Spatial and temporal inequity of urban land use efficiency in China: A perspective of dynamic expansion

In the face of conflicting land-resource supply and demand, land-use efficiency is critical for sustainable urbanization. In this study, we unified the consistent boundaries of land, population, and economic development, identified urban expansion patterns (infilling, edge expansion and leapfrogging), and precisely estimated urban land-use efficiency (ULUE) in 260 Chinese cities from the perspective of dynamic expansion during 2000-2015. With the consideration of the dynamics of outward expansion and internal development of urban land, the results showed that China's main expansion pattern gradually shifted from edge expansion with lower ULUEs to infilling with higher ULUEs. Over the 15-year period, ULUEs in all expansion areas increased from 0.065-0.18 to 0.093-0.31. Inequity remained significant in terms of expansion patterns, built-up layers, regions and urban sizes. ULUE increased more quickly in the super-large cities of the central and western regions, whereas it increased more slowly in the northeast and even decreased in expansion built-up area formed during 2005-2010 (EBUA (2005-2010)). Importantly, ULUE decreased in most cities with edge expansion. Based on the findings, we concluded that the urbanization of China was progressing toward sustainability but still had room for improvement, and we suggested that policymakers should pay more attention to the complex, systemic nature of urban development.