Swiss Alps glaciers have lost 5.5 per cent of their total ice volume in a single year — the second-largest percentage decline ever recorded — as record-breaking summer heat and a winter starved of snowfall drove an extraordinary melt season across the European mountain range. The scale of the loss has prompted glacier scientists to warn that Alpine glaciers face an existential threat under current warming conditions.
A Bare Matterhorn and What It Reveals About Swiss Glacier Loss
One of the most striking symbols of this year's melt crisis came in late September, when the iconic 4,478-metre Matterhorn — straddling the border between Switzerland and Italy — was photographed almost entirely stripped of its snow cover. The image, taken after an exceptionally hot summer and a warm autumn, alarmed researchers.
Geomorphologist Jan Blöthe of the University of Freiburg described the absence of snow above 4,000 metres at that time of year as "highly unusual". For a peak of the Matterhorn's elevation to be essentially bare heading into October is, by any scientific measure, deeply abnormal.
According to Switzerland's national meteorology and climatology body, MeteoSwiss, the country recorded its hottest summer on record in 2026, compounding an already fragile situation for glaciers that have been in long-term retreat.
Five Years of Accelerating Ice Loss
The figures released by GLAMOS, the Swiss glacier monitoring service, and the Swiss Academy of Sciences paint a grim trajectory. Over just the past five years, Switzerland's glaciers have shed nearly a fifth of their total ice volume — a rate of loss that researchers say is without historical precedent in the modern era.
The all-time record for a single year remains 2022, when summer heatwaves combined with low winter snowfall and an unusual deposit of reddish Saharan dust — which darkened glacier surfaces and caused them to absorb more solar heat — drove the largest percentage decline yet measured. This year's result is the second worst.
Critically, while the absolute volume of ice lost this year is lower than during the catastrophic 2003 heatwave, the percentage figure is actually higher — because Switzerland's glaciers are now roughly one-third the size they were 23 years ago. In 2003, a 3.5 per cent relative loss was considered alarming. Today, that baseline has shrunk dramatically.
Matthias Huss, who heads GLAMOS and holds a glaciology professorship at the Federal Polytechnic Institute ETHZ, was unequivocal about the cause: "The warming that we are experiencing now can be attributed 100 per cent to anthropogenic climate change. It's as simple as that. Without human emissions or fossil fuels, we wouldn't have any warming at the moment."
Why Winter Snow Matters — and What Happens Without It
Huss explained that winter snowfall plays a dual protective role for glaciers. First, a thick snow layer insulates the underlying ice from summer melt. Second, and just as importantly, snow accumulated at high elevation is the raw material from which glaciers regenerate — compressed over time into new ice. When winters run dry and warm, both of those mechanisms fail simultaneously.
The consequences this year were severe. Between July and September alone, Switzerland's glaciers lost an estimated 2.2 trillion litres of water — equivalent to roughly four times the annual water consumption of the entire country's population of approximately 9.1 million people. Individual glaciers thinned by an average of between 2.5 and 4 metres, with the tongues of some glaciers retreating by as much as 10 metres.
Europe's Water Tower Is Running Dry
The implications extend well beyond Switzerland's borders. The country is often described as the water tower of Europe, with its glaciers and snowfields feeding some of the continent's most significant river systems — including the Rhine, Rhone, Danube and Po. Accelerated glacier loss threatens the long-term flow of these waterways, which millions of people across multiple nations depend on for drinking water, agriculture and industry. Switzerland itself generates more than half of its electricity through hydropower, making glacier health directly tied to energy security.
The situation in the Alps mirrors broader global trends. Satellite data has documented vast shrinkage of glacier coverage in Greenland and Antarctica over the past half-century. Scientists have also linked global warming to the destabilisation of a Himalayan slope that collapsed in August, triggering catastrophic flooding across Nepal.
"Alpine glaciers have no chance of surviving in the long term under such conditions," GLAMOS and the Swiss Academy of Sciences warned. It is a conclusion that an unadorned photograph of the Matterhorn — rocky, brown and snowless — seems to confirm without the need for further elaboration.
