Impact attribution of European floods, 1950-2020
The magnitude of flood losses is regulated by multiple factors including climate variation, demographic and economic structure and growth, land use, river regulation and reservoir construction, flood adaptation and mitigation measures. Here, we re-evaluate recorded fluvial and coastal flood losses that have occurred between 1950 and 2020 in order to attribute them to change in climate forcing and to the evolving social and economic conditions.
We were able to reproduce and attribute a total of 1729 riverine, coastal and compound floods which were responsible for the vast majority of flood losses in 42 European countries since 1950. Therefore, the results are representative for overall changes in flood occurrence in the whole continent, distinguishing the following factors (see figure below): (1) change in hazard due climate-induced variation in river discharge and extreme sea levels; (2) human impact on catchment hydrology through changing land use, water demand and reservoir capacity, (3) increase in exposure related to demographic and economic growth; (4) further change in exposure driven by land use change and evolving structure of the economy, (5) changes in flood preparedness exhibited by flood protection levels (primarily from structural defences), and (6) change in flood vulnerability, i.e. flood impact relative to exposure at given intensity of flood.
As highlighted in the figure below, the magnitude of flood impacts has been regulated primarily by the opposing direct human actions. On one hand, the population and economic value at risk of flooding has increased, exacerbated by land use change. However, it was compensated by improved risk management manifested by better flood protection and particularly lower vulnerability. This suggests that adaptation has been largely successful so far, resulting in downward trends in flood fatalities and strongly constraining the growth in population affected and economic loss. Climate change and human alterations of river catchments were also found to be major drivers of impacts in many countries, but overall are more heterogeneous drivers than exposure and vulnerability.
The map presents how much each factor changed flood losses, relative to 1950, at the level on NUTS3 regions. All events between 1950 and 2020 are included in those aggregate attribution results. Attribution of individual events is available through the flood catalogues for events with (https://naturalhazards.eu/database) and without (https://naturalhazards.eu/database-without-impact) historical impact data. For example, the catastrophic 1997 flood in Poland is attributed here: view
Detailed methodological information in our publication
Paprotny D., Tilloy A., Treu S., Buch A., Vousdoukas M. I., Feyen L., Kreibich H., Merz B., Frieler K., Mengel M. 2024. Attribution of flood impacts shows strong benefits of adaptation in Europe. In preparation.
Impact attribution of European floods, 1950-2020, https://doi.org/10.5281/zenodo.13149828 HANZE v2.4 flood impact and attribution model, https://doi.org/10.5281/zenodo.13150853
