The melting of Alaska’s Juneau Icefield, which contains more than 1,000 glaciers, is accelerating and could reach a tipping point much sooner than predicted, according to research published Tuesday.
The research, which was published in the journal Nature communicationshows that ice loss from the Juneau Icefield began to accelerate rapidly after 2005.
The paper’s authors found that “the rate of glacier area shrinkage was five times faster from 2015-2019 than from 1979-1990,” while the loss of glacier volume — which had remained relatively constant from 1770-1979 — doubled after 2010.
“What will it look like in 40 years? I think the Juneau Icefield will be past the tipping point by then.”
“Since 2005, thinning of the ice field plateau has become ubiquitous, accompanied by glacier recession and fragmentation,” the study said. “As glacier thinning on the plateau continues, a mass balance-elevation feedback is likely to inhibit future glacier growth, potentially pushing glaciers beyond a dynamic tipping point.”
Lead study author Bethan Davies, a glaciologist at the University of Newcastle in England, said in a statement: “It is extremely worrying that our research has found a rapid acceleration in the rate of glacier loss in the Juneau Icefield since the early 21st century.”
“The Alaskan ice fields, which are predominantly flat plateau ice fields, are particularly vulnerable to accelerated melting as the climate warms, as the ice loss is occurring across the entire surface, meaning a much larger area is affected,” Davies continued. “Furthermore, flatter ice sheets and ice fields cannot retreat to higher elevations and find a new equilibrium.”
“As glaciers on the Juneau Plateau thin and the ice retreats to lower elevations and warmer air, the feedback processes this sets in motion are likely to inhibit future glacier growth, potentially pushing glaciers past a tipping point and into irreversible retreat,” she added.
Study co-author Mauri Pelto, a professor of environmental science at Nichols College in Massachusetts, saidThe Associated Press that the Juneau Ice Field is melting at a rate of about 180,000 gallons per second.
“When you go out there, the changes from year to year are so dramatic that it’s just overwhelming,” Pelto said. “In 1981, it wasn’t that hard to get on and off the glaciers. You could just hike up and you could ski down or hike all the way off the end of these glaciers. But now they have lakes on the edges from melted snow and crevasses forming that make it hard to ski.”
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Only four Juneau Icefield glaciers melted between 1948 and 2005. But 64 of them disappeared between 2005 and 2019, the study found. Many of the glaciers were too small to name, but one larger one, Antler Glacier, “is completely gone,” Pelto said.
Alaska climatologist Brian Brettschneider, who was not involved in the study, called the acceleration deeply concerning and warned of a “death spiral” for the thinning ice field.
Pelto said that “the tipping point is when the snow line comes up over your entire ice sheet, ice cap, ice glacier or whatever.”
“And so for the Juneau Icefield, 2019, 2018, we showed that you’re not that far from that tipping point,” he added. “We’re 40 years from the first time I saw the glacier. And so, what’s it going to look like in 40 years? I think the Juneau Icefield will be past the tipping point by then.”
It’s not just Alaska. Glaciers around the world, from Greenland to Switzerland to Africa to the Himalayas, are melting at an alarming rate. The United Nations Educational, Scientific, and Cultural Organization warned in 2022 that glaciers in a third of the 50 UNESCO World Heritage sites where they are found are on track to disappear by 2050, even if planet-warming emissions are curbed.
Another study published last year by researchers from Carnegie Mellon University and the University of Alaska found that even if humanity manages to limit global warming to 1.5°C above pre-industrial temperatures (the more ambitious goal of the Paris climate agreement), half of the Earth’s glaciers will melt by the end of the century.