Sustainable urban expansion and human development in China: An analysis using an environmentally improved human development index

Urban expansion poses a substantial challenge to sustainable regional development, but the spatiotemporal relationship between urban expansion and human development remains unclear. This paper proposed an improved human development index (IHDI) incorporating an environmental dimension and analyzed the spatiotemporal correlation between urban expansion and IHDI growth in China from 1990 to 2020. Significant increases in both urban expansion and human development levels were observed, and environmental differences between Eastern and Western China were effectively detected based on the IHDI, which also well reflected the geographical patterns bounded by the Hu Huanyong Line. In 1990, a significant disparity existed in the IHDI between the provincial capital cities and the entire province; by 2020, this gap had narrowed, and the prioritized development of provincial capitals subsequently propelled regional growth. Although positive correlations between urban expansion and IHDI growth in China were found from 2010 to 2020, the percentage of expansive negative decoupling between urban expansion and IHDI growth gradually increased, indicating a less sustainable relationship involved in urban expansion and human development in China. This study contributes to a comprehensive understanding of the spatiotemporal correlation between urban expansion and human development, and provides valuable insights for achieving sustainable development goals in China.