The world's largest permafrost crater
The Batagaika Crater is not a crater—it was not formed by a meteorite impact or volcanic eruption. It is technically a "thermokarst depression" or a "megaslump," the largest of its kind on Earth. Located in the East Siberian taiga, the gash in the landscape is approximately 1 kilometer (0.6 miles) long and reaches depths of up to 100 meters (328 feet). The local Yakutian people refer to it as the "gateway to the underworld," partly due to the booming and crashing sounds of collapsing earth and ice that echo from the slump in the summer.
Its formation began in the 1960s when a section of the surrounding forest was cleared. The removal of the trees' shade and the cooling effect of their transpiration warmed the ground surface. This initiated the thawing of the underlying permafrost, causing the ground to sink and slump. The process accelerated, and major flooding in 2008 significantly increased the depression's size. The crater's headwall now retreats by as much as 30 meters (98 feet) in warmer years, constantly expanding the feature and exposing more frozen ground to the air in a dangerous feedback loop.
An ice age archive
The collapsing walls of the crater are a vertical archive of Earth's past, exposing geological and biological history locked in ice for millennia. Scientists have dated the oldest layers of permafrost at the bottom of the crater to be approximately 650,000 years old, making it the oldest known permafrost in Eurasia. These sediment layers provide an unparalleled natural laboratory for understanding past climate changes.
As the permafrost thaws, it reveals a trove of well-preserved Ice Age fossils. Discoveries include the carcasses of a 42,000-year-old extinct Lena horse (Equus lenensis), prehistoric steppe bison (Bison priscus), woolly mammoths, and musk ox. The frozen ground has also preserved ancient forests, pollen, and even samples of ancient DNA, showing researchers of the flora and fauna that inhabited this region during past warm and cold periods. The thaw also releases enormous quantities of organic carbon—an estimated 4,000 to 5,000 tons per year—into the atmosphere as carbon dioxide and methane, further accelerating global warming.