Uneven Heat Effects of Urban Environment Across Climate Zone

Urban areas alter the surface energy balance, typically resulting in higher temperatures than surrounding rural regions, a phenomenon known as the urban heat island (UHI) effect. The UHI effect exacerbates the risk of heat-related mortality and magnifies the challenges posed by global climate change. While the magnitude of UHIs is influenced by factors such as city size, population, wind, and climate zone, the role of building configurations remains understudied. In this study, we investigate the global impact of building composition on UHIs, focusing on uneven heat effects across climate zones and temporal variations (day/night). We develop a machine learning-based model to estimate UHI intensity, incorporating building composition data from local climate zone (LCZ) classifications, background climate. Our findings reveal significant inequalities in the thermal impact of building composition across climate zones and time. During the daytime, building composition plays a notable role in tropical climates, where compact, low-rise structures exacerbate the local thermal environment through strong heat dissipation. Conversely, at night, the influence shifts to arid climates, with LCZ2 (compact mid-rise) types consistently demonstrating the largest thermal dissipation across all climate zones. The direct implication of these uneven heat impacts is that urbanization and mitigation strategies underscore the critical need for appropriately implemented based on a thorough understanding of the thermal effects of building structures across different climate zones, thereby advancing urban sustainability and resilience.