Antarctic ice shelf nearly the size of Los Angeles collapsed as temperatures soared to 40 above normal

(CNN)An ice shelf in Antarctica nearly the size of Los Angeles disintegrated in mid-March within days of extraordinary warmth on the continent, scientists say.

The Conger Ice Shelf, spanning approximately 460 square miles, collapsed around March 15. It was around the time temperatures soared to minus-12 degrees Celsius, more than 40 degrees warmer than normal, at the Concordia research station.
"I don't think there has been a shelf collapse like this in East Antarctica since we've been able to receive satellite data," Rob Larter, a marine geophysicist at the British Antarctic Survey, told CNN. "Conger is a very small ice shelf which has been decreasing in size for many years and this was just the final step which caused it to collapse."
    Antarctica is the coldest, iciest place on Earth, which makes the recent warming event particularly worrying for many scientists. Just a month ago, data showed Antarctica would set a record this year for lowest sea-ice extent — the area of ocean covered by sea ice around the continent.
      Ice shelves like the Conger are extensions of land-based ice sheets and glaciers that jut out over the ocean. They help prevent those ice sheets from feeding ice unabated into the ocean.
      When a shelf collapses, there tends to be an increase in the ice that flows from the land into the ocean, which leads to sea level rise— a phenomenon that threatens coastal communities around the world.
      Ted Scambos, a glaciologist at the University of Colorado at Boulder and lead scientist at the National Snow and Ice Data Center, said the ice shelf's collapse was likely a culmination of the record low sea ice conditions and the wave action hitting the shelf during the recent warm period, which was spurred by a 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 kind of been locked away in an icebox," he told CNN. "It's been used to being surrounded by this fringe of sea ice; it's been used to temperatures that are below freezing; and so those are big steps in terms of the kind of energy or the kind of processes that can happen to take away the ice from the edge of the continent."
        "And that's what happened at Conger — and it's an example of how Antarctica responds to these record events."
        Scambos said that for a long time the ice shelf had been wedged against an island, with the same effect as putting too much pressure on a piece of wood that later begins to splinter. Scambos said large rips had formed over time because of this pressure.
        Scambos said the Conger's collapse is another instance in which scientists get to observe what happens when an ice shelf is lost and a glacier is threatened.
        "It's not a very large shelf," Scambos said. "But every time we've seen a shelf that is braced against an offshore island or even the coast of a bay, the glaciers behind it sense that there's a back pressure, that there's a force that's resisting outward flow. In other words, they thin rapidly and they flow faster when the shelf is removed."
        Larter said that warming temperatures are making the collapse of ice shelves more likely. There has been a series of ice shelf collapses over the past 40 years, but those have mainly been in West Antarctica, which is warmer compared to the east.
        Last year, for example, researchers discovered that the ice shelf holding back the Thwaites Glacier — also known as the "Doomsday glacier" — could collapse within the next five years. From their camp in the middle of the Antarctic to their stations on the coast, Scambos and a team of researchers flew over the gargantuan Thwaites Glacier, the size of Idaho, for two hours.