In March 2023, the United Nations General Assembly requested an advisory opinion from the International Court of Justice (ICJ) on states’ responsibilities under international law to protect the climate system for current and future generations. The Court’s Opinion is expected to clarify the content and scope of human rights obligations and their implications for state responsibility. While this may seem unprecedented, regional human rights courts – the European Court of Human Rights (ECtHR) and the Inter-American Court of Human Rights (IACtHR) – have already begun shaping a legal narrative that frames climate change as both an environmental and human rights issue. Their jurisprudence provides critical precedents that the ICJ may draw upon. This post examines how these regional developments might inform the ICJ’s analysis, particularly regarding emerging doctrines of extraterritorial responsibility that aim to integrate environmental and human rights law in addressing the climate crisis.
What the ICJ Has Been Asked to Clarify
The ICJ has been asked to address two critical questions. First, what are states’ obligations under international law to protect the climate and other parts of the environment from greenhouse gas (GHG) emissions for the benefit of both present and future generations? Second, what are the legal consequences under those obligations for states whose actions or omissions cause significant climate harm, particularly to vulnerable states, such as small island developing states, and affected populations, both current and future? These questions are of particular importance because international environmental law has historically lacked effective enforcement mechanisms. Clarifying the role of human rights law could offer individuals a legal tool for demanding stronger climate action. While judicial and quasi-judicial bodies have increasingly recognised that climate change threatens the right to life, health, and culture, it remains unclear what duties states have, especially regarding transboundary harm, and whether individuals can seek redress for such harm from foreign states. Regional jurisprudence is beginning to close these gaps.
Regional Courts Leading the Way
Recent decisions from the European Court of Human Rights (ECtHR) and the Inter-American Court of Human Rights (IACtHR) offer important insights into how international law is evolving to address state responsibility for climate harm. In April 2024, the ECtHR issued three landmark rulings on climate change. While Carême v. France and Duarte Agostinho v. Portugal and 32 Others were dismissed on procedural grounds, KlimaSeniorinnen v. Switzerland marked a breakthrough. The judgment has been widely discussed mainly for three reasons (see here, here and here). First, the Court recognised for the first time that states have positive obligations under the European Convention on Human Rights to protect individuals from foreseeable climate risks (paras. 538-554). It found that Switzerland’s insufficient climate action violated Article 8 of the Convention, which guarantees the right to private and family life (para. 574). Second, the Court developed a framework for identifying climate victims, requiring individuals to face high exposure to climate threats and demonstrate a pressing need for protection (para. 487). Third, the decision clarified the requirements for the standing of associations, drawing on principles established under the Aarhus Convention (para. 501).
A particularly important, but less discussed, aspect of the judgment concerns the Court’s interpretation of state responsibility for GHG emissions under the ECHR. It identified three key elements: attribution, foreseeability, and capacity. First, the Court held that responsibility is not limited to territorial emissions; it includes emissions abroad attributable to the respondent state (para. 280). This covers emissions from international aviation, shipping, imported goods, and financial flows such as investments and loans (paras. 70–71). In addition, the Court noted that Switzerland was aware of the extraterritorial impacts of its policies, citing a study that showed Swiss equity funds were linked to global warming of 4–6°C (para. 71). Finally, the Court emphasised Switzerland’s capacity to adopt more ambitious mitigation measures, as acknowledged by the Government in the same study. Together, these criteria support a framework in which states could, in principle, be held responsible under human rights law not only for environmental harm within their own borders, but also for their contributions to global climate change.
The IACtHR adopted a similarly expansive approach in its 2017 Advisory Opinion on Human Rights and the Environment, reflected in two developments. On the one hand, the Court recognised that the adverse effects of climate change affect the enjoyment of human rights, including the right to a healthy environment (para. 47). It stated that in its collective dimension, this right constitutes a universal value owed to both present and future generations (para. 62). Moreover, as an autonomous right, it protects environmental components – such rivers and seas – as legal interests in themselves, even in the absence of clear evidence of risks to individuals (para. 62). On the other hand, the Court formulated the obligation to prevent significant transboundary environmental harm in human rights terms (para. 102). It held that under the American Convention, states are not only required to refrain from causing transboundary environmental damage but also to protect individuals abroad from domestic activities (para.133). This interpretation departs from the traditional “effective control” model of jurisdiction that has dominated human rights jurisprudence. By focusing on causality and the state’s capacity to prevent environmental harm, regardless of territorial boundaries, this development could have significant implications for the understanding of responsibility in the context of climate change.
While the African Human Rights System has not explicitly addressed extraterritorial environmental responsibility, its collective rights orientation and emphasis on states’ obligations to regulate private actors offer a solid basis for advancing climate accountability.
Extraterritorial Responsibility: From Fragmentation to Convergence?
The principle that states must avoid causing harm beyond their borders is well established in international environmental law. It’s enshrined in the “no-harm” rule, affirmed in the Trail Smelter arbitration (1941) and the Stockholm and Rio Declarations. However, integrating this principle into human rights law has been more fragmented. While the ICJ itself has acknowledged extraterritorial human rights obligations – for instance, in its 2004 Wall advisory opinion – the prevailing standard, which hinges on a state’s effective control over persons, is ill-suited for addressing the complex and diffuse harms posed by climate change.
This is where the evolving jurisprudence of regional courts offers new possibilities. The growing emphasis on foreseeability, attribution and causal contribution reflects a broader and more nuanced interpretation of jurisdiction. Under this emerging approach, legal responsibility may arise even in the absence of territorial or physical control, specifically when emissions linked to a state, including those from third parties under its jurisdiction or control, contribute to global climate harm. This reasoning, grounded in due diligence, is especially relevant to climate change, which is largely driven by a small group of major emitters with both the greatest capacity to mitigate and the most significant historical responsibility.
The Role of the ICJ: Charting a New Legal Paradigm
The ICJ has a unique opportunity to bring coherence to the fragmented legal approaches to state responsibility for climate-related harm. In addressing the first question, the Court could draw on developments in the jurisprudence of both the IACtHR and the ECtHR to clarify the content and scope of human rights obligations in the context of climate change. At the very least, the Court could affirm that international law –including human rights law – applies to state conduct that contributes to climate change, whether emissions occur within a state’s territory or beyond its borders. The preventive nature of these obligations, particularly in relation to the objective of limiting global warming to 1.5°C, positions human rights law as a legal tool not only for reparative justice but also for preventive action.
A more ambitious approach could see the Court ground its opinion in foundational principles of international law, including erga omnes, erga omnes partes, and jus cogens norms. First, the Court could recognise that climate change implicates rights and interests that transcend bilateral state relationships, engaging obligations owed to the international community as a whole. The right to a healthy environment – as affirmed by the IACHR and other international bodies — could support the view that protecting the global climate system constitutes an erga omnes obligation. Where climate harm violates treaties such as the International Covenant on Civil and Political Rights or the International Covenant on Economic, Social and Cultural Rights, state parties may be bound by erga omnes partes obligations owed to all treaty members, regardless of direct injury. Moreover, if environmental protection is deemed essential to safeguarding non-derogable human rights, such as the right to life or the prohibition of inhuman treatment, then grossly inadequate climate action could amount to a breach not just of treaty-based or customary obligations, but of peremptory norms from which no derogation is permitted. This has direct implications for the second question posed to the ICJ: what legal consequences follow from such breaches? The Court could clarify that active contributions to climate change may constitute aggravated violations of international human rights law, thereby clarifying states’ legal exposure and elevating the normative status of climate obligations within international law.