Recognizing urban shrinkage and growth patterns from a global perspective

Abstract

The incongruous patterns of urban growth often give rise to a myriad of issues, notably urban sprawl and urban shrinkage. These challenges frequently coexist and interact, presenting formidable obstacles to achieving sustainable city development. Therefore, investigations that endeavor to scrutinize both urban expansion and shrinkage in concert from a comprehensive perspective are essential. Present works of defining this trajectory are still vague, in which there is no clear clarification, and the relationship with socioeconomic also tends to be neglected. Thus, we proposed a new framework utilizing characteristic changes over 30 years in population and density to conduct a synthesis of urban growth patterns in 3911 cities worldwide along with their driving factors. We found that the development stage played a crucial role in urban growth pattern. Specifically, the densification cities were mostly found in the early stages of industrialization and urbanization. However, in accelerated industrialization and fast-developing regions, sprawl cities progressively gained dominance. Most cities followed the sprawl pattern and more shrinkage cities began to emerge in regions which in post-industrialization developed at high stages. Factors including industrialization level, urbanization rate, initial population density, terrain, and cultivated land conditions all exerted notable influences revolving around the urban growth process. Our study aims to help gain an overall sense of the global urbanization process as well as guide decision-makers to search for tailor-made management policies and urban planning for cities at various development stages. The patterns of expansion and shrinkage could offer support for a more comprehensive assessment of SDG indicators 11.3.1 and thus inform policies for urban sustainable development.