Seven Groundbreaking Insights from the Inter-American Court’s Climate Advisory Opinion

By Dr Mohammad Hazrati
Published on 22 July 2025

Introduction

On May 29, 2025, the Inter-American Court of Human Rights (IACtHR) delivered its Advisory Opinion OC-32/25, requested by Chile and Colombia, addressing States’ obligations to respond to the climate emergency within the framework of international human rights law. This landmark opinion represents a watershed moment in the global recognition of the deep connections between climate change, environmental protection and human rights. The Court not only reaffirmed existing standards but also introduced several innovative elements that advance the legal landscape, shaping climate governance in the Americas and beyond. The Opinion followed the most participatory process for an advisory opinion in the history of the IACtHR, with the submission of more than 260 amicus briefs and the involvement of over 180 delegations in the hearings. It forms part of a trio of advisory opinions on State obligations in the context of climate change. The International Tribunal on the Law of the Sea (ITLOS) issued its advisory opinion in 2024 under the UN Convention on the Law of the Sea, while the International Court of Justice (ICJ) is expected to release its opinion next week. The Opinion is structured as follows:
A. General obligations under the American Convention and the Protocol of San Salvador in the context of the climate emergency; B. Specific obligations related to substantive rights; C. Specific obligations related to procedural rights; D. Obligations toward vulnerable groups in the context of the climate emergency.

This blog post highlights seven of the most important and groundbreaking features of this 234-page Advisory Opinion. It does not aim to cover every detail but focuses on the key developments that may significantly influence future jurisprudence and policy.

A. General obligation

In the General Obligations section (A), the Court ruled on the scope of general obligations under the American Convention and the Protocol of San Salvador regarding substantive and procedural rights in the context of the climate emergency. It addresses the obligations to (A.1) respect, (A.2) guarantee, (A.3) adopt measures to ensure the progressive development of economic, social and cultural rights, (A.4) adopt domestic legal provisions and (A.5) cooperate. However, the concept of ‘enhanced due diligence’ for States is central to understanding how these obligations must be implemented in light of the risks posed by the climate emergency.

The standard of enhanced due diligence for States

The Court recalled that, under its jurisprudence, the obligation to guarantee rights—particularly the duty of prevention—is one of conduct, not result. A breach is not proven merely by the occurrence of harm but through failure to act with due diligence, a standard shaped by international law and widely applied in fields such as human rights, environmental law and the law of the sea.

In the context of the climate emergency, due diligence must be appropriate and proportionate to the level of environmental risk. It is a flexible concept that depends on scientific and technological knowledge, the likelihood and severity of harm, international standards and urgency. Given the seriousness and urgency of the climate crisis, States must act with enhanced due diligence to fulfil their preventive obligations under the American Convention.

The required level of diligence depends on the specific risks to each right. Crucially, the measures necessary to meet this standard may change over time with scientific advances and new knowledge and are binding on all States regardless of development level, though differentiated responsibilities apply. These risks are largely foreseeable and disproportionately affect vulnerable groups.

B. Substantive rights

The Court recalled that substantive rights—such as the rights to life, personal integrity, health and property—are especially vulnerable to environmental harm. In this section, beyond the right to a healthy climate and the obligations derived from the right to a healthy environment in the context of the climate emergency, two important concepts were developed that deserve special attention: the recognition of nature as a subject of rights, and the pronouncement on the jus cogens nature of the obligation not to cause irreversible damage to the climate and the environment.

Recognition of the right to a healthy climate as an autonomous human right

Perhaps the most significant innovation in this Advisory Opinion is the Court’s recognition of the right to a healthy climate as a distinct, substantive element derived from the right to a healthy environment, given the urgency and complexity of the climate crisis. While closely linked to broader environmental protection, the climate system has unique global functions that require specific legal attention. In this context, a healthy climate is understood as a climate system free from dangerous anthropogenic interference. The Court affirmed that this right has both individual and collective dimensions: individually, it protects each person’s ability to live and develop in a safe climate; collectively, it safeguards the shared interest of present and future generations—and Nature itself—in maintaining a balanced climate system. The failure of States to meet their obligations under international law not only threatens this right but also triggers international responsibility and a duty to provide full reparation. This recognition strengthens the Inter-American legal order and aligns with the evolution of international human rights and environmental law (Paras. 298–304).

