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.

Starting just after World War II, animal production in the United States became increasingly industrialized. Factory-like farms radically increased the number of cows, chickens and pigs they could raise and slaughter with economic efficiency. This is one reason meat consumption rose sharply in the United States after the war. So, too, worldwide, meat production has tripled over the last four decades and increased 20 percent in just the last 10 years, according to research by the Worldwatch Institute, an environmental research group.

This sweeping change in meat production and consumption has had grave consequences for our health and environment, and these problems will grow only worse if current trends continue.

Taking on this public health issue is well within the W.H.O.’s mandate. Addressing last year’s World Health Assembly, Margaret Chan, the organization’s departing director general, called antibiotic-resistant microbes, climate change and chronic diseases “three slow-motion disasters” shaping the global health landscape. Factory farming connects the dots among them.