WSL Extremes Research Program

As a consequence of globalization and climate change, extreme events are occurring with increasing frequency and intensity. What are the resulting impacts on the environment and society? How can we prepare for extreme events that have never occurred before? These are the questions we addressed in the Extremes Program.

From 2021 to 2025, five projects investigated the impacts on various environmental systems and developed solutions in collaboration with practitioners. In addition, overarching synthesis products were developed, to which the projects made significant contributions. Many of these synthesis products primarily summarize new knowledge on extreme drought, as four of the five projects focused on the effects of increasing heat and drought.

 

A look into the future

Climate models generally predict rising temperatures, more hot days, and more frequent and intense periods of drought. How will this affect soils, permafrost, natural hazards, bodies of water, trees and forests, biodiversity, agriculture, and much more? The interrelationships explored in the program have been compiled in a web app. This app shows how extreme weather events such as heat, drought, or heavy rainfall could impact the livelihoods of Switzerland over the next 20 years.

The 5 projects

Extreme Thaw

Unprecedented Permafrost Thaw – Unlocking Ground for New Life and Release of Old Soil Carbon, Pollutants, and Pathogen. 

The project shows how the thawing of permafrost is changing the alpine ecosystems of Switzerland.

MountEx

Mountain Spruce Forests As Hotspots for Extremes: Impacts, Resilience and Management Priorities. Together with BAFU, AWN and the Canton of St. Gallen, the project provided scientific foundations and practical tools for the management of spruce-dominated mountain forests under extreme events.

Malefix

Machine-Learning-Aided Forecasting of Drought-Related Extremes. In collaboration with various cantons, federal offices and power plants, MaLeFix developed an integrated, user-oriented early warning system that links several environmental models to provide actionable information on drought risk.

 

Emerge

The project “Providing data for effective mitigation and adaptation strategies to tackle extreme droughts in mountain regions” combines observations and model simulations to better understand the impacts of past and future extreme droughts in mountain regions – particularly in Switzerland. This serves to prepare policymakers for the challenges of these events.

Alanex

Artificial Light at Night: Mitigating an Extreme Disturbance for Humans and the Environment.

In collaboration with EKZ, ways have been developed to redesign the lighting, mitigating the negative effects of artificial light at night while ensuring that human lighting needs are met.

 

Key Results and Conclusions

The consequences of climate change, particularly heat waves and droughts, are becoming increasingly visible in Switzerland. Research is laying the groundwork for better predicting and preparing for climate-related extreme events and their impacts. The key conclusions from the program are:

  • Approaches to managing extreme events require close and early collaboration between academic and non-academic experts, as fostered, for example, in the WSL research program EXtremes (2020–2025).
  • In particular, involving practitioners as early as the project definition phase significantly contributes to ensuring that the results meet practical requirements.
  • Shared data (e.g., from extreme climate scenarios) for impact analysis across multiple program projects allows for broad integration and synthesis because the results are based on the same fundamental assumptions.
  • Switzerland has experienced several severe droughts in the recent past (2003, 2011, 2015, 2018, 2020, 2022), which have already had a significant impact on water availability and water-dependent sectors (nature, agriculture, cooling, drinking water, shipping, etc.). The impacts analyzed in the “Extremes” program show that even with average further climate warming (according to CH2018), considerably more severe drought events are likely, and that in extreme cases (extreme scenarios), such events could be significantly exceeded.
  • To manage such extreme droughts without excessively negative impacts, well-coordinated processes between the various sectors of civil protection are essential. The “Extremes” program has contributed to this optimization by developing and formulating a tabletop exercise on extreme drought in Switzerland in collaboration with the Federal Office for Civil Protection (FOCP) and the ETH Zurich Center for Security Studies (CSS). The first tabletop exercise was conducted at the WSL in 2025 with representatives from various civil protection organizations (crisis management teams, police, ambulance services, fire departments, etc.). Similar tabletop exercises have been conducted on a smaller or larger scale ever since, using the prepared materials.
  • These exercises have demonstrated how difficult it is for emergency services to prepare for an impending drought. Unlike the sudden extreme events for which emergency services are prepared (major accidents, earthquakes, large fires, floods, etc.), drought often develops very slowly, frequently over several months. It is therefore very difficult to accurately plan the timing of the next escalation stage, as this requires knowing what is still to come. Especially for such slowly developing and potentially very long-lasting extreme events, the integration of science and modeling is a crucial component in providing decision-makers with scenarios and associated probabilities.

Products and events

Synthesis Products

  • TableTop Drought
    Is Switzerland prepared for extreme drought? To answer this, the Extremes program, together with the Federal Office for Civil Protection and the ETH Center for Security Studies, developed a one-day simulation exercise. Using four cantonal drought scenarios, interdisciplinary teams analyzed available and additional resources needed to cope with a 1.5-year drought in Switzerland.
    PDF Trialog article: Bjoernsen et al. 2025. 
  • WebApp Extremes
    Based on current research, the interactive web app shows how extreme weather events such as heat, drought, or heavy precipitation could affect livelihoods in Switzerland—depending on the chosen climate pathway. With a deliberately provocative tone and a touch of humor, it illustrates impacts and chain reactions triggered by a few degrees of warming, while also presenting measures and solutions.
    WebApp  
  • Extreme Scenarios
    The program outlined key parameters for extreme drought scenarios from the perspective of different climate data users. These were calculated at ETH using “ensemble boosting” and downscaled at WSL to 100 m spatial resolution. They include drought periods of 1 to 5 years (two intensities), with either year-round or seasonal boosting.
  • WSL Report Extremes
    Published at the WSL Forum for Knowledge 2025, featuring contributions on drought, heat, permafrost, and disturbances in mountain forests.
    PDF proceedings
  • WSL Report Learning from Disturbances and Extreme Events in Forests
    Presented at the Forum for Knowledge 2023, providing scientific foundations for developing management measures.
    PDF Tagungsband
  • Herding Cats
    Managing large research programs can feel like herding cats—this also applies to the Extremes program. What are the main challenges of interdisciplinary and transdisciplinary collaboration, and how can they be overcome? Lisa Deutsch’s accompanying research explored these questions:
    Deutsch et al. 2025

Events

  • The WebApp Extremes will be exhibited at Umwelt Arena in Spreitenbach until 2030.
  • As an academic partner of Zurich Climate Week (May 4–9, 2026), the program is organizing a trialogue workshop on May 4, 2026, with authorities, researchers, and the insurance industry on drought resilience.
  • On May 7, 2026, the WebApp Extremes will be part of the Net Zero Day 2026 exhibition at ETH Zurich.
  • At the ALPS network conference “Dangerously beautiful, beautifully dangerous?” on June 1, 2026, in Bern, the WebApp will be presented along with a panel discussion on its development.
  • The EMERGE project exhibition Echoes of Drought (Aug 27–Sept 5, 2026, Zurich) presents the ecological, geopolitical, and socio-economic impacts of megadroughts on the Swiss Alps.