The advisory opinion AO-32/25, issued by the Inter-American Court of Human Rights (IACtHR) on 3 July 2025 contains many insights and innovations. The most significant among these have already been outlined by Tigre et al. This contribution aims to show that a comparison between the European Court of Human Rights’ (ECtHR) and the IACtHR’s approach reveals how much more far-reaching the latter is, particularly in its recognition of the equity dimension and the global nature of the climate crisis. The IACtHR’s advisory opinion follows the trajectory set by earlier Inter-American jurisprudence, which had already acknowledged the impact of environmental degradation and climate change on the effective enjoyment of human rights, beginning with Kawas Fernández v. Honduras and, more prominently, in AO-23/17. Building on these precedents, the IACtHR now introduces further elements, culminating in the recognition of a human right to a healthy climate – understood as a right to a climate system free from dangerous anthropogenic interference – derived from the right to a healthy environment, yet standing as an autonomous right.

In comparison, the ECtHR issued its three landmark cases regarding the climate crisis more than a year ago (see Verein KlimaSeniorinnen Schweiz, Duarte Agostinho, and Carême). Although delivered in the context of specific contentious procedures, the rulings set general standards, not unlike an advisory opinion. The ECtHR’s rulings affirm the interdependence between human rights and the climate crisis, but when compared with the Advisory Opinion AO-32/25, significant differences become apparent.

Two approaches

The IACtHR explicitly acknowledges the climate crisis  as an emergency, with a  significant portion of the text devoted to a detailed analysis of its causes, consequences, and the relevant international legal frameworks (AO-32/25, paras. 42–216).

This emphasis on the emergency nature of the climate crisis is complemented by a strong focus on its social implications and the resulting need for equity and climate justice. Noting that “the impacts of climate change are neither neutral nor automatic” (AO-32/25, para. 62), and that “those living in poverty—who have contributed the least to greenhouse gas emissions—are the least equipped to respond and will be the most adversely affected” (AO-32/25, para. 100), the IACtHR affirms the obligation to combat multidimensional poverty and ensure differentiated protection for vulnerable groups. The IACtHR bases this on a rigorous analysis grounded in the principle of equality and non-discrimination, which is regarded by the IACtHR as a jus cogens norm of international law (AO-32/25, para. 590). The IACtHR thus adopted an intersectional perspective that is open to new forms of vulnerability that may arise as a consequence of climate change (AO-32/25, paras. 588–629).

As will be shown below, while not entirely absent, considerations of equity and justice remain secondary in the ECtHR’s climate case law. Seeking to safeguard its institutional role and prevent a flood of applications, the Court adopted an abstract approach that insufficiently engages with these critical issues, despite their relevance given the presence of major global emitters in the European context.

This approach results in several conceptual shortcomings in the ECtHR’s decisions: persistent uncertainty over key elements of States’ climate obligations, the refusal to acknowledge extraterritorial jurisdiction, and inconsistencies in the recognition of standing. All of this leads to the exclusion of protection from the effects of climate change for the most affected people and areas (Schayani).

Fairness lost and regained

In defining the content of the State’s obligation, the ECtHR specifies that States must determine the remaining carbon budget (KlimaSeniorinnen, para. 573) and that their margin of appreciation is narrower in setting aims and objectives, but wider in choosing the means to achieve them (KlimaSeniorinnen, para. 549). However, the judgment fails to clarify several essential issues.

The ECtHR does not specify the boundaries of the margin of appreciation concerning the determination of the temperature goal (whether this should be the 1.5°C target advocated by the applicants, or any target established in the Paris Agreement).

Moreover, the ECtHR avoids any mention of fairness, despite repeated references by the applicants, intervenors, and even the Swiss Government to Switzerland’s “fair share” of the global climate mitigation burden (Humphreys). What constitutes a fair contribution by each State remains uncertain.

The Inter-American Court likewise does not quantify each State’s individual contribution. However, the obligation to define an adequate mitigation target (AO-32/25, paras. 323-332) clearly reflects the emphasis placed on equity and climate justice, as the responsible actors must determine its content in accordance with the principles of equity and common but differentiated responsibilities. Accordingly, AO-32/25 clarifies that the States must establish their mitigation target not only on the basis of the best available science, but also by taking into account their current and historical contribution to climate change, the resources at their disposal, and the conditions in which they find themselves, such as population size, income inequality, and unmet basic needs (AO-32/25, para. 327).

