El Niño; La Niña; ENSO; Southern Oscillation Index; African rainfall climatology; vulnerability; impacts; Africa
El Niño and La Niña phenomena are simply referred to as the warm and cold ENSO phases respectively. ENSO events generally last from 3 to 6 seasons, sometimes as long as 24 months, and tend to recur every 3 to 7 years. The warming/cooling (El Niño/La Niña) of the eastern and central equatorial Pacific Ocean are known to lead to worldwide anomalies in sea surface temperatures (SSTs) and the circulation of the ocean currents. The most significant influence is found in the tropics, but such influences have been found to vary significantly from place to place and from season to season, as well as with the evolution pattern of the ENSO phases. Although ENSO impacts are strongest in the Pacific Ocean region, past records in Africa show that some severe droughts and floods that have been observed over parts of the continent have been associated with ENSO events. As elucidated in this paper, the impacts of some of these extreme droughts and floods have seriously affected the social and economic development of various countries in the African continent.
The El Niño and La Niña phenomena have, in recent years, become widely known by the public at large around the world. These phenomena have a long historical base in Latin America.