Climate change made Europe's fatal floods more likely, study says
Heavy rainfall in Western Europe in July, which led to severe and fatal flooding, was made nine times more likely by , a new study claims. Almost 40 researchers from six European countries and the US calculated that downpours of the kind that caused last month's floods are now 1.2 to nine times more likely and this will increase further if the planet continues to heat up. Flooding from July 14 to 15 this year resulted in at least 184 fatalities in and 38 in Belgium and catastrophic damage to infrastructure, including houses, motorways, railway lines, bridges and key income sources. Swollen streams turned into raging rivers, sweeping away houses, roads and bridges, and causing billions of euros in damage. Road closures left some places inaccessible for days, cutting off some villages from evacuation routes and emergency response efforts. But the study suggests global warming makes the kind of extreme rainfall that caused the deadly flash flooding more likely. Extreme rainfall occurred in Germany, Belgium, Luxembourg and neighbouring countries from July 12 to 15, leading to severe flooding, particularly in North Rhine-Westphalia and Rhineland-Palatinate in Germany and along the river Meuse and some of its tributaries in Belgium and the Netherlands. Frank Kreienkamp of Germany's nation weather service DWD, one of the authors on the study, said the findings supported forecasts in a . 'Humans are clearly changing and warming up the Earth's climate,' he said. 'And with this warming we are also seeing a change in weather extremes.' The authors said the damage and loss of life last month highlight how nations need to do more to curb greenhouse gas emissions and prepare for such disasters. 'These floods have shown us that even developed countries are not safe from severe impacts of extreme weather that we have seen,' said Friederike Otto, associate director of the Environmental Change Institute at Oxford University. 'This is an urgent global challenge and we need to step up to it. The science is clear and has been for years.' For , researchers looked at two small regions where the recent flooding was most severe the Ahr and Erft rivers in Germany and on the Meuse in Belgium. In the Ahr-Erft region, 3.66 inches of rain fell in a day, while in the Meuse region, more than four inches fell over two days. They used historical records and computer simulations to examine how temperatures affected rainfall from the late 19th century to the present. While the study hasn't been assessed by independent scientists yet, its authors used widely accepted methods to conduct rapid assessments of specific weather events such as floods, droughts and heat waves. It found that across a large strip of western Europe stretching from the Netherlands to Switzerland the amount of rainfall in a single day increased by 3 per cent to 19 per cent over the period, during which global temperatures increased by 2.2F (1.2C). For every 1.8F (1C) the planet warms, the air can absorb seven per cent more water, and when that water is released, it causes more extreme rainfall. Flooding was caused by very heavy rainfall over a period of one to two days, as well as wet conditions already before the event, as soils were already saturated. The team also predicted what would happen if humanity failed to achieve the primary aim of the Paris Agreement, signed in 2016, which In a climate 3.6oF warmer than in preindustrial times, models suggest the intensity of a one-day event would increase by a further 0.8 to 6 per cent, the experts found, and the likelihood of such an event by a factor of 1.2 to 1.4. In summary, the researchers say human-induced climate change 'has increased the likelihood and intensity of such an event to occur and these changes will continue in a rapidly warming climate'. 'Given the rarity of the event it is clear this is a very extreme event that is reasonably likely to cause negative impacts,' they say. 'However, especially given events like this will occur more frequently in the future, examining how vulnerability and exposure can be reduced becomes critical to reducing future impacts.'