Assessment the urbanization sustainability and its driving factors in Chinese urban agglomerations: An urban land expansion - Urban population dynamics perspective

Achieving urbanization sustainability is considered to be both an important component of the Sustainable Development Goals and a key way to address the conflict between limited resource constraints and urban continued growth. Regarding the urbanization sustainability, the impact of ecological environment and resource consumption has been widely discussed, while the holistic effect of urban land expansion and urban population dynamics is under-researched. This paper evaluated the urbanization sustainability of 15 urban agglomerations in China from 2000 to 2020, and applied the Geodetector model to investigate its impact mechanism. The results show that at the national level, the level of urbanization sustainability exhibited a trend of first increasing and then decreasing, accompanied by significant spatial differentiation. Spatially, the level of urbanization sustainability in urban agglomerations located in the northeast regions had strong variability during the study period. In contrast, urban agglomerations located in the central region had a lower level of urbanization sustainability due to the unrestricted expansion of urban land. In addition, urbanization sustainability varied according to the development stage of urban agglomerations. Specifically, urbanization sustainability showed a downward trend in the initial development stage, early growth stage and later growth stage of urban agglomeration, and upward trend in mature stage. Economic development level, foreign direct investment, industrial structure and urbanization level were the primary determinants of differences in urbanization sustainability at both national and regional levels. These findings may help to formulate the urban sustainable development planning and differentiated land use policies.