For the first time, human beings are altering the basic operations of the Earth's atmosphere, geosphere and biosphere. The intent of this CMAJ series is to examine the links between environmental change and human health and to suggest programs and policies that will protect both health and the environment. In each article the authors present a brief state-of-the-science review of their topic, an interpretation of the problem, and suggestions for medical and public health responses. The essays do not address environmental hazards for which the association with disease is well understood, such as environmental lead poisoning and ozone air pollution; instead, they focus on global environmental changes precipitated by human activity and their likely role in emerging health problems.

This series was edited by Michael McCally of the Mount Sinai School of Medicine in New York. As McCally points out in the introductory essay, finding solutions to the threats posed by environmental change is the major health challenge of the next century.

1. Population, consumption and human health
2. Global climate change and health
3. Ozone depletion and ultraviolet radiation
4. Cancer
5. Impact of war
6. Endocrine disruption and potential human health implications
7. Species loss and ecosystem disruption — the implications for human health
8. Sustainable health care and emerging ethical responsibilities
9. The science of risk assessment