North Africa

Climate Changes in Prehistory and History
By Ken Hsu <ken@erdw.ethz.ch>

... Prof. Nicola Petit-Maire, at University of Marseilles, described the vast lacustrine deposits in the Sahara desert: the sediments were laid down during a humid phase between 9,500 to 4,000 BP. Rainfall was so abundant then that Mali was not a desert but land of great lakes. The Cro-Magnon people came across the Strait of Gibraltor from Spain to the savannas of Sahara. They hunted elephants, rhinoceros, buffaloes, hippopotamus, antelopes, and giraffes, as depicted in their wonderful rock paintings. The deserts of North Africa expanded, however, and an early clustering of cold centuries around 5200 BP caused the deteriozation of environments. Hunters and grazers left Sahara and settled on as farmers the alluvial plains of Egypt. The cooling and aridity continued and the last of the Saharan lakes dried up 4,000 BP, ending the Saharan civilization, at about the same time when the glaciers advanced in the Alps.

Mild and wet climate prevailed during the Climatic Optimum in the Near East. I visited the Canannite City Arad on the edge of the Negev Desert: it was a populous settlement of several thousand inhabitants during the Early Bronze Age. Suddenly Arad was abandoned. The deserted city showed no signs of destruction by war, the exodus was necessitated by a shortage of water supply. Indeed, the centuries-long drought in the Middle East was the cause of the collapse of the Early Brone Age civilization in Mesopotamia, as Prof. H. Weiss of Yale and his colleagues concluded. A marked increase in aridity caused the abandonment of setttlements in the north and the collapse of the Akkadian Empire in the south. The impact of was extensive: there were synchronous collapse of the civilizations in Hindus Valley and in Egypt. The climatic catastrophe started around 2200 BC and came to an end 300 years later. This was the expression of the 4000 BP Event in Middle East.