There will be floods
Mots clés : flood events in Europe, climate change, warmer atmosphere, change in weather systems, air pressure distribution, expansion of rainfall over Africa, spatial patterns
There will be floods
In the context of an international research project, Vienna-based researcher Günter Blöschl is investigating changes in the frequency of flood events in Europe. Climate change will increase their number in Western Europe in the future.
Austrian Science Fund – FWF
According to popular opinion, natural disasters are on the rise and floods in particular seem to be occurring more frequently than in the past. The blame, or so the theory goes, lies with the atmosphere, which has become warmer and can absorb more water, resulting in more heavy rainfall and floods. Günter Blöschl, a hydrologist at the TU Wien (Vienna University of Technology), however, disagrees with this popular explanation for the changes: "While our measurement data tell us that there is indeed more flooding in western Europe, the floods are tending to become less frequent in eastern Europe, where snow has an important impact." Hence, as so often in life, the situation is a bit more complicated. Blöschl wants to shed light on this within the context of a cooperative research project involving institutions from Germany, Austria and Switzerland. The Austrian Science Fund, FWF, is funding the Austrian part of the project.
The activities of the current FWF project are a continuation of work that Blöschl has carried out over the past ten years in the context of an ERC Advanced Grant from the European Commission. "We were in the fortunate situation to really break new scientific ground," says Blöschl. Previously, the scientific results on changes in flood frequency had been very heterogeneous. His team has created the first consistent database. "This coherent database offers the advantage that we don't pick out individual measuring stations, but look at many thousands of stations together. And suddenly, as if by magic, spatial patterns emerged that were previously invisible," says Blöschl.
Blöschl stresses that this research is strongly international in character. In the current project, his group in Vienna is responsible for the long-term cycles, and the group in Stuttgart is interested in the spatial distribution, while the Frankfurt group is dealing with atmospheric issues and the connection to the ocean. In addition, Günter Blöschl, until recently the president of the International Association of Hydrological Sciences, is in contact with research teams from all European countries. He reports that the network is very good and that the teams share their data with one another. The overall situation in Europe is of interest to all of them.
Floods on the rise
In the future, the current trend will intensify. This is a conclusion Blöschl can draw from his data with a high degree of reliability. "Austria lies in the transition zone between the northwest and the south of Europe. We are – and that's the good news – less affected by changes than England, for example, but we are affected," says Blöschl. "Floods will increase north of the main Alpine ridge. South of that ridge, in Carinthia for instance, the situation is more or less stable." But there may well be sharp increases in smaller river valleys that are not in the vicinity of the Danube, Salzach or Drava. England and the Netherlands are really badly affected. "But the administrations of these countries are aware of that," notes Blöschl and says that they are preparing for it – not least thanks to the findings of his research team and their international colleagues. .
|Günter Blöschl is a hydrologist and head of the Institute of Hydraulic Engineering and Engineering Hydrology at TU Wien. He is a visiting professor at international universities such as Tsinghua University in Beijing, and between 2017 and 2021 he was President of the International Association of Hydrological Sciences. He is the recipient of numerous awards, most recently the Prince Sultan Bin Abdulaziz International Prize for Water in 2018. He is interested in flood and drought prediction, scaling problems and the impact of climate change on the hydrological cycle. The international project “Long-term variability of extreme flood events” (2020-2023) is funded by the Austrian Science Fund FWF with 375,000 euros.
Bertola M., Viglione A., Vorogushyn S., Lun D., Merz B., Blöschl G.: "Do small and large floods have the same drivers of change? A regional attribution analysis in Europe", in: Hydrology and Earth Systems Sciences, Vol. 25, 1347–1364, 2021
Bertola M., Viglione A., Lun D., Hall J., Blöschl G.: "Flood trends in Europe: are changes in small and big floods different?", in: Hydrology and Earth Systems Sciences, Vol. 24, 1805–1822, 2020
Doris Duethmann and Günter Blöschl. "Why has catchment evaporation increased in the past 40 years? A data-based study in Austria", in: Hydrology and Earth Systems Sciences, Vol. 22, 5143–5158, 2018
Blöschl G., Hall J., Parajka J., Perdigão R. et al.: "Changing climate shifts timing of European floods", in: Science, 2017
Vienna Doctoral Programme on Water Resource Systems
SciLog – Austrian Science Fund FWF