On May 28 the Birch glacier in Switzerland’s southern Wallis region collapsed, sending tons of rock, ice and scree hurtling down the mountain slope and into the valley below. The barrage largely destroyed the hamlet of Blatten, which had been home to 300 people and was evacuated last week due to the impending danger.

A catastrophic event struck the Swiss village of Blatten on Wednesday afternoon when the Birch Glacier collapsed, burying nearly 90% of the village under a mix of ice, mud, and rock. Thanks to a timely geological alert, all 300 inhabitants were successfully evacuated. However, climatologists and geologists agree this was far from a routine natural disaster.

Researchers point to climate change, specifically global warming, as a driving factor behind the increasing instability of glaciers in the Alps. Rising temperatures are not only accelerating glacier melt but also disrupting the permafrost—frozen ground that acts like “glue,” stabilizing mountain slopes.

Swiss glaciologists warn that rising temperatures are destabilising permafrost, which typically holds rocks and glaciers in place. Data shows that Swiss glaciers lost around 10% of their volume between 2022 and 2023, with a further 2.5% decline in the past year. Since 1900, the Alps have warmed by about 2C, double the global average, resulting in a 50% reduction in glacial mass.

What is Permafrost—The Alps’ natural stabilizer?

Permafrost is ground that remains frozen for at least two consecutive years, commonly found above 2,500 meters in the Alps. It plays a vital role in stabilizing mountain terrain by binding rock faces and glaciers. As temperatures rise, permafrost thaws, increasing the risk of landslides, rockfalls and glacial collapses, like the one that struck Blatten.

The term “thaw” is crucial in the climate change context, referring to the melting of frozen materials due to warming. When permafrost thaws, it not only destabilizes the landscape but also releases greenhouse gases, creating a feedback loop that accelerates global warming.

Is climate change the only culprit?

This isn’t the first such event in Switzerland. In 2017, a landslide in Bondo killed eight hikers, and a similar collapse occurred in Brienz two years ago. While climate change is a significant factor, some scientists argue that natural geological processes, such as eroding mountainsides, may also contribute to glacial collapses.