Even higher temperatures in the future
The new scenarios confirm and expand on the picture of climate change understood thus far. They show four main changes that will shape the climate in Switzerland in the mid-century without increased global climate mitigation:
1. Dry summers
Average rainfall will decrease in the summer in the long term, while evaporation will increase with rising temperatures. Soil will thus become drier. The average near-surface air temperature will rise in the summer months of June to August by 2.5°C to 4.5°C in comparison to today. At the same time, there is up to a quarter less rainfall, and the longest dry period without precipitation in summer lasts nearly three weeks.
2. More hot days
The increases in the highest temperatures are even more pronounced than for the average temperatures. On the hottest days in summer, it will be 2°C to 5.5°C warmer than now. Hot summers such as those of the record years 2003 and 2018 could thus become the norm. Heatwaves will become more frequent and more extreme. Metropolitan areas will be especially affected by heat stress.
3. Heavy precipitation
Individual heavy precipitation events will be more frequent and more intense in the future than today. The heaviest precipitation falling on a single day will increase by about 10% on average.
4. Snow-scarce winters
Winters will be significantly warmer than current ones, with a possible temperature rise of 2°C to 3.5°C. Although there will be more precipitation, it will fall more frequently in the form of rain because of the higher temperatures. Snow will become less frequent and intense. The expected snow cover in low elevations will be halved compared to today. The zero-degree line will climb from today 850 m to 1500 m above sea level in winter. The snowy areas of Switzerland will therefore shrink considerably.