ClimateWire: Allan Savory’s project, titled “Operation Hope,” is an ongoing effort to reverse the desertification that is spreading across the world’s savannas and grasslands like a disease. It is rapidly changing farmland into deserts. What makes the effort unusual for Savory, a biologist, is his use of what he called “the most universally condemned tool in the world” — livestock. Farming is perhaps the oldest means by which humans have affected the world’s climate. The destruction of …