Melting of Alaska’s Juneau Icefield, home to more than 1,000 glaciers, is accelerating. The area covered by snow is now shrinking 4.6 times faster than in the 1980s, according to a new study.
Researchers meticulously tracked snow levels icy expanse of nearly 1,500 square miles going back to 1948 with data added in the 18th century. It slowly shrunk from its peak size at the end of the Little Ice Age around 1850, but then that rate of melting accelerated about 10 years ago, according to a study Tuesday. Nature Communications.
“What’s happening is how the climate is changing, we’re having shorter winters and longer summers,” lead study author Bethan Davies, a glaciologist at the University of Newcastle in England. “We have more, longer melting seasons.”
A group of people take in views of the Mendenhall Glacier on June 8, 2023, in Juneau, Alaska. (AP Photo/Becky Bohrer, File)
It’s melting so fast that ice flow into the water now averages about 50,000 gallons every second, according to study co-author Mauri Pelto, a professor of environmental science at Nichols College in Massachusetts.
“In fact, the shrinking of the glaciers in Alaska from 2000 to 2020, we’re losing more ice in Alaska than anywhere else,” Davies said.
Only four of Juneau’s ice field glaciers melted between 1948 and 2005. But 64 of them disappeared between 2005 and 2019, the study said. Many of the glaciers were too small to mention, but one larger one, Antler Glacier, “is completely gone,” Pelto said.
Alaska climatologist Brian Brettschneider, who was not part of the study, said the acceleration is more worrisome, warning of “a death spiral” for the thinning ice field.
An ice field is a collection of glaciers, while an ice sheet is something across the entire continent, and only two of them remain, in Greenland and Antarctica. The most famous glacier in the Juneau Icefield is Mendenhall Glacier, a tourist hotspot. The Arctic is warming four times faster than the rest of the globe with Alaska warming 2.6 degrees (1.5 degrees Celsius) since 1980, according to federal weather data.
People walk on a frozen Mendenhall Lake, with the Mendenhall Glacier in the background, February 18, 2024, in Juneau, Alaska. (AP Photo/Becky Bohrer)
“When you go there, the changes from year to year are so dramatic it blows your mind,” said Pelto.
Pelto first took to the Juneau ice rink in 1981 to try out for the U.S. Ski Team and has continued to study it ever since, giving up competitive skiing for research.
“In 1981, it wasn’t too difficult to get on and off the glaciers. You just walk up and you can ski to the bottom or walk to the bottom of these glaciers,” Pelto said. But now they have lakes on the edges from melting snow and crevasse openings that make skiing difficult, he said.
It’s also now like a bare stone staircase there, Pelto said. White snow and ice reflect the sun’s heat, dark rocks absorb it, making the ground warmer, melting more snow in a feedback effect that amplifies and accelerates warming-induced melting, the study said.
The main one is the snow height line. Below the snow line, the snow may disappear in summer, but there is year-round snow cover above. That snow line continues to move up, Pelto said.
The shape of Juneau’s ice field, which is fairly flat, “makes it vulnerable to particular tipping points” because once the snowline moves up, large areas are suddenly more prone to melting , Davies said.
“The tipping point is when that snow line goes over your entire ice field, ice sheet, ice glacier, whatever,” Pelto said. “And so for the Juneau ice rink, 2019, 2018, it showed that you’re not that far from that tipping point.”
Even if all the snow on the Juneau Icefield were to melt, and that’s a long way off, it wouldn’t add much to global sea levels, Pelto said. But it is a major tourist destination and cultural hotspot, Davies said.
“It’s worrisome because in the future the Arctic will transform beyond contemporary recognition,” said Julienne Stroeve, an ice scientist at the University of Manitoba who was not part of the study. “It’s just another sign of a major transformation in all the ice components (permafrost, sea ice, land ice) that communities depend on.”
Davies said the team was able to get such a long-term picture of ice melt from satellite images, aircraft flights, pictures stored in batteries in a warehouse and local historical measurements, piecing it all together like a giant jigsaw puzzle. with most parts being almost all white.
Five different outside experts said the research made sense and fit with other observations. Michael Zemp, head of World Glacier Monitoring Servicesaid it shows “that we need urgent and tangible action to save at least some of the remaining ice.”
“It’s been 40 years since I first saw the glacier. And so, 40 years from now, what will it look like?” said Pelto. “I think by then the Juneau ice field will have passed the tipping point.”
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