Recurring dipole flooding patterns in East Asia throughout the Holocene

Understanding how flood frequency and its distribution have changed over the Holocene in eastern monsoon China, a densely populated region, is vital for improving risk management and disaster mitigation. However, the spatiotemporal patterns of Holocene floods in this region remain poorly understood. Here, we reconstruct the history of large floods in the middle-lower Yellow River (north) and Yangtze River (south) basins. This provides the first clear evidence of a persistent dipole flooding pattern between these regions, with a ∼1.0 ka cyclicity across the Holocene. Proxy records and climate model simulations indicate that within the monsoon climate regime, increased flooding in the Yangtze River basin aligns with enhanced El Niño events, which are modulated by millennial-scale weakening of the Atlantic Meridional Overturning Circulation (AMOC). Sensitivity simulations further reveal that flooding in the Yellow River basin tends to peak during solar maxima, through modulation of a persistent La Niña-like background state. Our findings suggest that continued AMOC weakening in the future could lead to more intense El Niño events, potentially increasing the flood risk in southern China. This underscores the need to integrate long-term climate dynamics into future adaptation strategies.