Climate change | Peaks become scree

The Mölltal Glacier in Carinthia shrank into a narrow band of snow in the summer of 2026, which is partly protected from the heat by fleece. Photo: dpa/Franz Neumayr The Hochvogel is Germany's drama mountain. In June, around 2,000 cubic meters of rock fell into the valley from this 2,592 meter high peak in the Allgäu Alps. This didn't surprise anyone, at least in the region. Due to increasing rock falls, the hiking trail on the Austrian side of the Grenzberg has been closed since 2014. At that time, the first sensors were installed that measured vibrations in the rock.

There are now more than 30 sensors. Their signals and the data that can be obtained from drone flights with laser scanners make the Hochvogel one of the best-measured mountains of all. Thanks to the geoinformation platform AlpSenseRely by the Munich geographer and geologist Michael Krautblatter, even laypeople can study in detail which rock masses will sooner or later slide into the valley.

Heavy rainfall, also triggered by climate change, is not the only factor that threatens the mountains as we know them. Melting glaciers and thawing permafrost could cause even larger-scale changes. Andrea Fischer is Austria's glacier expert. The glaciologist from the Institute for Interdisciplinary Mountain Research at the Austrian Academy of Sciences has noted a dramatic decline in both the thickness and the extent of the glacier tongues. The magnitudes are: “From 1969 to 1998, there was a loss of thickness of around half a meter per year, in 2022 and 2026, three to four meters per year, and in the area from 2022 onwards, around 5 percent loss per year,” she tells “nd”.

“Large parts of the Alps will look like the Pyrenees now by 2050,” predicts Fischer. That means lots of brown tones, hardly any green at higher altitudes and only a few white speckles of snow and ice. Fischer thinks the Aletsch Glacier will last the longest. “There will probably still be something there towards the end of the century.” There are only a few years left for the Schneeferner below the Zugspitze. The glacier lift there is currently being dismantled.

"Large parts of the Alps will look like the Pyrenees do now by 2050."

How drastic the declines are in other Alpine glaciers can be easily and impressively understood using the glacier layers on the AlpSenseRely platform developed by the Technical University of Munich. What one can only imagine there, based on the records of the rock that has already fallen, is the thawing of the permafrost, that is, the permanently frozen ground or rock inside the mountains. Both phenomena are closely related. »The driving factor is the increase in temperature; in both cases ice melts. However, permafrost reacts with a delay because the temperature wave first has to penetrate the ground. That takes years,” says Fischer.

An additional problem: “We know the distribution of the glaciers, but we don’t know the distribution of the permafrost.” Measurements are taken; In Austria there is a data series from 2005 on the Hoher Sonnenblick, and Krautblatter has been measuring on the Zugspitze since 2007. An evaluation as part of the cryosphere monitoring Austria 2023, which summarized research on both the ice layers above the rock and inside the mountain, showed that the thawing layer of permafrost at Hoher Sonnenblick had doubled from around one to two meters between 2014 and 2022. This means that the thawing processes penetrate deeper into the ice layer in summer, the rock is therefore less tightly bound and rockfalls will occur more quickly and more frequently.

What seems small can have a big impact. Thawing permafrost has caused several landslides on the north face of the Eiger since 2006, the last of which was in 2025. The fall of around three million cubic meters of rock from the 3,369 meter high Piz Cengalo in the Swiss canton of Graubünden in 2017 claimed eight lives. Last year, the Swiss mountain village of Blatten was extensively buried by a debris avalanche. This August, larger masses of rock broke away from the Matterhorn almost 600 meters below the summit.

The mountain guides on the Italian and Swiss sides advised against further climbs. A mountaineer who attempted to climb had an accident on October 27th due to heavy rockfall and could only be rescued dead. Scientists like Fischer and Krautblatter currently only have the option of monitoring and warning. The melting of glaciers and the thawing of permafrost cannot be reversed.

What is even more depressing is that mountain sports and mountain tourism themselves are contributing to the worsening of the climate crisis. According to a study by the Bavarian Nature Conservation Association (BN), the biggest driver is travel, accounting for around 75 percent of carbon dioxide emissions in this area.

Politically, climate-damaging traffic with private cars is even being promoted. »A new full motorway is currently being built into the Allgäu. The B12 federal highway should be expanded to be wider than the motorway we currently have," criticizes Thomas Frey from BN to "nd". »We are taking legal action against this in court and saying: Don't put a billion into a new motorway in the Allgäu, but rather put the money into the railway. That would be the climate-friendly and ecological option, because that's where we have the well-known glaring deficits." In addition, the expansion would lead to the already polluted mountain regions being even more frequented.

Despite rockslides and mudslides, people continue to advance there. »We are experiencing increased pressure to use spaces that were previously less used. The village inn downstairs is closing. But weddings and other events are supposed to take place up at the mountain station,” says Frey, describing one aspect of the relocation.

The actually climate-friendly tourism with e-mountain bikes also leads to increased stress on nature. »That has increased by a factor of ten in the last few years. You can now reach regions with a motor that were previously difficult to reach with your own muscle power," says Frey, fearing the next boost from exoskeletons. The strap-on movement aids were originally developed in the healthcare and logistics sectors, but are now also conquering the outdoor market. Manufacturers advertise with sayings like: “No terrain is off limits.”

Motorized mountain bikers are already causing serious disruption to flora and fauna. »The rest and retreat areas of black grouse, capercaillie and ptarmigan are severely disturbed. The populations are declining,” says Frey. Restrictions on motorized traffic, be it on bicycles or for pedestrians powered by exoskeletons, are necessary here.

Plants and animals are also threatened by climate change itself. »We see that the most diverse groups of organisms are shifting their distribution areas in order to follow climate change. They slowly hike up the mountains. However, things no longer work on summits,” says biologist Johannes Hausharter from the University of Vienna “nd”. As part of an international long-term study, Hausharter examined the displacement of vegetation that had previously been adapted to cold periods by heat-loving species on 53 European peaks.

The finding is clear. The repression takes place, albeit with a delay. »A plant doesn't necessarily react immediately when something is no longer ideal. She stays at the location. But growth and seed production are lower. And over time you can clearly see the effects,” explains Hausharter.

The result: »We are losing diversity. Especially in mountains there are a lot of endemics, i.e. species with a very limited distribution area. If the species on the mountain dies out, it will be gone because it won't be able to make the jump to the neighboring peak," says the biologist and also predicts an aesthetic loss: "At some point, when you take a walk in the summer, the landscape up there will no longer have this characteristic variety of flowers, colors, shapes and growth forms, but will be a meadow just as species-poor as you see in the lowlands."

Not to mention black grouse and ptarmigan. And the question is, what kind of rock does the thawing mountain interior still leave for the creatures that live in the highlands?

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