The Rule of International (Environmental) Law and Complex Problems

Complexity thinking underscores that, while international law must provide stability to interactions around global climate change, it must also be flexible and highly adaptable. But what are the implications of this functional imperative for the international rule of law? The emergence and evolution of the UN climate regime lends itself to exploring the trajectory of international law in its encounter with complexity. For present purposes, the perhaps most significant trend in international environmental law-making has been the rise of a spectrum of more or less formal amendment processes, and of various modes of informal standard-setting under the auspices of multilateral environmental agreements (MEAs), including the UN Framework Convention on Climate Change (FCCC). Is this rise of informality indicative of a decline of the international rule of law? The paper pursues the argument that the “hard” vs. “soft” law distinction is not the most salient metric when it comes to exploring the trajectory of the international rule of law. It begins by highlighting the main features of climate change as a complex policy challenge. Next, drawing on the interactional account of international law developed elsewhere by Brunnée and Toope, it identifies key traits of legality and the rule of law in the international context. It then explores the evolution of customary, “soft” and treaty-based international environmental law. It focuses primarily on how treaty-based law has evolved to grapple with complexity on the one hand, and with meeting the demands of the rule of law on the other. The 2015 Paris Agreement, adopted under the auspices of the FCCC and employing an unprecedented range of legal “modes,” provides an excellent opportunity to reflect on this question