SIBERIA – A decade ago, a mysterious crater appeared in the Russian Arctic, forming a huge jagged hole hundreds of feet wide, plunging down into an inky abyss. It was surrounded by enormous chunks of soil and ice, testament to the violent forces that created it. Since 2014, more than 20 such craters have exploded, pockmarking the remote landscape of northwestern Siberia’s Yamal and Gydan Peninsulas — the most recent of which was discovered in August.

The craters have both intrigued and baffled scientists, who have spent years trying to unravel how they erupted into existence. A series of hypotheses have emerged, including wilder theories like a meteor strike or even aliens. Now, a team of engineers, physicists and computer scientists say they have found a new explanation. Their findings, set out in a study published last month, suggest it’s a mix of human-caused climate change and the region’s unusual geology.

Scientists were already in general agreement the craters form when gases trapped beneath the tundra — including planet-heating methane — build up underground, causing a mound to appear on the surface. When the pressure below exceeds the strength of the ground above, the mound explodes, belching out gases. What’s still up for debate are the more specific mechanisms of how the pressure builds, and exactly where the gas comes from. (CNN)

Photo: An aerial view of a crater on the Yamal Peninsula, northwestern Siberia. (Getty Images)…[+]