It is widely, often intuitively, understood that human societies and the well being and health of their populations depend on the flow of materials, services and cultural enrichment from the natural world. Nevertheless, to date there has been little formal description and study of the relationships between global environmental changes and human health, and of the ways in which social institutions and processes modulate those relationships. For several human-induced global environmental changes, particularly changes to the world's climate system and to the ultraviolet radiation-filtering functions of the stratosphere, there has been a recent increase in research into the main health risks. But for most other global environmental changes little formal research on the risks to human health has been carried out. Indeed, among the practitioners of the various scientific disciplines engaged in studying the processes and impacts of global environmental changes - including environmental sciences, ecology, geography, economics, etc. - there has been relatively little recognition that ecosystem disruptions, species extinctions, degradation of food-producing systems, the perturbation of cycling of elements and nutrients, and the spread of cities pose risks to the well being and health of human populations. This science plan and implementation strategy proposes to address this gap …