Germany Floods: A Stark Reminder for Geo-Engineers
Mary Antonette Beroya-Eitner and Hauke Zachert
Institute of Geotechnics, Technical University of Darmstadt
In July 2021, Germany suffered from catastrophic flooding as heavy rains swept across western Europe. Worst hit were the states of North Rhine-Westphalia and Rhineland-Palatinate. Neighbouring countries Luxembourg, Belgium and the Netherlands were also severely affected. In some of the affected regions, mostly in the valleys of low mountain ranges, as much rain fell in a single day as would normally be expected in a whole month. This extreme downpour caused rivers to burst their banks, leading to flash flood that was the worst the country has experienced in decades. At the Ahr river, the flooding is estimated to be a 500-year event or rarer, according to the preliminary analysis of the World Weather Attribution.
Scientists are in general agreement about the role of climate change in the disaster, and on how more of such an extreme event may be expected in the future. A recent Geophysical Research Letter article explains that the reason is two-pronged: Global warming makes intense rainstorms more likely because, on one hand, warmer air can hold more moisture. On the other hand, the movement of low pressure areas is slowed down, causing a longer dwelling time of storms, with the consequence that more rain falls over regionally limited areas. According to the study, the reason for the slow movement appears to be weakening of the upper level winds resulting from the reduced temperature difference between the poles and the equator. This reduced temperature difference is in turn due to the warming of the Arctic and Antarctic at a rate that is currently three times faster than the rest of the planet.
The flooding event not only claimed the lives of more than 200 people and caused the loss of houses and properties. It also resulted in considerable damage to critical infrastructures such as roads and highways, railway lines, bridges and dams, ensuring that its impact will continuously be felt long after the waters were gone. Thus, for geo-engineers, the flooding event is but a stark reminder of the urgent need to understand the impact of our changing climate on the stability of these structures most vital to a nation’s welfare. In this regard, the EU project GEOLAB: Science for Enhancing Europe’s Critical Infrastructure couldn’t be any timelier. Under this project, we will fervently endeavor for this understanding so we can actively contribute to the mitigation of the said impact, thereby enhancing the performance of these critical infrastructures.