Three decades of increasingly patchy rains and drought are taking a heavy toll on the people of the Sahel nations, the semi-arid countries strung along the southern fringes of the Sahara, according to a group of scientists and specialists on climate change. “We’ve noted an increasing number of extreme events across the Sahel, where you can have heavy rain all of a sudden then nothing for several weeks,” Arona Diedhiou, a research fellow at Senegal’s Institute for Research and Development (IRD), said after a weeklong seminar on climate change organised by the Amma-Afrique project.