Recognition of Nature as a subject of rights

This approach, the Court stated, ‘reinforces the protection of the integrity and functionality of ecosystems’ and is vital for confronting the ‘triple planetary crisis’ of climate change, pollution and biodiversity loss. A truly groundbreaking step is the Court’s explicit recognition of Nature and its components as subjects of rights, moving beyond a purely human-centred (‘anthropocentric’) legal framework. The Court recognised that ecosystems are complex and interdependent, and their degradation can trigger cascading harm to both nature and humans. Acknowledging nature as a subject of rights helps shift away from legal views that treat it merely as property or a resource and instead highlights its vital role in sustaining life on Earth. This perspective reflects a growing jurisprudential and normative trend across regional, global and domestic legal systems. On this basis, States have not only a duty to refrain from causing significant environmental harm, but also a positive obligation to protect, restore and regenerate ecosystems (Paras. 279–286).

The jus cogens nature of the obligation to prevent irreversible environmental harm

Another landmark finding is that the obligation to prevent anthropogenic conduct which irreversibly harms the climate and environment has attained the status of jus cogens—a peremptory, non-derogable norm of international law. This is the first time an international court has done so. The Court highlighted that the obligation to prevent irreversible damage to the climate and environment is a universal value of growing international concern. Scientific consensus identifies certain human behaviours—such as large-scale deforestation, biodiversity loss, pollution and severe climate change—as causing irreversible harm to ecosystems vital for life.

Since the balance of conditions for healthy life in the common ecosystem is a prerequisite for the present and future habitability of the planet, the obligation to preserve such a balance must be interpreted as an imperative international duty. The existential interests of individuals and collectives of all species, whose rights to life, personal integrity and health have already been recognised by international law, crystallise the obligation to stop anthropogenic behaviours that critically threaten the balance of our planetary ecosystems. As such, the prohibition against irreversible environmental harm is a jus cogens norm—an overriding, non-derogable principle of international law. It derives from general legal principles, the interdependence of human rights and the environment and growing international consensus. States must cooperate to uphold this imperative norm to ensure a habitable planet for present and future generations (Paras. 287–294).

C. Obligations arising from procedural rights

The Court emphasised that respecting and guaranteeing procedural rights is essential to ensure the legitimacy and effectiveness of climate action amid the challenges of the climate emergency. In this section, the Court examined (C.1) democracy and procedural rights in the climate context, followed by specific rights adapted to this crisis, including: (C.2) the right to science and recognition of local, traditional and indigenous knowledge; (C.3) access to information; (C.4) political participation; (C.5) access to justice; and (C.6) the right to defend human rights. Although many of these procedural rights have been affirmed by various international bodies, this section also introduces some elements that are notably innovative, particularly under the access to justice part.

The application of the pro actione principle, collective claims and extraterritorial standing

Under the right of access to justice and given the seriousness of climate risks and their disproportionate impact on vulnerable groups, the Court considered that judicial proceedings related to such risks should be guided by the pro actione principle. This requires avoiding interpretations or applications of procedural rules that unjustifiably hinder access to justice. Courts must favour interpretations that ensure access to jurisdiction and effectively guarantee material justice in the context of the climate emergency (Para. 543).

Also, under the right of access to justice, the Court highlighted that, given the collective nature of climate harms, States must adopt procedural mechanisms—such as collective, public or popular standing—so that protective measures can be pursued without needing to prove individual harm. This aligns with a trend in many legal systems in the Americas, which allow broad legal standing for collective, public or popular environmental defence. Guaranteeing access to justice in collective actions requires that civil society and competent State institutions have real means to act. This includes ensuring procedural rights and providing the necessary technical, financial and human resources for public institutions to function effectively (Paras. 547–549).

The Court recalled that climate damage is inherently transboundary and that States must promptly provide adequate and effective reparation to persons and States harmed by activities within their territory or jurisdiction, when there is a causal link to the damage. Therefore, the Court emphasised that access to justice requires allowing persons and entities outside the State’s territory to have standing to sue (Para. 551).

