Urbanization-induced warming amplifies population exposure to compound heatwaves but narrows exposure inequality between global North and South cities

• Published in: NPJ climate and atmospheric science Vol. 7; no. 1; pp. 154 - 10
• Main Authors: Gao, Shengjun, Chen, Yunhao, Chen, Deliang, He, Bin, Gong, Adu, Hou, Peng, Li, Kangning, Cui, Ying
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 704/172/4081; 706/689/694/2739; Air temperature; Amplification; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Cities; Climate Change/Climate Change Impacts; Climate Research; Climatology; Earth and Environmental Science; Earth and Related Environmental Sciences; Earth Sciences; Exposure; Extreme heat; Geovetenskap och miljövetenskap; Heat; Heat waves; Industrialized nations; Klimatforskning; Population density; Population studies; Surface temperature; Urban heat islands; Urban populations; Urbanization
• ISSN: 2397-3722; 2397-3722
• DOI: 10.1038/s41612-024-00708-z

Urban populations face heightened extreme heat risks attributed to urban heat islands and high population densities. Although previous studies have examined global urban population exposure to heatwaves, the influence of urbanization-induced warming is still not quantified. Here, leveraging satellite-derived near-surface air temperature data, we assess the impacts of urbanization-induced warming on heat exposure in 1028 cities worldwide. Additionally, we investigate its role in shaping disparities in heat exposure between global North and South cities. Our findings reveal that urbanization-amplified compound heatwaves exacerbate heat exposure risk in more than 90% of cities, and that this amplification is stronger in high urbanization areas. Moreover, our analysis highlights the potential for overestimating disparities between global North and South cities if urbanization-induced warming is overlooked. The inequality of higher heat exposure in the global South cities than in the global North cities will be narrowed in real scenarios due to more intense urbanization-induced warming in the global North cities. We emphasize the pivotal role of urbanization-induced heatwave intensification in heat exposure assessments and call for its inclusion in future population vulnerability evaluations to extreme heat.