Analysis of the coordinated development and influencing factors between urban population and environment: A case study of 35 metropolises in China

Abstract

Balancing the relationship between population and environment is crucial for urban sustainability nowadays. Research on the coordinated development of population and environment from the perspective of city size is relatively scarce. This study constructed a comprehensive evaluation system for demographic and environmental systems. It applied a relative development index, a modified coupling coordination degree (CCD) model, an obstacle degree model, and a two-way fixed effects model to explore the development trends, coupling coordination relationships and influencing factors of the Population-Environment (P-E) complex system in 35 metropolitan cities in China from 2006 to 2022. The results indicated that (1) the development levels of population and environment had generally improved, and there were significant disparities in the population development level among cities of different sizes; (2) population development lagged behind environmental development, though they became gradually synchronized; (3) the CCD of P-E complex system increased with city sizes; (4) major factors influencing P-E coordination included population reproduction, environmental investments, aging and migration. Larger-scale cities like megacities should prioritize to mitigate population aging, narrow urban-rural income gap, strengthen pollution control, and balance gender structure. Smaller-scale cities can focus on optimizing industrial and employment structures. These findings provided suggestions to promote urban coordinated, high-quality and sustainable development.