The IACtHR has jurisdiction in relation to the interpretation of the American Convention of Human Rights (“ACHR”) and the Additional Protocol to the ACHR in the area of economic, social and cultural rights (“San Salvador Protocol”). Twenty-three states in the Americas have ratified the ACHR, and twenty have recognised the jurisdiction of the IACtHR. The IACtHR is based in San José, Costa Rica.

It is the second advisory opinion by an international tribunal addressing the obligation of states and climate change. In May 2024, the International Tribunal for the Law of the Sea published its advisory opinion, requested by the Commission of Small Island States, on Climate change and International Law. Two other international tribunals, the International Court of Justice (“ICJ”) and the African Court of Human and Peoples’ Rights, are also in the process of preparing advisory opinions on climate change and states international obligations within their respective remit, with the advisory opinion of the ICJ due on 23 July 2025.

The IACtHR’s AO is expansive, both in terms of covering a wide range of topics, and in developing its human rights jurisprudence in the context of climate change. This blog seeks to provide an overview of some of the key findings of that AO.

Background to the Advisory Opinion

The AO was requested jointly by Colombia and Chile on 9 January 2023. Following acceptance of the request, the IACtHR invited domestic courts in the region to forward to the Court their jurisprudence on the climate emergency and human rights, with the aim of strengthening judicial dialogue (para. 7). In addition, the IACtHR received 263 written submissions from a range of actors, including state bodies, international organisations, NGOs, academic institutions and representatives from the public and private sector. Following the receipt of these submissions, oral hearings were held in Barbados and Brazil in April and May 2024 (para. 10).

Questions Answered

The court reformulated the questions asked by Chile and Colombia and split them up into three key categories:

1. What is the scope of the obligations to respect, guarantee and adopt the necessary measures to secure the substantive rights of the Convention (including, among other rights, the right to life and the right to health; the right to physical integrity and the right to private and family life)?
2. What is the scope of the obligations to respect, guarantee and adopt the necessary measures to secure the procedural rights (such as access to information, participation rights and access to justice) in light of the effects generated or exacerbated by the climate emergency?
3. What is the scope of the obligations to respect, guarantee and adopt the necessary measures to secure the rights of vulnerable groups without discrimination?

The structure of the AO

The AO is divided into two halves. The first part (“the Climate Emergency”), provides a background to climate change and its effects on people and the environment in which they live. It also addresses the international response to climate change, developing norms in the Americas and the climate emergency landscape. The second part (“States’ Obligations in a Climate Emergency Context”) focusses on the interpretation of the ACHR and San Salvador Protocol and addresses the scope and meaning of the obligations owed, both in terms of substantive and procedural rights more generally and the rights of vulnerable individuals and groups.

Part 1: The Climate Emergency (paras. 42-216)

It is striking that the IACtHR spends just under a third of its opinion setting out what it terms ‘the climate emergency’. The term ‘emergency’ is not one that usually features in judicial decisions or opinions and reflects the seriousness of the risks that the IACtHR perceives climate change to pose to the world as well as the limited time for action.

The AO starts by noting that climate change is only one aspect of the so-called “tri-planetary crisis” of climate change, pollution and biodiversity loss, and that this context cannot be lost (para. 42). It then discusses climate change and its causes (paras. 44-63); the impacts of climate change now and in the future (paras. 64-119); the international response to the climate emergency (paras. 120-171); the domestic regulatory developments (para. 172), and the growing level of domestic and international climate litigation (paras. 176-180).

There are three criteria by which the Court assesses whether climate change is an ‘emergency’: the urgent need for effective action, the severity of the impacts and the complexity of the required responses (para. 184). 

Taking all this into account, the IACtHR concludes that, according to the best available science, the present situation constitutes a climate emergency due to the accelerated increase in global temperatures arising from human activities. The Court finds that the incremental increase in global temperatures presents a grave threat to humanity, especially those who are vulnerable. It also finds that the climate emergency can only be adequately addressed through urgent and effective action on mitigation, adaptation and progress towards sustainable development.

Part 2: States’ Obligations in a Climate Emergency Context (paras. 217-629)

In the second part of the AO, the IACtHR outlines what it considers to be the obligations on States under the ACHR and the San Salvador Protocol and the scope of such obligations, in the context of the climate emergency. It is helpful to read this chapter alongside the chapter titled “Opinion” at the end of the document. In that chapter the IACtHR outlines its conclusions with respect to no less than twenty discrete issues (cross-referring to paragraphs in the body of the AO), and whether their conclusion on that issue was unanimous or otherwise.

In this blog, we summarise what we consider to be three of the most interesting conclusions of the court, namely the IACtHR’s conclusions on:

(a) General obligations under Articles 1 and 2 of the ACHR;

(b) The right to a healthy environment; and

(c) Procedural rights (including access to information, public participation and access to justice).

