Rainfall variability, drought and implications of its impacts on Zambia, 1886-1996

Abstract

The theory of runs was used in the investigation of frequency of occurrence, duration, magnitude and severity of drought in 46 districts of Zambia, 1886-1996. The 30-year "normal" rainfall was used as the threshold for drought occurrence with most analyses restricted to the 1921-1970 period. Analysis revealed that rainfall variability, indicated by increasing 11-year coefficients of variation (CVs) for selected stations and decreasing rainfall trends observed in southern Zambia after 1975, was not extraordinary as similar conditions were experienced before the turn of 19th century. What was new, however, is that the decreasing rainfall after 1975 seems to be related to the accelerated global warming associated withanthropogenic activities. Implications of impacts of drought were assessed from scenarios of drought occurrence under the threat of rising global warming. Various drought adaptation measures are discussed. It is concluded that, in Zambia drought is a chronic phenomenon which requires pre-planned measures for minimizing its impacts.