In July 2025, the Inter-American Court of Human Rights (IACtHR) issued Advisory Opinion 32/25 on the Climate Emergency and Human Rights, responding to a request submitted by Chile and Colombia in January 2023. The Opinion did what many had anticipated but few expected to see so fully realized: it recognized the right to a healthy climate as a standalone human right, declared a jus cogens norm prohibiting irreversible environmental harm, and affirmed the legal personhood of nature. These are not incremental developments. They are structural shifts in international environmental law, and they did not appear from nowhere. They are the culmination of more than two decades of jurisprudential construction — a story that begins, quietly, with an Indigenous community in Nicaragua in 2001.

This post traces that arc: from the earliest seeds of environmental protection through rights to life and property, through the transformative pivot of nature rights, through the consolidation of contentious jurisdiction in Lhaka Honhat v. Argentina and La Oroya v. Peru, to the doctrinal summit of AO 32/25. It also examines what comes next — including the petitions still pending before the Inter-American Commission on Human Rights (IACHR or Commission), as will be explained below, and the September 2025 filing by several youth plaintiffs against the United States in Juliana Youth v. United States, which tests whether the Commission is finally ready to hold a major emitter to account.

Indirect to Autonomous: The Long Construction of the Right to a Healthy Environment

The IACtHR did not arrive at environmental rights fully formed. Its earliest environmental jurisprudence was indirect and instrumental: the environment mattered because environmental harm threatened other, more established rights.

In Mayagna (Sumo) Awas Tingni v. Nicaragua (2001), the Court recognized, through a joint separate opinion of three judges, that the habitat of an Indigenous community was integral to their cultural identity and communal life — a dimension of the right to property under Article 21 of the American Convention on Human Rights (ACHR). Four years later, in Yakye Axa Indigenous Community v. Paraguay (2005), the Court held that the denial of access to ancestral lands constituted a violation of the right to a dignified life under Article 4. Environmental degradation was actionable, but only because it threatened human beings whose other rights the Court already recognized.

This indirect approach was not a weakness of vision so much as a constraint of jurisdiction. The ACHR does not mention the right to a healthy environment. That right appears in Article 11 of the Additional Protocol (the San Salvador Protocol), but violations of that article are not subject to individual petition before the Court. The Court worked within those constraints — until it decided it did not have to.

The turning point was Advisory Opinion 23/17, issued in November 2017 in response to a request by Colombia concerning environmental obligations in the context of large-scale infrastructure projects in the Caribbean Sea. The Court used the occasion to establish three things that would reshape the landscape of international environmental law.

First, it recognized the right to a healthy environment as an autonomous right under Article 26 of the ACHR — directly justiciable, with both individual and collective dimensions, extending to present and future generations. Second, it became the first international human rights tribunal to recognize an extraterritorial jurisdictional link based not on physical control over persons or territory, but on control over domestic activities with transboundary effects — opening the door to “diagonal” climate claims, where individuals in one state hold another accountable for harms arising from activities within that state’s territory (see, i.e., De Bellis). Third, it elaborated a duty of due diligence with real content: states must regulate, supervise, and monitor activities capable of causing significant transboundary harm; apply the precautionary principle where serious or irreversible damage is at stake; cooperate with and inform other states; and guarantee access to information, public participation, and justice in environmental decision-making.

From Advisory to Binding: Due Diligence in Contentious Cases

Advisory opinions carry authority, but not the binding force of judgments. The question after 2017 was how quickly the Court would translate its advisory doctrine into contentious jurisdiction. The answer came faster than expected.

In Lhaka Honhat Association v. Argentina (2020), the Court recognized, for the first time in a contentious case, the right to a healthy environment as an autonomous and directly enforceable right under Article 26. The judgment also confirmed that the duty of due diligence requires ex ante measures — states cannot wait for harm to materialize. They must monitor, regulate, and supervise activities by private entities as well as public authorities, and failure to do so constitutes a violation of the Convention regardless of whether the ultimate harm is caused by non-state actors.

Three years later, Residents of La Oroya v. Peru (2023) took the doctrine further in two important directions. First, it extended the autonomous right to a healthy environment beyond Indigenous populations to the general public — the residents of La Oroya had suffered severe air and water contamination from a century-old metallurgical complex operated by both state and private foreign investors. The Court held Peru responsible for failing to regulate those activities adequately, drawing explicitly on the UN Guiding Principles on Business and Human Rights and holding that due diligence obligations apply equally to public and private enterprises.

