Desertification and land degradation in the Sahel has
been studied and debated for almost a century.
That the Sahelian vegetation system is dependent
on rainfall is widely accepted.
The interannual variation in rainfall is also high over the Sahel
giving rise to large fluctuations in vegetation
growth and cover. The climate variation is illustrated
in the large graph above by the
latitudal (N-S) shift in the position of the
300 mm rainfall boundary (isohyet) 1931-2004.
