formed,
you can't stop it, because that water has heat, and it causes the ground
to thaw so fast. NARRATOR:
The lakes then start
releasing methane. WALTER ANTHONY:
As the methane escapes, it causes more
permafrost to thaw, and more methane to be
generated, which is more warming,
and you get what's called a positive feedback cycle. NARRATOR:
Positive feedback cycles from permafrost regions are another scenario not
sufficiently accounted for in current climate models. LEE:
As permafrost thaws, greenhouse gases
like CO2 and methane will be released back
to the atmosphere much faster. Warming is causing more warming. NARRATOR:
Due to positive feedback,
permafrost emissions could increase
the rate of warming, compounding the need for humans
to reduce their emissions if climate targets
are to be met. But permafrost carbon
isn't the only potential driver of a positive feedback cycle. Permafrost is actually not
the largest carbon reserve on Earth. There's much
larger carbon reserve in Earth's crust as
fossil carbon. But we often don't
talk about this carbon. This is because this carbon is
considered very stable. NARRATOR:
But some scientists now wonder if
this mega source of carbon is as stable
as they thought. Disturbing evidence comes from the bubbles
in Esieh Lake. Methane released
by thawing permafrost has a particular
chemical fingerprint. When the scientists
at Esieh Lake studied the methane
in the bubbles, they discovered it originated
deeper inside Earth. Much deeper. ♪ ♪ Miles beneath the permafrost,
deep in Earth's crust, lie huge fossil
methane reservoirs. While methane from permafrost comes from organic matter
thousands of years old, fossil methane
comes from organisms that decomposed
millions of years ago. But if it's miles
beneath the surface, how is this methane
getting through Earth's crust? And why here? Above ground, the landscape itself
gives scientists a clue. SULLIVAN:
Looking up at the peaks
around here, and studying
the local geology, we know that this is a highly fractured and
faulted region. NARRATOR:
As of 2021,
Alaska is the most seismically active state
in the U.S. In the territory
close to Esieh Lake, scientists
have discovered a network of geological fault lines. Although not on
a tectonic plate boundary, movements of Earth's crust
have caused it to crack here. The closest fault line
discovered so far is fewer than five miles
from the lake. Fault lines make cracks
in Earth's crust through which fossil methane
can rise to the surface. Though it
hasn't been confirmed, the scientists suspect
a fault line lies near, or directly beneath,
Esieh Lake. But if so, there's a mystery. Seismic evidence
from the area suggests Esieh Lake sits above 500 feet
of still-frozen permafrost. This should form
a rock-solid frozen barrier trapping the fossil methane
inside Earth. So how are these
deep stocks of greenhouse gas breaking through to the surface? So far, the team's sonar scan has revealed a 50-foot hole
in the lake floor. But what if
they could look deeper, into the permafrost itself? Geophysicist Nick Hasson joins the team,
with technology used by the military. 75 just after the shrub. HASSON:
I'm essentially scanning
the permafrost using a geophysical method
called Very Low Frequency. NARRATOR:
Very Low Frequency, or VLF, measures a special kind of
electromagnetic wave as it moves through Earth. These waves are sent out
globally by the Navy to communicate with
submarines. But as those waves
pass through the Earth below, Hasson's equipment
can pick them up. By measuring
the speed the wave travels, Hasson can tell whether
the ground deep beneath him is frozen or not. When it moves
through the ground, if there's permafrost or ice, these waves
are coming up against a lot of resistance. But if there's
no permafrost or ice, it quickly moves through. NARRATOR:
If they're strong enough, the electromagnetic VLF waves should enable Hasson to see
whatever lies beneath the lake. And so we can scan the Earth
similar to how a doctor scans you with a MRI. NARRATOR:
Esieh Lake is the biggest on-land methane seep
yet found in the Arctic, but no one has used VLF
to look beneath it. Until now. HASSON:
Wow. Fantastic signals. Yeah, so I'm starting
to notice a change. Well, we're
over the largest seep, and there's some sort of
large anomaly happening right here
where I'm located. And the VLF is picking it up. It's very exciting. The signals are
just outstanding. ♪ ♪ NARRATOR:
Back at camp, Hasson takes the first ever
high-resolution glimpse beneath Esieh Lake. This slice through 500 feet
of ground below the lake reveals an anomaly. So the dark blue
is the permafrost region. So anything that's
light blue to red is thawed. And so this shouldn't be here. There should be permafrost
covering this entire area. But for some reason, what you can see here
is a thaw chimney going from somewhere
below 150 meters to the surface, where we see
the rising bubbles. And so this is really unique. NARRATOR:
So far, the scientists
have only seen 50 feet beneath the lake. Now, Hasson's VLF image
lets them look ten times deeper. Below the lake stretches
a deep layer of permafrost. But the scientists
now know this hasn't just thawed
at the surface. Instead, a chimney of material
has thawed right through
the frozen permafrost: a warmer,
semi-permeable passageway through which fossil methane
rises to the surface. So, thawing permafrost
means not one, but two sources of methane
for our atmosphere. As it warms, permafrost
releases its own methane gas. And as thaw chimneys
