With each passing year, the world’s biggest permafrost crater, the Batagay megaslump, is expanding by 35 million cubic feet (one million cubic meters). When first discovered in the 1960s, Batagay looked like a small hole, but in the last 60 years, permafrost thaw caused by deforestation and climate change has turned it into a giant tadpole-shaped depression. It’s simply massive and growing deeper and wider with each passing day.

It is currently 800 meters wide, 1 kilometer long (0.6 miles), and has a depth ranging between 50 and 100 meters (164 and 328 feet). Technically, Batagay (also referred to as Batagaika) is not a crater but a thermokarst depression, a slump or hole formed by the melting of frozen soil (permafrost). 

The depression is located in the Chersky range of Siberia, a remote area in northern Russia. It is called a megaslump or, more poetically, a ‘gateway to hell’, because of its sheer size. While the expanding landform attracts many tourists to Siberia, scientists are more concerned about its impact on the environment and human health.

“The crater’s growth affects the environment through the mobilization of sediments and nutrients that were contained in permafrost, including carbon mobilization and greenhouse gas emission,” Alexander I. Kizyakov, first author of the study and a senior researcher at Lomonosov Moscow State University, told ZME Science.

Batagay’s expansion is triggering a vicious cycle

Permafrost acts as a massive carbon vault, holding vast amounts of carbon in the form of dead plants and animals that don’t decay completely in the frozen soil. Some parts of the Batagay have remained frozen for 650,000 years.

However, the warming climate is triggering rapid permafrost thaw in the Batagay crater region, causing the release of the stored carbon into the atmosphere as greenhouse gases, such as carbon dioxide and methane. This further exacerbates global warming and permafrost loss, turning into a vicious cycle that could continue until all the permafrost is lost. 

“About 4,000 to 5,000 tons of previously permafrost-locked organic carbon is released every year” from the crater, the study authors said. Moreover, “from its formation in the 1970s until 2023, the Batagay RTS – due to thermal denudation and headwalls retreat – mobilized a total volume of about 34.7 million cubic meters (1,225 cubic feet) including a total of about 169,500 tons organic carbon,” they added.

However, carbon isn’t the only thing that escapes. Many studies suggest that permafrost thaw could also release pathogens that have remained dormant and frozen for years. 

For instance, in 2016, a remote village in Siberia witnessed a mysterious anthrax outbreak caused by Bacillus anthracis. It was thought that the bacteria might have emerged from the frozen ground due to a heat wave. The outbreak took the lives of 2,649 reindeer and a 12-year-old boy. In 2022 also, a team of researchers discovered 13 previously unknown viruses in permafrost samples collected from Siberia. 

Not all microbes emerging from the thawing permafrost may be dangerous to human health or wildlife, but even a single escaped pathogen for which we have zero immunity could spell a disaster. Suppose a harmful but unknown ancient virus emerges from the Batagay crater, do we have any systems in place to deal with such threats?

Preventing further damage is crucial

The rapid expansion of the Batagay megaslump is driven by climate change. Currently, it is growing at a rate of 35 million cubic feet annually. However human activity can further increase this rate in the event of disturbance of the vegetation and soil cover near its edges. 

“This can result from a mechanical disturbance as a result of, for example, construction work or an anthropogenically caused fire that burns the vegetation,” Alexander Kizyakov told ZME Science.

Therefore, it is important to ensure that while we take steps to reverse climate change, no further damage is caused to the permafrost. Otherwise, the Batagay crater might end up losing all its frozen ground. 

The carbon emissions resulting from such an event would worsen the conditions for similar landforms located in Eurasian and North American ice-rich permafrost areas.

Hopefully, the findings from the current study will encourage people, governments, and organizations to implement more robust measures for mitigating and reversing climate change.  

The study is published in the journal Geomorphology.