Sheep wool tested as a greener way to protect Swiss glaciers

Two wool blankets now cover 200 square metres of ice at Glacier 3000. The trial, launched at the end of June in Les Diablerets, canton Vaud, is testing whether sheep wool can protect a glacier without adding more plastic-based material to the mountain environment.

The Summit Foundation placed the blankets as part of its “Keep it Wool” experiment, working with the University of Lausanne. Staff from the Swiss Glacier Monitoring Network, known as Glamos, are providing scientific supervision. Early observations indicate that the wool’s protective effect is close to that of the synthetic tarpaulins already used on some Swiss glaciers.

Those coverings can reduce melt in the protected areas by 50% to 70%, according to the foundation. That makes the Vaud experiment relevant to the ski and tourism infrastructure around Glacier 3000, where operators have used coverings to preserve snow and ice in selected locations.

The project also reflects a practical concern. As glaciers shrink, the materials used to slow local melt face greater scrutiny. A blanket that can perform a similar job while creating less persistent waste could offer Swiss mountain sites another tool, provided the field results hold up over time.

The experiment uses two blankets, each measuring 100 square metres. Their placement gives researchers a defined area in which to observe how wool behaves under alpine conditions, including intense sunlight, wind, precipitation and repeated changes in the ice surface.

Synthetic tarpaulins work by reflecting sunlight and limiting the energy reaching the ice. The same basic physical principle is being examined with wool. The Summit Foundation’s early assessment found a “very similar” protective effect, although the published account does not provide a final melt-rate comparison or a completed scientific evaluation.

The University of Lausanne is collaborating on the trial, while Glamos staff oversee its scientific side. That combination links field operations with Switzerland’s established glacier monitoring expertise. Continued measurements will be needed to determine how the blankets perform through the full period of use, how they cope with handling and weather, and whether their effectiveness changes as the glacier surface evolves.

The initial result is therefore a signal for further testing rather than a finished solution. A natural material may prove useful at selected sites, but its practical value will depend on durability, installation requirements, maintenance and the quality of the data collected at Glacier 3000.

Synthetic coverings can cut melt by 50% to 70% where they are installed. That figure explains why glacier blankets have become a familiar intervention at selected Swiss mountain sites, particularly where snow and ice support ski operations, access routes or tourist attractions.

Their environmental cost, however, remains part of the calculation. The synthetic textiles used to date are made from fibre-based materials, and the Summit Foundation has pointed to the risk of particles entering the water cycle. Sheep wool offers a different material profile. It is natural, renewable and biodegradable, and wool that has often had little use could gain a new application.

That does not make every wool blanket automatically low-impact. The full assessment would also need to consider sourcing, washing, transport, treatment, replacement and what happens to the material after use. Those questions are especially important in Switzerland, where glacier sites can be remote and access often depends on lifts, specialist vehicles or helicopters.

The trial’s appeal lies in its potential to reduce reliance on persistent synthetic materials without abandoning local, targeted protection. Its evidence will need to show that the environmental gains extend beyond the blanket itself and remain credible across repeated seasons.