This book seeks to better understand how International Environmental Law regimes evolve. The authors address throughout the major environmental, economic, and political tensions that have both shaped and constrained the evolution of international environmental policy within regimes, and its expression in international legal rule and norm development. Readers will gain an increased understanding of the growing role played by non-state actors in global environmental governance, including environmental non-government organisations, scientists, the United Nations, and corporations. The authors also look ahead to the future of International Environmental Law, evaluating key challenges and decisions that the discipline will face.