GeoJournal 48: 299–311, 1999. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 299 Drought in the Sahel C.T. Agnew 1 & A. Chappell 2 1 School of Geography, Manchester University, Oxford Road, Manchester, M13 9PL, U.K., e-mail: clive.agnew@man.ac.uk; 2 Telford Institute of Environmental Systems, Department of Geography, University of Salford, Manchester, M5 4WT U.K., e-mail: a.chappell@salford.ac.uk Received 6 May 1999; accepted in revised form 21 February 2000 Key words: desertification, desiccation, drought, drought classes, meteorological drought, Sahel Abstract The Sahel region of West Africa is well known as a region of environmental degradation. The reported incidence of desertification has been challenged but persistent and widespread drought is still widely accepted. Drought, defined solely as a function of rainfall, is believed to have commenced in the early 1970s and continued through to the present. It is usually defined as a meteorological phenomenon and standardised rainfall anomalies are employed to indicate the severity of negative departures from the ‘norm’. There are several difficulties with this approach. The period of standardising rainfall has changed from 1931–1960 to 1961–1990 but the impacts on drought occurrence have not been fully determined. The spatial aggregation of rainfall anomalies may mask important local variation and the purely statistical approach to defining drought takes little account of human impact. The first two issues, averaging period and spatial aggregation, are investigated through an analysis of rainfalls in Continental Sahel (Bukina Faso, Mali and Niger). A new classification of drought classes is suggested. Despite the clear evidence of negative rainfall anomalies for rainfalls aggregated across the Sahel region, it is found that the averaging period has a significant impact on our perceptions of the occurrence of what can be considered to be meteorological drought according to the definition employed and that there is significant spatial variation. Introduction The Sahel region in West Africa is renown for its twin en- vironmental problems of drought and desertification. The region has been described by Sivakumar and Wallace (1991, p. v) “as one of the harshest climatic regions of the world, with low and highly variable rainfall, high soil and air temperatures, high evaporative demand, and poor soils”. All recent decades have witnessed reports on drought in the Sahel which is seen by many authors to be both wide- spread and persistent. In the 1970s a downward rainfall trend was noted by several climatologists including Lamb (1974) and Winstanley (1973). Concern for the inhabitants of the region grew during the early 1970s and eventually the ‘Sahel drought’ became an international relief effort with the FAO (11/5/1973) announcing “In some areas there now appears serious risk of imminent human famine and virtual extinction of herds vital to nomad populations”. In the same year a UNICEF telex recorded “drought for four to five years, . . . desert is moving southward . . . problem of survival . . . drought stricken regions.” Several years later the Guardian newspaper (10 October 1977) reported that drought had struck again and noted the call from the Mau- ritanian Government for assistance from the international community to save human lives from death. The same concerns continued through the 1980s and a decade later Copans (1983) estimated that there had been 100,000 drought related deaths in the Sahel. A downward trend in rainfall was observed by many (Hare, 1984; Mac- Donald, 1986) with Tooze (1984) reporting that the drought in the Sahel has not yet ended. Tickell (1986) (then head of the Overseas Development Agency) went even further and announced that the documentary record for the last 70 years (in the Sahel) shows a slight decline of rainfall from 1955 and acute drought since 1968. Not all believed in a persistent drought but the view of Flohn (1987) that drought started in the late 1960s and never really ended is characteristic of the prevailing perception for the region. The same image of a drought ravaged landscape, some- times with an advancing desert front, can be found in the 1990s literature. Pritchard (1990, p. 246) “The desert is advancing partly because of recurring cycles of drought”; Odingo (1992, p. 6) “After a 20 year series of droughts, the Sudano-Sahelian region remained the most permanently vulnerable area.”; Nicholson and Palao (1993, p. 371) “The Sahelian region of West Africa is well known for the extreme droughts it experiences. The current one has prevailed since the late 1960s”; D’Amato and Lebel (1998, p. 956) “the pro- longed drought that has struck the Sahel for 25 years now”; and finally Zheng and Eltahir (1998, p. 2078) “Observations from West Africa indicate a significant decline in rainfall levels since the early 1960s”. In contrast 1994 was one of the wettest years in Niger since the late 1960s, and high rainfalls have been recently observed, but it is too soon to make any comment about