June 24, 2024

Drought in Southern Europe: Rain’s Last Hope

“A situation like the one we’re going through is becoming more and more common.”Manuela Bruner, WSL Institute for Snow and Avalanche Research

This should only be the beginning, until the end of the century the winter temperature will continue to rise. In any case, the number of days of snow cover in the Alps has already decreased by 36 days compared to the long-term average, Environmental researcher Marco Carrere of the University of Padua wrote in “The Nature of Climate Change” at the beginning of January. Together with colleagues, he reconstructed the winters of the past 600 years using growth rings from juniper bushes.

The lack of snow is unfortunate for skiing and its backers, but compared to the real problem in alpine countries, this is manageable. Because in addition to the lack of rain, there is no water tank for the summer months. “Today’s lack of snow is next summer’s drought,” says Manuela Brunner, a mountain hydrologist at the SLF in Davos. No prophetic gifts are required for these forecasts, it is enough to look at half of the past summer years.

Not even a wet spring will do

In a study in Geophysical Research LettersPublished in January 2023, Brunner examined how droughts developed in Switzerland and the role that thawed snow played in this. Their results are unequivocal: according to them, the summer drought builds up earlier in the winter and has an increasing effect in the warm season.

Between 1994 and 2017, the number of drought events caused by decreased snowmelt increased by 15 percent compared to the period from 1970 to 1993, the researcher found. The reason for the increasing trend towards drought is not only the lack of precipitation, but also the higher rates of evaporation, which continue to dry up rivers and soils. That is why Manuela Brunner is convinced that climate change will only make the problem worse in the future. “A situation like the one we’re going through now is becoming more and more common,” she says. Because the snow falls less and less, there is no barrier in spring and summer.

A rainy spring, therefore, would be a boon to the drought-stricken Alpine countries, and ideally half a year of rain would make up for the rather large deficit. But even a very wet spring may not be enough to completely end the hydrological drought in northern Italy, hydrologist Cristian Massari of the University of Perugia recently wrote on Twitter. If 2023 remains as dry as 2022, the severity of the drought will nearly double, as shown by simple simulations of the soil moisture index.

The problem will not go away

It’s not entirely clear if it will really be that bad in the end. However, the model clearly shows that the situation in the affected areas is indeed grave. A year of drought isn’t something rich countries like France, Italy, and Switzerland can’t handle, but a second in a row could spark distribution wars.