Improving indicators for coastal disaster risk assessment to produce climate change adaptation information

This study sought to improve the indicators used in coastal disaster risk assessment and evaluate their applicability in order to minimize uncertainty amid the increasing climate crisis. Busan was selected as the testbed. Among the 25 assessment indicators for coastal disaster risk assessment, inundation was assessed using the probability of inundation instead of the inundation area, and changes in coastal disaster risk assessment grades were analyzed. The storm surge coastal inundation prediction maps currently used in coastal disaster risk assessments do not consider various complex inundation factors, such as wave overtopping. To reduce uncertainty, the probability of inundation, which considers all scenarios used in the creation of coastal inundation prediction maps, was applied. The coastal disaster risk assessment grade changed by up to ±1 grade according to which inundation indicator was used. In the coastal areas of Busan, 6.2% showed a decrease of one grade, making the area relatively safer, while 5.8% showed an increase of one grade, making the area relatively riskier, and 88% showed no change in grade. Assessment using the probability of inundation provides a probabilistic assessment of potential inundation, allowing for the assessment of inundation that cannot be assessed using the specific return-period inundation areas . Coastal disaster risk assessment using the probability of inundation shows the potential to minimize uncertainty related to the changes in the coastal disaster environment and the results of climate change-induced inundation, and provides relevant adaptation information for the climate crisis.