Justin S. Mankin is a climate scientist. His research on climate variability and change is motivated by the risks global warming poses to ecosystems and people. Using both observations and process-based models, his efforts focus on constraining three of the major sources of uncertainty in climate changes, past, present, and future: the chaos innate to the climate system, the complexity of how people and ecosystems induce and respond to climate stress, and how model choices influence model answers. In his previous career, Dr. Mankin worked overseas as an intelligence officer.