The West Africa Sahel covers 9 countries. But the current review focuses on 5 of them (Burkina Faso, Mali, Mauritania, Niger and Senegal). The population of the 5 countries account for about 20% of West Africa total population. Population growth is very high compared to the rest of SSA. Niger has both the highest rate of population growth ( est. 3%) and the world highest women fecundity rate ( 7, 2 children/woman). The countries know differential situations resulting from different natural environments and different economic policies. Two countries (Senegal and Mauritania) have direct access to the sea while the 3 others are landlocked. The Sahel region which is characterised by low and instable rainfall has been most affected by the changes in rainfall patterns, owing to a fall of 20 to 30% in expected rainfall between 1931-60 and 1961-90 (Hulme, in Toulmin and Gueye, 2003)1 and more unpredictable seasonal distribution. The droughts of the 1970s and 1980s led to large-scale migration of crop and livestock farmers towards the south in a search for areas with more ample water. In western Burkina Faso more than 80% of the land is farmed by people who have come from elsewhere (Toulmin and Gueye, 2003). This “adverse” geography is more acute in certain countries like Niger where only 12% of the territory is favourable to agriculture over an area of more than 1,200,000 km ².