Flood fatalities and displacement influence human migration in floodplains of developing countries

Understanding what drives human migration in floodplains is critical for mitigating risks and enhancing resilience to floods. However, existing global analyses have not fully explored these complex dynamics. Here we introduce a metric, human-flood distance change, to track migration in floodplains from 2000 to 2018, exploring the interplay of climatic and anthropogenic influences. We find that in developing countries, including India, Argentina, Brazil and Nigeria, flood fatalities and displacement strongly influence migration decisions, often forcing populations to move away or toward flood-prone areas due to flood damage memory or resource needs. Conversely, regions with higher flood protection, such as the United States, show migration trends away from hazardous areas. Climatic drivers, like flood inundation area, exert stronger influences in Australia. Notably, in the Philippines and Kenya, the easing of drought-flood abrupt alternation has led to increased population movement toward flood-prone areas, underscoring the complex interactions between multiple hazards. In developing countries, flood fatalities and displacement impact people’s decision to migrate away, or toward flood zones, and in developed countries, people move away from flood areas, according to an analysis that uses a statistical approach and social and climate data.