In the remote Siberian tundra, the ground itself has begun to explode. Since 2014, more than 20 mysterious craters, each hundreds of feet wide, have torn open the Russian Arctic’s permafrost, leaving behind jagged holes filled with inky darkness. For years, scientists have been trying to explain these odd and, frankly, scary craters.

Once mistaken for meteor impacts or dismissed as eccentricities of frozen soil, these explosive voids may now have an explanation grounded in science — and climate change.

A Decade of Unanswered Questions

The first crater, a gaping chasm, appeared on the Yamal Peninsula in 2014. Over the next decade, similar craters erupted across Yamal and its neighbor, the Gydan Peninsula, sparking theories that ranged from gas buildups to more ridiculous explanations like alien interventions.

But now, a team of researchers has pinpointed a plausible culprit: climate change, interacting with Siberia’s unusual underground geology. Their findings, published recently in Geophysical Research Letters, describe how warming temperatures in this remote region lead to the explosive release of methane gas from deep underground. They believe these eruptions result from methane hydrates trapped within the frozen soil.

“We’re talking about a very niche geological space,” said Ana Morgado, a chemical engineer at the University of Cambridge and one of the study’s authors. The explanation for this phenomenon, according to Morgado, required the unique combination of permafrost, methane hydrates, and a thin layer of salty, unfrozen water known as “cryopegs,” buried between layers of permafrost.

The Role of Methane Hydrates and Climate Change

Methane hydrates are essentially solidified methane trapped in ice. They form at the high-pressure, low-temperature conditions found deep under Siberia’s permafrost. The stability of these hydrates can be perturbed even by slight shifts in the temperature of the soil above. Rising temperatures have melted the upper layers of permafrost, allowing water to trickle down to the cryopeg — a layer that, like salty quicksand, sits beneath frozen soil but remains liquid because of its salinity.

As meltwater from the upper permafrost enters this salty cryopeg through osmosis, pressure builds. Eventually, this force cracks the overlying soil. When these cracks reach the surface, they cause a sharp pressure drop in the cryopeg, destabilizing the methane hydrates. Next comes an explosive release of methane gas. “It’s a bit like detective work,” Morgado explained, as she recounted as her team had to sift through multiple lines of evidence to single out the “suspect”.

The scientists emphasize that this explosive chain reaction, involving melting permafrost and methane hydrates, could last decades. Warming that began in the 1980s might already be triggering today’s explosions, with more to come as the Arctic continues to heat up.

Concerns About Future Explosions

The explosions are obviously dangerous if you’re a Siberian local, but the effects may be felt worldwide. Methane is a potent greenhouse gas, with the ability to trap heat up to 80 times more effectively than carbon dioxide over short timescales. While two dozen methane crater explosions may be a drop in the bucket compared to other drivers of global warming, they serve as stark reminders of the accelerating changes in the Arctic.

“Climate change is likely a primary driver,” observed Lauren Schurmeier, a geophysicist at the University of Hawaii. She noted that these craters often appear following unusually warm summers, and that warming trends could make such craters increasingly common. “They are a terrifying sign that the Arctic is changing,” she told CNN.

However, the new study is not without its skeptics. Some experts believe the explanation may be too simple. Evgeny Chuvilin, a lead scientist at the Skolkovo Institute of Science and Technology in Moscow, argues that the process of meltwater infiltrating such thick, ice-rich permafrost to reach the cryopeg may be more complex than the study suggests. Chuvilin, who has studied the craters for years, believes that methane may also accumulate in smaller cavities nearer the surface before bursting through, as opposed to requiring deep cryopeg interactions, he told CNN.

While these interpretations diverge, most experts agree that climate change plays a significant role in weakening the frozen landscape. Ultimately, this makes it more vulnerable to explosive gas releases.

Watching for What Comes Next

The Russian Arctic is vast, and many of these crater sites lie in desolate, isolated terrain. Nonetheless, as more are discovered, scientists grow increasingly concerned about potential risks to people and infrastructure. The Oil and Gas Research Institute of the Russian Academy of Sciences, which monitors the region, has begun observing mounds near inhabited areas, wary of future explosions.

For Morgado and her team, the craters are emblematic of a deeper issue: humanity’s role in altering Earth’s climate. “It’s very fast,” she said. “It’s not millennia anymore; it happens in a couple of decades.”

As researchers seek to refine their understanding of these craters, they also aim to anticipate where future eruptions might occur, potentially saving lives and critical infrastructure from the Arctic’s underground forces.