This week, the World Health Organization, which works globally to improve human health, will meet in Geneva to select a new director general. We have a mission for that leader: take on factory farms, a major threat to health and the environment. The Institute for Health Metrics and Evaluation at the University of Washington has estimate d that over half a million deaths worldwide in 2015 were linked to diets high in processed and red meat, which the W.H.O. now classifies as carcinogenic and “probably carcinogenic,” respectively. A potentially greater problem is superbugs, the antibiotic-resistant bacteria that proliferate among confined animals in factory farms.