Human impact on land–ocean total phosphorus flux in the world's rivers

Rivers control the land-ocean phosphorus flux that affect ecosystem health and food security. Yet, systematic trend analysis of the global phosphorus flux is lacking, primarily due to sparse and inconsistent observations. Here, we develop a machine learning framework integrating multimodal data and 280,000 TP measurements to reconstruct TP flux patterns over 1980–2019 across 420 major rivers. Results reveal a deceptive global equilibrium. While TP flux declines in the Northern Hemisphere, driven by dam trapping, it rises in the Southern Hemisphere due to increased fertilizer use and deforestation. Notably, the number of small rivers with rising TP flux is nearly double that of large rivers. Our findings highlight a shifting global phosphorus landscape and underscore the need for more targeted, sustainable phosphorus management strategies.