Recent rainfall fluctuations in Africa and their relationship to past conditions over the continent

Abstract

This paper examines the rainfall conditions which have prevailed over Africa during the last two decades. Throughout this period rainfall has been abnormally low over most of the continent. These conditions are compared and contrasted with those which previously prevailed during historical and geologic times. A trend towards increasing aridity since about 1970 has been neither continuous nor apparent in all regions but is evident as an increase in the area affected by subnormal rainfall and in the size of the deficit in the semi-arid regions. These conditions contrast markedly with the 1950s and are unlike any which occurred earlier in the century, and may signal a major change in prevailing global- scale climate. The continental patterns of reduced rainfall are analogous to historical fluctuations, most notably those of the early nineteenth century, and are of relevance to understanding the causal mechanisms of climate change in the late Pleistocene. The patterns are supportive of an underlying climatic cause for recent desertification in Africa.