WSL's CCAMM research programme ends after eight years: researchers reveal how climate change is altering natural hazards in the Alps – and where action is now required.

Pizzo Cengalo, Piz Scerscen and Mesocco in the canton of Grisons and Blatten in the canton of Valais are just a few of the rock avalanches, debris flows and cascading events to have hit Switzerland in the first quarter of the 21st century. Meanwhile, Spitze Stei (canton of Bern), Les Diablerets (canton of Vaud), Wisse Schijen (canton of Valais) and other unstable rock masses are under observation. "The coming decades could bring events on a scale that we can hardly imagine today," says Michael Bründl, head of the Climate Change Impacts on Alpine Mass Movements (CCAMM) research programme run by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and its Institute for Snow and Avalanche Research (SLF).

The interdisciplinary and transdisciplinary project saw over 60 researchers spend eight years investigating the effects the changing climate will have on the Alps and how people living there can prepare for them. Bründl and project coordinator Alexander Bast have now presented the synthesis report (only in German), which includes chapters on climate, snow and avalanches, rock and sediment dynamics, cascading processes, adaptation and outlook. The synthesis report is supplemented by a project report of around 180 pages, summarising the results of the individual projects in a structured, consistent and uniform format.

Natural hazards are expected to occur increasingly frequently as a combination of different processes. Such cascading processes happen when one event triggers another – for example, when rock masses fall into a reservoir during a rock avalanche, creating a wave that ultimately triggers a debris flow. "Such process chains are difficult to predict," notes Bast.

Rapidly changing variables
Examining snow: How climate change affects snow and avalanches is presented in the new synthesis report of the CCAMM research program. (Image: Hahn+Zimmermann / SLF)

The programme has produced numerous models for simulating climate change impacts, from snowpack and debris flows to the climate itself. This is because climate models form the basis for assessing the impacts of climate change on alpine mass movements. However, the data they require was not available in sufficient spatial and temporal resolution. "So we developed a method for increasing the resolution," explains Bast.

The BergAb information app (only in German) was also created as part of the programme. Intended for widespread use in education and by the general public, it provides an accessible, scientifically sound and visually engaging explanation of what will change in the mountains and how, from avalanches, debris flows and rockslides to the impacts on society and the effects of precipitation.

"Meteorological factors have a major influence on alpine mass movements," adds Bründl. "This is particularly true of temperature and precipitation." And it is precisely these two variables that are changing rapidly. The average near-surface air temperature in Switzerland is already 2.9 degrees Celsius above pre-industrial levels. That is a significantly larger increase than the global average, and the figure is rising.

Lack of legal mandates
Communes, cantons and the Confederation must therefore respond urgently to the impacts of climate change. That is another of CCAMM's findings. "The lack of legal mandates and guidance from the public authorities is a major obstacle and makes it difficult to implement measures," says Bründl. He recommends legally enshrined, clearly defined mandates for all levels of government, from communes to cantons and the Confederation, as well as sufficient funding.

Early warning systems are another area where a lot more could be done, says Bast. "We should focus on developing more cost-effective systems that provide data with high temporal and spatial resolution." The Swiss public is also being urged to get involved. As citizen scientists, they can contribute important information about avalanches, rockslides and other phenomena, and thus plug gaps in the data. The CCAMM researchers list seven areas where action is needed in the years ahead. One thing is certain, they say: "We won't run out of work."

CCAMM in figures

• 8 years
• 60+ researchers
• 31 projects
• 7 work packages
• 31 subprojects
• 33 study sites
• 12 PhD theses completed