Water at the centre of the climate crisis


Humanity is not on course to limit global warming. The effects of the climate crisis are already noticeable and measurable, including in Switzerland. Moreover, they manifest themselves mainly in changes to the water cycle.

For Switzerland, this means that winters will be rainier and summers drier. The frequency of extreme weather events such as droughts, heatwaves, heavy rainfall and flooding will increase.

Conflicts of use due to drought

The effects that water shortages can also have in Switzerland were seen in agriculture in the summers of 2018 and 2022. In the lowlands, plant growth in fields was restricted and yields were significantly lower, while in alpine areas, cattle had to be supplied with fresh water by helicopter. The example of drought shows the great potential for conflict that extreme weather events bring with them. If there is a prolonged absence of precipitation, there are many conflicts of use and interest – between the protection of ecosystems and the preservation of biodiversity on the one hand and agricultural use, energy production, drinking water supply and artificial snow production for winter sports on the other. Solutions are therefore urgently needed as to how society and the economy can adapt to the changed conditions in the area of water availability. One possibility is to reuse water and thus close the water cycle. Eawag is therefore working on methods for recycling water.

Equipping infrastructure for extreme weather events

But it is not only the more pronounced dry spells with water shortages that present us with major challenges. Flooding is also becoming more frequent as a result of increasing heavy rainfall incidents. At present, urban infrastructures in many places are not designed for such extreme precipitation, and the enormous masses of water cannot drain away via the sewage system in such a short time. Eawag researchers are therefore investigating in real-world laboratories how existing infrastructures can be made fit for the future and how rainwater can be stored where it falls using retention areas. This increased retention also prevents untreated wastewater from polluting bodies of water. Among other things, state-of-the-art sensor networks are being used to record the basic hydrological and microclimatic conditions. High-resolution runoff models also make it possible to predict future floods and thus prevent damage to humans and infrastructure. At the same time, Eawag is investigating how urban infrastructures with green spaces and water features can reduce summer heatwaves, promote biodiversity and improve groundwater replenishment.

Solutions for areas with underdeveloped infrastructure

However, climate-related challenges do not occur only in Switzerland. The climate crisis is also increasingly leading to droughts and floods worldwide, which exacerbate economic crises and conflicts and cause health problems. The flooding of sanitary facilities, such as septic tanks, can pollute the environment and drinking water in areas with underdeveloped infrastructure and jeopardise people’s health. In addition, the stagnant water that remains after flooding, combined with inadequate sanitation systems, can promote infectious diseases. In order to better protect people and the environment from the effects of the climate crisis, Eawag researchers work with the affected population to develop suitable solutions and support local and international organisations in implementing appropriate measures.