Unveiling Causality: Does Demolishing Informal Settlements Cause Urban Surface Cooling?

Can demolishing informal settlements actually cool the urban surface? Despite widespread renewal efforts, the direct impact of these interventions on land surface temperatures (LST) remains unclear. Most prior research has been limited to identifying associations, lacking the methodological tools to distinguish cause from correlation. Conventional before-and-after or cross-sectional comparisons are unable to disentangle the specific impact of demolition from confounding influences like ongoing urbanization, climate variability, or overlapping policy shifts. Here we apply the difference-in-differences (DiD) approach—rarely used in this context—to rigorously decode the causal relationship between informal settlement demolition and LST dynamics. Drawing on a time series of Landsat satellite thermal images, we track 77 demolished informal settlements and 584 control sites across Beijing, Shanghai, and Guangzhou from 2002 to 2022. The DiD framework enabled us to filter out confounding factors and isolate the causal effect of urban renewal. Our findings reveal significant, city-specific cooling effects—3.04 ± 0.37 K in Beijing, 1.09 ± 0.27 K in Shanghai, and 1.23 ± 0.36 K in Guangzhou (all p < 0.05). This study provides robust causal evidence confirming that demolishing informal settlements can significantly mitigate urban heat in megacities. These findings underscore urban renewal’s potential as an effective tool for thermal management, enhancing our understanding of its direct environmental impacts.