form within it, they provide an escape route
for fossil methane that has been safely trapped
for millions of years. Scientists estimate there are
around 1.3 trillion tons of methane
stored beneath the Arctic. That's nearly 250 times
as much methane as there is in
Earth's atmosphere today. So is Esieh Lake's
thaw chimney unique? Or is fossil methane
escaping elsewhere? While the leak in Esieh Lake
is unusually large, smaller seeps of fossil methane are being discovered
across the Arctic. In Alaska alone,
over 70 sites have been found. ♪ ♪ There's no current sign
the entire reserve of fossil methane
is moving toward the surface. But the appearance
of even small amounts of this ancient greenhouse gas
has some scientists concerned. WALTER ANTHONY:
If permafrost thawed, then that's a scary wildcard
in the climate change story, because we think there's
a huge amount of methane and natural gas trapped inside permafrost
and under permafrost. So if permafrost
becomes like Swiss cheese, with lots of holes in it, then you can have chimneys
where that gas is erupting out. And that is not included
in climate models. ♪ ♪ NARRATOR:
If only a tiny fraction of the fossil reservoirs
were to reach the atmosphere, it could intensify warming, putting even more pressure on
human emissions targets. How fast
that's going to happen and just how much methane
will come out, we don't know. NARRATOR:
Scientists don't
currently understand how fast such a cycle
might occur, or what it would look like. But there's one place on Earth that gives
a chilling example of how a human-made permafrost
feedback cycle actually works. Northeast Siberia is home to
the Chersky Mountains. In the 1960s,
in a place called Batagaika, a stretch of forest
was cleared to make a road. Stripped of its tree cover, the permafrost was exposed
to the warming sun. As it thawed,
the ground sank, pulling down trees at its edge
and exposing more permafrost: a positive feedback cycle. ♪ ♪ Today,
the strip of cleared forest is a depression
nearly 300 feet deep and over half a mile wide. And it's growing. Scientists call it
a megaslump. LEIBMAN:
Batagaika, it is very big, but this, the size is because of
the initial human impact. And this one is already
more than one kilometer, and growing every summer. NARRATOR:
Batagaika reveals
how a small human impact can start a devastating
feedback cycle in permafrost. (birds chirping) Scientists are
now trying to discover what a feedback cycle could mean for
the entire permafrost region and whether it could
reach a point where it becomes irreversible. Such a phenomenon
is called a tipping point. SULLIVAN:
A tipping point is the proverbial straw
that broke the camel's back. You can get away with
adding straw for so long, and then you can't. And the tipping point
is the point of no return. ♪ ♪ NARRATOR:
It's a controversial idea
among climate scientists. But the prospect
of a tipping point has been raised for a number of
global climate systems, including Arctic sea ice and deforestation
in the Amazon. So far, there's
no conclusive evidence that a tipping point
is near for permafrost. However, some scientists
believe aspects of the thaw are now irreversible. (ground squelching) Vladimir Romanovsky
has spent decades studying the changing permafrost. Near Utqiagvik
in Northern Alaska, he investigates what happens as large wedges
of ice in the ground start to melt. ROMANOVSKY:
Before, it was more or less
flat area, but then ice melts and surface subsides. NARRATOR:
Romanovsky believes lakes formed
by melting permafrost ice have passed
a point of no return. ROMANOVSKY:
It took tens of thousands
of years to put this ice into the ground. Now, it's, it's melting. To put all this ice
into the ground back, you will need several
tens of thousands of years. So that's, for humans,
definitely irreversible process. It is tipping point. NARRATOR:
While melting ice forms lakes
in the wilderness, just a few miles away, it's
causing very different problems for the local community. In the roads
outside Utqiagvik, the effects of
rising Arctic temperatures are easy to see. NELSON:
Just from observation,
growing up here, coming out here
since I was a kid, the roads were a lot higher
than they are now. It is literally sinking. His bumper might get wet. NARRATOR:
Native Alaskan Inupiaq
Lars Nelson is an infrastructure consultant. He knows firsthand what permafrost thaw
is doing to his community. NELSON:
This road is for
subsistence use; we come out here and
stage our hunts. It's a big part of our history,
and it's important that we're able to access it
in case of an emergency. NARRATOR:
And it's not just the roads
that are sinking. In downtown Utqiagvik, Nelson meets
Inupiaq Anthony Edwardsen. These ones
are subsiding, too. Yeah. NARRATOR:
He's an expert on
the Inupiaq community with four decades' experience
in the construction industry. Yeah, look at--
this one is really messed up. Look at how it's just ... EDWARDSEN:
That's where the houses
are sinking. NARRATOR:
Local houses
are built on wooden pilings. If they were
built on the ground, the heat used
to warm the homes would thaw
the permafrost below. But now the permafrost
is thawing by itself, and the pilings
are starting to sink. EDWARDSEN:
When the piling is
a very small base, it doesn't hold
its structure. The communities, they need the house leveling, move houses,
houses need to be torn down. We're in the middle of
a housing crisis. NARRATOR:
Nelson believes strategic building
is the answer. We're on to it right now, and we're refining it
right now. We can build nice,
