A recent study has revealed that climate change has doubled the likelihood of extreme rainfall in central Europe. The research, conducted by World Weather Attribution (WWA), found that the planet’s warming caused by human activity intensified four days of heavy rainfall that devastated several countries in mid-September. Austria, Romania, and other parts of central Europe were hit with volumes of rain that would have been far less likely without global heating.
The WWA study identified that the intensity of the rain increased by at least 7% due to climate change. “If humans keep filling the atmosphere with fossil fuel emissions, the situation will be more severe,” warned Bogdan Chojnicki, a climate scientist at Poznań University of Life Sciences. The study emphasized that global warming is increasing the frequency and intensity of such extreme weather events.
Storm Boris, which stalled over central Europe, unleashed record-breaking rain in Austria, Hungary, Poland, and Slovakia, among other countries. The resulting floods claimed over two dozen lives, turned streams into raging rivers, and caused widespread destruction to homes and infrastructure. While flood defense measures helped mitigate the death toll, the damage was extensive.
Maja Vahlberg, a technical adviser at the Red Cross Red Crescent Climate Centre, noted the increasing costs of climate-related disasters. “These floods indicate just how costly climate change is becoming,” she said. Despite days of preparation, floodwaters ravaged towns, leaving thousands homeless and prompting the European Union to pledge €10 billion in aid.
The study used rapid attribution techniques to determine how much human influence contributed to the heavy rains. It compared the rainfall recorded during the storm to simulations of a world 1.3°C cooler — a temperature level reflective of pre-industrial conditions. The researchers found that human-caused warming doubled the likelihood of such a storm and increased its intensity by 7%.
These findings are considered conservative, according to the researchers, as current climate models may underestimate rainfall. Despite this, the study strongly suggests that global heating is a significant factor in these extreme weather patterns. The physics behind this is clear: warmer air holds more moisture, resulting in heavier rainfall when conditions are right.
Miroslav Trnka, a climate scientist from the Global Change Research Institute, likened the situation to a lottery. Global heating, he said, increases the chances of hitting the “jackpot” of extreme rainfall. Trnka explained that warmer seas enhance the hydrological cycle, leading to more intense rains in some areas, while other parts of the land experience drought.
Looking ahead, the study warns that if the world heats by 2°C above pre-industrial levels, similar extreme rainfall events will become even more common. Rainfall intensity could increase by another 5%, and the likelihood of such storms could jump by 50%.
Climate scientist Hayley Fowler from Newcastle University added that slow-moving storms, like Storm Boris, are becoming more frequent. “These large storms, cut off from the jet stream, are able to stagnate in one place and produce huge amounts of rainfall,” she said. As global warming continues, such weather patterns will likely intensify.
The WWA concluded that even minor increases in rainfall could lead to a disproportionate rise in damages. “A small increase in rainfall leads to a much larger increase in damages,” said Friederike Otto, a climate scientist at Imperial College London. These findings highlight the urgent need for stronger flood defenses, early warning systems, and better disaster-response plans to address the escalating risks of climate change.