Projections of heat-related mortality in Chinese cities: The roles of climate change, urbanization, socioeconomic adaptation, and landscape level strategies.

Abstract

BACKGROUND Physiological heat strain induced by extreme temperature in cities has led to significant heat-related deaths. Although socioeconomic adaptation is suggested to mitigate this issue, its effectiveness is limited. Conversely, there is a lack of comprehensive evaluation on the effectiveness of landscape level strategies for mitigating heat-related deaths. OBJECTIVES We developed a comprehensive modeling framework to estimate the impacts of environmental stresses and mitigating strategies on heat-related deaths in China's cities from 2016 to 2055. METHODS The framework assesses future heat-related deaths through five experiments considering the influences of climate change, urbanization, socioeconomic adaptation, and landscape level strategies. We used extrapolated region-specific exposure-response functions (ERF) and recent advancement of geo-statistics for public health to generate urban patch level ERF curves. We used these curves, temperature and population data to generate future heat-related deaths with 1 km resolution and conducted 5,000 Monte Carlo simulations for uncertainty analysis. RESULTS Our analyses estimated that heat-related mortality will increase from 136.5±16.5 deaths per million in 2016 to 175.7±27.5 deaths per million in 2055 under SSP2-RCP4.5 (shared socioeconomic pathways-representative concentration pathways) scenario and from 140.0±21.4 deaths per million to 230.2±38.7 deaths per million under SSP5-RCP8.5 scenario, despite socioeconomic adaptation and landscape level strategies. Socioeconomic adaptation (reducing deaths by 18.4-64.1 per million) and landscape level strategies (reducing deaths by 45.6-51.3 per million) significantly mitigate heat-related deaths with varying effectiveness across different income levels. Specifically, in high-income cities with dense populations, landscape level strategies are 2.2-4.3 times more effective than socioeconomic adaptation. Within these cities, implementing the same landscape level strategies in the high-density urban centers lead to an additional reduction up to 4.9-6.8 death•km-2 compared to surrounding areas. DISCUSSION Our framework helps to systematically understand the effectiveness of landscape level strategies in reducing heat-related mortality. Future sustainable city management should prioritize landscape level strategies along with socioeconomic adaptation to support healthy and comfortable communities. https://doi.org/10.1289/EHP15010.