Widespread Divergence Between Precipitation and Discharge Trends Across Global Rivers

Abstract Precipitation is widely perceived to drive river flow (discharge), yet many rivers have experienced declining flow despite increasing precipitation, or vice versa. Here we quantify the prevalence of such diverging trends and identify their drivers. Using the Caravan data set and Theil–Sen regression, we analyzed long‐term trends in precipitation and river discharge at 10,179 sites worldwide (1951–2020). River discharge declined at 48% of sites, while precipitation declined at 52%. Diverging trends occurred at 27% of sites, 40% of which showed declining discharge despite increasing precipitation; their magnitude increased with aridity. A random forest classification model identified the frequency of low (or high) precipitation days and runoff ratio as the most influential drivers of strong divergence, highlighting the importance of precipitation extremes beyond the extensively discussed role of evapotranspiration. These findings reveal widespread decoupling of precipitation and river flow, highlight heightened water risks in drylands, and underscore the need for sustained river discharge monitoring, as precipitation trends alone are insufficient to predict changes in water availability.