Current Status, Trends, and Future Challenges of the Alpine Cryosphere, illustrated by an Example from the Hohe Tauern National Park

Kurzfassung

Interwoven into European climate and anthropogenic activity, the Alps are central to the continent in physical and abstracted meaning. They are affected more strongly by global warming than the Northern Hemisphere on average, while their unique environment, made up of extremes in temperature, precipitation and topography, is especially sensitive to alterations in climate configuration. Within this thesis, climate change effects on temperature, precipitation, glacier, snow, permafrost and further impacts in the Alps are reviewed on a macro level and investigated at a single site. A structured literature review revealed that a warming of about 0.3 °C per decade within the second half of the 20th century, together with longer warm spells and an increased precipitation intensity have contributed to a higher frequency of compounding hazard events. Especially since the 1980s, warming has accelerated, resulting in a reduced snow cover duration, especially in spring, by up to more than 20 days per decade. Remote sensing has become a relevant tool in constructing spatially continuous data archives that aid in analyzing the response of cryosphere elements to climate change. Large ice masses, such as glaciers and permafrost, react with more inertia to sustained warming, so that their continued decline within the next decades and near-total wasting until the end of the century can likely not be halted. Extreme precipitation events and sustained glacier melt paired with high sediment availability can favor mass movement events. Higher evapotranspiration and lower runoff from snow and glacier melt may cause more frequent droughts with risks for alpine infrastructure and alpinism. Results from the literature review were underlined by the case study. The Neue Prager Hütte in the Hohe Tauern National Park of Austria has experienced water shortages in 2022, 2023 and 2024 due to a shorter snow cover duration. With the use of Sentinel-2 imagery and in-situ station data on temperature, precipitation and snow depth, a climatology was constructed that allowed for the characterization of individual years and the identification of variables relevant for modulating snow cover fraction in the catchment of the cabin. The analysis underlined the hot and dry conditions of the past years that lead to the premature closure of the cabin and related continuously increasing temperatures at the cabin to the reduced snow cover in spring and summer months. The climatology and random forest prediction model appeared as a promising framework for supporting hut wardens in the assessment of snow availability