12,000 years ago the Barents Sea was covered with ice. Warming caused ice sheets to recede and a lot of methane was released, leading to blowouts that left the Arctic Sea floor scarred with hundreds of craters. Researchers in Norway recently found these craters, which offer a warning for the future of our world wracked by climate change – and are still leaking methane.
The newly-found seafloor craters date all the way back to the end of our planet’s last Ice Age, when they were caused by explosive blowouts. Many of the Arctic Sea floor craters are huge, measuring around 0.6 miles wide. And many are not inactive, but continue to seep methane.
The ice on the Barents Sea for a time kept methane from hydrocarbon reservoirs from escaping. According to Gizmodo, the methane was stored as a hydrate in sediment, which led to pressurized conditions.
Study lead author Karin Marie Andreassen of the Center for Arctic Gas Hydrate, Climate, and Environment (CAGE) explained it this way: “As the ice sheet rapidly retreated, the hydrates concentrated in mounds, and eventually started to melt, expand, and cause over-pressure. The principle is the same as in a pressure cooker: if you do not control the release of the pressure, it will continue to build up until there is a disaster in your kitchen. These mounds were over-pressured for thousands of years, and then the lid came off.”
Her team found more than 100 craters between 980 and 3,280 feet wide, and hundreds more smaller craters under 980 feet wide. The also found 600 methane flares, where the gas is spewing out near the craters.
Methane concerns scientists because it is 30 times more potent than carbon dioxide when it comes to trapping heat in our atmosphere. And similar geological processes as the ones that led to these Arctic Sea floor craters are still in motion around the world, so scientists think climate change could lead to more methane explosions.