The European mountain cryosphere: a review of its current state, trends, and future challenges

Abstract

Abstract. The mountain cryosphere of mainland Europe is recognized to have important impacts on a range of environmental processes. In this paper, we provide an overview on the current knowledge on snow, glacier, and permafrost processes, as well as their past, current, and future evolution. We additionally provide an assessment of current cryosphere research in Europe and point to the different domains requiring further research. Emphasis is given to our understanding of climate–cryosphere interactions, cryosphere controls on physical and biological mountain systems, and related impacts. By the end of the century, Europe's mountain cryosphere will have changed to an extent that will impact the landscape, the hydrological regimes, the water resources, and the infrastructure. The impacts will not remain confined to the mountain area but also affect the downstream lowlands, entailing a wide range of socioeconomical consequences. European mountains will have a completely different visual appearance, in which low- and mid-range-altitude glaciers will have disappeared and even large valley glaciers will have experienced significant retreat and mass loss. Due to increased air temperatures and related shifts from solid to liquid precipitation, seasonal snow lines will be found at much higher altitudes, and the snow season will be much shorter than today. These changes in snow and ice melt will cause a shift in the timing of discharge maxima, as well as a transition of runoff regimes from glacial to nival and from nival to pluvial. This will entail significant impacts on the seasonality of high-altitude water availability, with consequences for water storage and management in reservoirs for drinking water, irrigation, and hydropower production. Whereas an upward shift of the tree line and expansion of vegetation can be expected into current periglacial areas, the disappearance of permafrost at lower altitudes and its warming at higher elevations will likely result in mass movements and process chains beyond historical experience. Future cryospheric research has the responsibility not only to foster awareness of these expected changes and to develop targeted strategies to precisely quantify their magnitude and rate of occurrence but also to help in the development of approaches to adapt to these changes and to mitigate their consequences. Major joint efforts are required in the domain of cryospheric monitoring, which will require coordination in terms of data availability and quality. In particular, we recognize the quantification of high-altitude precipitation as a key source of uncertainty in projections of future changes. Improvements in numerical modeling and a better understanding of process chains affecting high-altitude mass movements are the two further fields that – in our view – future cryospheric research should focus on.

Snow cover duration and extent for Great Britain in a changing climate: Altitudinal variations and synoptic‐scale influences

“…Studies have generally reported declining Northern Hemisphere snow cover duration where a clear trend exists (e.g., Brown, ; Durand et al , ; Choi et al , ; Marty et al , ; Beniston et al , ). Negative trends are predominantly from lower elevations, suggesting threshold effects exist related to the combined effect of temperature and precipitation on snowfall quantities as they co‐vary across both altitude (based upon the lapse rate) and latitude/longitude (Stewart, ; Fontrodona Bach et al , ).…”

Application of distributed temperature sensing for mountain permafrost mapping

“…Many of the world's major mountain ranges are underlain by permafrost (e.g.,), and mountain permafrost can exert an important control on earth system processes and engineering designs . Under recent climate change, mountain permafrost is degrading, leading to increased slope failure events and potential changes in hydrological regimes . However, the distribution of permafrost in mountainous regions is complicated by factors generally not encountered in low‐relief permafrost areas, including steep topography, deep snowpacks, and coarse blocky sediments (e.g., ).…”

Warm temperatures during cold season can negatively affect adult survival in an alpine bird

“…While our results suggest a link between warm temperatures and adult survival in female alpine chough, their survival did not show a clear negative trend (Figure ). The rate of warming in the region involved a +1.2°C mean temperature increase over the timespan of the study (Beniston et al, ; Ceppi, Scherrer, Fischer, & Appenzeller, ; Rangwala & Miller, ), which is one of the most intense warming rates for mountains in the world, but might not be enough to result in a clear trend in adult female survival given the 6°C variation of mean winter/spring temperatures in the different years of the study (Figure in Appendix ). High‐elevation regions are expected to experience more intense warming than lowlands over the 21st century (Pepin et al, ; Rangwala & Miller, ), as was the case in the 20th century.…”