The prohibition of causing serious damage to the environment as a ius cogens norm? The approach of the Inter-American Court of Human Rights in two acts: ‘La Oroya v. Peru’ (2023) and the advisory opinion on climate emergency and human rights (2025)

Abstract

This article analyses two rulings from the Inter-American Court of Human Rights that posit the existence of peremptory norms (ius cogens) for environmental protection. The first is the judgment in the case of La Oroya v. Peru (2023), which condemned the State for human rights violations stemming from industrial pollution. This ruling not only consolidates the autonomous right to a healthy environment within the Inter-American System but also—for the first time in international jurisprudence—suggests that the prohibition of causing severe environmental harm could constitute a norm of ius cogens. The second is the Advisory Opinion on the Climate Emergency and Human Rights (2025), in which the Court also affirms the existence of a peremptory norm with the same purpose. This study examines the Court’s reasoning and the separate opinions in both rulings to substantiate the potential existence of this environmental peremptory norm, which would prohibit severe, extensive, lasting, and irreversible damage. Through this analysis, the significance of these rulings will be demonstrated, and the relationship between environmental protection norms and other norms of International Law will be explored.