Do compound drought-flood events cause greater damages than standalone flood events?

Droughts and floods are becoming increasingly frequent and severe as a result of climate change, driven by rising temperatures and shifting precipitation patterns. Despite the growing recognition of the linkages between droughts and floods, no study has systematically analysed their combined impacts, particularly the economic consequences of compound drought-flood events (CDFEs). To address this gap, we developed a novel framework for identifying CDFEs and standalone flood events in Europe by utilizing various observational data, including precipitation, streamflow, and soil moisture. These events were then matched with flood impact records from the Historical Analysis of Natural Hazards in Europe (HANZE) database using both catchment-based and event-based approaches. By comparing the economic impacts of CDFEs with those of standalone flood events, we quantified the extent to which CDFEs result in higher impacts.

Our findings reveal that CDFEs impose higher economic impacts compared to standalone flood events. Significant differences are also observed in the upper tail of economic losses for CDFEs compared to standalone flood events, which implies that CDFEs are more likely to result in catastrophic losses, posing a greater challenge to risk management strategies. Our study highlights the critical need to consider the interactions between droughts and floods in disaster risk management.