The Global Pact for the Environment (GPE) is a draft treaty prepared by a French think tank, Le Club des Juristes, which aims at strengthening the effectiveness of international environmental law (IEL) by combining its most fundamental principles into a single overarching, legally binding instrument. In 2018, the United Nations General Assembly established an intergovernmental working group to discuss the feasibility of adopting an instrument such as the GPE. This paper discusses the extent to which codifying the fundamental principles of IEL into a treaty could increase IEL’s effectiveness, and the possibility that adopting such an instrument could generate unintended consequences that would hinder the development of more effective environmental standards in the future.