Abstract
Unlike the Namib Desert, long-term unstable climatic conditions prevail in North Africa. Climatic instability of Sahara is modulated by Milanković orbital cycles (of the order of 105 years) and the influences of the lower in frequencies, including solar activity cycle (of the order of 101 years).
The chapter describes the Pleistocene and Holocene history of cyclic wetting and drying of the Sahara.