CLIMATE INFORMATION
Adaptation - Security - Resilience
Scientific bases
Heat waves
Heat waves will be more intense and frequent.
A global warming of 2°C will lead to a temperature increase of approximately 4°C in Switzerland. The variability of extreme weather events will double or even triple (according to Jean Jouzel), meaning heat waves will be 8°C to 12°C more intense than in the past. Urban heat islands could add another 10°C.
Tropical currents
Global warming is causing changes in the jet stream. This important atmospheric current is slowing down and forming meanders that carry warm air far to the north and cold air to the south. Furthermore, air masses stagnate over land for up to a month, so heatwaves intensify over weeks. As a result, Western Canada was hit by a heat wave of 49.8°C in 2021, and Europe is experiencing much more intense heat waves.
The vegetation effect
During the first few days of a heatwave, plants transpire to protect themselves and moderate the temperature. Then the soil dries out. If the heatwave continues, temperatures will rise even further.
Humid heat
When it's hot, our bodies cool down by sweating. However, global warming increases atmospheric humidity, making it harder for our bodies to cool down. Humid heat is more dangerous.
Heat islands
Asphalt and concrete heat up considerably in the sun. The densest parts of cities can be 10-12°C warmer than the forecast temperature.
