This book focuses on three questions: How are we to identify the stage of the environmental assessment process and the level of evidence that would justify an alert) and what forms might an alert take? Assuming that there could be agreement on a level of evidence justifying an alert, what would be its economic, social, legal and political implications? What is the role of an international organization like UNEP in assessing hazards and alerting the world community to possible risks? Co-published with the Aspen Institute.