The 1970s droughts in particular brought television images of starving people and dehydrated livestock to the world. While drought continues to be common in West Africa, the length and intensity of the droughts of the 1970s and 1980s was, as far as is known for the past several centuries, unprecedented.
The Table of Contents of my work on Sahelian drought mechanisms and rainfall is available.
This site last updated July 14, 1997. Reference
Adams, W.M., 1992. Wasting the Rain: Rivers, People, and Planning in Africa. London: Earthscan Publications Ltd.
Milich, L., 1997. Sahelian drought. http://ag.arizona.edu/~lmilich/sdrought.html.