A county-level analysis of spatiotemporal variation and human causes of urban heat islands in the Guangdong-Hong Kong-Macao Greater Bay Area

The Urban Heat Island (UHI) effect, poses significant challenges in rapidly developing regions like the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). Understanding the anthropogenic drivers of UHI and their interactions is critical for effective urban planning and climate mitigation strategies. To investigate the anthropogenic drivers and their interactions in GBA UHI over a long time series, this study employed Sen’s slope and the Mann-Kendall (MK) test for trend analysis. This study examined the impacts of nine human activity factors on UHI formation using the geodetector. The results indicate that from 1990 to 2020, the GBA experienced a notable increase in UHI, with the average land surface temperature increasing by 5.25 degrees Kelvin. The areas with notable increasing trends were mainly Dongguan City, much of Shenzhen City, northwestern Guangzhou, and some eastern counties of Foshan City. Interaction factor analysis revealed that human settlement intensity had the highest influence, with the gross domestic product (GDP) and building height (BH) being the most significant factors, with q values of 0.434, 0.319, and 0.451, respectively. Notably, the interaction between carbon emission intensity and land development exhibited the highest explanatory power for UHI changes, with a q-value of 0.85. These findings can promote ecologically conscious development in urban agglomerations and provide insights for urban planners.