A sheet of ice the size of Delaware is almost certain to break away from Antarctica soon, after a crack in an ice shelf grew dramatically at the end of 2016, researchers say.
A 2,000-square mile section of the Larsen C shelf, the northernmost major ice sheet in Antarctica, is now hanging on to the continent with a meager 12-mile stretch of frozen water. A rift that threatens to shear the sheet away grew more than 10 miles in just a couple weeks in December, the BBC reported, and scientists have said it’s likely the crack will soon end a decades-long standoff.
“If it doesn’t go in the next few months, I’ll be amazed,” Adrian Luckman, the lead researcher behind Project MIDAS, which monitors the ice shelf, told BBC News. “It’s so close to calving that I think it’s inevitable.”
If and when the section of Larsen C breaks away, it’ll remove between 9 and 12 percent of the ice shelf area and leave the sheet at “its most retreated position ever,” Luckman and his team said last year. The ice shelf, which floats completely over the ocean off Antarctica, is about 350 meters thick and the rift cuts completely through the entire sheet, according to NASA.
When the sheet breaks off, it’ll create one of the 10 largest icebergs ever recorded, Luckman told the BBC. The event could trigger the eventual collapse of the entire Larsen C, which spans some 21,000 square miles, Luckman continued, although he noted such models are hard to predict.
“We would expect in the ensuing months to years further calving events, and maybe an eventual collapse ― but it’s a very hard thing to predict, and our models say it will be less stable; not that it will immediately collapse or anything like that,” he said.
NASA reports that even if the shelf were to break away and melt, it wouldn’t contribute directly to sea level rise because the shelf is already floating. But the Larsen C helps hold back other glaciers on land that, if exposed to the ocean, could in turn melt and increase sea levels.
Two other ice shelfs in the region, the Larsen A and Larsen B, have already collapsed in spectacular fashion, in 1995 and 2002 respectively. When Larsen B broke up, the National Snow and Ice Data Center said the world had lost an ice sheet that had “likely existed since the end of the last major glaciation 12,000 years ago,” The Washington Post reports.
A video that NASA released shows the dramatic disintegration of Larsen B below.