Climate change particularly pronounced in Switzerland

Tropical nights disrupting the sleep of those living in cities, vegetable farmers struggling with overly dry soil, and homeowners preparing for impending floods ¨C that is the future we can expect if climate change continues unchecked, based on the results of the new Swiss climate scenarios. Many of the impacts can already be felt and measured today. "The new climate scenarios give us a clearer picture of changes in Switzerland's climate in the decades ahead. They help us to assess developments and to plan appropriate measures, with a view to protecting our environment, cities and agriculture," said Ms Baume-Schneider at the presentation.

The four main changes in the climate scenarios

Commissioned by the Swiss federal government and compiled by MeteoSwiss, the new scenarios build on the results of the 2018 climate scenarios. They confirm and expand on the picture that had already emerged regarding climate change in Switzerland. The warming in Switzerland until now (2024: 2.9 ¡ãC up on pre-industrial levels) is above the global average (2024: up 1.3 ¡ãC). Aspects of climate change are proving more pronounced for Switzerland than the mean situation worldwide, partly due to the country's geographical location. In an overall global warming scenario of 3 ¡ãC, the temperature in Switzerland is expected to rise significantly more than that, by around 4.9 ¡ãC.

Such warming has many impacts. The climate scenarios set out four main changes that will shape the climate in Switzerland in a world with 3 ¡ãC of global warming:

1. More extreme heat
   Heat events particularly affect regions at low altitudes, especially urban areas. However, they may also increasingly occur in regions in the Alps and Alpine foothills in the future. The hottest day of the year will on average be around 4.4 ¡ãC warmer than in the period from 1991 to 2020. Hot days and tropical nights will also become a much more frequent occurrence. For example, the city of Zurich is expected to experience approximately five times more tropical nights per year, on average.
   
2. Drier summers
   The soil in Switzerland will increasingly dry out in the summer as a result of higher temperatures, more evaporation and less summer rainfall. Summer droughts have already increased over the past 4 decades. A typical summer drought will be 44% more intense in the future. Droughts and the risk of forest fires will increase.
3. Heavy precipitation, happening more frequently
   In the long term, heavy precipitation will increase in all seasons. The biggest rises are expected especially during heavy thunderstorms involving short, sharp bursts of rainfall. In summer, more intense precipitation does not necessarily mean that there will be no drop in the total amount of precipitation, as it might rain less often but with more rain falling in a brief period during individual events.
4. Rising zero-degree line and less snow
   In winter, there will be a slight increase in precipitation levels, but this will fall more often as rain than as snow. The average zero-degree line in winter will rise by 550 metres to around 1,450 metres. The natural snowpack will decline further in the future, especially at low altitudes, due to the increasing warming and the resulting rise in the zero-degree line.

Growing importance of climate change adaptation

Measures to reduce emissions will mitigate the effects of climate change. Alongside this, the federal government will deploy measures based on the climate scenarios to help the Swiss public adapt to extreme events such as increasing heat, drier summers, more intense rainfall and less snow. The 2025 climate scenarios use global warming levels to illustrate what global climate targets mean for Switzerland. In the Paris Agreement, Switzerland joined the international community in committing to keep global warming well below 2 ¡ãC ¨C and ideally 1.5 ¡ãC ¨C compared with pre-industrial levels. To limit the effects of climate change, emissions reductions are needed worldwide. The climate scenarios show how climate change mitigation measures affect climate change ¨C every tenth of a degree Celsius saved can reduce the impacts on Switzerland's nature, society and economy. "With ambitious climate change mitigation and global net-zero emissions by 2050, most of the future long-term warming and therefore many of the resulting further impacts could be averted," said ETH Zurich climate researcher Reto Knutti.

Despite all the efforts being made, global warming can at best be limited, but not reversed. The 2025 climate scenarios are a regularly updated centralised resource that forms a basis for planning the Federal Council's strategy on adaptation to climate change. Every instance of averted warming makes a measurable contribution to climate change mitigation and reduces the effort required for adaptation. However, adapting to climate change is becoming increasingly important.