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 expected, according to research released Tuesday.
A study that was published in the journal The nature of communicationshows that ice loss from the Juneau Ice Field began to accelerate rapidly after 2005.
The paper’s authors found that “the rate of area reduction was five times faster in 2015-2019 than in 1979-1990”, while the loss of glacier volume – which remained relatively consistent from 1770-1979 – doubled after 2010.
“What will it look like in forty years? I think by then the Juneau ice field will be past the tipping point.”
“Drive has become ubiquitous across the plateau ice fields since 2005, accompanied by glacier recession and fragmentation,” the study says. “As plateau glacier thinning continues, it is likely that weight-elevation feedbacks will inhibit future glacier regrowth, potentially pushing glaciers past a dynamic tipping point.”
Lead study author Bethan Davies, a glaciologist at Newcastle University in England, said in a statement: “It is incredibly concerning that our research has found a rapid acceleration in the rate of glacier loss in the Juneau Ice Field since the beginning of the 21st century.”
“Alaska’s ice fields – which are mostly flat, upland ice fields – are particularly vulnerable to accelerated melting as the climate warms because ice loss occurs across the surface, meaning a much larger area is affected,” Davies continued. “In addition, flatter ice caps and ice fields cannot retreat to higher altitudes and find a new equilibrium.”
“As glacier thinning on the Juneau Plateau continues and ice retreats into lower levels and warmer air, the feedback processes this triggers will likely prevent future glacier regrowth and potentially push glaciers past the tipping point into 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,” Pelto said. “In 1981, it wasn’t too difficult to get on and off the glaciers. Just go up and you could ski down to the bottom or hike right at the end of those glaciers. But now the lakes are rimmed with slush and crevasses are opening up, making it difficult to ski .”
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Between 1948 and 2005, only four Juneau ice glaciers disappeared. 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, 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 sheet.
Pelto said that “the tipping point is when the snow line goes over your entire ice field, ice sheet, glacier, whatever.”
“And so for the Juneau ice field, 2019, 2018 showed that you’re not that far from that tipping point,” he added. “It’s been 40 years since I first saw the glacier. So what will it look like in 40 years? I 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. In 2022, the United Nations Educational, Scientific and Cultural Organization warned that glaciers in one-third of the 50 UNESCO World Heritage Sites where they are located will disappear rapidly by 2050 – even if planet-warming 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 warming to 1.5°C above pre-industrial temperatures – the Paris Agreement’s more ambitious goal – half of Earth’s glaciers are expected to melt down by the end of the century.