Slowing down the retreat of the Morteratsch glacier, Switzerland, by artificially produced summer snow: a feasibility study

Johannes Oerlemans,Felix Keller,Martin Haag

doi:10.1007/s10584-017-2102-1

Abstract

Many large valley glaciers in the world are retreating at historically unprecedented rates. Also in the Alps, where warming over the past decades has been more than twice as large as the global mean, all major glaciers have retreated over distances of several kilometers over the past hundred years. The Morteratsch Glacier, Pontresina, Switzerland, is a major touristic attraction. Due to strong retreat, the lowest part of the glacier is getting out of sight from the gravel road that provided direct access to the glacier front. The Community of Pontresina has commissioned a preparatory study to find out if it is possible to slow down the retreat of the Morteratsch Glacier in an environmentally friendly way. In this article, we report on the outcome of such a study, based on a modeling approach. Our analysis is based on a 20-year weather station record from the lower part of the glacier, combined with calculations with a calibrated ice-flow model. We arrive at the conclusion that producing summer snow in the ablation zone over a larger area (typically 0.5 to 1 km2) may have a significant effect on the rate of retreat on a timescale of decades. We consider various scenarios of climate change: (i) no change, (ii) a rise of the equilibrium-line altitude (ELA) by 1, 2, and 4 m/yr. Projections of glacier length are calculated until the year 2100. It takes about 10 years before snow deposition in the higher ablation zone starts to affect the position of the glacier snout. For the case of modest warming, the difference in glacier length between the snow and no-snow experiments becomes 400 to 500 m within two decades.

Highlights

Worldwide glacier retreat is one of the most obvious and impressive manifestations of climate change (e.g., Mernild et al 2013; Leclerq et al 2014; Zemp et al 2015)
Inspired by the apparent effect of summer snow, we have investigated the possibility of making the mass budget of the VdM positive, or at least less negative, by artificially producing summer snow (Bmeltwater recycling^)
Based on a modeling approach, we have investigated the potential effect of deposition of artificial snow on the future evolution of the VdM

Summary

Introduction

Worldwide glacier retreat is one of the most obvious and impressive manifestations of climate change (e.g., Mernild et al 2013; Leclerq et al 2014; Zemp et al 2015). On the lowest part of the glacier, temperatures are too high, which implies that the upper ablation zone is probably the best location to cover the melting ice surface by snow (the gently sloping part between km 3 and 4, marked in Fig. 2 by the blue area). The long meteorological record from an AWS (Automatic Weather Station) located in the ablation zone of the VdM (Fig. 1) provides a solid basis to investigate the possibility of producing summer snow in sufficient amounts.

Results

Conclusion