The melting of Alaska’s Juneau ice field—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
study, which was published in the journal Nature Communications, shows that ice loss from the Juneau ice field began accelerating rapidly after 2005.
The paper’s authors found that “rates of area shrinkage were five times faster from 2015-2019 than from 1979-1990,” while glacier volume loss—which had remained relatively consistent from 1770-1979—doubled after 2010.
“Forty years from now, what is it going to look like? I do think by then the Juneau ice field will be past the tipping point.”
“Thinning has become pervasive across the icefield plateau since 2005, accompanied by glacier recession and fragmentation,” the study states. “As glacier thinning on the plateau continues, a mass balance-elevation feedback is likely to inhibit future glacier regrowth, potentially pushing glaciers beyond a dynamic tipping point.”
Study lead author Bethan Davies, a glaciologist at Newcastle University in England, said in a statement, “It’s incredibly worrying that our research found a rapid acceleration since the early 21st century in the rate of glacier loss across the Juneau ice field.”
“Alaskan icefields—which are predominantly flat, plateau icefields—are particularly vulnerable to accelerated melt as the climate warms since ice loss happens across the whole surface, meaning a much greater area is affected,” Davies continued. “Additionally, flatter ice caps and icefields cannot retreat to higher elevations and find a new equilibrium.”
“As glacier thinning on the Juneau plateau continues and ice retreats to lower levels and warmer air, the feedback processes this sets in motion is likely to prevent future glacier regrowth, potentially pushing glaciers beyond a tipping point into irreversible recession,” she added.
Study co-author Mauri Pelto, a professor of environmental science at Nichols College in Massachusetts, told The Associated Press that the Juneau ice field is melting at a rate of about 50,000 gallons per second.
“When you go there the changes from year to year are so dramatic that it just hits you over the head,” Pelto said. “In 1981, it wasn’t too hard to get on and off the glaciers. You just hike up and you could you could ski to the bottom or hike right off the end of these glaciers. But now they’ve got lakes on the edges from melted snow and crevasses opening up that makes it difficult to ski.”
As the
AP reported:
Only four Juneau ice field glaciers melted out of existence between 1948 and 2005. But 64 of them disappeared between 2005 and 2019, the study said. Many of the glaciers were too small to name, but one larger one, Antler glacier, “is totally gone,” Pelto said.
Alaska climatologist Brian Brettschneider, who was not part of the study, said the acceleration is most concerning, warning of “a death spiral” for the thinning ice field.
Pelto said that “the tipping point is when that snow line goes above your entire ice field, ice sheet, ice glacier, whichever one.”
“And so for the Juneau ice field, 2019, 2018, showed that you are not that far away from that tipping point,” he added. “We’re 40 years from when I first saw the glacier. And so, 40 years from now, what is it going to look like? I do think by then the Juneau ice field will be past the tipping point.”
It’s not just Alaska. Glaciers around the world—from Greenland to Switzerland to Africa and the Himalayas—are melting at an alarming rate. The United Nations Educational, Scientific, and Cultural Organization warned in 2022 that glaciers in one-third of the 50 UNESCO World Heritage sites where they are found are on pace to disappear by 2050—even if planet-heating emissions are curbed.
Another study published last year by researchers at Carnegie Mellon University and the University of Alaska found that even if humanity manages to limit planetary heating to 1.5°C above preindustrial temperatures—the more ambitious goal of the Paris agreement—half of Earth’s glaciers are expected to melt by the end of the century.
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