Health systems contribute significantly to the forces driving climate change, given the vast quantities of energy they consume and the enormous volumes of waste they generate. In the US, the health sector produces eight percent of the nation’s total emissions, while Brazilian hospitals account for 10 percent of that country’s energy use. Health systems can reduce their carbon footprint by shifting to renewable energy, constructing more efficient buildings, managing medical wastes, conserving water, and more. The twin responsibilities of global citizenship and business stewardship argue for climate-resilient health care.