Evaluating inequality divides in urban development intensity between the Global North and South

Abstract

As the significance of cities worldwide with regard to human activities increases, Urban Development Intensity (UDI) becomes an increasingly critical factor for achieving Sustainable Development Goal (SDG) Target 11.3 and serves as a scientific foundation for establishing urban land development guidelines. However, the existing literature lacks systematic quantification of fine-scale UDI on the global scale. In this study, we propose a comprehensive framework for evaluating UDI globally, utilizing multi-source surveys to compare spatial variations between the Global North and South. We created structured grided UDI layers at a 1-km resolution covering urban areas worldwide, considering various aspects of urban development on land surface characterized by three-dimensional (3D) building metrics, population density, nighttime lights, and transport constructions. By employing composite models and the inequality index, we assessed UDI disparities across 6986 cities and metropolitan areas globally to investigate variations in UDI levels and heterogeneity among the Global North–South regions, inter-city, and intra-city contexts. Furthermore, the bivariate local Moran’s I statistic and k-medoid algorithm were utilized to identify spatial and pattern clusters of UDI among global cities. Our findings revealed diverse spatial distribution of multi-source UDI differences globally, with urban areas in the Global North generally exhibiting higher and more equitable intensity than that exhibited by urban areas in the Global South, where the intensity tends to be lower at the urban peripheries and highly concentrated in city centers. Recognizing the disparities and clustering patterns of UDI levels of global cities underscore the importance of promoting urban equalization to ensure containment and drive improvement in UDI towards diverse models under local urban circumstances for effective implementation of sustainable urbanization development across cities both in the Global North and South.