Sheep's wool blankets match plastic tarps in slowing Alpine glacier melt

In a field test on the Tsanfleuron Glacier, scientists covered 200 m² of ice with wool blankets produced by Swiss textile firm Fisolan and compared their performance to standard plastic tarps. Over the summer, melt measurements taken every two weeks indicated that the wool reduced ice loss by roughly the same margin as the synthetic geotextiles, which are known to cut local melting by 50-70 %. The project, initiated by four master’s students and later expanded with the Summit Foundation, the University of Lausanne and the Swiss Glacier Monitoring Network, highlights a biodegradable alternative to plastic covers.

Wool’s durability against wind, rain and temperature swings surprised project partner Niklaus Zegeser. While the method may protect ski-area ice and critical infrastructure, it can only shield a tiny fraction—about 0.02 %—of Switzerland’s glacier surface, limiting its role in broader climate mitigation.