Second, and perhaps more consequentially for what would come in AO 32/25, the Court adopted an explicitly ecocentric framing. The right to a healthy environment, it held, protects components of the environment — forests, rivers, seas — as legal interests in themselves, independent of any demonstrated risk to individual human beings. States are obligated to protect nature not only for its instrumental value to humans but for its intrinsic significance. This was not yet a formal recognition of rights of nature, but it was the doctrinal foundation on which that recognition would be built.

The procedural dimensions of La Oroya also matter for climate litigation. The Court found Peru liable for withholding health risk information from affected residents and for failing to ensure meaningful participation in environmental decision-making — violations grounded in Articles 13 and 23 of the ACHR. In a climate context, this reasoning obligates states not only to reduce emissions but to disclose the nature and pace of climate-related risks and to enable affected communities to shape both mitigation and adaptation policy.

The Commission’s Role: Petitions, Resolutions, and the Paradigm Shift

Before turning to AO 32/25, it is worth tracing the parallel evolution of the IACHR, whose trajectory mirrors the Court’s but begins with a more cautious posture.

The Commission’s first encounter with a climate petition came in 2005, when the Inuit Circumpolar Conference filed a complaint against the United States alleging that US greenhouse gas emissions violated the human rights of Inuit peoples in the Arctic. The Commission rejected the petition, finding insufficient evidence of a direct causal link between US emissions and specific rights violations. The decision was widely criticized but reflected real evidentiary limits that climate attribution science had not yet overcome.

The Arctic Athabaskan Council filed a comparable petition against Canada in 2013, focused on black carbon emissions and their effects on Athabaskan peoples’ ability to exercise cultural rights on ancestral lands. That petition remains pending — and the legal landscape it faces today, after AO 23/17, Lhaka Honhat, La Oroya, and AO 32/25 bears almost no resemblance to the one that confronted the Inuit in 2006: in the intervening years, the Court has recognized the right to a healthy environment and significantly strengthened the protection of human rights in the context of environmental degradation and climate change.

The Commission’s posture shifted formally with Resolution 3/21 on the Climate Emergency, adopted jointly with the Special Rapporteur on Economic, Social, Cultural and Environmental Rights (REDESCA) in 2021. The Resolution is significant because it systematizes, for the first time in an IACHR instrument, the positive obligations of states in the context of climate change. It specifies that States must adopt and implement mitigation targets consistent with the Paris Agreement, assess cumulative GHG emissions in environmental impact assessments, implement adaptation measures, and remedy resulting damages — all subject to the due diligence principle derived from the Court’s evolving jurisprudence.

A third petition, filed in 2021 by Haitian children in Cité Soleil, alleges violations of the rights of the child, the right to dignity, the right to a healthy environment, and the right to judicial protection, arising from toxic waste disposal whose harms are aggravated by climate change. It is the first climate case filed after the Court’s green jurisprudence had fully matured, and it draws on children’s particular vulnerability — a framing that has proven effective in climate litigation globally.

AO 32/25: Three Doctrinal Breakthroughs

Advisory Opinion 32/25 is the culmination of this trajectory, and its three central innovations deserve to be understood in that context rather than in isolation.

The first is the articulation of a jus cogens norm prohibiting irreversible environmental harm. By elevating the prohibition to the highest tier of international law — one from which no derogation is permitted — the Court signals that catastrophic, irreversible harm to the environment is not a policy choice subject to balancing against economic interests, but a categorical legal prohibition. No international tribunal had previously made this claim. The implications for climate litigation are significant: arguments framed around the risk of irreversible warming could now invoke not just treaty obligations but peremptory norms.

The second is the recognition of nature’s legal personhood. Building directly on the ecocentric reasoning of La Oroya, the Court formalized what that judgment had implied: nature is not merely a resource that humans have an interest in protecting but a legal subject capable of bearing rights. This opens the possibility of litigation brought on behalf of ecosystems — rivers, forests, glaciers — as rights-holders in their own right, not merely as conditions for the enjoyment of human rights.

The third, and arguably most immediately actionable, is the recognition of the right to a healthy climate as a standalone human right derived from Article 26 of the ACHR. The Court characterized it as both individually justiciable and collectively held — capturing the intergenerational and interspecies dimensions that make climate change distinctive as a legal problem. And it imposed concrete state obligations: ambitious, binding, and progressively scaled mitigation targets calibrated to the 1.5°C global temperature goal.

The Opinion also elaborated the three procedural pillars associated with the Escazú Agreement — access to information, public participation, and access to justice — and addressed the disproportionate impact of climate change on structurally vulnerable populations, including children, Indigenous peoples, Afro-descendant communities, and campesino and fishing communities.

