Human flood adaptation characteristics: A comparative study of three global river deltas

River deltas are critical socio-economic and ecological regions but face heightened flood risks due to climate change and urbanization. Taking the Ganges-Brahmaputra-Meghna (GBM) River Delta, the Mississippi River Delta, and the Yangtze River Delta as case studies, this research aims to reveal the characteristics and formation mechanisms of human adaptation to flood risks across different deltaic regions. Through integrating hydrodynamic modeling, spatiotemporal analysis, and multi-source datasets, this study systematically investigates flood adaptation characteristics across three major deltas based on a newly developed comprehensive framework of Human-Flood Distance (HFD) and resilience. The results show that: spatially, while these three deltas exhibit varying degrees of inundation extent, each faces unique flood vulnerability challenges; temporally, the GBM River Delta exhibits stabilized population growth and HFD recovery after initial contraction, the Mississippi River Delta shows significant fluctuations in both population and HFD, while the Yangtze River Delta demonstrates continuous population growth with steady HFD increase; in terms of adaptation mechanisms, resilience assessment indicates that the Mississippi River Delta demonstrates the highest resilience, primarily driven by recovery capacity, the Yangtze River Delta shows limited but structurally supported resilience, while the GBM River Delta exhibits negative indices due to multiple constraints. These findings emphasize the importance of developing context-specific flood risk management strategies and provide feasible flood prevention solutions for policymakers, particularly in formulating adaptation strategies that comprehensively consider both flood safety and sustainable development.