The European mountain cryosphere: a review of its current state, trends, and future challenges M. Beniston, D. Farinotti, M. Stoffel, L.M. Andreassen, E. Coppola, Nicolas Eckert, A. Fantini, F. Giacona, C. Hauck, M. Huss, et al. To cite this version: M. Beniston, D. Farinotti, M. Stoffel, L.M. Andreassen, E. Coppola, et al.. The European mountain cryosphere: a review of its current state, trends, and future challenges. The Cryosphere, Copernicus 2018, 12 (2), pp.759-794. 10.5194/tc-12-759-2018. hal-02608958 HAL Id: hal-02608958 https://hal.inrae.fr/hal-02608958 Submitted on 16 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The Cryosphere, 12, 759–794, 2018 https://doi.org/10.5194/tc-12-759-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 3.0 License. The European mountain cryosphere: a review of its current state, trends, and future challenges Martin Beniston1,2, Daniel Farinotti3,4, Markus Stoffel1,5,6, Liss M. Andreassen7, Erika Coppola8, Nicolas Eckert9, Adriano Fantini8, Florie Giacona1,9, Christian Hauck10, Matthias Huss10, Hendrik Huwald11, Michael Lehning11,12, Juan-Ignacio López-Moreno13, Jan Magnusson7, Christoph Marty12, Enrique Morán-Tejéda14, Samuel Morin15, Mohamed Naaim9, Antonello Provenzale16, Antoine Rabatel17, Delphine Six17, Johann Stötter18, Ulrich Strasser18, Silvia Terzago19, and Christian Vincent17 1Institute for Environmental Sciences, University of Geneva, Switzerland 2Department of Physics, University of Geneva, Switzerland 3Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland 4Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland 5Department of Earth Sciences, University of Geneva, Switzerland 6Department F-A Forel for Aquatic and Environmental Sciences, University of Geneva, Switzerland 7Norwegian Water Resources and Energy Directorate, Oslo, Norway 8Abdus Salaam International Centre for Theoretical Physics, Trieste, Italy 9Institut National de Recherche sur les Technologies pour l’Environnement et l’Agriculture (IRSTEA), Saint Martin d’Hères, France 10University of Fribourg, Department of Geosciences, Fribourg, Switzerland 11École Polytechnique Fédérale de Lausanne, Laboratory for Cryospheric Sciences, Lausanne, Switzerland 12Swiss Federal Institute for Avalanche Research (SLF), Davos, Switzerland 13Institute for Pyrenean Ecology (IPE-CSIC), Zaragoza, Spain 14University of the Balearic Islands, Palma de Mallorca, Spain 15Météo France, Centre d’Études de la Neige, Saint Martin d’Hères, France 16CNR, Institute of Geosciences and Earth Resources, Pisa, Italy 17Univertisé Grenoble-Alpes, CNRS, IRD, G-INP, IGE (UMR 5001), 38000 Grenoble, France 18University of Innsbruck, Institute of Geography, Innsbruck, Austria 19CNR, Institute of Atmospheric Sciences and Climate (ISAC-CNR), Turin, Italy Correspondence: Martin Beniston ([email protected]) and Markus Stoffel ([email protected]) Received: 20 December 2016 – Discussion started: 9 January 2017 Revised: 16 January 2018 – Accepted: 18 January 2018 – Published: 1 March 2018 Abstract. The mountain cryosphere of mainland Europe is lated impacts. By the end of the century, Europe’s mountain recognized to have important impacts on a range of environ- cryosphere will have changed to an extent that will impact the mental processes. In this paper, we provide an overview on landscape, the hydrological regimes, the water resources, and the current knowledge on snow, glacier, and permafrost pro- the infrastructure. The impacts will not remain confined to cesses, as well as their past, current, and future evolution. the mountain area but also affect the downstream lowlands, We additionally provide an assessment of current cryosphere entailing a wide range of socioeconomical consequences. Eu- research in Europe and point to the different domains re- ropean mountains will have a completely different visual ap- quiring further research. Emphasis is given to our under- pearance, in which low- and mid-range-altitude glaciers will standing of climate–cryosphere interactions, cryosphere con- have disappeared and even large valley glaciers will have ex- trols on physical and biological mountain systems, and re- perienced significant retreat and mass loss. Due to increased Published by Copernicus Publications on behalf of the European Geosciences Union. 