On July 3, 2025, the Inter-American Court of Human Rights (IACtHR) issued Advisory Opinion No. 32—the most important and progressive document yet released by an international court on the climate crisis. In this landmark ruling (still only available in Spanish, with official English and Portuguese translations expected on Friday, July 11), the IACtHR interprets the obligations of States under regional human rights law in light of what the IACtHR considers to be a climate emergency. The opinion outlines what the American Convention on Human Rights requires of governments in the face of escalating climate impacts and rising inequality, providing authoritative guidance on the legal foundations of climate action and accountability.

Spanning over 200 pages, AO-32/25 is the longest advisory opinion ever issued by the IACtHR. In it, the IACtHR affirms that the right to a healthy climate falls within the scope of human rights protections under the American Convention on Human Rights. It outlines the responsibilities of Organization of American States (OAS) Member States to prevent and remedy climate-related harms, protect vulnerable groups and future generations, and ensure procedural rights, including public participation, access to information, and access to justice. The opinion builds on and extends the IACtHR’s groundbreaking 2017 Advisory Opinion (AO-23/17), which recognized the autonomous right to a healthy environment and affirmed State responsibility for transboundary environmental harm (see here).

This opinion arrives amid a global wave of climate-related advisory proceedings—following similar initiatives before the International Court of Justice (ICJ), the International Tribunal for the Law of the Sea (ITLOS), and the African Court on Human and Peoples’ Rights (AfCtHPR). Yet the IACtHR’s role stands apart: grounded in a robust human rights framework, supported by extensive civil society engagement, and informed by a jurisprudential tradition that explicitly recognizes the autonomous right to a healthy environment.

There is much to explore in both the content of the opinion and its broader implications. To foster dialogue and critical reflection, the Sabin Center’s Climate Law Blog and Verfassungsblog are launching a symposium on AO-32/25. In the coming days, we will feature a series of commentaries by legal scholars and practitioners, offering diverse perspectives on the opinion’s legal reasoning, policy relevance, and broader significance for the evolving field of climate law. In this opening post, we provide background on the advisory proceedings and highlight why this is a defining moment for rights-based climate litigation.

Context: From AO-23/17 to AO-32/25

The request for this opinion was submitted on January 9, 2023, by the governments of Chile and Colombia (see here and here). It asked the IACtHR to clarify the scope of States’ human rights obligations under the American Convention in the context of the climate crisis, explicitly building on its 2017 advisory opinion. The request raised a wide range of questions across key areas of climate governance, including mitigation, adaptation, loss and damage, access to justice, and reparations. 

The IACtHR’s response was shaped by a process that was both procedurally and substantively unprecedented. Hearings held in Barbados and Brazil centered on the experiences and expertise of those most directly impacted by climate change. More than 260 amicus briefs were submitted, and over 160 delegations participated in the proceedings, including States, Indigenous and Afro-descendant Peoples, youth, academics, and civil society organizations. The Sabin Center submitted an amicus brief and presented it at the oral hearing in Barbados. 

The scale and inclusiveness of the process reflect a broader vision of adjudication: one grounded in public participation, scientific evidence, and democratic legitimacy. AO-32/25 reflects this vision—not only in its content but also in the way it was shaped.

10 Key Takeaways from the Advisory Opinion

The IACtHR’s findings are as comprehensive as they are groundbreaking, spanning areas from procedural requirements for mitigation measures to the protection of environmental defenders. What follows is not an exhaustive account but a selective overview of ten key takeaways, chosen to illustrate the opinion’s legal and practical significance. These highlights merely scratch the surface of a far-reaching advisory opinion whose implications are explored in greater depth in the contributions that follow.

1. Recognition of the right to a healthy climate

The IACtHR recognized, for the first time, that the conditions necessary for a stable and safe climate system are protected under the Inter-American human rights framework. Building on its 2017 recognition of the autonomous right to a healthy environment in AO-23/17, the IACtHR affirmed that a stable climate is essential to the exercise of a wide range of fundamental rights, including the rights to life, health, water, food, housing, and a dignified existence. As a substantive element of the right to a healthy environment, the right to a healthy climate has individual and collective dimensions, protecting present and future generations (para. 302). Significantly, the right to a healthy climate should be articulated with the protection of the rights of nature, which were recognized by the IACtHR (para. 315).   

2. Recognition of the rights of nature

The IACtHR recognized nature as a subject of rights protected by the American Convention. The IACtHR views this recognition as a contemporary manifestation of the interdependence between human rights and the environment, in line with the principle of progressivity under Article 29 of the American Convention (para. 282). The IACtHR rejected the legal view that nature exists exclusively as an object of property or an exploitable resource. It pointed to a growing recognition of the rights of nature as support, citing developments in Bolivia, Brazil, Canada, Ecuador, Mexico, Panama, and Peru, and in tribal and local governments in the U.S. (para. 286). Consequently, nature has the right to maintain its essential ecological processes (para. 279). This, in turn, imposes a positive obligation on countries to adopt measures to ensure the protection, restoration, and regeneration of ecosystems (para. 283). 

