The desert conditions along the coast of South West africa between 15 and 33 are caused by the multiple aridifying effects of the South Atlantic anticyclone, the cold Benguela Current, the upwelling of cold South Atlantic Central Water and the divergence of the South East Trades along the coast. This climatic system has an aridifying effect on the whole area of South West Africa and Botswana. During glacial times both the climatic zones and the Benguela Current shifted northwards and caused extensive aridification of the coastal are as far north as Cape Lopez. This drying influence penetrated far into northern Angola and Zaire. Proofs for such changes are provided by geomorphological, oceanographic and palynological evidence. The Namib Desert could only develop after cold water produced in the Southern Ocean since the Early Oligocene was able to penetrate northwards. The antiquity and high degree of endemism of the biota corroborates the old age of the desert. The accumulation of the Kalahari strata during the Miocene, Pliocene and Quaternary can be correlated with northward shifts of the South Atlantic anticyclone and the Benguela Current to lower latitudes as a consequence of glaciations in Antarctica and in the Northern Hemisphere. These events were also of great importance for the origin of the biome of the Flora Capensis.