On the benefit and cost of artificial glacier melt reduction

The artificial reduction of glacier melt is gaining increased attention due to accelerated ice wastage with atmospheric warming. In Switzerland, active coverage of glaciers using geotextiles is performed at currently ten sites and since more than 15 years. The measures represent an efficient method to locally safeguard the operability of ski slopes or other touristic attractions. Furthermore, ideas for large-scale technical interventions to save glaciers using artificially produced snow were proposed, with considerable resonance in the international media.

Here, an assessment of the benefit and applicability, as well as the costs and the drawbacks of different techniques to artificially reduce glacier melt is presented. On the one hand, observational data (in situ and remote sensing) across the Swiss Alps are used to analyze the efficiency and the spatial extent of the applied technical measures in the past. On the other hand, an integrative model approach is presented for investigating the potential of large-scale artificial snow production to limit the retreat of an entire glacier over the 21^st century, including an evaluation of the related costs and risks.

Presently, about 0.18 km², or 0.02% of the total Swiss glacier area, are covered by geotextiles, with a doubling of the covered area since 2012. Up to 350,000 m³ of ice melt per year have been mitigated by this technique. It is estimated that 1 m³ of saved glacier ice comes at a cost of 0.6 to 7.9 CHF m^-3 yr^-1, depending on the type of installation and its location on the glacier. These relatively high costs are an indication for the considerable economic value attributed to glacier ice.

It is shown that artificial melt reduction is not scalable. Whilst local interventions can be efficient and profitable, climate scenario-based model results for large-scale interventions indicate that saving Alpine glaciers by technological solutions is neither achievable nor affordable. It is a challenge to adequately communicate this gap between feasible local-scale ice-melt reduction, and the impractical technological 'saving' of entire glaciers to a broader public.