More urbanization, more polarization: evidence from two decades of urban expansion in China

This article examines whether the patterns of urbanization in China over the past twenty years have resulted in a more balanced or increasingly polarized city size distribution. China is an important study area due to the immense scale of its urbanization and the substantial role of its planners in coordinating and striving for more balanced development patterns. This study utilizes measures of the spatial and temporal characteristics of built-up area (BUA) expansion across 23 urban agglomerations in China, focusing on size dynamics through the urban primacy index and Pareto exponent. The BUA within these 23 UAs increased by 280.90% in the study period. Coastal urban agglomerations were larger in size at baseline and maintained relatively high annual growth rates compared to inland agglomerations, indicating rising polarization. Changes within agglomerations were indicative of declining polarization, as evidenced by the reduction in the urban primacy index and the increase of Pareto exponent. Policies implemented to achieve enhanced urbanization coordination in China appear to be partially successful, but the growth of urban regions with existing large size continues to fuel uneven urban development and polarization.