Historic Advisory Opinion by the Inter-American Court of Human Rights on the climate emergency

On 3 July 2025, the Inter-American Court released a historic Advisory Opinion on the positive obligations of states in light of the climate emergency. Ben Cooper KC, Toby Fisher, Finnian Clarke and Louise Willocx, acting pro bono for The Centre for Justice and International Law (Cejil) and two environmental charities, Global Action Plan and Kyklos, contributed to this momentous Advisory Opinion by way of an amicus brief. 

Louise Willocx, who also teaches on the intersection of human rights and international environmental law at the Catholic University of Leuven has analysed some of the key features of the ruling. 

Ius Cogens

The Inter-American Court of Human Rights (IACtHR) has recognised the obligation not to cause irreversible damage to the climate and the environment as a ius cogens norm. The importance and magnitude of such a ruling cannot be overstated. Up until now, this was an idea floated by academics and no domestic or international court had ever made such a finding. As the existence of a ius cogens norm depends on its acceptance by the international community of states, this is an incredibly bold move.

Being accepted as a ius cogens norm has major consequences. Treaty obligations conflicting with ius cogens norms have no legal force. States are under an obligation to cooperate to bring any serious breaches of a ius cogens norm by another state to an end. States can also invoke the legal responsibility of another state for ius cogens breaches. 

The IACtHR’s recognition of this ius cogens norm should be celebrated as it can set into motion a wave of recognition by other states, courts, or international organisations. Nevertheless, those engaging in strategic litigation will have to thread carefully, as the legal basis for the IACtHR’s recognition will be controversial. That being said, the judgment provides a platform for the issue of whether the international community of states will recognise irreparable harm caused to the environment or climate as a ius cogens norm. The best way to consolidate the position will be by testing the waters domestically and awaiting the response of individual states. Using an incremental approach, will help establish a wider consensus about the acceptance of such a ius cogens norm before the point is further pursued before another international court. 

Nature as a subject of rights

The IACtHR further formally recognised for the first time that nature, just like humans, is a bearer of human rights. It thereby follows various other national courts, lawmakers, and local authorities around the world who have recognised such rights. The Court also builds on its earlier jurisprudence in Advisory Opinion 23-17 [at para 62], where it found that: “as an autonomous right, the right to a healthy environment, unlike other rights, protects the components of the environment, such as forests, rivers and seas, as legal interests in themselves, even in the absence of the certainty or evidence of a risk to individuals. This means that it protects nature and the environment, not only because of the benefits they provide to humanity or the effects that their degradation may have on other human rights, such as health, life or personal integrity, but because of their importance to the other living organisms with which we share the planet that also merit protection in their own right. 

The consequences of the IACtHR’s finding will have to be explored further in litigation before the Court. So far, the only concrete consequence identified by the Court was that States are under “a positive obligation to adopt means to guarantee its protection, its restauration and the regeneration of the ecosystems”. 

Nevertheless, it begs the question whether this formal recognition means that the Court has opened the door to bring procedural standing to those representing nature, which has been a key element in many domestic recognitions of rights of nature. It also raises the question as to what rights nature has and what, if any, connection those rights have to the American Convention of Human Rights. The Convention itself is rather clear that it applies to human beings only [Article 1.2]. Nevertheless, in its Advisory Opinion, the Court has stated that rights of natureit will empower indigenous groups and it will be interesting to see how rights of nature will be invoked in the future.

Reinforcing jurisdiction and emissions norms with a focus on vulnerable groups

The Court also reaffirmed some of its earlier progressive jurisprudence and approach to environmental issues and climate change. 

Importantly, the Court built on their earlier Advisory Opinion 23-17 and found now for the first time that the right to a healthy environment includes the right to a stable climate. As a result, they found that States were under an obligation to set goals for reductions in GHG emissions which are in accordance with the best available science, that they, are coherent with their internal and international obligations, and that these goals are binding norms.

Moreover, the IACtHR was the first international human rights court to accept jurisdiction for environmental transboundary harm. Generally speaking, human rights courts will only accept claims relating to violations which have occurred on their States’ territory, subject to a couple of narrow exceptions. In its earlier Advisory Opinion 23-17, the Court created a significant and novel exception in light of the transboundary character of environmental harm and the need for adequate remedies. They held that “States may be held responsible for any significant damage caused to persons outside their borders by activities originating in their territory or under their effective control or authority” [para 103]. 

With the IACtHR having opened the door for so many new victims of environmental harm, claimants ran the same argument before the European Court of Human Rights, in the hope that this precedent would be followed. Unfortunately, the ECHR refused to create a similar exception to its jurisdictional rules. It was therefore reassuring to see that the IACtHR reaffirmed its jurisprudence on jurisdiction in cases of transboundary harm and did not back down [para 277-278]. 

Importantly, the IACtHR also found that states had a positive obligation to provide adequate administrative and judicial mechanisms to ensure victims receive reparations if they or nature have been harmed. This should not be limited to damages but requires full restitution, meaning nature should be restored in its original state. 

Further, the Court did not neglect to recognise that those most vulnerable, such as children, suffer more than others from climate change and require additional protection. We had emphasised the physical and mental harm to children in our amicus brief and were therefore pleased to see the Court recognise and address this directly. 

Lastly, the Court also pointed to the specific vulnerability of environmental activists and called for the decriminalisation of their protests. It is hoped that this brings important perspective to the manner in which civil disobedience is dealt with in the UK as well.