Lake Geneva threatened by high temperatures

Lake Geneva, the largest of the Alpine lakes, is a sentinel of the climate. Its waters have never been so warm, with an average of 13.6°C in 2023, an unprecedented temperature. Éric Jacquier has been fishing on the lake for 37 years and observes the warming every day when he casts his nets. More perch are brought up, a species which traditionally spawns from May onwards.

Oxygenation of deep waters no longer occurs

Rising temperatures could favor certain species and threaten others. The consequences of warming on the lake are being scrutinized by scientists. A platform, unique in the world, was installed five years ago on the lake. Sensors measure its evolution. In winter, usually, surface waters, rich in oxygen, mix with deep waters, which is essential for oxygenation and biodiversity. This phenomenon has stopped for several years. The solution to stabilizing the temperature of the lake is to limit global warming.