The chapter begins with a brief problematization of the way in which conventional IR theory has dealt with the environment. It focuses on three relevant traditions, including realism, liberal institutionalism and global governance. The chapter argues that in terms of vertical integration, all three approaches exhibit serious deficits, mostly related to their well-known state-centrism. It aims to illustrate the concept with a brief description of the process that led to the creation of the Mamiraua Sustainable Development Reserve, located in the Brazilian state of Amazonas. As an analytical framework, governance seems more suitable for assessing the role of non-state actors in the international system and, hence, more convergent with the idea of vertical dialogue. Socio-environmentalism offers a more complex and layered picture, linking the global and the local by crossing state jurisdictional boundaries. Empirically too, socio-environmentalism operates as a transnational movement that has led to non-state forms of deterritorialized governance by non-state and state actors.