Swiss glaciers lost over 5% of their ice volume following a hot summer and at least two disappeared altogether, an acceleration of melting that threatens the tourism lifeblood of Alpine communities.
Lack of snowfall in winter and abnormally high temperatures over the summer caused a retreat just shy of the record year of 2022, bringing the glacial loss in the Swiss Alps to nearly 20% over the past five years, according to data from the glacier monitoring network Glamos and the Swiss Academy of Sciences.
“There’s a doubling of ice losses over the past five-year period,” said Matthias Huss, a glaciologist and the head of the Glamos network.
“We didn’t expect to see such a huge loss, especially not so concentrated in time – it’s much faster than the scenarios indicated.”
The pace of the melting leaves Alpine glaciers no chance of surviving over the long term, the researchers concluded. While glaciers all over Earth are shrinking, the rate of loss is higher in the Alps.
The melting permafrost is making mountain slopes unstable, posing threats to mountaineers and hikers.
An unusual number of rockfalls in the Alps at the height of the tourism season caused at least three deaths – two Czech climbers were struck by falling rocks while crossing the Gouter corridor in the Mont Blanc massif in July, and a French climber training to become a mountain guide died from a sudden rockfall in August as he climbed the Aiguille du Genepi, also in the Mont Blanc area.
The threats to human life from receding glaciers are smaller in the Alps than in densely populated places like Nepal, where more than 1,400 people were killed in August after a glacier’s collapse triggered mudslides and mass flooding.
Scientists have long forecast glaciers shrinking, a direct consequence of the warming of the planet caused by human-emitted greenhouse gases, although losses over individual years are also influenced by local weather events.
The past winter in Switzerland was among the 10 least snowy winters since measurements began and the country experienced at least one heat wave every month from May to September, according to Glamos.
The thickness of individual glaciers fell between 2.5m and 4m through the end of the summer, while glacier tongues pulled back as much as 10m in some places during summer months, the research showed.
As a consequence, climbs once considered safe and popular with visitors have become dangerous, leading authorities in Switzerland and France to close mountain refuges this year to discourage people from accessing unstable areas.
In August, melting conditions forced a temporary safety closure of the high-altitude ice ridge exit of the iconic Aiguille du Midi cable car in the French town of Chamonix-Mont-Blanc, which offers tourists a panoramic view of the French, Swiss and Italian Alps.
The Swiss village of Randa in the canton of Valais – a base for mountaineers accessing some of Switzerland’s highest peaks – was put on alert for possible evacuation in August, as an acceleration of movements in the Weisshorn East glacier nearby raised fears of a collapse similar to the one that levelled the Swiss village of Blatten last year.
“For people who are starting in Alpinism, the month of August can bring in potentially dangerous conditions that make some simple climbs much more technical,” said Oceane Vibert, director of La Chamoniarde, a non-profit organisation that brings together rescue workers in the Mont Blanc massif and provides free information to hikers and climbers about conditions on the mountains.
(Alpinism is the sport or activity of climbing high, challenging mountains using specialised technical skills and equipment for rock, snow, and ice.)
While no one tracks the precise number and scale of rock-falling events, anecdotal reports make this year “exceptional”, Vibert said.
Alpinists need to change their mindset and plan climbs in springtime, rather than during summer, said Kilian Jornet, a professional trail runner who has broken multiple speed records for mountain climbing including on Mont Blanc.
“Ten years ago, the Alps were snowy mountains all covered in white in summer,” said Jornet, speaking from Chamonix, France.
“Now they’re rock mountains.”
Huss’ research confirms the perception veteran mountaineers like Jornet have from the ground. The report released recently noted the freezing level was higher than 4,000m above sea level on 76 days this summer.
By September, no snow remained at or lower than 3,500m above sea level.
Professional athletes across sports are suffering the consequences of the warmer climate. Summer competitions in Europe and the United States are increasingly being cancelled due to higher temperatures and wildfires, and athletes like Jornet are starting to train in hot conditions to be able to withstand heat during competitions.
“We are still in a state of denial because every year we think it’s a one-off event, but these things keep happening year after year,” Jornet said.
“The system we have today is not fit for today’s climate.”
In August 2024, Jornet personally experienced changes in the Alps during his Alpine Connections challenge, in which he climbed all 82 peaks of 4,000m above sea level or more in just 19 days. He often ran through the night and, despite being at high altitude, weather conditions were never freezing and he could often feel snow on glaciers softening and melting beneath his feet.
Ridges that used to be icy had become sandy due to permafrost thawing and some collapsed as he ran along them, increasing the risk of a fall. While rappelling down, rocks the size of fridges and small cars would often fall near him.
“I came out of there asking myself why had I done that,” he said. While a lot of planning ahead was involved during that mission, “... you just can’t plan for rocks falling – the risk has become really random.” – LAURA MILLAN/Bloomberg
