Monsoon

The importance of monsoons is demonstrated by the experience of the Sahel, a band of land on the southern fringe of the Sahara Desert. This area would also be arid if it were not for the seasonal monsoon, whose rains normally transform it to a grassland suitable for grazing livestock. The wetter southern Sahel can support agriculture, and many residents migrated to the area during the years of strong monsoons. Beginning in the late sixties, however, the annual monsoons began to fail. The pasture areas in the northern Sahel dried up, forcing nomadic herders and their livestock southward in search of pasture and water. The monsoon rains did not return until 1974. In the intervening six years, the area suffered devastating famines and loss of life, both human and animal, and placed extreme stress on the countries of central Africa.

Because of their tremendous effect on many tropical areas, atmospheric scientists continue to study the formation and variability of monsoons. Monsoon variations are still not entirely understood, making the prediction of the monsoon a distant goal. However, researchers have shown that monsoons are affected by El Niño, the changes in winds and sea water that occur in the tropical Pacific Ocean. Research continues into modeling monsoon circulations with complicated computer simulations.