The Evidence of Climate Change in West Africa: The Role of the Multivariate El Niño‐Southern Oscillation ( ENSO ) Index

ABSTRACT Climate change has a profoundly negative impact on West Africa, posing a significant threat to its development and economic growth. This study examines the climatic trends and patterns of rainfall and temperature using data from the Global Precipitation Climatology Centre (GPCC), Climatic Research Unit Time Series (CRU TS), and Multivariate ENSO Index (MEI) data from 1901 to 2016 for West Africa. The study area is subdivided latitudinally into three zones: the Guinea Coast, the Savanna, and the Sahel. Results from the trend analysis revealed a decrease in rainfall amount over the whole region, with a magnitude of 0.92 mm per year from 1901 to 2016. Latitudinally, the Savanna sub‐region is noted to be the wettest, followed by the Guinea Coast, and then the Sahel, with no significant change. The onset and cessation of the monsoon season are indicated by the predominantly high rainfall amount received between the 6th and 8th months of the year. Trends in annual temperature show a rising trend for all regions, with a temperature increase of 0.19°C per year. For further insight, a comparison between the 21st and 20th centuries reveals that the annual rainfall regime has declined across the entire region, with the lowest annual total rainfall recorded in 1983, during which a famine occurred in West Africa. The climate has not recovered since then. The climate over West Africa has been warmer since the beginning of the 21st century, with increasing temperatures compared to the previous century. Wavelet analysis revealed a relationship between MEI, precipitation, and temperature at different time scales and must be intensively studied to improve knowledge about the impact of ENSO on West Africa. Robust climate change policy efforts should be directed towards climate‐smart agriculture as a method for enhancing climate resilience and adaptation, thereby securing the future and promoting development in West Africa.