The Sahel is one of the most vulnerable regions in the world and its climate future remains extremely uncertain. A team of researchers has just reconstructed the history of the water balance in the Sahel over the last 1600 years, based on the geochemical analysis of fossil shells from the Saloum estuary in Senegal. The climate of the last decades appears to be a situation of extreme and unprecedented drought, the result of an aridification that began abruptly 200 years ago. Over the entire study period, precipitation is shown to be lower as global temperatures are higher, consistent with climate theories that predict a future worsening of the region’s drought.