Emerge

Concept

As the climate changes, mountain regions are increasingly likely to experience extreme droughts, which could push ecohydrological systems to their limits.

Project Description

The EMERGE project used observations and simulations to better understand the ecohydrological impacts of past and future extreme droughts in mountain regions – especially the Swiss Alps. Its findings will help communities, stakeholders and policymakers to prepare for the challenges posed by these events.

Key Findings

  1. Multi-year droughts are becoming bigger, drier and hotter, and are having an increasingly negative impact on vegetation, globally.

  2. Extreme droughts in mountain regions can trigger a complex chain of impacts including both increases and decreases in evapotranspiration, decreases in streamflow, soil moisture and snow cover, plant mortality, and accelerated glacier melt that will weaken the power of glaciers to buffer streamflow in the future.  
  3. Compared to recent droughts, future droughts in the Swiss Alps could be substantially more severe in terms of their impacts on vegetation and water availability.

Main products and outcomes

  • A high-resolution global dataset of standardized drought indices (Chen et al., 2024).
  • A high-resolution dataset of climatologies for Switzerland (Zilker and Karger, 2025).
  • A high-resolution soil moisture reconstruction for Switzerland (contact Álvaro Ayala).
  • A high-resolution dataset of climate variables during extreme droughts in Switzerland (contact Franziska Zilker).
  • A high-resolution dataset of ecohydrological simulations of extreme droughts in Switzerland (contact Michael McCarthy).

Ongoing and future Projects

  • The EU Water4All project MegaWat, coordinated by Francesca Pellicciotti at ISTA, Austria, is simulating extreme droughts and future megadroughts at the European scale. WSL's Dirk Karger is a Co-PI.
  • The Swiss–wide joint initiative project SPEED2ZERO is simulating future climatic extremes to help guide Switzerland’s net-zero transition. WSL's Dirk Karger, Franziska Zilker and Michael McCarthy are in the Research Team.
  • The Echoes project Exploring climate change impact scenarios through holistic experiences of science-based audiovisual art for outreach to the Swiss public, led by Sophie Falkeis and Dirk Karger, fosters dialogue between science and society with respect to extreme droughts through audiovisual art.
Occurrence, extent and duration of the top 10 multiyear drought (MYD) events within the period 1980 to 2018 (Chen et al., 2025).

Publications