Profile of Anthony J. McMichaelMcMichael, elected in 2011 to the National Academy of Sciences, is a strong proponent of expanding epidemiology research from individual- to population-level studies. To this day, researchers focus more on the environmental and economic repercussions of a warming world than on how such changes might affect human health—a potentially dangerous distraction, he says. To remedy that oversight, McMichael’s Inaugural Article explores how major climatic events over the past 12,000 years have influenced human health and survival, and how even mild to moderate climate change can lead to the disruption and collapse of societies (1). With the global temperature likely to increase by 3 °C to 4 °C over the next 100 years—considerably more than the fraction-of-a-degree fluctuations that influenced the outbreak and spread of the bubonic plague in mid-14th century Europe—the risk to human health is graver than we realized, he says. “Climate change is not just about disruptions to the local economy or loss of jobs or loss of iconic species. It’s actually about weakening the foundations the life support systems that we depend on as a human species.”