4 - The Growth or Shrinkage Dichotomy of Chinese Cities Between the Demographic Siphon-Effect and the Economic Spillover Effect

Most Chinese cities are now in a dynamic balance of population inflow and outflow. Urban shrinkage often exist in the alternating relationship between the demographic siphon-effect and the economic spillover-effect of several core cities: (1) In the relatively remote areas, where the siphon-effect of the core city is strong while the spillover effect is weak, the population outflow and local economic development in a low pace; (2) In areas closer to the core city, the population outflow and economic spillover are both significant, so the economy of the shrinking cities are still developing. Under such a mechanism, the growth and shrinkage of China's cities are manifested in: (1) Most county-level cities, towns and rural areas have experienced a net outflow of population, resulting in hollowing out; (2) There are shrinkages within large cities, where districts and areas with "perforated" shrinkage of population, such as Wuhan, Chengdu, Chongqing, etc.; (3) Under the influence of population siphon effect, a large number of small and medium-sized cities with shrinking population appear on the periphery of metropolitan areas with rapid economic development. Through observation at a cross-regional scale, city-regions in China often present a spatial pattern in which population growth and shrinkage are embedded in each other under the influence of "growing urban agglomerations/metropolitan areas, shrinking rural areas, and depopulation of medium-sized cities under severe siphon effects."