Abstract
The Grotian Moment concept provides a lens through which to reflect on the enduring hold of state sovereignty on international environmental law. The article traces the development of the field’s customary rule framework and canvasses efforts to push its conceptual boundaries beyond the inter-state paradigm. Given their dominant role in the field, the article then provides a brief overview of treaty-based approaches to the development of international environmental law. It focuses on the global response to the climate emergency, as illustrative of how international environmental law has evolved in response to the challenges posed by complex crises. The article concludes by suggesting that international environmental law is unlikely to see a Grotian Moment at the level of customary international law, but that it does hold potential for the new thinking and new approaches that could produce a ‘quasi’ Grotian Moment.