The IACtHR also notes that the 1.5°C limit does not eliminate risks for millions of people and must be treated as a minimum starting point – not a final goal – for setting national mitigation targets (AO-32/25, para. 326).

Climate-related harm and States’ extraterritorial jurisdiction

The IACtHR had already affirmed the principle of States’ extraterritorial jurisdiction concerning transboundary environmental harm in the advisory opinion on the environment and human rights (AO-23/17, para. 103).

AO-32/25 further clarifies that climate-related harm is inherently transboundary, as it does not remain confined within the territory of the State that contributed to its occurrence but necessarily extends beyond its borders (AO-32/25, para. 295). Consequently, violations of the American Convention on Human Rights arising from climate harm (and their victims) fall within the jurisdiction of the State responsible for causing or contributing to such harm (AO-32/25, para. 296).

In contrast, the ECtHR, in its Duarte Agostinho judgment, declined to recognize States’ extraterritorial jurisdiction (para. 213).

This firm stance by the Grand Chamber was reaffirmed in two recent rulings by the First Section, which declared inadmissible the Uricchio and De Conto applications, both filed in 2021 by Italian citizens and modelled on the Duarte case.

Denying the concept of extraterritorial jurisdiction and limiting the responsibility of high-emitting States for human rights violations exclusively to victims within their own territory, once again, fails to account for the global nature of the climate crisis and its far-reaching implications for equity and justice.

In KlimaSeniorinnen and Duarte, the ECtHR engaged in a process of abstraction and domestication, severing climate change from its injustices and broader implications (see Heri on this point).

In other words, the Duarte decision seems to implicitly revive the problematic logic from the Banković judgment of a self-contained European espace juridique within which alone human rights violations may be recognized (Heri).

The need for broad standing in climate litigation

AO-32/25 also focuses on access to justice within States parties for the protection of individual and collective interests harmed by climate change. It stresses that the urgency and complexity of the climate crisis require States to apply the pro actione principle and ensure flexible standing requirements (AO-32/25, para. 543).

The IACtHR highlights that many American legal systems allow broad standing for environmental protection through collective, public, or popular actions and that these should also apply to climate litigation. State authorities must adopt or interpret procedural mechanisms to enable such broad access, without requiring proof of individual harm (AO-32/25, para. 549). For claims directed to the protection of individual interests affected by climate change, States may maintain personal standing requirements but must ensure access to justice, also for vulnerable groups and extraterritorial victims (AO-32/25, paras. 550-551).

Beyond  its regional implications, this emphasis on procedural flexibility and collective standing could also be relevant in Europe, particularly in legal systems lacking adequate tools for protecting collective interests.

A large part of the KlimaSeniorinnen judgment addresses the issue of victim status and standing before the ECtHR, establishing an unprecedented distinction between individual applicants and associations. The latter may be granted standing regardless of their status as victims, under permissive criteria (challenging the prohibition of actio popularis within the Convention system). By contrast, admissibility of applications by individuals remains contingent upon recognition of victim status, assessed according to restrictive criteria (KlimaSeniorinnen, paras. 487-494, 502).

Combined with the narrow approach to the Convention’s territorial scope, this excludes protection for individuals – particularly from the Global South – harmed by climate change who do not meet the strict admissibility criteria for individual applications. 

Regarding access to national courts, the ECtHR states that Article 6 § 1 of European Convention on Human Rights does not require the admissibility of actio popularis complaints (KlimaSeniorinnen, para. 631).

Once again, the ECtHR’s solution appears significantly more limited than the far-reaching considerations of the IACtHR. Nevertheless, the Strasbourg Court recognizes the admissibility of actions, at least when brought by associations, aimed at protecting human rights threatened by climate change in cases of insufficient State action on climate change mitigation. Moreover, it emphasizes the key role of domestic courts in climate litigation. Building on this recognition, European judges should ensure broad and effective access to justice in climate-related cases.

To conclude

AO-32/25 represents a landmark development in international climate jurisprudence, particularly due to its explicit and thoughtful engagement with principles of equity and climate justice. Its innovative and inclusive approach offers a compelling model that should also be embraced within the European context. Indeed, the contrasting stance so far adopted by the ECtHR, neglecting the equity dimension and the global nature of the climate crisis, has led to conceptual inconsistencies, notably regarding extraterritorial jurisdiction, standing, and the distributional dimension of States’ climate obligations. Hopefully, the IACtHR’s advisory opinion will help shape the future of climate litigation in Europe and encourage the ECtHR to revise some of its positions in forthcoming cases.