By Rachel Ramirez and Hafsa Khalil | CNN
An ice floe in Antarctic nearly the size of Los Angeles disintegrated in mid-March in a few days of extraordinary heat on the mainland, scientists say.
The Conger Ice Shelf, which spans approximately 460 square miles, collapsed around March 15. It was at the time when the temperatures rose to minus-12 degrees Celsiusmore than 40 degrees above normal, at the Concordia research station.
“I don’t think there has been a shelf collapse like this in East Antarctica since we were able to get satellite data,” Rob Larter, a marine geophysicist at the British Antarctic Survey, told CNN. “Conger is a very small ice shelf that has been shrinking in size for many years and it was only the last stage that caused it to collapse.”
Antarctica is the coldest and most icy place on earth, which makes recent global warming particularly worrying for many scientists. Just a month ago, data showed Antarctica would set a record this year for smallest extent of sea ice — the ocean area covered by sea ice around the continent.
Ice shelves like the Conger are extensions of land-based ice caps and glaciers that jut out over the ocean. They help prevent these ice caps from relentlessly feeding on ice in the ocean.
When a shelf collapses, there is usually an increase in the amount of ice flowing from land to ocean, resulting in the sea level rises— a phenomenon that threatens coastal communities around the world.
Ted Scambos, a glaciologist at the University of Colorado at Boulder and senior scientist at the National Snow and Ice Data Center, said the ice shelf collapse was likely the culmination of record low sea ice conditions and from wave action hitting the shelf during the recent warm period, which was boosted by strong winds from the warmer north.
Scambos said it could be a preview of what’s to come as the climate crisis eats away at the continent.
“Antarctica as a whole has been kind of locked in an icehouse,” he told CNN. “He’s used to being surrounded by this fringe of sea ice; it has been used at sub-freezing temperatures; and so these are big steps in terms of the type of energy or the type of process that can occur to remove the ice from the edge of the continent.
“And that’s what happened at Conger – and that’s an example of how Antarctica is responding to these record-breaking events.”
Scambos said that for a long time the pack ice was stuck against an island, with the same effect as putting too much pressure on a piece of wood which later starts to break. Scambos said large tears formed over time from that pressure.
Scambos said the Conger collapse is another example in which scientists can observe what happens when an ice shelf is lost and a glacier is threatened.
“It’s not a very big shelf,” Scambos said. “But whenever we’ve seen a plateau pressing against an offshore island or even the coast of a bay, the glaciers behind feel that there’s a back pressure, that there’s a force that resist outward flow, meaning they thin out quickly and flow out faster when the shelf is removed.
Larter said warming temperatures make it more likely that ice shelves will collapse. There have been a series of ice shelf collapses over the past 40 years, but these have mostly occurred in West Antarctica, which is warmer than the East.
Last year, for example, researchers discovered that the pack ice holding back the Thwaites Glacier – also known as “Doomsday Glacier” – could collapse in the next five years. From their camp in the middle of Antarctica to their stations on the coast, Scambos and a team of researchers soared over the gigantic Thwaites Glacier, the size of Idaho, for two hours.
Scambos told CNN they could see “massive cracks in this pack ice, places where the ice is tearing,” a clear sign of Earth’s climate change.
Larter said this happens less frequently in East Antarctica because the ocean water there is much colder.
“The trend in East Antarctica is for the ice sheet to lose ice at the edges and gain ice in the middle,” Larter said. “Overall it’s not unbalanced, but some on the periphery are clueless.”
One glacier that has caught the attention of scientists is the Totten Glacier, which could raise sea levels by around 10 feet if its pack ice collapses.
Scambos said the recent record-breaking events in Antarctica are further evidence of how quickly the climate crisis is accelerating.
“It’s something that’s very hard to stop once it’s started,” he warned. “If we don’t put the brakes on, if we don’t slow down this process, then we’re going to have very rapid rates of sea level rise probably before the end of the century.”
Scambos noted that the children alive right now would be the ones who would suffer these repercussions.
“And even though I won’t be there to see it, there are people here with us today – they’re a bit smaller than most of us – but they’ll be there for it,” Scambos added. . “And that means we owe it to them to try to deal with it as soon as possible.”