An ice sheet has collapsed in the eastern part of the continent for the first time since satellites began observing Antarctica nearly half a century ago, scientists said.
The collapse of the 450 square mile Conger ice shelf in a part of the continent called Wilkes Land occurred in mid-March. It was first detected by scientists with the Australian Bureau of Meteorology and appeared in satellite images taken on March 17, according to the National Ice Center in the US.
Ice shelves are tongues of ice floating at the end of glaciers in Antarctica that serve as outlets for the continent’s huge ice sheets. The stresses cause cracks in the floating ice, and melt water and other factors can cause the cracks to erode and grow to a point where the shelf crumbles rapidly.
According to the National Ice Center, the largest piece of the Conger shelf after the collapse was an iceberg called C-38, measuring about 200 square miles.
The loss of a shelf could allow the glaciers behind it to move faster, resulting in faster ice sheet loss and therefore more sea level rise. Ice shelf loss is a major concern in West Antarctica, where warming due to climate change is having a greater impact than east.
a few many Major glaciers in West Antarctica They’re already flowing faster, and if the ice shelves were to collapse completely, sea levels could rise 10 feet over the centuries.
But the two glaciers behind the Conger layer are small, and even if they were to accelerate, they would have minimal impact at sea level in fractions of an inch in a century or two, says senior researcher Ted Scambos. Earth Sciences and Observation Center at the University of Colorado Boulder.
As some ice shelves collapse in West Antarctica – especially much larger Larsen B in 2002 Catherine Walker, a glaciologist at the Woods Hole Oceanographic Institution in Massachusetts, said the Conger collapse was the first observed in East Antarctica since 1979, when the era of satellite imagery began.
Following the ice shelf for several months, Dr. Walker said the ice shelf has been in retreat for several years. “In the beginning it was just an unhealthy little shelf of ice,” he said. But it has stabilized between the mainland and a small island, he said.
Therefore, although the collapse was not a complete surprise, it happened sooner than expected.” He and Dr. The Scambos agreed that recent weather in that part of Antarctica may have played a role.
In mid-March, an atmospheric river, a cloud of air heavy with water vapor, swept East Antarctica from the ocean to the north. It resulted in record-breaking temperatures in some places, with temperatures as high as 70 degrees Fahrenheit than normal for this time of year.
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The heat could have caused the Conger ice shelf to melt further at the surface, helping to further erode its fissures and hasten its collapse. However, Dr. Scambos, windy conditions from the atmospheric river, record low sea ice He played a bigger role around Antarctica this season.
Sea ice acts as a buffer, dampening waves rolling from sea to shore. Southern Ocean. With less ice and the wind stirring the ocean even more, the floating shelf flexed more than it normally would. Dr. “The stretching probably weakened the more stable parts of the ice that held the shelf together,” Scambos said.
“The warm pulse probably didn’t do much,” he said, “but wind events and warm temperatures in the air and ocean certainly don’t help ice shelf stability.”
East Antarctica was considered the more stable region of Antarctica, with less warming and even ice gains in some areas. Dr. The collapse of the Conger ice shelf didn’t really change that view, Walker said. “We don’t see any signs that this will happen in the rest of East Antarctica anytime soon,” he said.
Studying the more at-risk ice shelves and glaciers in West Antarctica, Dr. Scambos said it would be interesting to see what happened to the glaciers behind Conger. “Every time one of these things happens,” he said, “it tells us a little more about how larger parts of Antarctica will react when larger events occur.”