Europe’s recent heat waves erased the snow atop Switzerland’s glaciers far earlier in the year than normal, exposing bare ice that could melt away in extraordinary volumes in the coming months.
“We are now in a state where we should normally be in August,” said Matthias Huss, a glaciologist at the Swiss university ETH Zurich. “It is really a worrying situation.”
The glaciers of the Alps supply water across Europe for drinking, farming, generating hydropower and cooling nuclear plants. Each winter, fresh snow piles up on the glaciers, shielding them from the sun in the spring. But once the snow has melted, the ice itself begins to disappear, and the water is effectively lost to the glacier forever. That leaves less water for future use, bringing closer the day when water in Europe becomes an erratic resource.
“It’s not something that is just in 100 years or so,” Dr. Huss said. “It’s in 10, 20 years from now.”
Switzerland’s glaciers started this spring with 25 percent less snow than the average from 2010 to 2020. Two hot spells then came in quick succession. Temperatures reached record highs across France, Britain, Germany, Switzerland and other nations, in an extended bout of severe heat that climate scientists said would not have been possible without the influence of global warming caused by humans.
As a result, the total amount of snow and ice on Switzerland’s glaciers had shrunk back to its level from before last winter by June 29, a month sooner than normal, according to scientists’ estimates. Only in 2022, another record-hot year for Europe, was that milestone crossed earlier, by just three days.
The sooner the snow is gone, the more time the summer sun has to eat away at the ice. Over the past two decades, Swiss glaciers have shed between 1 and 4 percent of their ice each year, and even more in exceptionally hot years.
Dr. Huss took measurements on two Swiss glaciers last week and saw their depleted state firsthand. At one spot on the Rhône Glacier, he and his colleagues found that the ice had thinned by a meter, or more than three feet, in 10 days in June.
High up on the Alps’ longest glacier, the Great Aletsch, more than 11,300 feet above sea level, the snow was slushy and visibly melting. “Really, conditions that you don’t expect to see at this elevation,” Dr. Huss said.
The snow line at Great Aletsch, or the boundary between the glacier’s snow-covered and snow-free areas, rose in elevation by more than 1,300 feet during the heat wave in June, according to an analysis of satellite images by Mauri S. Pelto, a glaciologist at Nichols College in Dudley, Mass.
Scientists today have a lot of high-tech methods for monitoring glaciers, but one key tool hasn’t changed much since the 19th century: long poles, stuck into holes drilled in the ice, that reveal how the glacier’s surface thins.
Dr. Huss and his colleagues try to drill holes that are deep enough for their poles to give depth readings for a full year. But if the ice melts abnormally fast, they may need to venture back onto the ice and drill new holes so their measurements can continue. That, he said, is looking like a distinct possibility this summer.
Leanne Abraham contributed reporting.
