The ICJ’s Advisory Opinion on Climate Change - A Compensation for Climate Justice?
- Alden Lee
- 3 days ago
- 9 min read
Cover image by Lyn Pei
*This article is published in collaboration with Doomscroll Diplomacy, your next one-stop platform for all things foreign affairs. Check out Doomscroll Diplomacy's telegram channel here.
Amidst the flurry of politico-legal opinions by the International Tribunal on the Law of the Seas (“ITLOS”), the Inter-American Court of Human Rights (“IACHR”) and the European Court of Human Rights (“ECHR”), climate activists and commentators alike have lauded these milestones as turning points in our pursuit of climate justice. While small island developing states have historically suffered the brunt of climate change and the asymmetries of our “rules-based order” as enshrined in the United Nations (“UN”) Charter, they have demonstrated their autonomy in exercising their legal statecraft to achieve their national interests. For submerging states like Tuvalu which is threatened to be the world’s first Digital Nation that calls into question its legal personality and territorial integrity, such interests are of existential imperatives (Yeo, 2024).
Therefore, as a legal declaration by the highest judicial organ of the UN, is the International Court of Justice’s (“ICJ”) Advisory Opinion a victory for our climate and small states or a mere compensation for climate justice at best?
ICJ’s Advisory Opinion as a Legal Instrument
In our international legal system, the Advisory Opinion can be perceived largely in two ways: As a legal instrument for textual interpretation, or as an embodiment of customary norms that demand universal adherence. As a written document, it will be intuitive to first examine the legal implications of the opinion as a legal instrument.
When the request for the Advisory Opinion was submitted to the ICJ, the outcome was never going to be legally-binding on any states. With the increased geopoliticisation of international courts which are pressured to pronounce legal judgements upon fundamentally political questions, the Advisory Opinion has to accommodate the sensitivities of states to the thorny issue of climate change in ensuring compliance, especially from the bigger powers who are instrumental in driving multilateral efforts but ironically contribute the most to our climate crisis and are gradually retreating from this global effort (Odermatt, 2025).
The United States under the Trump administration is a case in point as he once again withdraws the country from the Paris Agreement - a cornerstone of our climate regime.
While Article 96 of the UN Charter confers upon the UNGA with the power to “request the International Court of Justice to give an advisory opinion on any legal question” (Charter of the United Nations, 1945, Art. 96), what is not as evident is the fact that unlike the court’s contentious jurisdiction, the Advisory Opinion is inherently constrained by the questions posed to it.
In fact, the court is unable to comment even on related issues if they were not intended for in the original request, including the aforementioned which highlights the Advisory Opinion’s failure in attributing the individual and collective culpability of states for their damages caused to our climate ecosystem (Odermatt, 2025). To ensure that its provisions remain palatable to states, it was further drafted in an abstracted and generalised manner. But for proponents of Living Constitutionalism, this approach does allow space for future enunciation and interpretation of the obligations that it imposes to safeguard its relevance amidst the ever-evolving climate situation.
Yet, one will be mistaken to conclude that the Advisory Opinion’s unwillingness to engage with the central questions of state attribution and subsequent reparation means that it is impossible for any climate framework to hold states commensurately accountable for their actions. One of its notable progressive elements is its recognition that “it is scientifically possible to determine each State’s total contribution to global emissions, taking into account both historical and current emissions” (Obligations of States in respect of Climate Change, 2025, para. 429).
Building upon the agreement to establish the Loss and Damages Fund at the 29th Conference of Parties (“COP”), this aspirational formulation is significant in taking the first step towards operationalising such climate funds, which systemically shifts the past regime of voluntary climate financing to a legal commitment to make financial compensation for the harmful impacts that states caused (Dunne et al., 2025).
This transition from voluntary to justiciable legal obligations is underpinned by a doctrinal affirmation that all states are simultaneously bounded by specific climate agreements, such as the UN Framework Convention on Climate Change (UNFCCC), as well as the “general principles of law” (Statute of the International Court of Justice, 1945, Art. 38(c)), as long as the climate treaties do not explicitly exclude such general obligations.
