Urban growth is a defining feature of the 21st century, yet its trajectories are shaped not only by demographic and economic forces but also by physical geographic constraints. Here we analyze 7385 cities worldwide from 1990 to 2020 using global satellite-derived urban footprint data and gridded socioeconomic datasets. We construct two indicators—the share of barriers and nonconvexity—to quantify the extent and spatial configuration of undevelopable land, and estimate their impacts using panel regression models. We show that cities with higher geographic constraints experience slower horizontal expansion, lower population and GDP growth, and reduced expansion elasticity, but adapt through greater increases in built-up height and density. Differences between the Global North and South reveal convergence in constraint levels as urbanization accelerates. These findings highlight the critical role of geographic constraints in shaping long-term urban development trajectories. Geographic constraints systematically limit the horizontal expansion of urban areas but promote denser, taller urban development worldwide, according to an analysis that uses urban and climate data, geographic and growth urban metrics, and a statistical approach
Wang et al. (Sun,) studied this question.