This article analyses the recent Advisory Opinion of the Inter-American Court of Human Rights on Environment and Human Rights and argues that it constitutes a milestone effectively reorientating interna¬tional environmental law. The article is divided as follows. First, it analyses the most salient aspects of the Advisory Opinion inter alia (1) The right to a healthy environment as binding law and; (2) The Advisory Opinion as a landmark in the gradual development of international jurisprudence on cross-border (or “diagonal”) human rights obligations (i.e. the possibil¬ity for human rights claims to be brought by individuals not under the territorial jurisdiction of the State whose international responsibility for environmental harm is invoked). Second, it contextualizes the Advisory Opinion by discussing what we consider to be four key vectors currently affecting the trajectory of the ongoing development of international environmental law and how the advances made in the Advisory Opinion fit with those developments. Third, it places the Advisory Opinion in the wider context of developments moving towards a needed reorientation in international environmental law, in particular: integration (or de-fragmentation) of international law, the operationalization of environmental principles into working-level legal norms, and a focus on practical remedies. It is argued that as the world experiences the pressure for more effective environmental law and accountability, some of the most sophisticated and innovative thinking on international environmental law today, is emanating from countries in the Southern hemisphere, as attested to by the Advisory Opinion.