Test shows sheep’s wool could protect glaciers as well as plastic

Sheep’s wool has passed an early test as a possible alternative to plastic glacier covers. In June, the environmental group Summit Foundation covered 100 square metres of the Tsanfleuron Glacier in Les Diablerets with different wool blankets and placed synthetic geotextiles over a neighbouring area of the same size.

The experiment, conducted with the participation of the University of Lausanne, was named “Keep it Wool,” a pun on the English phrase “Keep it cool.” Initial measurements showed that the wool reduced glacier melt as effectively as the synthetic coverings, by between 50% and 70%, according to the organisation.

The foundation says wool avoids the risk of synthetic fibres entering the water cycle. It describes the material as natural, renewable and biodegradable, and notes that sheep’s wool often goes unused.

The findings do not offer a way to stop the retreat of the Alps’ glaciers. Coverings are too laborious and expensive to use across large areas. Textiles protect only about 0.02% of Switzerland’s total glacier surface. They preserve roughly 300,000 cubic metres of snow each year, compared with nearly one billion cubic metres lost annually.

Swiss glaciers lost almost 40% of their volume between 2000 and 2024.