Megadroughts in the Water Towers of Europe

Megadroughts, which are prolonged periods of severe and widespread drought, have occurred across the globe over the last 2000 years, impacting societies and economies substantially. While Europe hasn`t experienced a megadrought in recent history, there is growing evidence that it might face extended droughts lasting decades by the end of this century. Understanding the potential impacts of megadroughts is crucial, yet we lack knowledge, especially in the context of Europes mountain regions. Unlike lowland regions that have been extensively studied for heatwaves and droughts, mountainous areas play a vital role as the world`s water towers, where water is generated, stored, and released. Glaciers act as essential buffers against droughts by providing much- needed meltwater during the summer. However, prolonged droughts could deplete snow and ice storage, leading to a tipping point where their buffering capacity is exhausted. The role of glacier runoff in multi-year droughts is not fully understood, making it a critical area of research. Additionally, vegetation, often overlooked, can worsen the decline of river flow during extremely dry periods through increased evapotranspiration. This project utilizes advanced models incorporating detailed processes related to glaciers, snow, vegetation, and soils to enhance our understanding of megadrought impacts on the mountain water cycle. The project aims to: i) Understand the conditions leading to megadroughts and explore how catchment characteristics can amplify or mitigate their effects. ii) Investigate the impact of megadroughts on the mountain water cycle and downstream water resources. iii) Apply this knowledge to future scenarios, testing the resilience of Europes water towers under potential glacier extent changes. iv) Provide European stakeholders with advanced projections of the potential impacts of future megadroughts on mountain catchments, along with new tools for adaptation and water resources management.