Environmental concerns figure prominently in the work of the United Nations, and especially in the United Nations Educational, Scientific and Cultural Organization. One focus of UNESCO has to do with the ethical principles at stake in environmental sciences and policies. What is the moral value of the environment? What in nature is worth protecting, preserving or respecting? What do we mean by global sustainability? How much should we care for the interests of future generations? What are the implications of the principle of justice for policy decisions related to environmental issues? In this volume, eight experts in environmental ethics from around the world, advising the World Commission on the Ethics of Scientific Knowledge and Technology, come together to address these questions. The studies presented here analyze the state of the art in the relatively new area of applied ethics that is environmental ethics. They also develop approaches to determining how international policy can promote ethical reflection about the environment.