Industrial palm oil production is coming to Africa, its ancestral home. The world’s most productive oil seed has been a boon to Asian economies, but the looming arrival of large-scale plantations in Africa is raising fears that some of the same issues plaguing Malaysia, Indonesia, and other leading producers — deforestation, greenhouse gas emissions, biodiversity loss, conflicts with local people, and poor working conditions — could befall one of the world’s most destitute regions.