Urban life cycle theory: Past, present, and future

The urban life cycle theory was proposed by Hall and Van den Berg and colleagues based on European urban research. According to the changes in the population of the urban core and rings, the urban spatial evolution process is divided into four stages: Urbanization, suburbanization, deurbanization, and reurbanization. The stage alternation and specific stages described by the theory have also been confirmed by subsequent empirical research, and this theory has been widely applied in identifying and studying the stages of urban development. However, this theory has been criticized and questioned as follows: 1: The process of urban development cannot be measured solely from a single population change perspective; 2: There are heterogeneities in urban development under different backgrounds; 3: The division of stages is unreasonable and debatable; and 4: Urban space does not always evolve linearly in a unidirectional order. In this context, many studies have made revisions, supplements, and improvements to this theory, and some new theories have been proposed, but there is still room for breakthroughs and development. Future breakthroughs can be made in the following aspects: 1: Incorporate marginal cities, shrinking cities, gentrification, and new urban phenomena into research of the post crisis and post pandemic period, and consider changes in people's lifestyle and thinking, socioeconomic background, and so on, to expand the applicability of the theory; 2: Refine urban types to identify the diversity of evolution, and conduct comparative research to identify urban life cycle models that are suitable for China; 3: Incorporate population structure and integrate the data of population size, age, and household and socioeconomic characteristics to enhance the depth of urban spatial analysis; and 4: Increase research on the migration of residents and businesses, expand micro-scale perspectives, and integrate multiple urban systems to enhance the comprehensiveness of urban spatial evolution theory.