The dramatic change in the Sahel from wet conditions in the 50s and 60s to much drier conditions in the 70s, 80s and 90s probably represents the strongest inter-decadal signal on the planet in the 20th century. Superimposed on this, marked interannual variations can result in extremely dry or wet years with devastating environmental and socio-economic consequences. Tragic examples of this were the exceptionally dry years within the 70s and 80s that lead to famines in 1972-74 and 1983-85. Vulnerability of West Africa to climate variability is likely to increase in the next decades as demands on resources increase in association with one of the World's most rapidly growing populations. Strategies need to be developed that are able to reduce the socioeconomic impacts of climate variability. A major component of this includes the need to develop our understanding of West African climate variability and to develop our ability to predict it including its impact on water resources.

Motivated by these issues the AMMA project has two overarching aims:

(1) To improve our understanding of the West African monsoon and its influence on the physical, chemical and biological environment regionally and globally.

(2) To provide the underpinning science that relates climate variability to issues of health, water resources and food security for West African nations and defining relevant monitoring strategies.

This will require a major coordinated international effort involving a multidisciplinary approach to the West African monsoon. The AMMA project will include a field campaign in the West African region with a long-term multi-year component and a year with more intensive observing periods focused on key periods of the WAM annual cycle such as the rainfall onset and other periods when weather systems such as easterly waves and mesoscale convective systems are most active. Currently the field campaign is planned to begin in 2004 and intensive observing periods are provisionally planned for 2005.