Dynamic modeling and policy simulation to reduce heat-related illness risk from urban heatwaves in Seoul, South Korea

Integrated and systematic studies on heat-related illness risk from urban heatwaves are lacking. The effects and predictions of risk reduction policies for heat-related illness risk should not be limited to a particular area of study but should be calculated in a feedback process considering the budget. In this study, we performed dynamic modeling and policy simulation aimed at reducing the risk of heat-related illnesses caused by urban heatwaves in Seoul, Korea. A causal map of the urban heatwave system was created using data from 2010 to 2021, and simulations were performed up to 2040. In analyzing the effect of reducing the incidence of patients with heat-related illnesses compared to the budget invested, the number of patients with heat-related illnesses to be reduced in support policies for the vulnerable group, high-efficiency air conditioners, heatwave shelters, green areas, and eco-friendly cars would be reduced by 0.44, 0.09, 0.0046, 0.0045, and 0.0005 people/billion won in 2035, respectively. The number of heat-related illnesses decreased by 78.0% when policy simulation, which produced the maximum effect with the lowest budget, was performed. The current urban heatwave system in Seoul would not reduce the incidence of patients with heat-related illnesses in the future but, rather, would increase it. Urban heatwave policies did not contribute considerably to the reduction of patients with heat-related illnesses because the intensity of heatwaves owing to climate change outweighed the impact of heatwave policies. We suggest additional budget increases in the order of higher return on investment (ROI).