Habitability, health, and environmental justice will be challenged as the adverse effects of climate change interact with factors that are characteristic of older people. This article describes the potential of climate change to affect the environment in a number of ways that place increased stress disproportionately on the most vulnerable populations, including the old, the young, and the poor. Older people are among the most at risk because of decreased mobility resulting from age, changes in physiology, and more restricted access to resources, all of which may limit adaptive capacity. The article describes the challenges older people will face, why these have potentially far-reaching implications for the health of individuals and the population as a whole, and strategies for coping.