In the heart of Siberia’s boreal forest, a massive crater the locals call the “gateway to the underworld” has been growing for the last fifty years. It appears in the form of a huge gash on earth, a kilometer long and one hundred meters deep at one end.
Named after the nearby flowing Batagayka river, a tributary of the river Yana, the Batagaika crater is what geologists call a thermokarst depression —cave-ins which results when the permafrost melts, and although the Batagaika crater has no connection to the underworld, as the Yakutian people believe, it is still something to be feared of as these “slumps”, that are increasingly appearing across the northern hemisphere, could represent an ominous sign of things to come as the world continues to warm.
The Batagaika crater, in the Sakha Republic in Russia, started to form in the 1960s after a chunk of forest was cleared for industrial use, triggering a series of catastrophic geologic and environmental events. The vegetation provides insulation that keeps the ground cool. Once that was removed, the summer heat was able to penetrate deeper into the ground causing the permafrost to melt, and the area began to slump. The crater has been growing ever since, becoming bigger and bigger with each passing year as the climate continues to change.
Dr. Julian Murton, a geology professor at the University of Sussex, believes that the Batagaika ‘megaslump’ —so called because of its gigantic size— will continue to grow until it runs out of ice or becomes buried by slumped sediment. If the Siberian climate gets warmer or wetter, which he believes is quite likely, we are going to see other megaslumps develop in the region.
“In some sense, Batagaika does provide a view to what has happened in the past and what is likely to happen in the future. As the climate warms – I think there’s no shadow of a doubt it will warm – we will get increasing thaw of the permafrost and increasingly development of these ‘thermokarst’ features. There will be more slumps and more gullying, more erosion of the land surface,” Dr Murton said.
“I think there’s growing evidence over the last few decades that thermokarst activity in the northern hemisphere has been increasing in extent and intensity,” he adds.
This satellite image of the northern Siberian coast shows dozens of thermokarst lakes which forms by the accumulation of water released by thawing permafrost. The water in these lakes is generally warm compared to the surrounding frozen ground, and they keep the ground underneath from freezing. As water wears away at this soft unfrozen ground, the lake can deepen and expand over time causing more permafrost to melt. Photo credit: NASA
The melting of the permafrost has side-effects that are far-reaching than a couple of sinkholes. The frozen soil contains vast amounts of methane, a greenhouse gas much more potent than carbon dioxide. If the permafrost were to melt and the methane released into the atmosphere, it would cause an unprecedented rise in global temperature tipping the planet into an extreme scenario.
There is no immediate worry of the permafrost melting though, as parts of Siberia still experience temperatures more than fifty degrees below freezing.
The Batagaika crater exposes a huge cross-section of the permafrost that offers geologists a rare glimpse into the ice age history of northeast Siberia. The soil in the megaslump is estimated to be about 200,000 years old and has already revealed to be a treasure trove of fossils. Paleogeologists have recovered frozen remains of a bison, a musk ox, mammoth, and a 4,400-year-old horse.
The last time Siberia saw slumping of this magnitude was 10,000 years ago, as Earth transitioned from the Paleolithic Ice Age into the current-day Holocene.
The Batagaika Crater. Photo credit: Research Institute of Applied Ecology of the North/Alexander Gabyshev
Satellite image of the Batagaika Crater. Photo credit: Google Maps
Permafrost thaw ponds in Hudson Bay, Canada. Photo credit: Steve Jurvetson/Wikimedia
Glacial thaw slump on a lake in Alaska, in 2007. This feature was roughly 100 m across the widest point at the time this photo was taken. However, the feature has since expanded significantly. Photo credit: lternet.edu
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