Jus Cogens and the Climate Crisis

While there are many aspects of the Inter-American Court of Human Rights (IACtHR)’s Advisory Opinion 32/25 (AO-32/25) that are new and groundbreaking, the inclusion of a reflection on jus cogens might have surprised some observers. The legal consequences of the recognition as jus cogens of the obligation not to create irreversible damage to the climate and the global environment are profound. Treaties violating the norm are void, customary international law rules cannot exist, nor does the persistent objector rule apply.