Drylands Research Working Paper 25

Abstract

Rainfall data from five stations (Kano, Magaria, Maradi, Nguru and Zinder) are analysed for the period 1931-1999, to show long-term trends, seasonal changes, and the incidence and severity of droughts. The first of these analyses shows that long-term trends were spatially persistent and that the record is dominated by a long downward trend from the 1950s to the 1970s, two severe troughs in the early 1970s and early 1980s separated by a short recovery, and followed by divergent trends (rising in Kano and persistently low in Zinder) during the 1990s. The long-term trends provide no reliable basis for predicting future rainfall. The second analysis shows that inter-annual variability and long-term decline differ from month to month, with the steepest decline in August and the greatest variability in May and June. The third analysis shows that all the five stations are equally affected, though not to the same degree every year, by drought (defined in terms of Standard Precipitation Indexes based on deviation from mean annual rainfall). The success of rural households in adapting to the challenge of climate change can be evaluated against these measures.