The relationship between climate change and the development of Old World riverine civilizations is poorly understood because inadequate dating control has hindered effective integration of archaeological, fluvial, and climate records. This paper presents the most comprehensive and robustly dated archaeological and paleoenvironmental data sets yet compiled for the desert Nile. It focuses on the valley floor hinterland of the Kingdom of Kerma (2400–1450 B.C.) in northern Sudan. Kerma emerged as a rival to Egypt during Africa’s first “Dark Age” drought. In contrast to other irrigation-based agriculturists in Egypt and Asia, Kerma flourished during the environmental crisis ca. 2200 B.C. We have studied the stratigraphy and archaeological records of paleochannels across an 80 km reach of the Nile upstream of Kerma using optically stimulated luminescence to date when channels flowed and when they dried up. The dynamics of the local alluvial environment were critical in determining whether climatic fluctuations and changes in river flow represented an opportunity for floodwater farmers (5000–3500 B.C.), a hazard that could be managed (2400–1300 B.C.), or an environmental catastrophe that resulted in settlement abandonment (after 1300 B.C.).