The human right to a safe climate

Abstract

The advisory opinions by the Inter-American Court of Human Rights (IACtHR) and the International Court of Justice (ICJ) in 2025 mark a turning point in aligning international law with climate science. Both affirm climate change as a human-caused exis- tential threat. The IACtHR recognized the right to a safe climate and the disproportionate harms to vulnerable groups (for example, women, Indigenous Peoples, Afro-descendants, peas- ant farmers, small-scale fishers and youth) that worsen inequalities. The ICJ declared that a clean, healthy and sustainable environ- ment is a precondition for other human rights (such as life and health) and affirmed states’ duties to prevent significant climate harm — placing 1.5 °C within legal obligation, shaped by science and Conference of the Parties (COP) decisions. This fills a gap left by the United Nations Climate Convention despite recognition of this principle in the 1992 Rio Declaration. The ICJ also stressed the need to interpret climate obligations coherently with other multilateral agreements (for example, United Nations Convention on the Law of the Sea and the Convention on Biological Diversity), human rights law and customary international law. Although the ICJ stopped short of extending this coherence to trade and investment agreements, as one dissent- ing opinion proposed, both rulings relied on scientific evidence brought by plaintiffs, coun- tering the rise of anti-climate and pro-fossil fuel misinformation.