This chapter provides a critical history of international environmental law. It suggests that the ideologies at the heart of international law and international environmental law projects cannot protect the environment. First, the chapter considers the influence of classical liberalism on the conception of nature in international law prior to World War II, especially in the context of fisheries. Then, the chapter turns to emerging environmental issues after World War II, when international law was concerned with marine pollution. During this period, international law took a welfarist approach to environmental problems, but with no substantial change to a liberalist conception of nature. Thereafter, international environmental law as a distinct branch emerged in the 1970s. This new branch remains rooted in liberal principles, but is also influenced by neoliberalism, as reflected in its general principles and marketised approach to problems such as climate change and biodiversity protection. As international environmental law has failed to provide solutions to the problems for which it was enacted, the conclusion calls for an ideological rethinking of founding principles.