Nations in the African Sahel, the semi-arid region south of the Sahara Desert, face significant demographic challenges. The region, which is one of the poorest in the world and also one of the most food insecure, has some of the highest population growth rates in the world. Climatic changes—rising temperatures and severe droughts—are contributing to water scarcity, desertification, and soil erosion, and exacerbating tensions between herders and farmers. If gender inequality is addressed, child marriage is abolished, greater investments are made in education, and access to family planning services improves, the region could benefit from an economic boom, what economists and demographers describe as the “demographic dividend.” For countries like Niger and Mali, however, time may be running out.