One day in late 2010, a farmer – I will call him Opik – woke up in his village in the remote Ethiopian province of Gambella. In this lush lowland area of savanna bordering South Sudan, the semi-nomadic Anuak people have lived for centuries, cultivating sorghum and maize, swimming in the river and gathering nuts, berries and fruits from the trees and wild honey from the forest. “It was paradise,” Opik recalled.