Status: 08/24/2021 00:00
The flood disaster on the Ahr and Erft was not only exceptional in terms of the amount of rain – it is also a result of climate change. This is shown by an international study.
First came the heavy rain and then the flash flood with its dire damage: devastated areas of land, destroyed livelihoods and 220 deaths on the Ahr and Erft. In view of the obvious weather data, it was clear to many meteorologists early on: Such extreme rainfall with 93 liters per square meter has not occurred in Germany since the beginning of weather records.
39 scientists from several countries
A study by World Weather Attribution in collaboration with the German Weather Service (DWD) now also shows the less visible: The extreme heavy rainfalls in July and the associated flood damage are very likely also a consequence of climate change.
In the past few weeks, 39 researchers from Europe, Great Britain and the USA have been working under high pressure on a so-called attribution study, which should clarify the possible connection between climate and disaster. With the help of statistical analyzes and computer simulations, they compared today’s climate with the climate before the global average temperature rose by 1.2 degrees Celsius since the end of the 19th century – with significant learning progress for the researchers.
Precipitation levels not seen in 90 years
“On the one hand, we learned that it was a very rare event,” says Frank Kreienkamp, the head of the regional climate office at DWD in Potsdam. In Germany in 90 years and in Europe in 70 years of weather observation, such amounts of precipitation have not yet occurred.
On the other hand, this weather event can also be clearly assigned to climate change: “We see very clearly that climate change has significantly increased the probability of occurrence and that it has increased the intensity.”
In the flood region, which stretched from France via Germany to Switzerland in July, the scientists were able to determine that the maximum amount of precipitation has increased by between three and 19 percent as a result of climate change. In addition, according to the researchers, under the current climatic conditions it is to be expected that such heavy rain events will occur significantly more frequently in the entire region. The probability of this occurring has increased by a factor between 1.2 and 9.
Plöger: “Study helps with weather forecasts”
ARDWeather and climate expert Sven Plöger sees the results of the study as an important contribution to understanding the events in July. “These are very important results because they show us that there actually was an influence of climate change on this event. That was initially an assumption, and now it can be proven in numbers.”
And Plöger also takes a lot from the results of the study for his weather forecasts: “It helps me a lot because I can make this connection between climate change, weather forecast and weather events even more strongly in the event of future severe weather warnings. And that without frightening people or causing them to panic move, but to inform. ”
Because extreme rainy weather can actually have extreme consequences not only in Bangladesh or other distant countries, but also here, according to Plöger.