Few issue areas exemplify the centrifugal forces that have prompted the emergence of global law scholarship better than the environment. With its propensity to blur or transcend conventional distinctions between national and international, public and private, and formal and informal, environmental governance offers a consummate case study to test the promise and perils of global law. In this article we situate global environmental law in the broader debate about lawmaking and application beyond the nation state, tracing the evolution and elusive boundaries of this nascent field. Our survey allows us to identify conceptual ambiguities and missed opportunities in the literature on global environmental law, including challenges to its normativity and legitimacy. From there, however, we proceed to outline a twofold opportunity for the global environmental law project: (i) an opportunity to enrich environmental law with more diverse and inclusive practices; and (ii) an opportunity for collaborative self-reflexivity by the scholars and practitioners of environmental law as these not only interpret and apply but, through their work, actively shape the content of the law.