From the Atlantic Ocean to the Red Sea, the semi-arid Sahel saw spatially homogeneous drought throughout the 1970s and 1980s. It is anticipated that the rebound that followed will only continue in the east and center, excluding the west. We demonstrate the presence of these two patterns in both instrumental observations and simulations with constant or time-varying external forcing: uniform variation and east-west contrast. The east-west disparity is sown by global warming boosting the monsoon, while external forces from the 20th century amplifies uniform variance. The change to a North Atlantic cooling in relation to the world’s tropical waters in the middle of the twenty-first century exacerbates this disparity and has the greatest impact on the western Sahel. The results vary, ranging from a wetter central and eastern Sahel to a suddenly drier western Sahel.