Primary GHG emitters have perennially claimed under the principle of lex specialis that they are only subjected to the specific climate agreements that they have ratified, which supersedes any general obligations owed to protect the environment. The Advisory Opinion has crucially dismissed this submission that narrowly defined climate instruments absolve states from their broader commitments under international law (Dunne et al., 2025). This avoids the Free Rider Problem of “developing” states stepping back from their responsibilities for other countries to pick up their slack.
As such, despite its non-binding character, as a soft-law instrument, the Advisory Opinion is able to leverage the institutional legitimacy of the ICJ and its deliberative process of receiving states’ oral and written submissions on this issue to apply great public pressure on states to comply with their climate obligations. It further value-adds to the often misconstrued principle of Common But Differentiated Responsibility (“CBDR”) - as a facade for developing states to hide behind their “diminished responsibility”.
Instead, the Advisory Opinion recognised that any country’s development status is temporal and their climate obligations should be determined in relation to their present national circumstances (Dunne et al., 2025). This avoids the Free Rider Problem of “developing” states stepping back from their responsibilities for other countries to pick up their slack.
The process of deductively determining the specific extent of harm caused and restitution due for each state still remains complex and daunting. This is even before the question of the legality of such retroactive application of reparation obligations comes into the forefront.
Nevertheless, we are hopeful that the Advisory Opinion is able to empower climate activists, national governments and courts to invoke its authoritative language in climate litigation proceedings in order to hold states accountable for the material breaches of their climate obligations (Wewerinke-Singh, 2025).
ICJ’s Advisory Opinion on Customary Norms
The Advisory Opinion can also be understood as an embodiment of customary norms that prescribe state’s behaviour and obligations to the climate. While the existing body of customary norms under international environmental law is rich and self-reinforcing, the Advisory Opinion goes a step further in recognising the interdependency of climate responsibilities with the sanctity of human rights (Wewerinke-Singh, 2025).
As the climate challenge becomes increasingly complex, it is inextricably connected with issues of human rights. As our environment deteriorates, our rights to the natural resources that it provides are undermined. This impairs other rights that are dependent on our access to a clean, healthy and sustainable environment.
Yet, the regimes of international human rights and environmental law have developed in parallel to one another, with minimal crossroads which acknowledge that a sustainable climate is a human right that is indispensable for the existence of other rights. The Advisory Opinion can thus be said to bring both systems of law closer to one another.
Against the fragmentation of our international legal order, the Advisory Opinion critically promotes the principles of harmonious interpretation and systemic integration to be at the heart of our climate regime - that is to give effect to every climate and human rights provisions that are not mutually excluding nor fundamentally irreconcilable and to take into account every relevant rule of international law in addressing our climate challenge (Wewerinke-Singh, 2025).
But does this merely serve an interpretative function than a substantive one that truly delivers climate justice?
The Advisory Opinion still fell short of explicitly affirming the customary nature of “the right to a clean, healthy and sustainable environment” (Odermatt, 2025).
At most, it recognised “that, under international law, the human right to a clean, healthy and sustainable environment is essential for the enjoyment of other human rights” without asserting the normative status of this right that all states are required to guarantee as “a precondition for the enjoyment of many human rights, such as the right to life, the right to health and the right to an adequate standard of living, including access to water, food and housing” (Obligations of States in respect of Climate Change, 2025).
Furthermore, to the degree that it added nuance to the principle of CBDR as previously mentioned, it failed to explicitly endorse the customary nature of the principle of equity embedded within to take a bolder step towards climate justice (Wewerinke-Singh, 2025).
As a manifestation of customary norms, the Advisory Opinion has reaffirmed the customary duty of states to exercise due diligence in their efforts toward climate adaptation beyond mitigation, by advancing the obligation to regulate the activities of private actors in ensuring a coordinated public-private effort in addressing climate change (Schaugg et al., 2025). While we saw the endorsement of human rights and equity norms, it remains to be seen whether the opinion can foster them as customary norms through its influence over state practice.
Looking Ahead: Beyond the ICJ’s Advisory Opinion
Arguably, the Advisory Opinion’s most monumental contribution to the progressive development of our climate regime was to bridge the past with the present in order to lay the foundations for the future. Since the International Law Commission’s (“ILC”) Articles on State Responsibility for Intentionally Wrongful Acts back in 2001, there was never a link drawn between state responsibility and climate obligations despite the scientific evidence clearly indicating the primary responsibility of state actors in contributing to the degradation of our environment.