3. Special Protection of Vulnerable Groups

The IACtHR formulated extensive obligations for states with regard to particularly vulnerable groups, such as children, Indigenous peoples, tribes, people living in particularly poor regions, and other groups. Most importantly, state measures in response to the climate emergency require differentiated protection that takes into account the specific contexts and vulnerabilities of regions and populations (paras. 595–596). The IACtHR builds on its Advisory Opinion No. 23, where it had already emphasized that rights violations caused by environmental degradation are experienced differently across groups. It now uses Advisory Opinion No. 32 to further elaborate the specific impacts of the climate crisis and the resulting concrete state obligations. 

According to the IACtHR, climate change “creates extraordinary and increasingly serious risks to the human rights of certain population groups whose situation of vulnerability is increased by the confluence of intersectional and structural factors of discrimination.” (para. 594). Differentiated protection is “necessary to guarantee real equality in the enjoyment of rights in the context of the climate emergency” (para. 596). The climate emergency gives rise to new forms of vulnerability, which States must identify and respond to with special measures (para. 629). Legally, the IACtHR grounds this requirement of differentiated treatment in the principle of equality and non-discrimination. This principle entails the obligation of States to adopt positive measures to reverse or change discriminatory situations (para. 591). With regard to children and adolescents, for example, the IACtHR considers that States, among other obligations, must provide this group with access to comprehensive health services that respond to  the health impacts of climate change on children’s health (para. 599). Further, States must safeguard the democratic and procedural rights of children and adolescents (paras. 602, 604). 

4. Setting Mitigation Targets in line with 1.5 °C

The IACtHR found that the right to a healthy climate includes specific obligations to mitigate greenhouse gas emissions by setting an ambitious mitigation target. This mitigation target must be set on the basis of (1) the current and historical emissions of each country, (2) the capabilities of each country, and (3) the circumstances of each country (para. 328-30). This, in turn, means that countries with the highest historical emissions, highest current emissions, and highest level of development must take the lead in emissions reductions. According to the IACtHR, for each OAS Member State, mitigation targets must be as ambitious as possible, binding, include deadlines for achievement, and be progressively increased (para. 331). The IACtHR referenced the ITLOS advisory opinion and the Klimaseniorinnen v. Switzerland decision by the European Court of Human Rights, in establishing this obligation. 

The IACtHR framed required mitigation targets in terms of the 1.5 °C goal established in the Paris Agreement and the obligation to set progressively determined nationally determined contributions (NDCs) that reflect the highest possible ambition. It clarified that this obligation applies without exception to all OAS Member States, and non-compliance cannot be invoked as an excuse for non-responsibility (para. 325). Furthermore, since the 1.5 °C target does not eliminate the risk to people in the region, it should be considered a “minimum starting point” to determine the mitigation target of each State (para. 326). 

5. States Duties to Prevent, Regulate, and Cooperate

The IACtHR affirmed that States have an imperative duty to prevent irreversible harm to the climate system. This obligation stems from the recognition that the preservation of the vital ecological balance of the planet is a prerequisite for the effective protection of fundamental human rights. Accordingly, the duty to safeguard the common ecosystem must be understood as a jus cogens norm, a peremptory rule of international law that does not admit derogation (paras. 290–292).

Central to this duty is the standard of due diligence, which the IACtHR described as a dynamic and context-dependent obligation that becomes heightened in the face of the climate emergency. Drawing on the ITLOS’ advisory opinion, the IACtHR underscored that due diligence varies depending on the nature of the risk, the availability of scientific and technological information, international standards, and the urgency of preventing harm (para. 232). Given the foreseeability, gravity, and irreversibility of climate-related risks, States must act with particular rigor, foresight, and ambition to avoid harm to human rights (para. 233).

Enhanced due diligence entails a series of interlinked obligations. States must identify and assess risks in a detailed and continuous manner; adopt forward-looking and ambitious preventive measures grounded in the best available science; ensure that all climate-related policies integrate a human rights perspective; and prevent the creation or deepening of vulnerabilities. They must also monitor and revise their policies over time, ensure full compliance with procedural rights such as access to information, participation, and justice, maintain transparency and accountability, and adequately regulate and supervise private actors. Importantly, this standard encompasses strengthened international cooperation, especially with respect to technology transfer, climate finance, and capacity building (para. 236).

