It was previously thought that Swiss rivers temperature and discharge were relatively preserved from climate change. Using data from 52 catchments in Switzerland, researchers have recently discovered that the increasingly warm air is indeed causing the temperature of bodies of water to rise.
While some alpine catchments are still preserved by cold water advection coming from snow and glacier melt, some evidences show that glacier disappearance will lead to an important rise of the temperature in these rivers.
“Observed water temperature trends are really close to air temperature trends, whereas we were expecting the mountainous topography and climatology of Switzerland would preserve rivers from warming”, says Adrien Michel, lead author of Hydrology and Earth System Sciences’s recent publication titled ‘Stream temperature and discharge evolution in Switzerland over the last 50 years: annual and seasonal behaviour’, co-authored by Tristan Brauchli, Michael Lehning, Bettina Schaefli, and Hendrik Huwald.
Warmer rivers and lakes impact both wildlife – the spread of fish diseases, for example - as well as human activity: the industrial sector, for one, relies on cool water to control the temperature of its energy production facilities such as nuclear power plants.
“Continued warming is expected in the future, which will certainly create conflicts between the different water uses in Switzerland, especially in summer,” says Adrien.
Citation
Michel, A., Brauchli, T., Lehning, M., Schaefli, B., and Huwald, H.: Stream temperature and discharge evolution in Switzerland over the last 50 years: annual and seasonal behaviour, Hydrol. Earth Syst. Sci., 24, 115–142, https://doi.org/10.5194/hess-24-115-2020, 2020.
Photo by Sean Wareing