The Advisory Opinion finally plugs this gap by affirming that state responsibility is applicable to the context of climate change, laying the legal grounds for the jurisprudence of climate reparations to develop (Reetz, 2025).
So does the Advisory Opinion achieve the elusive ideal of climate justice? Without being able to overcome its intrinsic political framework where its legal principles bend around geopolitical considerations, climate justice will never be realised as disparities and inequity are allowed to persist between major emitters and small states.
As a youth advocate, intergenerational equity is the most pressing concern pertaining to how we tackle climate change today in a way that accounts for the interests of and preserves our future generations. It is hopeful that the Advisory Opinion has moved to incorporate this and the importance of sustainable development into the corpus juris that governs our climate, but there is still room to specify how reparations can be made for marginalised youths threatened by our environment.
Moving forward, with avenues for future elaborations and interpretations of the Advisory Opinion, the ICJ and regional/domestic courts should seize the opportunity and the moral weight of the opinion, as both a legal instrument and an embodiment of customary norms, to identify states who are violating their environmental obligations, spell out the specific acts and omissions and enforce the resulting state reparations to uphold the rule of law (Odermatt, 2025). This is especially for prima facie breaches such as a failure to set in good faith ambitious NDCs or to sufficiently regulate GHG emissions.
As more states increasingly accept the pervasive authority of the Advisory Opinion and align their practice with our overarching climate objectives, there are reasons to be optimistic that such climate obligations can finally morph into peremptory norms (“jus cogens”) that demand the strictest compliance from states - a feat long achieved by our nuclear and non use-of-force regimes.
It is about time that climate justice receives the same treatment as we navigate the “polycrisis” of our time…
References
Charter of the United Nations, 1945, Art. 96.
Dunne, D., Gabbattis, J. and Lempriere, M. (2025) ICJ: What the World Court’s landmark opinion means for climate change, Carbon Brief. Available at: https://www.carbonbrief.org/icj-what-the-world-courts-landmark-opinion-means-for-climate-change/ (Accessed: 02 November 2025).
Odermatt, J. (2025) What the Court didn’t say, Verfassungsblog. Available at: https://verfassungsblog.de/what-the-court-didnt-say/ (Accessed: 02 November 2025).
Obligations of States in respect of Climate Change (Advisory Opinion) (International Court of Justice, General List No. 187, 23 July 2025).
Reetz, N.S. (2025) State responsibility and the ICJ’s advisory opinion on Climate Change, Verfassungsblog. Available at: https://verfassungsblog.de/state-responsibility-and-the-icjs-advisory-opinion-on-climate-change/ (Accessed: 02 November 2025).
Schaugg, L., Jones, N. and Qi, J. (2025) Historic International Court of Justice Opinion confirms states’ climate obligations | International Institute for Sustainable Development, Historic International Court of Justice Opinion Confirms States’ Climate Obligations. Available at: https://www.iisd.org/articles/deep-dive/icj-advisory-opinion-climate-change (Accessed: 02 November 2025).
Sefeti, S. (2025) ‘we were heard’: The Pacific students who took their climate fight to the ICJ – and won, The Guardian. Available at: https://www.theguardian.com/world/2025/jul/25/pacific-students-who-won-climate-case-icj-international-court-of-justice-hague (Accessed: 02 November 2025).
Statute of the International Court of Justice, 1945, Art. 38.
Wewerinke-Singh, M. (2025) Harmonizing sources, hardening duties – inside the ICJ’s advisory opinion on Climate Change, Climate Law Blog. Available at: https://blogs.law.columbia.edu/climatechange/2025/08/11/harmonizing-sources-hardening-duties-inside-the-icjs-advisory-opinion-on-climate-change/ (Accessed: 02 November 2025).
Yeo, S. (2024) Tuvalu: The Disappearing Island nation recreating itself in the metaverse, BBC News. Available at: https://www.bbc.com/future/article/20241121-tuvalu-the-pacific-islands-creating-a-digital-nation-in-the-metaverse-due-to-climate-change (Accessed: 02 November 2025).
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