Alaska’s Juneau Icefield Melting 4.6 Times Faster: Researchers Warn of Imminent Tipping Point

The Juneau Icefield in Alaska, encompassing over 1,000 glaciers, is experiencing an accelerated melt. A recent study reveals that the icefield’s snow-covered areas are shrinking 4.6 times faster than in the 1980s. Researchers have meticulously tracked snow levels since 1948, extending data back to the 18th century. The icefield has been steadily shrinking since its peak after the Little Ice Age around 1850, but the melting rate significantly increased about a decade ago, according to the study published in Nature Communications.

Bethan Davies, a glaciologist at Newcastle University and the study’s lead author, explained, “What’s happening is that as the climate is changing, we’re getting shorter winters and longer summers. We’re having more melt, longer melt season.” This accelerated melting is contributing to a substantial flow of ice into the water, averaging about 50,000 gallons per second, according to study co-author Mauri Pelto, a professor of environmental science at Nichols College.

“In fact, glacier shrinkage in Alaska from the year 2000 to the year 2020, we’re losing more ice in Alaska than anywhere else,” Davies added. The study highlights a stark increase in the number of glaciers disappearing: only four Juneau Icefield glaciers vanished between 1948 and 2005, but 64 disappeared between 2005 and 2019. Many of these glaciers were unnamed due to their small size, but notable larger glaciers like Antler Glacier have completely vanished.

Alaska climatologist Brian Brettschneider, not involved in the study, emphasized the alarming acceleration, warning of a “death spiral” for the thinning icefield. An icefield, different from an ice sheet, is a collection of glaciers. Ice sheets cover entire continents, with only two remaining in Greenland and Antarctica. The Mendenhall Glacier, a prominent glacier in the Juneau Icefield, is a popular tourist destination. The Arctic, including Alaska, is warming four times faster than the global average, with Alaska warming by 2.6 degrees (1.5 degrees Celsius) since 1980, according to federal weather data.

Pelto, who first visited the Juneau Icefield in 1981 aiming to join the U.S. ski team, has studied it ever since, forsaking competitive skiing for research. Reflecting on the changes, he said, “When you go there the changes from year-to-year are so dramatic that it just hits you over the head.” He noted the ease of accessing the glaciers back in 1981, “In 1981, it wasn’t too hard to get on and off the glaciers. You just hike up and you could ski to the bottom or hike right off the end of these glaciers.” Nowadays, melted snow forms lakes at the edges, and crevasses make skiing difficult.

The icefield now resembles a staircase of bare rocks. White snow and ice reflect sunlight, but dark rocks absorb it, warming the ground and accelerating the melting in a feedback loop. The critical factor is the snow elevation line; below this line, summer can melt the snow, while above it, snow remains year-round. Pelto explained that this snow line keeps moving upward, increasing the areas prone to melting.

Juneau’s flat icefield shape makes it particularly vulnerable to tipping points. Davies noted, “The shape of Juneau’s icefield, which is rather flat, makes it vulnerable to particular tipping points because once the snow line moves up, large areas are suddenly more prone to melt.” Pelto emphasized, “The tipping point is when that snow line goes above your entire icefield, ice sheet, ice glacier, whichever one. And so for the Juneau icefield, 2019, 2018, showed that you are not that far away from that tipping point.”

Despite the significant melting, the Juneau Icefield’s complete melt wouldn’t drastically affect global sea levels, though it remains a crucial tourist and cultural site. Julienne Stroeve, an ice scientist at the University of Manitoba, not part of the study, remarked, “It is worrisome because in the future the Arctic is going to be transformed beyond contemporary recognition. It’s just another sign of a large transformation in all the ice components (permafrost, sea ice, land ice) that communities depend on.”

The study team compiled their findings using satellite images, airplane overflights, archived photographs, and historical local measurements, creating a detailed long-term picture of the icefield’s melting. Michael Zemp, head of the World Glacier Monitoring Service, and five other outside experts affirmed the study’s findings, with Zemp stating, “We need urgent and tangible actions to save at least some of the remaining ice.”

Pelto, reflecting on his decades of study, pondered, “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 icefield will be past the tipping point.” The future of the Juneau Icefield appears bleak, with accelerated melting trends posing significant environmental challenges.