A sheep wool-covered snow protection test site is pictured during a press conference presenting the results of the "Keep It Wool" glacier protection experiment in Les Diablerets, Switzerland, September 2, 2026. The project tested wool coverings on the Tsanfleuron Glacier at Glacier 3000 as a biodegradable alternative to synthetic geotextiles used in snow farming to help slow glacier melt. Much of the wool produced in Switzerland is not commercially used and is often composted or incinerated. Pho
For years now, synthetic tarpaulins have been laid in summer over areas of ice and snow to reflect sunlight and reduce heat absorption as global warming melts away the ice sheets that have defined the high Alpine landscape for millennia.
But those tarpaulins are typically made from plastic and can shed polluting microfibres. The "Keep It Wool" project, led by the environmental group Summit Foundation and the University of Lausanne, is instead using wool to slow the melting of the Tsanfleuron Glacier in western Switzerland.
This summer's record heat has melted snow on the glaciers weeks earlier than usual, leading almost inevitably to more of the ice loss blamed for exacerbating rockslides like the one that devastated the village of Blatten in 2025 - and triggered last week's cataclysmic flash flood in the Himalayas.
Sheep wool covering the Tsanfleuron Glacier in Les Diablerets, Switzerland, during a test of the biodegradeable alternative to help slow glacier melt, September 2. Photo: Reuters
Project manager Timothee Steiner said the team wanted to explore a biodegradable alternative while finding a use for Swiss wool, 40-70% of which is discarded each year.
Four university master's degree students had the idea and worked to put it to the test.
In June, two prototype wool blankets made by the Swiss firm Fisolan were laid on 200 sq metres (2,100 sq feet) of the Tsanfleuron Glacier. Throughout the summer, researchers compared their performance with that of a conventional geotextile cover. Early results have exceeded expectations.
A drone view shows a snow protection test site covered with sheep wool material (bottom left) and a traditional snow farming cover during a press conference presenting the results of the "Keep It Wool" glacier protection experiment in Les Diablerets, Switzerland, September 2, 2026. The project tested wool coverings on the Tsanfleuron Glacier at Glacier 3000 as a biodegradable alternative to synthetic geotextiles used in snow farming to help slow glacier melt. Much of the wool produced in Switzerland is not commercially used and is often composted or incinerated. Photo: Reuters
Steiner said measurements taken every two weeks showed the wool covers limited melting as well as the synthetic ones.
Fisolan's Niklaus Saegesser said he was surprised by the material's durability. "I thought it wouldn't be stable enough."
Student Elliot Gaffiot said the team hadn't been sure what to expect. "Now we have a result we can see and even touch. It worked incredibly well."But the project's backers stress that wool blankets are not a solution to global warming.
Geotextiles are pictured during a press conference presenting the results of the "Keep It Wool" glacier protection experiment in Les Diablerets, Switzerland, September 2, 2026. The project tested wool coverings on the Tsanfleuron Glacier at Glacier 3000 as a biodegradable alternative to synthetic geotextiles used in snow farming to help slow glacier melt. Much of the wool produced in Switzerland is not commercially used and is often composted or incinerated. Photo: Reuters
Only about 0.02% of Switzerland's glacier surface is covered by protective sheets, and scientists say reducing greenhouse gas emissions - mostly produced by fossil fuels - remains the only meaningful long-term way to slow the loss of ice.
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