Climate change in the Alps: what changed in 2025 and what it means for mountain sports enthusiasts

When I stood at the Aletsch Glacier last summer, I noticed how far the ice had retreated in just five years. The moraine we once crossed to reach the ice without difficulty is now hundreds of metres from the glacier’s edge.

The Alps are warming twice as fast as the rest of the world. While the global average temperature has risen by around 1.2 degrees since pre-industrial times, the Alpine region has already warmed by around 2 degrees. At higher altitudes, the effect is even more pronounced, with far-reaching consequences for glaciers, permafrost, water balance and the entire Alpine ecosystem.

Globally, 2024 was the hottest year since records began. The United Nations therefore declared 2025 the International Year of Glaciers’ Preservation – a clear signal of the urgency of the situation.

The figures are alarming: worldwide, glaciers lose an average of 273 billion tonnes of ice per year. That is equivalent to five and a half times the volume of Lake Constance – every year.

The Alps are particularly affected: with a 39 per cent loss of mass between 2000 and 2023, they have the fastest melting rates worldwide. The Austrian Alpine Club documented the greatest glacier retreat since measurements began in 1871 for 2021/22.

The difference is now visible to the naked eye: routes that crossed ice 20 years ago now run over bare rock. Old guidebooks no longer reflect reality in many areas.

Scientists refer to ‘peak glacier extinction’, the point at which glacier melt reaches its height. In the Alps, this could be reached as early as 2033. It sounds paradoxical, but it simply means there will no longer be enough ice left to melt.

Even under optimistic climate scenarios that limit global warming to 1.5 degrees, only around 430 glaciers (12 per cent) will remain by the end of the century. At four degrees of warming, just 20 would remain, or one per cent of today’s glaciers.

On 28 May 2025, a disaster struck Switzerland’s Lötschental valley, tragically illustrating the link between climate change and alpine natural hazards. Around nine million cubic metres of ice, mud and rock broke away above the village of Blatten.

The debris avalanche hit the Birchgletscher below, which gave way under the added pressure. Ninety per cent of the village was buried. “The unimaginable has happened. We have lost the village,” said municipal president Matthias Bellwald at a press conference.

The Blatten landslide was not an isolated event. In 2017, eight people died on Piz Cengalo in Switzerland when around three million cubic metres of rock fell into the valley. The Marmolada glacier collapse in the Dolomites in 2022 also claimed lives.

The cause is the same in every case: thawing permafrost destabilises rock, rising temperatures cause glaciers to collapse, and heavy rainfall intensifies erosion.

Permafrost is less well known than glaciers, yet it is at least as important for the stability of the Alps. The Alps actually contain more permafrost than glaciers by area. This year-round frozen layer of sediment, rock and soil holds rock masses together like invisible glue. On south-facing slopes, it occurs from around 3,000 metres; on north-facing slopes, from around 2,400 metres.

When this frozen ground thaws, rocks lose their cohesion.

In many places, the active layer of permafrost grows deeper in summer. Water can then penetrate the rock, and water pressure destabilises rock masses. Water also collects in fissures, expands when it freezes and literally splits the rock apart.

Researchers at the University of Geneva have studied rockfall since 1920 using tree damage. Their conclusion: from the mid-1980s, activity reached a new and previously unprecedented level.

For mountaineers and hikers, the changes are becoming increasingly noticeable. Classic high-alpine routes are becoming impassable or significantly more dangerous. Mountain huts face water shortages, debris flows destroy paths, and the risk of rockfall continues to rise.

The route on Mont Blanc is particularly notorious: in summer, a rockfall comes down across the ascent route every 37 minutes in the Goûter Couloir. The risk on the Matterhorn has also become high. Routes considered safe decades ago are now high-risk undertakings.

A mountain guide from Chamonix told me: “We now have to adjust our route recommendations almost every week. What was still possible yesterday may already be too dangerous today.” Mountain huts are reporting fully booked dormitories earlier, as safe weather windows shift. Old guidebooks from the 1990s no longer reflect current reality in many areas.

The effects are also being felt in alpine infrastructure. Mountain huts are facing water shortages during dry summers, damage from heavy rainfall and increasing ground instability. In some places, alpine huts are sinking as the permafrost beneath them shifts.

More frequent debris flows caused by heavy rainfall mean more maintenance work on paths. Glacier retreat has left many routes no longer passable in their original form: access routes have changed and bridges over glacier crevasses have disappeared.

Winter sports are particularly affected by climate change. A study by the SLF Institute for Snow and Avalanche Research in Davos predicts 70 per cent less snow in the Alps by the end of the century. In the past 15 years, around 60 ski resorts have already closed.

Austria’s Central Institution for Meteorology and Geodynamics has calculated that, across all elevations, the duration of snow cover has decreased by 40 days since 1961. Munich now has an average of 20 fewer days of snow cover than it did in the 1950s.

The forecasts are clear: by 2100, there will be hardly any natural snow at lower elevations unless far-reaching climate protection measures take effect. At an altitude of 1,000 metres, the duration of snow cover would decrease by 70 per cent.

Many ski resorts rely on artificial snow as a solution, but it requires significant energy and water and merely shifts the problem higher up the mountain. The industry faces the challenge of diversifying its offer rather than relying on skiing alone.

The Alps are not only a recreational area, but also Europe’s largest freshwater reservoir. They provide around 40 per cent of the continent’s freshwater and supply millions of people through major river systems including the Rhine, Danube, Po and Rhône.

With an annual average of around 1,450 mm of precipitation, the Alpine region carries 216 billion cubic metres of water into the surrounding lowlands each year: via the Rhine to the North Sea, via the Inn, Isar and Danube to the Black Sea, and via the Po and Rhône to the Mediterranean.

Currently, 60 to 70 per cent of the water in high-mountain streams during the summer months comes from glacier melt. By the middle of the century, discharge in such streams will amount to only 25 per cent of today’s water volume, with far-reaching consequences for water supplies downstream.

The Rhône has already shown a marked decline in discharge since 1990. Around 50 per cent of the water in the four major Alpine-fed rivers originates in the Alpine arc. As this reservoir dwindles, the consequences reach far beyond the mountain regions.

Climate change is not only transforming the Alps’ physical landscape. The entire animal and plant world is affected, and species loss is becoming increasingly likely, warns biodiversity researcher Stefan Dullinger of the University of Vienna.

The problem: rising temperatures mean that mountain flora is retreating ever further towards the summits. Heat-loving species are spreading uphill and displacing the species native to those altitudes. But at the summit, there is nowhere left to go.

Climate change threatens edelweiss and many gentian species with extinction on many mountains. Studies suggest that some mountain regions could lose more than 80 per cent of their specialised plant species.

The outlook for animals is similar: in the Italian Alps, the treeline will shift around 350 metres uphill by the end of the century. This means a reduction of up to 50 per cent in ptarmigan habitat, with no possibility of moving to even higher elevations.

Climate change in the Alps is a challenge for society as a whole, but as a mountain athlete you can take action, both for your own safety and to help protect the mountain environment.

You can also make a difference at a political level. Organisations such as the German Alpine Club campaign for climate action and sustainable mountain management. Membership and active involvement strengthen their voice.

The reality is that the changes of the coming decades are already unavoidable. But the scale of what happens after 2050 depends on whether we meet our climate targets. Every tonne of CO2 saved makes a difference.