Practices to include assessments of future climate change in flood risk management in Germany and the Benelux countries

Ongoing climate change, resulting in heavier rainfall and potentially higher flood peaks, can challenge flood risk management in many European regions. In particular, flood design values and flood hazard and risk maps can be challenged by future climate conditions. The devastating July 2021 floods in western Europe highlighted the need for transboundary cooperation in adapting flood risk management to climate change. In the JCAR-ATRACE Initiative (Joint Cooperation programme on Applied scientific Research – Accelerate Transboundary Regional Adaptation to Climate Extremes), we review and synthesize how climate change information is integrated into flood risk management in regions of Germany, the Netherlands, Belgium, and Luxembourg. We assess whether regions have published flood policy papers, developed future climate and flood scenarios, and translated these scenarios to flood hazard and risk maps and/or flood design values. Our findings reveal that while all 17 sub-national regions have adaptation plans addressing climate change, only 6 regions have developed future flood projections, with even fewer (3) incorporating climate-adjusted design values and only one providing flood hazard and risk maps under future climate scenarios. Practices vary widely: for example, Flanders in Belgium uses a full range of emission scenarios (CMIP5 RCP2.6 to RCP8.5), while Baden-Württemberg and Bavaria in Germany rely on the high-end scenario (CMIP5 RCP8.5) only. The Netherlands adopts a robust approach using 33 CMIP6 global climate models and a dynamic adaptation pathway framework to address uncertainties. Some regions like Saxony in Germany argue that the spread of projections is too large to derive design values and emphasize the need for standardized scenarios and methods. In summary, our synthesis highlights substantial gaps in incorporating climate change projections into flood risk management and significant regional variation in approaches. The synthesis will hopefully contribute to cross-border learning and foster uptake of climate change adaptation in flood risk management in Europe.