Melting of Alaska’s Juneau Glacier, home to more than 1,000 glaciers, is accelerating. The snow-covered area is now shrinking 4.6 times faster than in the 1980s, according to a new study.
Scientists carefully monitored the snow level in an ice area of nearly 1,500 square miles going back to 1948 with added data up to the 18th century. It had been slowly shrinking from its maximum size at the end of the Little Ice Age around 1850, but then that melting rate accelerated about 10 years ago, according to a study on Tuesday. The nature of communication.
“What’s up, it is.” the climate is changing, we have increasingly shorter winters and longer summers,” lead study author Bethan Davies, a glaciologist at Newcastle University in England. “We have more melting, a longer melting period.”
A group of people look at Mendenhall Glacier on June 8, 2023 in Juneau, Alaska. (AP Photo/Becky Bohrer, File)
According to study co-author Mauri Pelt, a professor of environmental science at Nichols College in Massachusetts, it’s melting so fast that ice flow into the water now averages about 50,000 gallons every second.
“In fact, the shrinking of the Alaska glacier from 2000 to 2020, we’re losing more ice in Alaska than anywhere else,” Davies said.
Between 1948 and 2005, only four Juneau glaciers disappeared. However, 64 disappeared between 2005 and 2019, the study said. Many of the glaciers were too small to name, but one larger one, the Antler Glacier, “is completely gone,” Pelto said.
Alaska climatologist Brian Brettschneider, who was not part of the study, said the acceleration was most concerning and warned of a “death spiral” for the thinning ice field.
An ice field is a collection of glaciers, while an ice sheet is something for an entire continent and only two of them remain, in Greenland and Antarctica. The most famous glacier in the Juneau Ice Field 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 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,” Pelto said.
Pelto first took to the ice fields in Juneau in 1981 to try to make the U.S. Ski Team and has since continued his studies, giving up competitive skiing for research.
“In 1981 it wasn’t too difficult to get on and off the glaciers. You just go up and you could ski all the way down or hike right at the end of these glaciers,” Pelto said. But now they have snowmelt lakes on the edges and crevasses opening up that make skiing difficult, he said.
Now it’s also like a staircase of bare stones, Pelto said. White snow and ice reflect the sun’s heat, dark rocks absorb it, warming the ground and melting more snow in a feedback effect that amplifies and accelerates warming-induced melting, the study said.
The snow elevation line is key. Below the snow line, the snow may disappear in summer, but above there is snow cover all year round. That snow line is still moving up, Pelto said.
The shape of Juneau’s ice field, which is rather flat, “is vulnerable to specific tipping points,” because once the snow line moves up, large areas are suddenly more susceptible to melting, Davies said.
“The tipping point is when the snow line goes over your entire ice field, ice sheet, glacier, whichever one,” Pelto said. “And so the Juneau ice field in 2019 and 2018 showed that you’re not that far from that tipping point.”
Even if all the snow in the Juneau Icefield melted, which is still a long way off, it wouldn’t add much to global sea levels, Pelto said. But it is a major tourist destination and a cultural hot spot, Davies said.
“It’s worrisome because in the future the Arctic will change to what we currently recognize,” 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 of 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 the melting ice field from satellite images, aircraft overflights, images stored in storage drums and historical local measurements, stitching them all together like a giant jigsaw puzzle with most of the pieces almost all white.
Five different external experts said the research made sense and fit with other observations. Michael Zemp, Supervisor World Glacier Monitoring Servicehe said it shows “that we need urgent and tangible measures to save at least some of the remaining ice.”
“It’s been 40 years since I first saw a glacier. So what will it look like in 40 years?” Pelto said. “I think by then the Juneau ice field will be past the tipping point.”
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