760 M. Beniston et al.: The European mountain cryosphere air temperatures and related shifts from solid to liquid pre- Both political and scientific programs are calling for better cipitation, seasonal snow lines will be found at much higher preparedness and for the development of strategies aimed at altitudes, and the snow season will be much shorter than to- averting possible conflicts of interest, such as between eco- day. These changes in snow and ice melt will cause a shift nomic goals and environmental protection (Beniston et al., in the timing of discharge maxima, as well as a transition of 2014). runoff regimes from glacial to nival and from nival to plu- In the following, we provide an overview of the current vial. This will entail significant impacts on the seasonality of knowledge of European mountain permafrost, glaciers, and high-altitude water availability, with consequences for wa- snow and the observed changes. We focus on mainland Eu- ter storage and management in reservoirs for drinking wa- rope, in particular the European Alps and Scandinavia, but ter, irrigation, and hydropower production. Whereas an up- also include – where possible – the Pyrenees and other mid- ward shift of the tree line and expansion of vegetation can latitude European mountains. An assessment of the chal- be expected into current periglacial areas, the disappearance lenges that need to be addressed in cryosphere research is of permafrost at lower altitudes and its warming at higher provided, and we identify areas where further progress is re- elevations will likely result in mass movements and process quired to improve our understanding of climate–cryosphere chains beyond historical experience. Future cryospheric re- interactions. We argue that such improved understanding is search has the responsibility not only to foster awareness of the key for better predicting future changes and impacts and these expected changes and to develop targeted strategies to for appropriate adaptation measures to be developed. Our precisely quantify their magnitude and rate of occurrence but views largely reflect the opinions of a body of scientists that also to help in the development of approaches to adapt to convened during the “Riederalp Cryosphere Workshop“ held these changes and to mitigate their consequences. Major joint in Switzerland in 2016. We therefore do not claim that all as- efforts are required in the domain of cryospheric monitoring, pects of cryosphere sciences are exhaustively covered or that which will require coordination in terms of data availabil- all possible elements of the cryosphere are discussed (we ne- ity and quality. In particular, we recognize the quantification glect, for example, lake ice, river ice, and ice in caves), but of high-altitude precipitation as a key source of uncertainty we have summarized, in an effective manner, both the current in projections of future changes. Improvements in numerical state and the future challenges in the domain of European modeling and a better understanding of process chains affect- mountain cryosphere research. ing high-altitude mass movements are the two further fields that – in our view – future cryospheric research should focus on. 2 Past and future trends in European mountain cryosphere and their impacts 2.1 Changes in snow 1 Introduction Snow cover is the most important interface between the atmosphere and the ground, strongly influencing the sur- Ongoing climate change and the importance of its anthro- face energy balance of the cryosphere. Snow affects glaciers pogenic component have gained wide recognition (IPCC, through albedo and mass balance and affects permafrost 2013). Thereby, some regions are likely to be more vulner- through its thermal insulation properties and meltwater in- able than others, in both the expected physical changes and put. It also plays a key role for sustaining ecological and so- the consequences for ways of life. Mountains are particularly cioeconomic systems in mountains as well as in the lowlands subject to rapid and sustained environmental changes (Gob- downstream of the mountain ranges. The extreme spatiotem- iet et al., 2014), and the cryosphere is the physical compart- poral variability of the snow cover remains one of the key un- ment that exhibits the most rapid ones. Changes in mountain certainties when quantifying the impact of climate change on snow, glaciers, and permafrost have resulted in significant the cryosphere. Snow observations are therefore a prerequi- downstream impacts in terms of the quantity, seasonality, and site for understanding the related processes and for providing quality of water (Beniston et