Summary: Observed changes in the Earth's climate over the past 100 years appear to be consistent with theoretical models of greenhouse warming. These models suggest that, without major changes in environmental policy, we could expect to see even greater changes in global climate over the next 100 years. In addition to the global changes associated with greenhouse warming, a continuing depletion of stratospheric ozone would lead to increased rates of skin cancer, cataracts, and immune suppression. The focus of concern to the conference participants was the substantial risks to human health that are believed to be associated with changes in global climate. The most difficult to cope with are indirect effects, such as those posed by emerging and reemerging infectious diseases such as cholera, malaria, dengue fever, and Hantavirus. Participants identified a number of actions that should be taken.