The African continent is climatically diverse. Humid tropical conditions
prevail in Western and Central Africa and in the Western Indian Ocean
islands; most Southern African countries experience arid and semiarid
conditions, while semi-deserts and deserts are features of Northern Africa.
The region experiences a high degree of variability and uncertainty in
climatic conditions. Climate variability is therefore the single most
important atmospheric phenomenon in Africa.
In comparison to other regions, African countries emit negligible amounts
of air pollutants and anthropogenic greenhouse gases. For example, Africa
contributes less than 3.5 per cent of global emissions of CO2
(Marland, Boden and Andres 2001). Nevertheless, anthropogenic atmospheric
pollution is a problem in Northern and Southern Africa, and in some large