The duty to regulate flows directly from the obligation to prevent. States must adopt and continuously update domestic legal frameworks to respond to the climate emergency in a stable, consistent, and science-based manner (para. 246). These frameworks must cover both public and private activities and establish clear obligations to mitigate, adapt, and repair climate-related harm. The duty also extends extraterritorially when a State’s conduct contributes to transboundary harm, reinforcing the obligation to regulate and oversee actions that may affect the rights of persons beyond its borders (paras. 278, 296).

The IACtHR also emphasized the obligation to cooperate, which must be interpreted in accordance with the principles of equity and common but differentiated responsibilities (para. 258). Cooperation is essential to ensure that States, especially those with fewer resources or heightened vulnerability, can meet their climate-related human rights obligations. This includes good faith engagement in international processes, support for mitigation, adaptation, and reparation efforts across borders, and active participation in the sharing of resources, knowledge, and technologies (paras. 259, 264).

Taken together, the obligations to prevent, regulate, and cooperate are not isolated or optional measures. They form a continuous and mutually reinforcing set of duties that structure how States must respond to the climate emergency in compliance with the American Convention. The IACtHR made clear that inaction, regression, or failure to adopt effective measures—whether by States or through omissions in regulating private actors—may amount to a violation of human rights. These obligations must be fulfilled in accordance with the principles of precaution, non-regression, and progressivity, with particular attention to persons and groups in situations of vulnerability (paras. 221–223, 228–230, 235). 

6. Procedural Rights and Access to Justice

The IACtHR identified several climate-related procedural obligations of OAS Member States, centered around three subjects – access to information, public participation, and access to justice. 

Under Article 13 of the American Convention, States must produce climate information, disclose relevant climate information, and take measures against disinformation. States have a positive obligation to produce climate information to protect human rights, including early warning systems on disaster risks, and data necessary to establish, implement, and update mitigation and adaptation goals (para. 505). States have an obligation to publish and regularly disseminate on the state of the environment and their progress toward achieving climate goals (para. 521). And States are required to ensure that climate information is clear, truthful, accessible and timely. This includes an obligation to refrain from disseminating information that is not supported by the best available science (with criteria established by the IACtHR in para. 486) or by relevant local, traditional or Indigenous knowledge (para. 525). 

Under Article 23, States must guarantee processes that ensure meaningful participation in climate change decision-making and policies, and ensure prior consultation of Indigenous and tribal peoples. This extends to public participation in mitigation goals, adaptation and risk management plans, finance, international cooperation, and redress for damages (para. 535). 

Further, under Article 1, 8, and 25, States must ensure access to justice in the context of the climate emergency. To ensure access to justice, States must, among other things, (1) provide ongoing climate training and resources to judicial bodies (para. 542), (2) make progress towards supporting broad forms of legal standing, such as collective standing, that do not require individual impact (para. 549), (3) develop evidentiary standards (such as presuming a causal link between GHG emissions and degradation of the climate system) that do not impose unjustified procedural barriers to victims (paras. 552-555), and (4) enable victims to access full reparation for climate-related human rights violations, including through restitution, rehabilitation, and compensation measures (paras 556-558). Importantly, although without clarifying in detail, the IACtHR noted that State obligations to address transboundary harm from climate change includes the presumption that persons not residing in a territory have standing to sue for climate harms (para. 551). 

7. Intergenerational Equity

In line with several international treaties and building on earlier decisions, the IACtHR recognizes that the idea of intra- and intergenerational equity plays a crucial role in the context of the climate emergency. Intergenerational equity is not only part of the text of many constitutions and domestic legislation in States across the Americas; there is also an emerging trend toward recognizing future generations as rights-holders (para. 307). Most recently, the IACtHR ruled in La Oroya—with regard to the right to a healthy environment—that this right is of “universal interest owed to present and future generations” (para. 141). With regard to the climate emergency, the IACtHR affirms that the new right to a healthy climate must be interpreted in light of the guarantees of intra- and intergenerational equity (para. 313).

8. Duty to Adapt

The IACtHR interpreted adaptation as a core component of the State’s duty to respect, protect, and fulfill human rights in the context of climate change. This cross-cutting obligation integrates environmental governance, social equity, and procedural guarantees, and must be supported by both national planning and international cooperation.

In particular, States are required to adopt, regularly update, and implement national adaptation plans, consistent with the Paris Agreement and the UNFCCC (para. 380). Adaptation must be guided by the best available science (para. 388), respect for procedural rights (paras. 388, 425), heightened due diligence (para. 385), the principles of progressivity and precaution (para. 390), and non-discrimination (para. 391). The IACtHR emphasized the iterative nature of adaptation, encompassing risk assessment, planning, implementation, monitoring, and revision—a cycle that must integrate cross-cutting issues such as gender equality, ecosystem protection, disaster risk reduction, and poverty eradication (paras. 381, 389).

