Evaluation of urban comprehensive carrying capacity in the Guangdong–Hong Kong–Macao Greater Bay Area based on regional collaboration

The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is the most prominent urban agglomeration in China, with plans for further development. Using the regional collaboration theoretical framework for assessing urban comprehensive carrying capacity (UCC), the improved entropy method is applied to establish an index system based on a social, economic, environment, and transportation perspective to compare UCCs of the GBA's 11 cities for 2000–2016. Results show that the social subsystem is central to the evaluation system. Cities' performances vary significantly, with six becoming overloaded in 2016 and the other five remaining loadable. Guangzhou performed best, with a rising UCC; Shenzhen rebounded after a long period of decline; Hong Kong's capacity rose slightly, with some fluctuation; and Macao performed worse and continues to slide, with no signs of improvement. Overall, the UCC of the urban agglomeration showed a downward trend, with only a few cities continuing to improve. The spatial distribution for UCC was high in the north and low in the south, showing scope for improvement. The study enriches regional collaboration theory and proposes policy implications for GBA development.