Balancing Physical and Human-Driven Morphodynamic Changes: Insights From the Pearl River Estuary

The Pearl River Estuary, home to one of the world's densest human populations, exemplifies the delicate balance between natural dynamics and anthropogenic pressures. Our study explores how human activities and environmental changes interact to reshape this vital system, potentially driving it toward a tipping point. By integrating historical data, a Bayesian Network model, and a process-based morphodynamic model, we quantify the relative contributions of sediment supply, land reclamation, dredging, sand mining, and sea-level rise to estuarine evolution. Sediment supply remains the dominant driver, but human interventions and rising sea levels significantly disrupt the system's dynamics potentially leading to a tipping point in the estuarine morphodynamics of the Pearl River Estaury. We identify three distinct phases of estuarine evolution, revealing how cumulative pressures driven by anthropogenic pressure could force the estuary into different states with ecological, economic and societal consequences. These findings provide a general and transferable framework for detecting human impacts on estuarine systems and inform climate adaptation strategies.