Coupling coordination degree and spatiotemporal dynamics: diagnosing the Nile Delta urban ecosystem and socioeconomic lag

Rapid urbanization has profoundly altered socioeconomic–ecological interactions, particularly within environmentally sensitive deltaic systems. This study evaluates the spatiotemporal evolution of socioeconomic–ecological coordination in the Nile Delta, Egypt, from 2010 to 2023, using the coupling coordination degree model (CCDM) and spatial autocorrelation analysis. Multi-source remote sensing data processed through Google Earth Engine (GEE) were used to construct consistent socioeconomic and environmental indicators, while the entropy weight method (EWM) was applied to determine objective indicator weights. The results reveal a nonlinear temporal coordination trajectory, with the average CCD declining from 0.72 in 2010 to a low of 0.54 in 2015, followed by a limited recovery to 0.55 in 2020 and a stronger recovery to 0.63 in 2023. Furthermore, the dominant constraint shifted from ecological lag in 2010 to socioeconomic lag during the 2020–2023 period, indicating that improvements in environmental conditions were not accompanied by comparable socioeconomic advancement. Spatially, the Delta shifted from a polarized center–periphery pattern toward greater spatial homogeneity at moderate coordination levels, although significant spatial dependence persisted and low–low clusters expanded along the northern coastal fringe. These findings demonstrate how dominant constraints and spatial configurations of socioeconomic–ecological coordination can change over time within a highly dynamic delta system. By extending CCD-based assessment to an underrepresented African deltaic context, this study advances the understanding of the spatial and temporal patterns of socioeconomic–ecological coupling under environmental change.