Western Africa faces challenges arising from climate variability-especially in the arid Sahelian zone where drought is recurrent-and from the predicted impacts of climate change on food production, freshwater availability, and desertification. Localized problems of air quality have also been identified as priorities for action.
Desert landscape, Mali
Romano Cagnoni/Still Pictures
The climate of the Western Africa sub-region varies greatly from north to south and is mainly governed by the seasonal movements of the ITCZ. Desert and semidesert regimes, characterized by annual precipitation of 100-300 mm, prevail along the border of the Sahel covering Mauritania, northern Senegal, Mali, and Niger. There is substantial inter-annual variability in precipitation with no perennial run-off and flash floods occurring in small basins during rainy periods. In addition, evaporation rates are very high (more than 4 m/year). Further south, temperatures and evaporation rates are lower, although widespread flooding occurs because of the marked hydrological degradation, relatively high run-off and large areas of flat land. The coastal zone experiences warmer, wetter conditions, with annual rainfall in excess of 1 000 mm/yr, and greater reliability of rainfall, although floods are not uncommon.
The last Sahelian drought, one of the worst on record, persisted for a whole decade from 1972-84; during this period, more than 100 000 people died, and more than 750 000 people in Mali, Niger and Mauritania were totally dependent on food aid in 1974
Drought is a recurrent problem in the Sahelian zone of Western Africa, although the equatorial zone is rarely affected. The last Sahelian drought, one of the worst on record, persisted for a whole decade from 1972-84, and reduced precipitation was even noted in the equatorial zone. During this period, more than 100 000 people died, and more than 750 000 people in Mali, Niger and Mauritania were totally dependent on food aid in 1974 (Wijkman & Timberlake 1984). The drought also resulted in power shortages in Benin, Chad, Mali, and Nigeria because of hydropower failures at the Kainji Dam on the River Niger (IPCC 1998). Desertification is also a problem in the region, especially in the arid and semi-arid zones, but it also affects the sub-humid zones. For example, as in Central Africa, the falling level of Lake Chad could have major economic implications for the millions of people in Western Africa who depend on its resources.
All the countries of Western Africa have ratified the UNCCD. Benin, Burkina Faso, Cape Verde, Gambia, Mali, Niger, and Senegal have produced National Action Plans, and The Economic Community of Western African States (ECOWAS), together with the CILSS, has produced a Sub-regional Action Plan (UNCCD 2001).
Other recent projects in the sub-region include an assessment of the vulnerability of production systems in Burkina Faso, Mali, Niger and Senegal. A Sahel Sahara Observatory has been set up, within the framework of the UNCCD, to act as a sub-regional coordinating body and to provide improved access to and sharing of information, and to implement scientific and technical capacitybuilding projects in land and water resource management. Areas of specific interest for this project include development of data banks, preparation of manuals and handbooks, facilitating of north-south exchanges of experience and knowledge, and provision for the transfer of know-how between the various areas of Africa.