The last fully intact ice shelf in the Canadian Arctic has collapsed, losing more than 40% of its area in just two days at the end of July, researchers said Thursday.
The Milne Ice Shelf is located on the edge of Ellesmere Island in the sparsely populated northern Canadian territory of Nunavut.
“Above-normal air temperatures, offshore winds and open water in front of the pack ice are all part of the recipe for pack ice,” the Canadian Ice Service said on Twitter when it announced the loss on Sunday.
“Entire cities are this size. These are big chunks of ice, ”said Luke Copland, a glaciologist at the University of Ottawa who was part of the research team studying the Milne Ice Shelf.
The area of the plateau has shrunk by about 80 square kilometers. By comparison, Manhattan Island in New York City covers approximately 60 square kilometers.
“It was the largest remaining intact ice shelf, and it basically disintegrated,” Copland said.
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The Arctic has been warming at twice the global rate for the past 30 years, due to a process known as Arctic Amplification. But this year, temperatures in the polar region have been intense. Polar sea ice reached its lowest extent in July in 40 years. Record heat and forest fires burned Siberian Russia.
Summer in the Canadian Arctic this year in particular has been 5 degrees Celsius above the 30-year average, Copland said.
This has threatened smaller ice caps, which can melt quickly because they don’t have the volume needed for larger glaciers to stay cold. As a glacier disappears, more bedrock is exposed, which heats up and speeds up the melting process.
“The very small ones, we lose them considerably,” he said, citing the researchers’ criticism of satellite imagery. “You feel like you’re on a sinking island looking for these features, and they are great features. It’s not like it’s a little patch of ice that you find in your backyard.
The collapse of the ice shelf on Ellesmere Island also resulted in the loss of the last known Lake Epishelf in the Northern Hemisphere, a geographic feature in which a body of fresh water is dammed by the shelf. ice forms and floats above ocean water.
A research camp, including instruments to measure the flow of water through the ice shelf, was lost when the shelf collapsed. “It’s lucky we weren’t on the ice when this happened,” Carleton University researcher Derek Mueller in Ottawa said in an August 2 blog post.
Ellesmere also lost its two St. Patrick’s Bay ice caps this summer.
“We saw them go, like a person with terminal cancer. It was only a matter of time, ”said Mark Serreze, director of the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.
Serreze and other NSIDC scientists had published a 2017 study predicting that the ice caps were likely to disappear within five years. It is believed that ice caps formed several centuries ago.
The disappearance was confirmed last month, when NASA satellite images of the area revealed a complete lack of snow and ice, said Serreze, who studied caps as a graduate student on his maiden trip. in the Arctic years ago. Back then, he says, caps had seemed like still parts of geography.
“When I was there in the 1980s, I knew every square inch of these ice caps,” he says. “You have the memories. It’s like your first girlfriend.
Meanwhile, two other Ellesmere ice caps – called Murray and Simmons – are also shrinking and are likely to disappear within 10 years, Serreze said.