(a) General obligations (paras. 218-265)

Articles 1 and 2 of the ACHR establish general obligations respect, guarantee and adopt the necessary measures to make effective the rights in the ACHR.

Thus Article 1 of ACHR provides, “The States Parties to this Convention undertake to respect the rights and freedoms recognized herein and to ensure to all persons subject to their jurisdiction the free and full exercise of those rights and freedoms without any discrimination for reasons of race, color, sex, language, religion, political or other opinion, national or social origin, economic status, birth, or any other social condition”. By Article 2, “Where the exercise of any of the rights or freedoms referred to in Article 1 is not already ensured by legislative or other provisions, the States Parties undertake to adopt, in accordance with their constitutional processes and the provisions of this Convention, such legislative or other measures as may be necessary to give effect to those rights or freedoms.”

Bearing these general obligations in mind, the IACtHR unanimously held that in order to comply with the obligation to respect human rights in the context of the climate emergency, States must refrain from any conduct that sets back or slows down the outcome of measures necessary to protect human rights in the face of climate change as well as refraining from adopting regressive measures (paras. 221-222).

The IACtHR further held (again unanimously) that the obligation to guarantee rights entails a duty of ensuring that third parties in the private sphere do not violate the protected legal interests; a duty of prevention; and a duty of enhanced due diligence (paras. 224-237). This obligation of enhanced due diligence requires assessment of climate risks, adoption of preventive measures, use of the best available science, the integration of a human rights approach into the formulation, implementation and monitoring of measures, and compliance with procedural rights (para. 236).

(b) The Right to a Healthy Environment (paras. 269-376)

The Right to a Healthy Environment is expressly recognised in Article 11 of the San Salvador Protocol, in the following terms:

1. Everyone shall have the right to live in a healthy environment and to have access to basic public services.

2. The States Parties shall promote the protection, preservation, and improvement of the environment.

Following a discussion on the long-established right to a healthy environment (including how it is a fundamental human right and autonomous right), the Court narrowly concludes (by a majority of 4 to 3) that it is appropriate to recognise the legal personality of Nature as a component of the right to a healthy environment (paras. 279-286). In doing so, it arguably draws not on the text of the ACHR nor on the San Salvador Protocol, but on the growing international trend to afford nature legal personhood.

Second, the court holds that the right to a healthy environment requires States to adopt measures that prevent significant environmental damage within or outside their territory. Where damage occurs outside their territory but is caused from within a State’s borders, those persons affected by the damage are within their jurisdiction (para. 277).

Third, drawing on its explanation of the climate emergency, the Court also declares that the obligation not to create irreversible damage to the climate and environment is jus cogens, ie a peremptory norm of international law (paras. 287-294).

Fourth, the court finds that the right to a healthy climate should be considered an independent right derived from the right to a healthy environment. This is justified on the basis that there needs to be the clear delimitation of specific state obligations in the face of the climate crisis (paras. 295-304).

The IACtHR then discusses the obligations arising from the right to a healthy environment as including obligations of regulation, monitoring, and the use of environmental impact studies (paras. 317-377). 

(c) Obligations arising from procedural rights (paras. 458-587)

The Court articulates a number of procedural rights which it argues arise in the context of climate change. These include the right to science and the recognition of local, traditional and indigenous knowledge (paras. 471-487); the right to access of information in the context of the climate emergency (which includes the production of information regarding climate change) (paras. 488-500); the right to political participation (paras. 530-539), the right of access to justice (paras. 540-560); and the right to defend human rights and the protection of environmental defenders (paras. 561-587).

The discussion on the right of access to justice specifically addresses evidentiary standards, in particular noting the difficulties showing causation in many cases concerning climate change. The court thus advocates for the relaxation of certain evidentiary standards to ensure access to justice in the climate context (para. 552).

Concluding Comment

Framing climate change as a “climate emergency” was perhaps inevitable since that was the manner in which Chile and Colombia posed their joint request. However, it might be argued that the analysis of why climate change should be treated as an emergency forms part of the IACtHR’s justification for their expansive interpretation of the ACHR and Protocol of San Salvador later in the AO, permitting it to develop its jurisprudence in ways not necessarily grounded in the legal text it is interpreting.

Stephanie Bruce-Smith is a barrister at Francis Taylor Building.

Emma Rowland is a pupil at Francis Taylor Building.

The authors of this blog have referred to the Spanish language version of the Advisory Opinion and to an unofficial translation of the same published by the Global Climate Change Litigation database from the Sabin Centre for Climate Change Law (www.climatecasechart.com). As such, the translation and/or terms used in this blog may differ from the official English translation, which is due to be published on 11 July 2025.