Historical nile floods and their implications for climatic change.

Analysis of Nile flood stages from A.D. 640 to 1921 reveals major episodes of low Nile discharge during the years 930 to 1070 and 1180 to 1350 and major episodes of high Nile floods during 1070 to 1180 and 1350 to 1470. Examination of Nile flood maxima and minima and comparison with water levels in Lake Chad reveal a correlation between high Nile discharge and greater rainfall in equatorial East Africa. There is also apparently a correlation between low Nile discharge and cold climate in Europe.