Global warming could have significant consequences for human health, ranging from a higher incidence of heat stress and a worsening of air quality to an increase in potential risks of infectious diseases such as malaria and dengue fever. But many unanswered questions remain about how serious those impacts are likely to be, which people will be affected, and what should be done to reduce the vulnerability of our society and others to the health effects of climate change. We are just beginning to understand the potential risks, said Joel Scheraga, director of the U.S. Environmental Protection Agency's Global Change Research Program. Scheraga served as chief moderator of an EPA-sponsored conference on climate change and public health, held March 11-12, 1998, in Atlanta.