Europe’s flash drought comes as heat causes ‘atmospheric thirst’, scientists say
Rivers and water flows low as evaporation rates rise in extreme warm conditions, study finds
Europe was suffering a “flash drought” after a series of heatwaves starting in spring drove an “atmospheric thirst” as a result of climate change, particularly affecting central and eastern countries, scientists said.
The drying of river systems in Italy, France, Poland, England, the Rhine and the Danube has disrupted cargo, threatened hydropower, hit harvests and led to some countries putting bans on non-essential water use.
Scientists from 12 European countries in the World Weather Attribution group found that long-term rain patterns varied widely and western Europe had started the year with more winter rainfall than the east.
But the series of early heatwaves starting in May had made the onset of drought more rapid as the warmer air had dried out soil more quickly.
Imperial College researcher Theodore Keeping described a “flash drought, where basically these extreme hot, dry conditions drive a much more rapid drying of that soil bed than we have seen historically in a lot of places”.
The WWA group, which tracks the relationship between weather shifts and climate change, analysed trends in rainfall, soil moisture and evaporation potential.
The study of this year’s trend was not yet peer-reviewed but found that across western Europe in the April-to-June study period, a lack of rain was not clearly driven by climate change.
But extreme heat driven by global warming had made it about 80 times more likely that the evaporation potential was increasing, it concluded.
Across eastern Europe, from the January-to-June study period, heat-driven evaporation potential was made about 40 times more likely.
“Despite more wintertime rainfall across most of Europe, we now see an enhanced tendency for unusual soil drying already in spring, before summer has even begun,” said Dominik Schumacher of the Institute for Atmospheric and Climate Science at ETH Zurich.
“That is our own doing: as temperatures climb, the atmosphere’s thirst increases quickly, sucking moisture out of rivers, lakes, reservoirs and the soil.”
The UK has put in place bans on the use of hosepipes, and the Netherlands last week lifted its drought scale to level 2, or an “actual water shortage” with measures needed to manage water supplies.
Prolonged dry conditions affecting the Rhine and wider basin have also put pressure on water resources in parts of the Alps, Germany, France and Belgium, while the Danube water levels in Romania were the lowest since 1996.
The early wet period in western Europe, including Spain, France and Portugal, had encouraged the growth of vegetation that then became quickly very dry, providing the “prime ingredients” for wildfires, Schumacher said.
An EU directive about water management was not mandatory and shifts would be needed for continent-wide adaptation measures, said Merel Laauwen of Wageningen University in the Netherlands, to deal with disparate leakage and water-reuse policies for industry and agriculture.
“Knowing what we know about how climate change is shortening the return periods of these severe drought events, which also means less recovery time in between, there are some shifts needed for adaptation across the continent,” she said.