August 24, 2026 • 10 mins
The Batagaika crater (or, technically, megaslump) is a massive pit caused by thawing permafrost -- and it's only getting bigger. Learn what paleontologists have found there (and why geoscientists are worried about it) in today's episode of BrainStuff, based on these articles: https://science.howstuffworks.com/environmental/earth/geology/batagaika-crater.htm; https://science.howstuffworks.com/environmental/earth/geology/permafrost.htm
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Speaker 1 (00:01):
Welcome to BrainStuff, a production of iHeartRadio. Hey, BrainStuff. Lauren
Vogelbaum here. There is a massive and growing pit in
the frozen landscape of Siberia that's inspired even serious-minded scientific
publications to use tabloid-style terminology like the doorway to hell
(00:24):
and gateway to the underworld. The Batagaika crater was first
spotted by mid-1960s surveillance satellites, images from which were then classified,
and has since grown from an insignificant gully to a
huge depression that's weirdly tadpole-shaped, covers over 200 acres or
80 hectares of area, stretches at least two-thirds of a mile,
(00:48):
that's a kilometer in length, and is some 330 feet
deep today, that's about 100 meters. The area of this
crater increased by about three times from 1990 through 2020,
and it's still growing by an estimated 100 feet or
30 meters a year. So what is the Batagaika crater,
(01:10):
how did it get there, and why does it keep growing?
First off, the Batagaika crater isn't actually a crater. That's
a term reserved for holes in the ground that are
caused by events like the impact of meteorites, volcanic eruptions,
or an explosion of some sort, either natural or human-made.
(01:30):
The Batagaika is rather what's called in the geosciences a
retrogressive thaw slump, which basically means that it formed when
part of a landscape's permafrost thawed out, causing a hollow
or slump that's getting bigger. It is, in fact, the
largest retrogressive thaw slump in the world. While a layperson
(01:52):
might assume that the perma in permafrost means that it
stays frozen permanently, that's not necessarily the case. As we know,
water typically freezes at 32 degrees Fahrenheit or zero Celsius.
A permafrost is any ground material, like soil, sediment, or rock,
that remains at or below freezing temperatures for at least
(02:13):
two consecutive years. About 15-25% of all of the exposed
land area in the Northern Hemisphere is known to contain permafrost,
mostly found around high latitudes in Siberia, Canada, Alaska, and
parts of Scandinavia, but also in high altitudes like the
Tibetan Plateau and the Swiss Alps. It's less common in
(02:36):
the Southern Hemisphere, but does underlie parts of New Zealand,
the Andes, and Antarctica. Often, permafrost sits beneath an active
layer of ground that thaws and refreezes seasonally. Permafrost itself
has been observed measuring anywhere from a few feet thick,
like a meter or so, to over 5,000 feet thick,
(02:56):
that's 1,500 meters. And it can get patchy. One type
of land surface that occurs over permafrost is called thermokarst.
Karst refers to terrain where deposits of soluble minerals like
limestone in the earth have led to sinkholes, caves, springs,
and other features. So thermokarst is similar. It can comprise
(03:21):
an irregular series of pits and ponds that are created
by thaws and melts over time. For the article this
episode is based on, HowStuffWorks spoke with Roger Michelides, an
assistant professor of Earth, Environmental, and Planetary Sciences at Washington
University in St. Louis. He said, With rising air temperatures
across the Arctic, permafrost can thaw, and when it thaws,
(03:45):
it can result in dramatic changes to the landscape. In
areas of ice-rich permafrost, permafrost thaw induces melting of ground ice.
which causes the ground to subside and form irregular depressions
in the ground surface. Some of these depressions can fill
with pooling water and form thermokarst lakes, and sometimes the
(04:05):
initiation of thermokarst can result in large gashes and slumps
of ground as permafrost continues to thaw and become unstable.
That's more or less what happened with the Batagaika crater.
Certain types of landscapes are better at resisting thermokarst. A snowfall,
perhaps counterintuitively, insulates ground heat well, so heavy snowfalls can
(04:29):
actually trap heat in the ground and thaw permafrost. On
the other hand, the existence of peat is a boon
to permafrost. Peat is substrate that's made up of partially
decayed organic matter, think mosses and swamp plants from long ago.
Peat helps keep layers of the earth beneath it cool.
