It is simple reasoning: if there is a drought, it is because at some point there was a lack of rain. When there is no lack, it means something is out of order. In Europe, battered by a historic series of heat waves and droughts this season, such disorder has a name: climate change.
An attribution study published on Wednesday (22) shows that drought in Western Europe's agricultural soil became five times more likely due to global warming, driven primarily by the burning of fossil fuels. In Eastern Europe, where the drought has already lasted six months, the likelihood of the condition occurring is 11 times greater.
Meanwhile, the current evaporation potential driven by the season's intense heat has become 80 times more likely to occur in the western part of the continent and 40 times more likely in the east. The variable, known by its English acronym PET, measures the atmosphere's "thirst," or its capacity to evaporate moisture. It is this variable that exposes human activity's responsibility for the climate extreme being experienced across the continent this season.
"Europe's climate is changing rapidly. Although rainfall patterns remain varied, our findings show that extreme heat is becoming the primary driver of drought on our continent," says Sarah Kew, climate scientist at the Netherlands Meteorological Service.
Together with 11 other colleagues, the specialist is taking part in the World Weather Attribution (WWA) analysis, led by Imperial College London, which investigates the degree of responsibility the climate crisis bears for extreme events shortly after they occur.
Even in Eastern Europe, where the summer was preceded by a precipitation deficit, the conditions observed this year would not have caused such a severe drought on a planet 1.4°C cooler — the pre-industrial era benchmark used in climate models.
The problem is that the most severe heat wave in the continent's history, also caused by climate change — a conclusion reached by other recent WWA studies — is drawing moisture from the soil with unusual speed and ahead of the typical schedule.
"What normally happens in winter and also in spring is that there is not that much evaporation; there is plenty of precipitation, which helps to load soils with water," explains Dominik Schumacher of the Swiss Federal Institute of Technology in Zurich. "That is what happened earlier this year on the Iberian Peninsula and in parts of France."
From April onward, however, a series of high-pressure systems brought very hot, sunny and dry weather to the region. "Conditions that started out quite wet and then became very, very dry — the main ingredients for an extreme wildfire season."
Spain and France have been battling forest fires for weeks, which have already consumed 116,000 and 42,000 hectares respectively in those two countries this year.
Further east, the story was somewhat different, the researcher notes. "Groundwater and river levels were already quite low, even before the heat arrived. In Austria, 90% of river gauges indicated below-average levels in May."
And all of this happening much earlier in the year. "In Switzerland, soil moisture measurements resemble those of August 2022, when there was also a drought. But now we are reaching those figures in June, with half the summer still ahead."
The WWA study found no evidence that climate change has altered rainfall patterns this season. The evaporation potential, on the other hand, has been strongly affected by global warming. Europe is the fastest-warming continent on the planet.
The list of damage this year is enormous. On Wednesday, French authorities updated the number of excess deaths from June 17 to July 2, the peak of the heat wave in the country: 5,764 deaths. The government itself noted that it is the highest toll caused by high temperatures since 2003, when a historic heat wave killed 70,000 people in Europe, 15,000 of them in France.
In addition to human losses, the continent has already recorded crop failures, disrupted river transport, restrictions on energy supply and on water use by the population. Half of France's corn production was lost, as well as one million hectares of agricultural land in Romania.
Cited by the study, Simon Stiell, the UN's climate chief, states that the worsening of droughts is a "red alert" that cannot be ignored. "Until humanity stops burning enormous amounts of coal, oil and gas, these brutal droughts caused by climate change will only become more severe and more costly."
Stiell repeated his call for a rapid adoption of renewable energy, "which today is cheaper than polluting fossil fuels." The study's authors also call for drought prevention and management plans in the European Union to be standardized and made compulsory across all 27 member states of the bloc.
