How cracks emerged in Africa's plan to plant a wall of trees across the continent

Emmanuel Siakilo smiles a lot. More than you’d expect for someone who spends his time working on the impacts of biodiversity loss and climate change in his native Kenya. And certainly more than you’d expect for someone who had to leave his home in Trans-Nzoia County, on Kenya’s western border, because of flooding caused by the climate emergency. “What can I say? I’m an optimist,” he says on video call from Nairobi, where he now lives.

Siakilo knows firsthand how immediate these issues are. When he was a child, his region would flood perhaps twice in a year. “The houses could be submerged in water. … Crops and livestock would be swept away, and you’d have to start from zero. No food, no farms, nothing to pay school fees with,” he says.