Inter-Americanization in Practice and What Comes Next

The significance of this jurisprudence extends well beyond the formal jurisdiction of the Court. The process of “Inter-Americanization” — the dynamic exchange between regional standards and domestic legal systems — means that these doctrines travel.

Brazil’s Supreme Federal Court demonstrated this in its 2022 Amazon Fund decision, explicitly citing Lhaka Honhat to ground the principle of prevention as customary international law and holding the federal government’s dismantling of Amazon Fund governance structures unconstitutional. Panama’s Supreme Court, in invalidating a copper mining concession in November 2023, relied directly on AO 23/17 and IACHR Resolution 3/21 to find that an outdated environmental impact assessment and the exclusion of affected communities from decision-making violated both constitutional and international human rights obligations.

The most consequential test of this trajectory may come from the petition filed on September 23, 2025, before the IACHR by fifteen former plaintiffs from Juliana v. United States, together with Our Children’s Trust and Dignity Rights Advocates. The petition argues that over five decades of US fossil fuel policies, pursued with knowledge of their harmful consequences, violate the petitioners’ rights under the American Declaration on the Rights and Duties of Man, including the rights to life, health, security, family, cultural benefits, and property. It also argues that the US Department of Justice’s sustained efforts to block the Juliana litigation from reaching trial — upheld by federal appellate courts — constitute a denial of access to justice and an effective remedy. Expressly invoking AO 32/25 and the International Court of Justice’s climate advisory opinion, the petition applies those rulings directly to the circumstances of one of the most prominent climate cases of the last decade.

Whether the Commission will receive the petition, and how it will engage with the question of causation that defeated the Inuit in 2006, will be a crucial test of how far the system has actually traveled. The science of climate attribution has advanced enormously since then; the jurisprudence has advanced even further.

Conclusion

The IACtHR did not set out to transform international environmental law. It responded, case by case, to the specific legal questions before it, building a body of doctrine through the patient accumulation of precedent. What it has built over twenty-five years is nevertheless remarkable: an autonomous right to a healthy environment, enforceable against both public and private actors; a duty of due diligence calibrated to the scale of foreseeable harm; extraterritorial jurisdiction grounded in effective control over damaging activities; and now, with AO 32/25, a jus cogens prohibition on irreversible environmental harm, the legal personhood of nature, and a standalone right to a safe climate.

The significance of this jurisprudence extends beyond the Inter-American system. Regional human rights courts increasingly occupy a central role in the development of climate-related obligations. The European Court of Human Rights, through cases such as Verein KlimaSeniorinnen Schweiz v. Switzerland, has recognized positive state duties to protect individuals from climate harms and has begun to articulate procedural and institutional requirements for climate governance. The African Court on Human and Peoples’ Rights is now considering its own advisory opinion on climate change and human rights, presenting an opportunity to develop climate jurisprudence grounded in the African Charter and the continent’s particular experiences of vulnerability, development, and environmental justice. Across these systems, courts are confronting common questions concerning causation, risk, intergenerational equity, scientific uncertainty, and the relationship between environmental degradation and fundamental rights.

The IACtHR has emerged as one of the most ambitious participants in this judicial dialogue. Its jurisprudence has often moved beyond the approaches adopted elsewhere, not only recognizing environmental rights as autonomous and justiciable, but increasingly treating climate change as a structural human rights challenge requiring legal responses commensurate with the scale of the threat. Whether other regional tribunals embrace similar doctrinal innovations remains uncertain. Yet the IACtHR’s influence is already evident in the growing cross-referencing among international tribunals, the increasing reliance on scientific consensus as a basis for legal obligation, and the broader shift toward understanding environmental protection as a prerequisite for the enjoyment of human rights.

The same dynamic is now unfolding at the universal level. The recent advisory opinions of the IACtHR, the International Tribunal for the Law of the Sea, and the International Court of Justice reflect a convergence around the proposition that climate change is not merely an environmental issue but a matter of legal obligation. Although each institution operates within a distinct mandate, together they contribute to an emerging body of principles concerning prevention, due diligence, cooperation, vulnerability, and the protection of future generations. The precise contours of these obligations remain contested, but the direction of travel is increasingly clear.

The petitions still moving through the Commission — Athabaskan, Cité Soleil, Juliana Youth — will determine whether these doctrinal achievements translate into accountability for specific states. That translation is never automatic. Advisory opinions establish frameworks; contentious proceedings test their practical consequences. Yet the legal infrastructure is now in place. The question is no longer whether climate change falls within the ambit of international human rights law. The question is whether the institutions charged with enforcing those rights are prepared to apply the principles they have articulated to the concrete realities of climate harm.