Understanding how large river systems will respond to an invigorated hydrological cycle as simulated under higher global temperatures is a pressing issue. Insights can be gained from studying past wetter-than-present intervals, such as the North African Humid Period during the early Holocene Epoch (~11–6 thousand years ago). Here we present a 1,500-year-long annually laminated (varved) offshore sediment record that tracks the seasonal discharge of the Nile River during the North African Humid Period. The record reveals mobilization of large amounts of sediments during strong summer floods that may have rendered the Nile valley uninhabitable. More frequent and rapid transitions between extremely strong and weak floods between 9.2 and 8.6 thousand years ago indicate highly instable fluvial dynamics. Climate simulations suggest flood variability was paced by El Niño/Southern Oscillation on interannual timescales, while multi-decadal oscillatory modes drove changes in extreme flood events. These pacemakers have also been identified in the Nile flow records from the Common Era, which implies their stationarity under contrasting hydroclimatic conditions.

了解大型河流系统将如何响应全球气温升高下模拟的活跃水文循环是一个紧迫的问题。通过研究过去比现在湿润的时期，例如全新世早期的北非湿润时期（约 11-6 千年前），可以获得见解。在这里，我们展示了长达 1,500 年的年度层状（varved）近海沉积物记录，该记录追踪了北非湿润时期尼罗河的季节性流量。该记录显示，在夏季强烈洪水期间，大量沉积物流动，可能导致尼罗河谷无法居住。 9.2 至 8.6 万年前极强和极弱洪水之间的转换更加频繁和迅速，表明河流动力学高度不稳定。气候模拟表明，洪水的变化是由厄尔尼诺/南方涛动在年际时间尺度上决定的，而数十年的振荡模式则推动了极端洪水事件的变化。这些起搏器也在公元元时期的尼罗河流量记录中被识别出来，这意味着它们在对比水文气候条件下的稳定性。