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.

Protective textiles cover only around 0.02% of Switzerland’s glacier area. The figure places the Glacier 3000 experiment in context: even highly effective blankets can influence only a tiny fraction of the ice exposed to a warming climate.

The Summit Foundation has warned that tarpaulins alone cannot stop glacier retreat. Their effects remain local, confined to the covered surfaces. They can preserve snow or ice at specific sites, but they do not change rising temperatures, altered precipitation patterns or the long-term loss of glacier mass across the Alps.

That distinction matters in Vaud, home to Glacier 3000 and the Les Diablerets mountain resort. Local protection can help manage a tourist area or maintain an important surface for a limited period. It cannot secure the wider hydrological role of glaciers, which store winter precipitation and release meltwater during warmer months.

Swiss glacier monitoring has documented the broader pressure on these ice bodies for decades. The wool project sits within that larger picture. It tests whether a more biodegradable covering can make targeted interventions less damaging, while acknowledging that the scale of the climate problem is far beyond what blankets can address.

The next stage will determine whether wool can move from a promising trial to a practical Swiss conservation tool. Researchers and the Summit Foundation will need to compare melt beneath the blankets with nearby uncovered ice and established synthetic coverings, while tracking the material’s condition in the field.

The relevant tests are both scientific and operational. Wool must withstand ultraviolet exposure, moisture, wind and repeated installation. It must remain manageable for crews working at altitude. Researchers will also need to assess whether it can be reused, how quickly it biodegrades under local conditions, and whether any treatments applied to improve performance alter its environmental profile.

A successful result would not replace climate policy or large-scale emissions cuts. It could improve the environmental footprint of site-specific glacier protection in Switzerland, where operators and researchers already use coverings sparingly. The current figure of around 0.02% of glacier area covered shows how selective those interventions remain.

For now, Glacier 3000 is functioning as a field laboratory. The wool blankets offer an opportunity to test whether an underused agricultural material can serve a high-altitude purpose, with Glamos and the University of Lausanne providing the evidence needed for a broader decision.