The Court also recognised that strict evidence rules can block access to justice in complex climate cases. Judicial authorities should adapt by considering challenges such as difficulties in proving causation, unequal access to evidence and the concentration of technical information among powerful actors. This requires applying principles like availability of evidence, procedural cooperation and the pro persona, pro natura and pro actione principles. Access to justice demands alternative evidentiary standards based on the best available science to establish a causal link between risks and harm, without always requiring direct proof. The Court highlighted the possibility of presuming causation between greenhouse gas emissions, climate system degradation and resulting risks to people and nature. Evidentiary rules should be interpreted flexibly to prevent unjustified barriers, especially for vulnerable victims. Measures such as reversing the burden of proof may be necessary to ensure effective access to justice (Paras. 552–555).

D. The obligations arising from the principle of equality and non-discrimination

To address the final question in this Advisory Opinion, the Court examined the specific obligations required to uphold the principle of equality and non-discrimination for individuals and groups in situations of special vulnerability within the context of the climate emergency. This section covers: (D.1) the scope of the principle of equality and non-discrimination; (D.2) forms of differentiated protection in the climate emergency; and (D.3) the fight against poverty and inequality as intersectional factors shaping vulnerability to climate impacts.

Duty to address structural discrimination

The Court affirmed that equality and non-discrimination are fundamental to human rights and now form part of jus cogens. This principle involves two key obligations: prohibiting arbitrary distinctions and adopting positive measures to address existing discrimination. This includes a special duty to protect against third-party actions that sustain discriminatory conditions. The Court reiterated its past findings that multiple intersecting vulnerabilities in a person increase their risk of discrimination. It stressed that vulnerable individuals deserve special protection, requiring States not only to avoid rights violations but to adopt positive measures tailored to each person’s specific needs. The Court also repeated that States bear internationally responsible when they fail to address structural discrimination with appropriate actions (Paras. 589–594).

The Court further held that States must gather information on climate risks, identify and characterise affected groups and ensure that public policies and climate actions include differential measures to guarantee real equality in the enjoyment of rights. This requires special protection and targeted measures for vulnerable groups such as children, indigenous peoples, Afro-descendants and persons with disabilities (Paras. 595–629).

Fighting poverty in the context of the climate emergency

The Court recognised that poverty is a structural factor of vulnerability that heightens exposure to human rights violations and limits access to justice and reparation. Climate change exacerbates multidimensional poverty by impacting food, water, housing, health and education, especially for those already disadvantaged. The poor are disproportionately affected due to where they live, degraded livelihoods, weaker support systems and limited resources. Intersectional factors such as gender, disability and age further increase vulnerability. In this context, States must collect relevant information and adopt policies to ensure access to essential goods and services and to reduce structural causes of climate vulnerability, integrated into broader sustainable development, mitigation and adaptation strategies. They must ensure that climate transition measures do not deepen poverty but promote inclusion, resilience and rights fulfilment. The Court also stressed that vulnerability is dynamic, and not all at-risk groups are traditionally protected; hence, States have a duty to identify emerging vulnerable populations and adopt specific, reasonable and differentiated measures to prevent and reduce climate risks and safeguard the full range of rights affected by the climate emergency (Paras. 619–629).

Conclusion

The Advisory Opinion of the IACtHR marks a historic milestone in shaping the legal framework for climate governance, particularly as the world awaits the forthcoming advisory opinion from the ICJ. Demonstrating a clear and in-depth understanding of the link between justice and climate change—one that goes beyond a purely human-centric perspective—the Inter-American Court introduces significant legal and judicial innovations in defining states’ obligations related to climate change and human rights. This blog post highlights seven of the most innovative elements of the Opinion, drawn from the Court’s responses to the three questions presented. These elements offer a solid foundation for future developments. Although not legally binding, the advisory opinion provides a coherent, justice-oriented and human rights-centred framework for climate action and outlines a roadmap for equitable climate governance from a Global South perspective.

Dr Mohammad Hazrati is Senior Research Fellow at the Centre for International Law, National University of Singapore, specialising in energy, environmental, and climate change law and policy, with a particular focus on the energy transition.