good, healthy homes. We just got to pay
attention to our foundation, pay attention to the tundra
we're building on more closely. Because it's such
an awesome spot, you know? It's the top of the world. ♪ ♪ NARRATOR:
But as the permafrost
continues to thaw, others in Alaska are looking at
more drastic solutions. GRIFFIN HAGLE:
So this is our portable,
adjustable, sled-base home. It is on a giant steel sled, as opposed to the pilings. NARRATOR:
C.E.O. of the regional housing
authority Griffin Hagle has a more radical plan
for sinking homes. HAGLE:
What we would do if we
needed to, to move this, we would be hooking up
our tow chains to these two attachment points. We've got one on this side and one on that corner
of the building over there. Hook that up to a piece of
heavy equipment, Caterpillar, and then drop it off the pads and basically tow it
across the snow in the wintertime. ♪ ♪ NARRATOR:
As temperatures rise, Hagle is searching for ways to protect some of the most
isolated communities in the United States. HAGLE:
This is the largest municipality in the world,
I think, by land area. We provide affordable housing in eight villages across
an area the size of Minnesota, only without any roads. NARRATOR:
No Alaskan homes
have been sledded away, yet. But Arctic warming has forced
some towns to relocate. And Hagle thinks houses
will soon be on the move. And there are several,
you know, communities, especially in rural Alaska,
Native communities, that are increasingly
at risk of relocation due to global warming. And so this
gives us an advantage in having the option,
the adaptability, to move that, that structure
if it becomes necessary. Native people,
the Indigenous communities that have called this place home
for thousands of years, have come up with
all sorts of innovations to make life work here. So we draw a lot of inspiration
from that, and we see that as
kind of the continuation of a long, long tradition
of innovation. ♪ ♪ NARRATOR:
As inhabitants across the Arctic adapt to
their changing world, scientists strive
to build a better picture of our climate future. The methane craters are
just one sign of a region undergoing
unprecedented changes... ...placing communities
with deep ties to this land at risk. BROWER:
We've been whaling here well over 4,000 years. (birds cawing) We've adapted
time and time again. Today, we might not be able
to do it by ourselves. NARRATOR:
But the big thaw is
not just a regional problem. What's happening in the Arctic
could really affect everyone on Earth. NARRATOR:
Arctic greenhouse gases will intensify
future global warming. How quickly
is difficult to predict. And positive feedback cycles could accelerate
beyond human control, making our choices today
even more urgent. LEE:
Because it's very difficult
to take control over the natural systems, it's even more important
for us to lower our emissions. NATALI:
These craters are a really important
and concerning indicator that things are changing,
and the Arctic is melting, and the Arctic is thawing. And the future of the Arctic is a very different place
than it was several decades ago. ♪ ♪ ♪ ♪ ANNOUNCER:
Episodes of "NOVA" are available
with Passport. This program is also available
on Amazon Prime Video. ♪ ♪ ♪ ♪
SS: Eye-opening episode on the newest season (season 49) of NOVA on PBS, which premiered last night. The permafrost melt situation is far worse than we could have ever imagined, and none of the current climate models take this into account. The permafrost is melting at an astounding rate - even as much as 500ft down into the ground in some areas. It’s releasing a shocking amount of methane into the atmosphere, clearly accelerating the rate of climate change. There’s no way to predict how quickly it will continue to melt, and indigenous communities are bearing the brunt of the landscape changes. Seeing the frozen tundra literally explode methane when putting a flame to it is unsettling to say the least. This ground has been frozen for tens of thousands of years, so there’s no easy fix or way to reverse this. Plus, who knows what else is lurking in the ground below. This relates to collapse on so many levels: warming/changing climate, greenhouse gas emissions, destruction of ecosystems, loss of towns & indigenous communities that have relied on the land for thousands of years, potential biological/viral consequences too (bacteria or life frozen & dormant for thousands of years being released).
NOVA is wonderful, but not available to view outside the USA
I have a question.
I have been trying to find if there is any research regarding the amount of water that is being released/could be released by the thawing of the Arctic Circle?
I mean, water is being released, therefore, that water will flow to streams to rivers, lakes, and ultimately the ocean. So, will or how much will the thawed water of the Arctic contribute to rising sea levels and such disruptive issues?
Interesting that the show makes no mention of the permafrost on the Eastern Siberian Arctic Shelf. There is a huge amount of carbon stored in it, and the water column is shallow enough that the ocean cannot absorb the methane before it reaches the surface. Measurements taken from the water have found an increasingly large amount of methane seeps out there.
I was thinking about linking this. Its a great watch.
David Koch huh
what fucking morons they are! or they're outright lying! i became FURIOUS when i heard that woman say she has NO IDEA what could cause it. is she just incredibly stupid? IT'S METHANE, YOU DINKS!