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 used to reach the ice without difficulty now lies 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 the pre-industrial era, the Alpine region has already warmed by around 2 degrees. The effect is even more pronounced at higher altitudes, with far-reaching consequences for glaciers, permafrost, water balance and Alpine ecology as a whole.

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

The Alps are particularly affected: with 39 per cent mass loss between 2000 and 2023, they have the fastest melting rates worldwide. The Austrian Alpine Club documented the greatest glacier loss 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. In many areas, old guidebooks no longer reflect reality.

Scientists refer to ‘peak glacier extinction’, the point at which glacier melt reaches its peak. In the Alps, this could happen as early as 2033. It sounds paradoxical, but it means there will simply 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. With four degrees of warming, there would be just 20, 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 additional pressure. Ninety per cent of the village was buried. ‘The unimaginable has happened. We have lost the village,’ municipal president Matthias Bellwald said at a press conference.

The Blatten rockslide was not an isolated event. In 2017, eight people died at Piz Cengalo in Switzerland when around three million cubic metres of rock fell into the valley. The glacier collapse on the Marmolada 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 events intensify erosion.

Permafrost is less familiar to many people 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 permanently 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, rock loses its cohesion.

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

Researchers at the University of Geneva have studied rockfall since 1920 using damage to trees. Their conclusion: from the mid-1980s onwards, 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 are struggling with water shortages, paths are destroyed by mudslides, and the risk of rockfall continues to rise.

The route on Mont Blanc is particularly notorious: in summer, a rockfall crosses the ascent route in the Goûter Couloir every 37 minutes. The danger on the Matterhorn has also increased considerably. 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 possible yesterday may already be too dangerous today.’ Mountain huts report that their dormitories fill up earlier because safe weather windows are shifting. In many respects, old guidebooks from the 1990s no longer reflect current conditions.

The effects also extend to alpine infrastructure. Mountain huts are struggling with water shortages during dry summers, damage caused by heavy rainfall and increasing ground instability. In some places, alpine huts are sinking as the permafrost beneath them shifts.

More frequent debris flows triggered by heavy rainfall mean greater maintenance demands on paths. As glaciers retreat, many routes can no longer be followed in their original form: access routes have changed and bridges over 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. Over the past 15 years, around 60 ski resorts have already ceased operations.

Austria’s Central Institute for Meteorology and Geodynamics has calculated that, across all altitudes, the duration of snow cover has decreased by 40 days since 1961. In Munich, there are now an average of 20 fewer days with snow cover than in the 1950s.

The forecasts are clear: by 2100, there will be hardly any natural snow at lower altitudes 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 large amounts of energy and water and merely shifts the problem further uphill. The industry faces the challenge of diversifying its offering rather than relying solely on skiing.

The Alps are not only a place for recreation, but also Europe’s largest freshwater reservoir. They provide around 40 per cent of continental freshwater and supply millions of people through major river systems such as 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 each year into the surrounding lowlands: 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, during the summer months, 60 to 70 per cent of the water in high-mountain streams comes from glacier melt. By the middle of the century, the flow 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 comes from the Alpine arc. As this reservoir dwindles, the consequences extend far beyond the mountain regions.

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

The problem: as temperatures rise, mountain flora is retreating ever further towards the summits. Heat-loving species are spreading upwards and displacing the species native to these areas. 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 is similar for animals: in the Italian Alps, the tree line 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 retreating to even higher ground.

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

You can also make a difference at a political level. Organisations such as the Deutscher Alpenverein advocate 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.