(04:50):
Evergreen forests can help, too. With their ever-present and thickly-needled branches,
trees like pines limit the amount of sunlight and snow
that reaches the ground, preventing permafrost from thawing. Researchers think
that the Batagaika originated with Soviet-era industry cutting down forests
in the area. This altered the thermal equilibrium of the
(05:12):
surrounding permafrost landscape, leading to the depression that showed up
in those old satellite images. Michelides explained, Without a vegetation canopy,
more thermal energy from the sun was able to thaw permafrost,
leading to the formation of a downslope gully. The formation
of this gully can lead to even more thaw of
(05:32):
permafrost during subsequent summer seasons, which causes the gully to
expand and grow larger. As larger surface areas of exposed
permafrost are liable to thaw, this process accelerates and a
megaslump can form. the result is a massive, slowly expanding
collapse feature. As permafrost thaws, its structural strength goes from
(05:56):
something like concrete to wet mud, and on a sloping
land surface like here, this causes the ground to slump.
As Siberia warms at an unprecedented rate due to climate change,
the Batagaika slump has continued to grow. It's expanded from
a narrow gully to its current form, with a wide
(06:18):
head and narrow tail, like a massive tadpole or stingray,
and is only getting bigger. Which is scary, but in
some ways, the growth of this crater is a gift
to science. Michelides said, As this permafrost thaws, it also
reveals a treasure trove of paleontological information in the form
(06:38):
of fossils from the last ice age, and potentially older.
In 2018, for example, scientists recovered the remains of a
baby horse with well-preserved skin, hair, tail, and hooves that
died 42,000 years ago. Its species has since gone extinct.
That specimen yielded the oldest sample of liquid blood ever found.
(07:01):
The site has also offered up the remains of cave lions, wolves,
woolly rhinos, a prehistoric step bison, a saber-toothed cat cub
with fur and whiskers intact, and the best-ever preserved specimen
of a 50,000-year-old baby mammoth. But the massive slump is
also potentially worrisome. On a local level, the growth of
(07:23):
the Batagaika could cause ecological problems, such as the further
loss of forest, added stress on wildlife, changes to the
water cycle, and pollution in waterways. When permafrost thaws, it
destabilizes entire landscapes, meaning local human populations and infrastructure could
be affected too. Beyond that, the thawing of permafrost on
(07:45):
such large scales has global implications. It yields not only
interesting remains, but also a lot of other organic, that
is previously living, stuff that's been encased in ice for millennia.
And that's not a good thing. HowStuffWorks also spoke via
email with Sarah Cadhew, now a senior lecturer and the
(08:08):
associate director of environmental science at New York's Rensselaer Polytechnic Institute.
She said, As the crater grows, material that's been frozen
and inaccessible for 650,000 years is being exposed. This includes
organic matter and carbon. It's estimated that permafrost soils hold
(08:28):
at least twice as much carbon as the atmosphere does.
Why that's potentially so bad is that the formation of
this kind of thermokarst system can act as a geological
feedback loop. What happens is that as organic matter in
the permafrost thaws and becomes exposed, the microorganisms that live
(08:50):
all around us will break it down and release stuff
like methane and carbon dioxide into the atmosphere. These greenhouse
gases warm the planet in general and the local surface
air in particular. which then thaws more permafrost. In the
past 50 years, the Arctic has already warmed by almost
(09:10):
5.5 degrees Fahrenheit. That's a little over 3 degrees Celsius.
That's three times faster than the rest of the world
is warming. Some studies suggest that the sudden collapse of
thawing permafrost in the Arctic could double the warming of
the planet from greenhouse gases. But okay, how big could
(09:31):
the Batagaika crater get? We don't really know. Michalides said,
the underlying mechanisms responsible for its growth, this runaway thermokarst
formation superimposed on a downward-facing slope, are not going to dissipate.
As long as the surrounding area is subject to above-zero
air temperature for an extended period of the year, and
(09:54):
there is additional downslope permafrost that the Batagaika megaslump can
propagate into, we can expect it to continue growing in size.
At the very least, advances in satellite imagery over the
years have made observing these changes, and hopefully learning from them,
a lot easier. Today's episode is based on the article,
(10:20):
Siberia's Batagaika Crater Just Keeps Growing, and That's Not Good,
written by Patrick J. Kiger. And Is Permafrost Really, Well, Permanent?
written by Mark Mancini, both on HowStuffWorks.com. BrainStuff is a
production of iHeartRadio in partnership with HowStuffWorks and is produced
by Tyler Klang. For more podcasts from iHeartRadio, visit the
iHeartRadio app, Apple Podcasts, or wherever you listen to your
(10:43):
favorite shows.
