WASWAC

Fluvial sediment transport, a key pathway for global biogeochemical cycling, has changed markedly in the Anthropocene. However, disaggregating the compound effects of anthropogenic stresses on fluvial sediment transport at the global scale remains a challenge. Here we map the suspended sediment concentrations for global river channels, based on satellite observations, between 1985 and 2020, and estimate long-term changes in land–ocean sediment transfer. We find significant (P < 0.05) changes in suspended sediment concentrations in 67.8% (3.2 × 105 km) of the examined river channel length, with 43.4% (2.05 × 105 km) displaying a significant increasing trend, driven mainly by rising rainfall erosion and climate warming. Consequently, a global net increase (+0.58 Gt year-1) in land–ocean sediment flux has been observed over the past four decades, despite sediment trapping by recently constructed dams, mostly in Asia. Our study provides a new baseline for source-to-sink fluvial transport in the Anthropocene that can inform global water resource management and delta management and protection.