The floods that have devastated parts of western Germany and parts of Belgium, Luxembourg and the Netherlands this week were of unprecedented magnitude. What was the cause of this flood and why did it cause so much destruction?
Exceptional meteorological event
“Masses of air, loaded with abundant water, were blocked at altitude by temperatures
cold that made them stagnate for four days in the region “Jean Jouzel, climatologist, former vice president of the IPCC, the UN’s group of climate experts, told AFP. The result was Intense rains, between July 14 and 15, which reached “100 and 150 millimeters”, which is equivalent to two months of rain, according to the World Meteorological Organization.
While the region is used to heavy rains, they were “exceptional, both in the amount of water spilled and in its violence,” says Kai Schröter, a hydrologist at the University of Potsdam.
The debate is intense. Several European political leaders clearly establish a link between the two, but the German extreme right refutes this explanation and shouts for “instrumentalization”. “At the moment, it cannot be said with certainty that this event is related to climate change,” but such extreme events are becoming “more frequent and more likely” due to warming, estimates Kai Schröter.
The increase in the temperature of the planet mechanically increases the evaporation of water from the oceans and rivers, which brings “greater masses of water into the atmosphere,” he adds.
This phenomenon can increase the risk of intense and violent rainfall, says the researcher. More generally, lextreme weather events are more likely due to global warming, according to the IPCC.
Poorly protected water courses
Why so many victims? The rainfall suddenly increased the flows of small rivers and river tributaries, which did not have the capacity to withstand such an amount of water and were not protected with sufficiently high banks.
“The Rhine is used to floods, the biggest problem is the small rivers, the tributaries,” stressed the president of the German region of North Rhine Westphalia, Armin Laschet, on Friday.
“Big rivers are slower and wider, the water rises more slowly and we have more time to prepare, unlike small rivers,” says Schröter.
Lack of preparation?
Some German media and experts question the lack of preparation of the authorities, who would not have alerted the population well in advance. “Analysts … issued alerts, yet the warnings were not taken seriously and preparations were insufficient,” estimates Hannah Cloke, a professor of hydrology at the University of Reading in the UK.
In addition, the lack of awareness of the population living in flood areas regarding these risks is pointed out.
“Some victims underestimated the danger and did not respect two basic rules during heavy rains: avoid basements where the water enters, and immediately cut off electricity,” says Armin Schuster, president of the BBK, a public body specialized in natural disasters, in the Bild newspaper.
Dozens of dead were found in their basements.
Some experts point to urbanism and the increasing amount of cement in the soils of western Germany, the economic center of Europe.
“Urbanization, important in these regions, played a role in the tragedy. Would so many people have died forty years ago? ”Asks Jean Jouzel.
The artificialization of the land prevents water from infiltrating the soils, which no longer play a sponge role, increasing the risks of flooding.
With information from AFP