Welcome to BrainStuff, a production of iHeartRadio. Hey, BrainStuff. Lauren
Vogelbaum here. There is a massive and growing pit in
the frozen landscape of Siberia that's inspired even serious-minded scientific
publications to use tabloid-style terminology like the doorway to hell
(00:24):
and gateway to the underworld. The Batagaika crater was first
spotted by mid-1960s surveillance satellites, images from which were then classified,
and has since grown from an insignificant gully to a
huge depression that's weirdly tadpole-shaped, covers over 200 acres or
80 hectares of area, stretches at least two-thirds of a mile,
(00:48):
that's a kilometer in length, and is some 330 feet
deep today, that's about 100 meters. The area of this
crater increased by about three times from 1990 through 2020,
and it's still growing by an estimated 100 feet or
30 meters a year. So what is the Batagaika crater,
(01:10):
how did it get there, and why does it keep growing?
First off, the Batagaika crater isn't actually a crater. That's
a term reserved for holes in the ground that are
caused by events like the impact of meteorites, volcanic eruptions,
or an explosion of some sort, either natural or human-made.
(01:30):
The Batagaika is rather what's called in the geosciences a
retrogressive thaw slump, which basically means that it formed when
part of a landscape's permafrost thawed out, causing a hollow
or slump that's getting bigger. It is, in fact, the
largest retrogressive thaw slump in the world. While a layperson
(01:52):
might assume that the perma in permafrost means that it
stays frozen permanently, that's not necessarily the case. As we know,
water typically freezes at 32 degrees Fahrenheit or zero Celsius.
A permafrost is any ground material, like soil, sediment, or rock,
that remains at or below freezing temperatures for at least
(02:13):
two consecutive years. About 15-25% of all of the exposed
land area in the Northern Hemisphere is known to contain permafrost,
mostly found around high latitudes in Siberia, Canada, Alaska, and
parts of Scandinavia, but also in high altitudes like the
Tibetan Plateau and the Swiss Alps. It's less common in
(02:36):
the Southern Hemisphere, but does underlie parts of New Zealand,
the Andes, and Antarctica. Often, permafrost sits beneath an active
layer of ground that thaws and refreezes seasonally. Permafrost itself
has been observed measuring anywhere from a few feet thick,
like a meter or so, to over 5,000 feet thick,
(02:56):
that's 1,500 meters. And it can get patchy. One type
of land surface that occurs over permafrost is called thermokarst.
Karst refers to terrain where deposits of soluble minerals like
limestone in the earth have led to sinkholes, caves, springs,
and other features. So thermokarst is similar. It can comprise
(03:21):
an irregular series of pits and ponds that are created
by thaws and melts over time. For the article this
episode is based on, HowStuffWorks spoke with Roger Michelides, an
assistant professor of Earth, Environmental, and Planetary Sciences at Washington
University in St. Louis. He said, With rising air temperatures
across the Arctic, permafrost can thaw, and when it thaws,
(03:45):
it can result in dramatic changes to the landscape. In
areas of ice-rich permafrost, permafrost thaw induces melting of ground ice.
which causes the ground to subside and form irregular depressions
in the ground surface. Some of these depressions can fill
with pooling water and form thermokarst lakes, and sometimes the
(04:05):
initiation of thermokarst can result in large gashes and slumps
of ground as permafrost continues to thaw and become unstable.
That's more or less what happened with the Batagaika crater.
Certain types of landscapes are better at resisting thermokarst. A snowfall,
perhaps counterintuitively, insulates ground heat well, so heavy snowfalls can
(04:29):
actually trap heat in the ground and thaw permafrost. On
the other hand, the existence of peat is a boon
to permafrost. Peat is substrate that's made up of partially
decayed organic matter, think mosses and swamp plants from long ago.
Peat helps keep layers of the earth beneath it cool.
