Assessment of the flood damage reduction effect of climate change adaptation policies under temperature increase scenarios

Due to the rapidly changing climate, the frequency of extreme rainfall has increased worldwide. Consequently, various climate change adaptation policies have been proposed to mitigate the increasing flood risk. However, few studies have examined the effects of these adaptation policies on flood damage. Therefore, this study developed a research framework to evaluate the flood damage reduction effect of adaptation policies to the changing climate. A flood damage function developed for 15 administrative districts in South Korea was integrated with an adaptation policy effect assessment module based on a non-linear regression model and a climate change impact assessment module based on non-stationary frequency analysis. Historic climate data and future climate projection data from CMIP6 global climate models were used for the frequency analysis. The flood damage reduction effect of climate change adaptation policies was determined across various future projection periods and temperature increase scenarios. It was found that the flood damage gradually increased from the +2 degrees C scenario to the +5 degrees C scenario, though this flood damage was reduced by 43-44% with the implementation of corresponding adaptation policies. The macro-scale assessment framework proposed in this research, which incorporates flood damage records, climate observations, socioeconomic data reflecting flood mitigation capabilities, and climate model outputs for future projections, has the potential to be employed for a wide range of applications.