The Need for Climate Risk Assessment in Response to the Increasing Occurrence of Compound Drought-Heatwave Events in Republic of Korea

Abstract

In recent years, the frequency of compound drought-heatwave events (CDHEs) has increased significantly. Previous studies have shown that CDHEs have a greater impact on society and ecosystems than individual hazards. Therefore, it is necessary to assess climate risk of CDHEs. However, few studies have investigated the current status of CDHEs in Republic of Korea and conducted related risk assessments. In this study, we used the MYRIAD-Hazard Event Sets Algorithm (MYRIAD-HESA), which generates multi-hazard pairs using daily heatwave and drought data, to analyze the occurrence of CDHEs during the May-October period from 1979 to 2023. The results were then used to assess climate risks in the health and agricultural sectors across the country's 17 administrative districts. The analysis revealed an increasing trend in the number of CDHEs in recent years, with an average duration of about 11.4 days. The districts most affected by CDHEs were Seoul, Gyeonggi-do, Gyeongsang-do, and Jeollanam-do, which experienced a higher hazard intensity than a single heatwave or drought. The risk assessment identified Gyeonggi-do as having a 'very high' risk of CDHEs in the health sector, while Jeollanam-do and Gyeongsangbuk-do, both major rice-producing regions, had the same risk in agricultural sector. In particular, when risk assessments focused only on individual hazards without considering CDHEs, the risk was found to be underestimated in Gyeongsangnam-do and tance of further research into the occurrence of compound hazards such as CDHEs, and underscores the need for climate risk assessments targeting these events.