(04:50):
Evergreen forests can help, too. With their ever-present and thickly-needled branches,
trees like pines limit the amount of sunlight and snow
that reaches the ground, preventing permafrost from thawing. Researchers think
that the Batagaika originated with Soviet-era industry cutting down forests
in the area. This altered the thermal equilibrium of the
(05:12):
surrounding permafrost landscape, leading to the depression that showed up
in those old satellite images. Michelides explained, Without a vegetation canopy,
more thermal energy from the sun was able to thaw permafrost,
leading to the formation of a downslope gully. The formation
of this gully can lead to even more thaw of
(05:32):
permafrost during subsequent summer seasons, which causes the gully to
expand and grow larger. As larger surface areas of exposed
permafrost are liable to thaw, this process accelerates and a
megaslump can form. the result is a massive, slowly expanding
collapse feature. As permafrost thaws, its structural strength goes from
(05:56):
something like concrete to wet mud, and on a sloping
land surface like here, this causes the ground to slump.
As Siberia warms at an unprecedented rate due to climate change,
the Batagaika slump has continued to grow. It's expanded from
a narrow gully to its current form, with a wide
(06:18):
head and narrow tail, like a massive tadpole or stingray,
and is only getting bigger. Which is scary, but in
some ways, the growth of this crater is a gift
to science. Michelides said, As this permafrost thaws, it also
reveals a treasure trove of paleontological information in the form
(06:38):
of fossils from the last ice age, and potentially older.
In 2018, for example, scientists recovered the remains of a
baby horse with well-preserved skin, hair, tail, and hooves that
died 42,000 years ago. Its species has since gone extinct.
That specimen yielded the oldest sample of liquid blood ever found.
(07:01):
The site has also offered up the remains of cave lions, wolves,
woolly rhinos, a prehistoric step bison, a saber-toothed cat cub
with fur and whiskers intact, and the best-ever preserved specimen
of a 50,000-year-old baby mammoth. But the massive slump is
also potentially worrisome. On a local level, the growth of
(07:23):
the Batagaika could cause ecological problems, such as the further
loss of forest, added stress on wildlife, changes to the
water cycle, and pollution in waterways. When permafrost thaws, it
destabilizes entire landscapes, meaning local human populations and infrastructure could
be affected too. Beyond that, the thawing of permafrost on
(07:45):
such large scales has global implications. It yields not only
interesting remains, but also a lot of other organic, that
is previously living, stuff that's been encased in ice for millennia.
And that's not a good thing. HowStuffWorks also spoke via
email with Sarah Cadhew, now a senior lecturer and the
(08:08):
associate director of environmental science at New York's Rensselaer Polytechnic Institute.
She said, As the crater grows, material that's been frozen
and inaccessible for 650,000 years is being exposed. This includes
organic matter and carbon. It's estimated that permafrost soils hold
(08:28):
at least twice as much carbon as the atmosphere does.
Why that's potentially so bad is that the formation of
this kind of thermokarst system can act as a geological
feedback loop. What happens is that as organic matter in
the permafrost thaws and becomes exposed, the microorganisms that live
(08:50):
all around us will break it down and release stuff
like methane and carbon dioxide into the atmosphere. These greenhouse
gases warm the planet in general and the local surface
air in particular. which then thaws more permafrost. In the
past 50 years, the Arctic has already warmed by almost
(09:10):
5.5 degrees Fahrenheit. That's a little over 3 degrees Celsius.
That's three times faster than the rest of the world
is warming. Some studies suggest that the sudden collapse of
thawing permafrost in the Arctic could double the warming of
the planet from greenhouse gases. But okay, how big could
(09:31):
the Batagaika crater get? We don't really know. Michalides said,
the underlying mechanisms responsible for its growth, this runaway thermokarst
formation superimposed on a downward-facing slope, are not going to dissipate.
As long as the surrounding area is subject to above-zero
air temperature for an extended period of the year, and
(09:54):
there is additional downslope permafrost that the Batagaika megaslump can
propagate into, we can expect it to continue growing in size.
At the very least, advances in satellite imagery over the
years have made observing these changes, and hopefully learning from them,
a lot easier. Today's episode is based on the article,
(10:20):
Siberia's Batagaika Crater Just Keeps Growing, and That's Not Good,
written by Patrick J. Kiger. And Is Permafrost Really, Well, Permanent?
written by Mark Mancini, both on HowStuffWorks.com. BrainStuff is a
production of iHeartRadio in partnership with HowStuffWorks and is produced
by Tyler Klang. For more podcasts from iHeartRadio, visit the
iHeartRadio app, Apple Podcasts, or wherever you listen to your
(10:43):
favorite shows.
BrainStuff News
Host
Lauren Vogelbaum
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