Trends in European flood risk over the past 150 years

TL;DR

This study analyzes 150 years of European flood data, revealing increased flood exposure and affected populations, but decreased fatalities and financial losses, while highlighting the impact of underreporting on trend analysis.

Contribution

It introduces a comprehensive gridded flood exposure dataset and a new flood damage database, improving trend analysis over a long historical period.

Findings

Increase in flood-affected area and population since 1870

Decrease in flood fatalities and financial losses in recent decades

Underreporting significantly affects observed flood trend patterns

Abstract

Flood risk changes in time and is influenced by both natural and socio-economic trends and interactions. In Europe, previous studies of historical flood losses corrected for demographic and economic growth ("normalized") have been limited in temporal and spatial extent, leading to an incomplete representation in trends of losses over time. In this study we utilize a gridded reconstruction of flood exposure in 37 European countries and a new database of damaging floods since 1870. Our results indicate that since 1870 there has been an increase in annually inundated area and number of persons affected, contrasted by a substantial decrease in flood fatalities, after correcting for change in flood exposure. For more recent decades we also found a considerable decline in financial losses per year. We estimate, however, that there is large underreporting of smaller floods beyond most recent years, and show that underreporting has a substantial impact on observed trends.