Summary/Abstract
From May until October 2022, large parts of West Africa experienced large-scale flooding caused by above average seasonal rainfall. The effects were especially acute around a large area encompassing Lake Chad, leading to flooding from Mali to Cameroon. With at least 612 and 195 fatalities respectively, the floods over Nigeria and Niger are among the deadliest in the countries’ histories. Several hundreds of thousands of hectares of land have been inundated, causing damage to more than 300 thousand homes and over half a million hectares of farmland. This review article synthesizes peer-reviewed data which examines the impact of anthropogenic climate change on the probability and intensity of the flood, using observed datasets and climate modeling. The models conclude that anthropogenic climate change made the event about twice as likely and 5% more intense in the lower Niger Basin, and about 80 times more likely and 20% more intense in the Lake Chad region. Under current climate conditions, an event of this scale is expected to occur once every ten years over the Lake Chad basin and once every five years over the lower Niger Basin. Human impacts were found to be exacerbated by the proximity of settlements to floodplains, ongoing political and economic instability, and the release of the Lagdo Dam in Cameroon.