Experts Warn of Increasing Flood Risk

"Due to climate change, unfortunately, we must increasingly prepare for natural hazards such as floods, storms, and droughts," said the president of the EGU "Division for Natural Hazards," Heidi Kreibich, in a release from the Austria Center Vienna, the venue for the large conference.

How the probability of extreme events such as heavy rainfall and subsequent flooding, especially in Europe, is increasing has been highlighted by numerous studies in recent months and years. Prime examples of the growing dangers include the massive flooding of September 2024, particularly in large parts of eastern Austria, or the devastating floods in Germany's Ahr Valley in 2021. In the context of so-called attribution studies, which use data on similar weather conditions in the past and statistically compare them with climate simulations, it has been repeatedly shown that the now significantly increased average temperatures and the associated changes in the climate and weather system make a measurable contribution.

Flood Risk: North-South Divide in Austria

What was once considered an event that occurred on average only about every 1,000 years now sometimes has a significantly shorter occurrence probability, experts calculated several years ago as part of the largest annual scientific meeting of its kind in Europe, held in Vienna. Austria is more or less exactly at a crossroads in terms of flood risk: In the journal "Science," a team led by the hydrologist and former EGU chairman, Günter Blöschl, from the Vienna University of Technology (TU Wien), was able to clearly demonstrate the impact of climate change using comprehensive data as early as 2017.

Thus, unusually high water levels in northern Europe have become more frequent on average, while in the south of the continent, the risk of drought continues to rise. For Austria, the risk of major floods in the north of the country is expected to continue to increase. In the south, however, the probability remains roughly the same.

Multiple Risks Demand Proactive Action

In March, Austrian scientists demonstrated in an analysis of two measurement series spanning over 100 years that short-term heavy rainfall events in this country today bring noticeably more precipitation than was the case in 1980. The experts presented the world's first such detailed work on the subject in the journal "Nature".

When events occur more frequently "that have never been experienced in this magnitude before," it is accordingly "critical," said Kreibich. Nevertheless, the awareness that "dikes and retention basins have an upper design limit" and lose their effectiveness when this is exceeded is still not sufficiently developed in many places. Risk management is "usually introduced or adjusted reactively after major floods and drought periods, while proactive, forward-looking strategies are rare. In addition, we must prepare for multiple risks in the future, such as drought first, then flooding," said the researcher from the German Research Centre for Geosciences (GFZ) in Potsdam. Austria is now quite well positioned in this area due to the experiences with the major summer floods of 2002 and 2013, especially along the Danube, as experts repeatedly emphasize.

University of Vienna Geocenter Opens Doors

How science can support flood risk analysis and management is one of the topics of the EGU conference. This is traditionally accompanied by a wide thematic range, which, in addition to geological and earth science analyses, also includes new findings on environmental pollution and disasters, climatic development, or new data from space missions. The "EGU25" and the "Planet Earth Day" yesterday, Tuesday, are also taken as an occasion by the University of Vienna to open its Geocenter in the ninth district of Vienna to interested laypeople on Sunday: At a "Science Market," there will be "joint research, discussion, experience, play, and discovery" in the afternoon, according to a press release.

(APA/Red)

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