Any ground that has been completely frozen for at least two years is considered permafrost. Permafrost covers nearly a quarter of the land area of the Northern Hemisphere, with Russia, the home of Siberia, accounting for a disproportionately large portion.
Permafrost and the Gateway to the Underworld
Batagay Ice Hole is also known as "Gateway to the Underworld" and Batagaika Crater.
Wildfires in Siberia could permanently alter the region's permafrost, causing the Batagay megaslump to expand. Locals refer to this as the "gateway to the underworld" because it is a huge scar in the landscape, Newsweek reports.
Permafrost is thought to play a key role in climate change because it stores massive amounts of carbon dioxide and other global warming gases, which are released if it melts.
According to the Natural Resources Defense Council (NRDC), permafrost in the Arctic holds nearly double the amount of carbon currently found in the atmosphere.
Melting permafrost also has the potential to change the landscape dramatically. When ice-rich permafrost melts, it can cause a thaw slump, in which the ground collapses and a large hole is left behind.
Thaw slumps can spread quickly and cause infrastructure damage. The Batagay megaslump in Siberia is considered to be the world's largest thaw slump.
According to NASA's Earth Observatory, the slump is of interest to researchers as it holds clues to prehistoric life on Earth, holding about 200,000 years of geological and biological history frozen in its depths.
This year, deadly wildfires swept through Siberia, prompting Russian President Vladimir Putin to order regional officials to take action to prevent a repeat of last year's fires, which were the country's worst in modern history.
Opening the Gateway to the Underworld
According to experts, there is a risk that the fires and further warming of the region may cause the "gateway to the underworld" to get even larger, Newsweek reports.
Thomas Opel, a paleoclimate and permafrost researcher at the Alfred Wegener Institute in Germany, explained that it can be assumed that further warming of the region could lead to accelerated growth of the slump.
The researcher added that it appears as though the slump's growth rate had already been increasing in recent decades, with wildfires posing an even greater risk.
Opel pointed out that the area around Batagay has been subject to severe wildfires over the last few years. He added that fire will cause some damage to the vegetation cover that protects permafrost from thawing.
To Opel's memory, some slumps have been initiated due to wildfire.
Opel suggested that a growing slump would mainly "consume" or "eat" the existing landscape.
Julian Murton, professor of permafrost science at the U.K.'s University of Sussex Department of Geography, agrees with Opel and echoes the point.
Murton said that the fires would need to be very close to the crater to directly affect its growth. The fires may trigger permafrost thaw and, possibly in time, new slumps at sites where they sweep over-sensitive, ice-rich permafrost.
According to the professor, if fires kill or destroy the protective vegetation cover above the permafrost, it can result in rapid soil warming and permafrost thawing for years to decades, depending on how long it takes for vegetation to re-establish.
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