The IACtHR further delineated adaptation obligations as they relate to specific rights, including the right to life, health, and physical integrity (paras. 393–402); the right to private and family life, housing, and property (paras. 403–413); mobility, displacement, and residence rights (paras. 414–434); access to water and food (paras. 435–440); the right to work and social security (paras. 441–447); cultural rights (paras. 448–452); and the right to education (paras. 453–457).

This holistic and rights-based approach—grounded in the wide scope of protections under the Inter-American system—reinforces the centrality of adaptation in responding to the climate crisis and in ensuring that no one is left behind.

9. Regulation of Company Behavior 

The IACtHR found that, given the central role that companies play in contributing to climate change, States must directly regulate companies to prevent climate-related human rights violations (para. 345). These obligations are relevant to State regulation of all companies domiciled or operating in their jurisdiction, with higher obligations imposed on high current and historic greenhouse gas emitters. The obligations of States to regulate include (1) requiring companies to disclose the greenhouse gas emissions of their value chain, (2) requiring emissions reductions by companies, and (3) setting standards to discourage greenwashing and undue influence on the political and regulatory sphere (para. 347). 

10. Rights of Environmental Rights Defenders 

Last but not least, it is worth highlighting the important role the IACtHR assigns to environmental rights defenders in the climate crisis. Especially from a democratic perspective, they are considered indispensable due to the urgency, gravity, and complexity of the measures required to address the climate emergency. This crucial role and the need to protect environmental rights defenders are also recognized in other international instruments and reports by UN Special Rapporteurs. Despite their key role, environmental rights defenders often find themselves in a “general climate of criminalization” (para. 570). In addition to the repression of protests and acts of violence, they are also subjected to arbitrary detentions and strategic legal actions in the form of SLAPPs (Strategic Lawsuits Against Public Participation) (para. 568). According to the IACtHR, in light of the violence and intimidation faced by environmental rights defenders, States have a range of obligations. These include collecting data on such incidents, designing and implementing policies and strategies to address the structural causes of this violence, and adopting measures to defend the right to defend environmental human rights in all spheres of the State, as well as in society more broadly (para. 575). States must also identify where the law is being applied selectively to target environmental defenders (para. 587).

International Repercussions and Global Climate Governance

Without a doubt, the highlights sketched above are as far-reaching as they are progressive, but will they also generate any significant impact? We believe there are good reasons to be optimistic in this respect, both with regard to regional and global implications. 

Regionally, as is well known, advisory opinions by the IACtHR exert significant influence on how domestic courts interpret human rights obligations. However, it is not only courts but also governments that would be well-advised to study the Opinion closely, since, for instance, a failure to adopt binding, progressively increasing mitigation targets with specific deadlines could violate States’ obligations under the Convention. At this point, a major strength of AO-32/25 becomes apparent: instead of remaining mainly at the level of general principles, it specifies very concrete State obligations and provides States with actionable benchmarks when designing domestic climate policies.

At the global level, it is first important to view AO-32/25 against the backdrop of several other pending requests for advisory opinions that, taken together, address various legal dimensions of the climate emergency. As has recently been argued, such requests increasingly seek to redefine the boundary between rule and exception — for example, conduct related to the climate crisis that was normally considered lawful may be deemed unlawful under international law following an advisory opinion. The recently issued ITLOS advisory opinion, for instance, held that greenhouse gases may constitute marine pollution. The upcoming ICJ’s Advisory Opinion (expected on July 23, 2025) will address broader questions of general international law, whereas the recent request to the African Court on Human and Peoples’ Rights focuses on human rights issues that, although related, have a different emphasis than the IACtHR’s Advisory Opinion.

One expected effect (which can already be observed) is that this new wave of climate-related advisory opinions will not only influence domestic climate litigation. States will also need to take these rulings into account at the level of climate diplomacy — for example, at the upcoming COP30 in Brazil. 

Looking Ahead: A Symposium on Rights, Climate, and Justice

This post launches a blog symposium featuring reflections from legal scholars, climate advocates, and practitioners across multiple regions. In the coming days, contributors will analyze the opinion’s implications for litigation strategy, policy reform, international cooperation, and the evolving relationship between climate science and human rights law. We invite readers to follow the symposium, engage with the contributions, and share their own reflections as we collectively unpack this historic ruling.

Related Work: The Sabin Center and Verfassungsblog recently partnered on two similar blog symposia — one exploring three key rulings from the European Court of Human Rights on states’ obligations to combat climate change, and the other examining the ITLOS advisory opinion on climate change.

Maxim Bönnemann

Maxim Bönnemann is an International and Comparative Law Research Scholar at University of Michigan Law School.