This book proposes a conceptualisation of Multilateral Environmental Agreements as a form of International Organisations, exploring the ways in which they have expanded over time by discussing the nuances of authority in global governance.

Multilateral Environmental Agreements are the key type of cooperation between states to address environmental concerns globally. While their activities regularly attract much attention from an academic and non-academic audience, their peculiar hybrid nature in-between treaties and full-fledged International Organisations, means they are often underestimated. This book proposes a new and innovative conceptualisation of Multilateral Environmental Agreements as a specific type of International Organisation which allows for a more accurate understanding of their dynamic nature, and uncovers expansive tendencies which have so far gone almost completely unnoticed. Based on a modern understanding of authority in global governance, the book shows how Multilateral Environmental Agreements represent a separate entity, and expand beyond the boundaries originally set by their member states. The book draws upon the neo-functionalist concept of spillover, as well as multiple other theoretical frameworks, to identify the two main drivers of expansion in Multilateral Environmental Agreements. To illustrate these drivers, the empirical chapters conduct six structured case studies, analysing specific cases of authority expansion in ozone and climate protection, including the Green Climate Fund under the UN Framework Convention on Climate Change. Overall, this book offers an invaluable contribution to the theoretical discussion on informal types of organisations, and provides new and extensive empirical insights into unexpected past and recent developments in global environmental governance.

As such, this book will be of great interest to students and scholars of International Relations and International Law who focus on informal types of cooperation and legislation, dynamic institutional development, and international environmental politics generally.