The ICJ Advisory Opinion of 23 July 2025 on states’ obligations in respect of climate change is, for many reasons, pathbreaking. Some of such features pertain to international human rights law. Ramindo Perera discussed one aspect, the ICJ’s recognition of the right to a clean and healthy environment as a ‘new’ human right. Here, I am seeking to highlight an important contribution made by the ICJ in relation to a ‘classic’ human right, namely the right to life.

One small paragraph in the Advisory Opinion reads:

378. The Court considers that conditions resulting from climate change which are likely to endanger the lives of individuals may lead them to seek safety in another country or prevent them from returning to their own. In the view of the Court, States have obligations under the principle of non-refoulement where there are substantial grounds for believing that there is a real risk of irreparable harm to the right to life in breach of Article 6 of the ICCPR if individuals are returned to their country of origin (see Human Rights Committee, Teitiota v. New Zealand, 24 October 2019, UN doc. CCPR/C/127/D/2728/2016, para. 9.11).

We can expect this paragraph to be quoted before domestic courts and tribunals, regional human rights courts and UN human rights treaty bodies, other international judicial or quasi-judicial institutions, and of course in academic and political discourse. Issues of non-refoulement and people fleeing climate change are major themes in human rights debates and litigation, and will be even more so in years and decades to come, unfortunately with accelerating pace. If what the ICJ said will be taken, as it should, as an authoritative pronouncement concerning the status of international law and states’ obligations under it, then paragraph 378 alone will be a game-changer.

Let us remember that in Teitiota, cited by the ICJ, the answer given by the Human Rights Committee under Article 6 of the ICCPR was: ‘not yet’. The complainant, Ioane Teitiota had been denied refugee status in New Zealand and was deported back to Kiribati where the preconditions of human society were threatened by sea level rise. In a submission of December 2016, he asserted that Kiribati was losing land mass and ‘can be expected to survive as a country for 10 to 15 more years’ (para. 7.2). This phrase was picked up by the Human Rights Committee which accepted the complainant’s claim that sea level rise was likely to render Kiribati uninhabitable, but then continued: ‘However, it notes that the time frame of 10 to 15 years, as suggested by the author, could allow for intervening acts by Kiribati, with the assistance of the international community, to take affirmative measures to protect and, where necessary, relocate its population.’ Hence, there had been no violation of ICCPR Article 6 – as of October 2019 when the case was decided.

Since Teitiota, the reference to ’10 to 15 years’ has become a mantra repeated in many subsequent decisions or debates, including by the Human Rights Committee itself in Billy (para. 8.7), another landmark case on human rights and climate change, also cited by the ICJ.

Notably, there is no reference to ’10 to 15 years’ or the ‘not yet’ assumption in the ICJ’s Advisory Opinion. Instead, paragraph 378 is written in the present tense: ‘… States have obligations under the principle of non-refoulement…’ (emphasis added). The reason for dropping the ‘not yet’ phrase is simple: almost ten years have very soon passed since Teitiota’s counsel presented the argument in December 2016 (see, also, para. 16 of my Expert Report, submitted by Vanuatu to the ICJ). While the ICJ, of course, did not address the factual situation in Kiribati or any other territory faced with sea-level rise, it established a standard for a state obligation of non-refoulement when ‘there are substantial grounds for believing that there is a real risk of irreparable harm to the right to life’ in a person’s country of origin because of climate change.

Another remarkable aspect of the ICJ’s Advisory Opinion is that the reference to non-refoulement is made directly under international human rights law and ICCPR Article 6, with no reference to the Refugee Convention or its caveats and delimitations. The word ‘refugee’ does not even appear in the Opinion. There need not be a discussion on whether people fleeing climate change are ‘refugees’, as the state obligation of non-refoulement is triggered by their place of origin having become unsuitable for human life.

Let’s face it: The ICJ has affirmed the phenomenon often referred to as ‘climate refugees’ as a factual situation that triggers a state obligation of non-refoulement as a legal consequence under ICCPR Article 6 and public international law. The scope of that obligation, however, was not determined by the ICJ. In a prospective timeframe of some decades, hundreds of millions of people may be entitled to protection under the principle of non-refoulement if they physically make it into the jurisdiction of another state. There will be two major factual challenges: to reach the jurisdiction of another state, and to demonstrate that there are substantial grounds for believing that there is a real risk of irreparable harm to the right to life in one’s place of origin. What comes to the law, the ICJ Opinion will be relied upon as authority. Scope will nevertheless remain for debate on what counts as such irreparable harm, for instance in respect of the notion of ‘life with dignity’ flagged by the Human Rights Committee in its General Comment No. 36 (para. 3, as compared to para. 30).

Those who think that migration by and resettlement of hundreds of millions of people fleeing climate change is ‘unrealistic’ need to ask what, then, is ‘realistic’: not an unprecedented bloodbath at the coasts and other borders of potential receiving states, but a global commitment, mobilisation and investment in climate change mitigation and adaptation. Planned resettlement schemes, such as the one agreed between Australia and Tuvalu, will be one part of the package. Urgent and massive measures to mitigate and stop GHG emissions, so as to give a part of the people threatened by climate change a possibility to stay where they are, is another. And helping peoples, communities and individuals to adapt their lives, livelihoods and cultures to the new realities of climate change is a third one, and of particular relevance to indigenous peoples or similarly situated communities whose culture is so intimately tied to a specific geographical location that relocation will be a measure of last resort and everything possible should be made to enable them to live a life with dignity on their traditional lands. Here, the Billy case remains highly instructive.