Melting of Alaska’s Juneau Icefield — which contains more than 1,000 glaciers — is accelerating and may reach a tipping point much sooner than predicted, according to research published Tuesday.
The study, which was published in the journal Nature Communicationsshows that ice loss from the Juneau Ice Field began to accelerate rapidly after 2005.
The paper’s authors found that “the rate of area shrinkage was five times faster from 2015-2019 than from 1979-1990”, while the loss of glacier volume – which had remained relatively stable from 1770-1979 – doubled after of 2010.
“Forty years from now, what will it look like? I think by then the Juneau ice field will have passed the tipping point.”
“Thinning has become widespread across the ice plain since 2005, accompanied by recession and glacier fragmentation,” the study says. “As glacier thinning on the plateau continues, an altitudinal mass balance feedback is likely to inhibit future glacier regeneration, potentially pushing glaciers beyond a dynamic tipping point.”
The study’s lead author, Bethan Davies, a glaciologist at the University of Newcastle in England, said in a statement: “It is extremely concerning that our research found a rapid acceleration since the beginning of the 21st century in the rate of glacier loss in Juneau Ice Field”.
“Alaska’s ice fields – which are mostly flat, plateau ice fields – are particularly vulnerable to accelerated melting as the climate warms as ice loss occurs across the surface, meaning a much larger area is affected big,” Davies continued. “Furthermore, flatter ice sheets and ice fields cannot retreat to higher altitudes 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 will likely prevent future glacier resurgence, potentially pushing glaciers beyond a tipping point in irreversible recession,” she added.
Study co-author Mauri Pelto, a professor of environmental science at Nichols College in Massachusetts, saidAssociated 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 it blows your mind,” said Pelto. “Back in 1981, it wasn’t too difficult to get on and off the glaciers. You just go up and you can ski to the bottom or walk to the bottom of these glaciers. But now they have lakes on the edges from melting snow and openings of cracks that make skiing difficult.”
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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.
Pelto said “the tipping point is when that snow line goes over your entire ice field, ice sheet, ice glacier, whatever.”
“And so for the Juneau ice field, 2019, 2018, it showed that you’re not that far from that tipping point,” he added. “We’re 40 years from when I first saw the glacier. And so, 40 years from now, what will it look like? I think by then the Juneau ice field will have passed 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 a third of the 50 UNESCO World Heritage sites where they are found are on pace to disappear by 2050 – even if emissions of the warming of the planet is restrained.
Another study published last year by researchers at 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 most ambitious goal of the Paris agreement – half of Earth’s glaciers are expected to disappear. to melt until the end of the century.