Risks of heat waves in South Korea using structural equation modeling and entropy weighting

Heat waves are natural disasters that can result in large numbers of casualties. The frequency and damage caused by heat waves have been increasing in Korea due to climate change. The regional impacts of heat waves can vary according to environmental and socioeconomic factors regardless of duration and intensity. This study assessed the risks posed by heat waves for administrative districts in Korea according to climate change scenarios and the risk assessment framework of Fifth Assessment Report presented by the Intergovernmental Panel on Climate Change. The risk of heat waves is usually based on a combination of hazard, exposure, and vulnerability. Unlike previous studies using subjective weights, this study employed partial least squares—structural equation modeling (PLS-SEM) and entropy weighting, which are more objective methods of determining the indicators and weights, to estimate the exposure and vulnerability of heat waves. The results showed that at least 40% and 46% of administrative districts are expected to experience a high level of risk according to the representative concentration pathway scenarios, i.e., RCP 4.5 and 8.5, respectively. In addition, significant differences were observed in the heat wave risks calculated in this study for the upper and lower regions, with respect to cumulative heat-related morbidity rates, whereas the heat wave risk reported by the Korean Ministry of Environment was found to be insignificant. The results of this study can be used to prepare for heat waves and minimize damage caused by them.