Quantifying global-scale mechanisms of urban morphological change: A novel Structural Equation Model based on the Pressure-State-Response framework

Understanding the drivers of urban morphological change is vital for sustainable urban development, yet quantitative analyses of long-term, global-scale urban morphological evolution remain limited. In this study, we examined spatiotemporal changes in urban morphology across 27 major cities in the Global North and South from 2000 to 2020, using a structural equation model (SEM) integrated with the Pressure-State-Response (PSR) framework. We integrated global datasets to quantify latent variables (e.g., Pressure, State, Response) and their observed indicators, including building fraction (BF), building height (BH), socioeconomic and environmental metrics. Results indicate that horizontal expansion (BF) outpaced vertical growth (BH), particularly in Global South cities, with BF increasing by 41.7 % relative to a 2.0 % net decrease in BH. The influence of economic growth on urban morphology exhibited a weakening trend in the Global South, with the mean path coefficient shifting from 0.34 to −0.60, whereas this influence remained persistently negative in Global North cities. Meanwhile, environmental constraints intensified, as evidenced by mean negative coefficients intensifying from −0.22 to −0.32 in the Global North and from −0.25 to −0.22 in the Global South. Notably, the role of vertical growth in urban adaptation underwent a significant transition from a negative to a positive influence, with path coefficients shifting from −0.25 to 0.18 to promote urban sustainability. These findings highlight the divergent evolutionary trajectories of global urban morphology, underscoring the need for tailored planning strategies that manage rapid expansion in emerging cities and optimize urban forms in developed cities to enhance global urban sustainability.