Improved elasticity estimation model for typhoon storm surge losses in China

The enormous losses caused by typhoon storm surges in coastal areas highlight the importance of assessing direct economic losses induced by typhoon storm surges. It is assumed that the trend of losses is mainly caused by the change in storm intensity resulting from climate change and the exposure and vulnerability of socioeconomic levels. This study constructed a hazard dataset of typhoon storm surges covering zero-loss events in mainland China from 1989 to 2019. Following the annual data trend analysis, the improved elasticity estimation model was used innovatively to assess and attribute the occurrence and the amount of typhoon storm surge-induced direct economic losses. The results show that the risks of typhoon storm surge are more sensitive to changes in climate-induced hazard intensity factors than socioeconomic factors. A 1% increase in minimum pressure decreases the hazard occurrence probability ratio by nearly 130% and disaster losses by approximately 47%, while a 1% increase in gross domestic product per capita increases the ratio by 1.4% and decreases losses by approximately 0.98%. A 1% increase in population density would increase the ratio by 0.97% and disaster losses by 0.63%. However, the rapid socioeconomic development of the typhoon storm surge-affected area is the main factor for the loss trend during the study interval. Wealth increments and population concentrations in coastal areas have contributed to the increasing possibility of loss occurrence. The growth in wealth has also contributed to the improvement of disaster risk management and the reduction of the loss amount. This study clarifies the quantitative relationship between typhoon storm surge risk (the occurrence and the amount of losses) and physical and socioeconomic drivers, and highlights how socioeconomic dimensions contribute to storm surge losses. The model can be used for risk predictions given the considerations for climate change and future socioeconomic development in coastal regions of China and can be further applied to risk management and disaster prevention and mitigation of storm surges.