Reflections on Paradigm Shift in Urban System Reconstruction

In the era of agricultural civilization, the city size and layout adapted to nature and natural productivity; while in the era of industrial civilization, the constraints of natural productivity were broken by technological means, and the increasing returns to scale have enabled the urban population size to exceed 10 million and the urban population density to exceed 10,000 people/km2. Under the paradigm of industrial civilization, the spatial agglomeration of resources is driven by economic rationality. Besides, China’s urban hierarchy has become a barrier and further strengthened the polarization trend of city size, resulting in an urban system in which the cities at higher administrative levels concentrate a lot of resources while suffering from prominent urban diseases, small- and medium-sized cities lack development vitality, and urban and rural areas are separated from each other. The historical experience that the flow of resource factors between urban and rural areas facilitates a relatively balanced spatial distribution of quality resources is worth learning. Under the paradigm of ecological civilization, it is important to harmonize humans with nature in the transformation and reconstruction by pursuing nature-based solutions, and build a low-carbon, resilient, and coordinated urban system.