Climate change will have an effect on the health and well-being of the populations cared for by practicing physicians. The anticipated medical effects include heat- and cold-related deaths, cardiovascular illnesses, injuries and mental harms from extreme weather events, respiratory illnesses caused by poor air quality, infectious diseases that emanate from contaminated food, water, or spread of disease vectors, the injuries caused by natural disasters, and the mental harm associated with social disruption. Within several years, such medical problems are likely to reach the doorsteps of many physicians. In the face of this reality, physicians should assume their traditional roles as medical professionals, health educators, and community leaders. Clinicians provide individual health services to patients, some of whom will be especially vulnerable to the emerging health consequences of global warming. Physicians also work in academic medical institutions and hospitals that educate and provide continuing medical education to students, residents, and practitioners. The institutions also produce a measurable carbon footprint. Societies of physicians at national, state, and local levels can choose to use their well-developed avenues of communication to raise awareness of the key issues that are raised by climate change as well as other environmental concerns that have profound implications for human health and well-being.