Harro van Asselt

Ten years after the Paris Agreement’s adoption, this article takes stock of international climate change law through the lens put forward in The Art and Craft of International Environmental Law . The article first outlines the distinctive features of the approach to international environmental law in Art and Craft and how the Paris Agreement exemplifies them. Next, the article examines several key developments in international environmental law since the original publication of Art and Craft in 2010—namely, the changing role of non-state actors, a turn to (international) courts, and the growing complexity of the legal architecture—and discusses how these changes are reflected in international climate change law. To the extent these developments become embedded in international climate change law, they reflect a shift from the state- and treaty-centric paradigm described in the first edition of Art and Craft to a new, more polycentric form of governance.

The Advisory Opinion on Obligations of States in Respect of Climate Change by the International Court of Justice (ICJ) breaks new ground by clearly identifying fossil fuel production, licensing and subsidisation among the activities to which international climate change obligations apply, going as far as suggesting that such activities may constitute internationally wrongful acts. In this article, we examine the proceedings in the context of fossil fuels and offer an in‐depth analysis of the ICJ's Advisory Opinion's findings. We discuss the scientific and legal background that led to the inclusion of the topics of fossil fuel production and fossil fuel subsidies in the proceedings. We then systematically analyse the written and oral proceedings, setting out the diverging ways in which States and other participants addressed these topics. Finally, we assess the Court's reasoning, identifying its key findings in relation to the material scope of the questions, States' obligations and the legal consequences arising out of their breach. We conclude that while it may be too early to declare that international law requires the phase‐out of fossil fuels, the Advisory Opinion will likely have implications for domestic and international litigation, putting fossil fuel‐producing States and companies on notice. Moreover, the Advisory Opinion's clarifications related to fossil fuel production may indirectly influence intergovernmental processes, including the international climate regime.