Introduction
On 23 July 2025, the ICJ delivered its unanimous advisory opinion on the Obligations of States in respect of Climate Change, recognising the legally binding obligations of States regarding climate change. Yet, the opinion leaves a critical gap. The ICJ’s overly cautious stance has resulted in missed opportunities: what could have been a landmark in climate justice instead offers limited legal protection, with consequences that may be far more severe than they first appear, especially for the Global South. This blog argues that the ICJ’s failure to define the temporal scope stems from flawed reasoning that has far-reaching impacts on the Global South. Moreover, it offers insights into the attribution of historical emissions.
The Limits of the ICJ’s Opinion: What Was Left on the Table
While examining the scope of the questions posed by the UNGA in resolution 77/276, the Court sought to clarify the scope —territorial, temporal, and material—applying the standard set in the Advisory Opinion of 19 July 2024 (para 284). The Court observed that there is no territorial bar to the questions (para 96) and considered ‘all actions or omissions by the state that contribute to the full range of human activities that contribute to climate change as a result of the emission of greenhouse gases [GHGs], including both consumption and production activities’ to fall under the material scope of the question (para 95).
The ICJ’s definition of temporal scope is based on flawed reasoning. The Court regarded temporal scope-setting as falling outside the ambit of the questions posed and relevant only for an in concreto assessment, on the basis the questions did not involve the invocation of responsibility for specific States (para 97). However, the Court erred in conflating two distinct issues: the in concreto assessment which involves identifying the precise moment a pre-existing legal obligation is violated by a specific State or group of States, grounded in detailed evidence; and the broader question of the temporal scope of the legal obligations referred to in Question (A), namely the period in which the relevant legal obligations were applicable. The latter is fundamental for attributing historical emissions as an internationally wrongful act, relevant for Question (B).
The task entrusted to the Court went beyond merely stating the obligations concerning climate change; it also included assessing the legal consequences arising from the obligations. In this assessment, the court identified three key legal consequences: obligations of cessation, non-repetition, and reparation (para 445). The Court further noted that breaches of States’ obligations do not affect the continued duty of the responsible State to perform the obligation breached (para 445). However, this assessment is significantly undermined by failing to define the temporal scope of those obligations. Without clarity on when an obligation applies, its legal consequences cannot be meaningfully assessed.
The Court rightly held that GHG emissions, by themselves, do not constitute an internationally wrongful act; rather, it is the violation of the conventional and customary obligations that trigger State responsibility (para 427). The Court unfortunately overlooked the fact that conventional obligations only became applicable from 1992 onwards, and even customary obligations relevant to GHG emissions were not clearly recognised until the late 1980s. GHG emissions, by contrast, have occurred since the pre-industrial era. According to the IPCC, approximately 58 per cent of total historical emissions occurred between 1850 and 1989—a period during which the Court failed to identify any binding legal obligations (Para B.1.3).
Customary obligations to prevent harm were recognised in the Trail Smelter arbitration, as early as the 1940s. Yet to what extent can a customary rule bind States when, at the time, there was no awareness that GHG emissions by themselves were responsible for harming the environment? The duty regarding GHG emissions, as noted separately by Judge Nolte (para 23), was only recognised in the latter part of 1980 with UNGA Resolution 43/53.
While some contemporary commentary reads the ICJ opinion as affirming that historic responsibility will be recognised—whether on the basis that past emissions can now be measured scientifically, or through its discussion of the Kyoto Protocol and Paris Agreement—both interpretations overstate the Court’s position. The Court merely observed that past emissions can be measured scientifically (para 429), failing to address the question of legal accountability. Interpretations stemming from the Court’s discussion of the Kyoto Protocol and Paris Agreement still only address post-1992 emissions, offering no assurance regarding historical emissions. This omission reflects the Court’s cursory handling of causation, offering only a general standard while avoiding the complex issues posed by multiple contributing factors and omissions. The determination of the general scope of the applicable legal regime could—and should—have addressed these as purely legal issues.
Regrettably, the Court missed a significant opportunity to explicitly invoke the precautionary approach as a basis for extending legal liability. However, by incorporating the precautionary approach within the broader customary duty of due diligence, the Court offers limited relief (para 294). This framing potentially allows States to extend liability in periods where scientific certainty about the harm caused by GHG emissions was lacking.
By failing to clarify the temporal scope of legal consequences in Question B, the Court left questions such as attribution of historical emissions unresolved, which undermines the opinion’s contribution to climate justice and accountability.
The Court’s Silence on Retroactive Liability
One of the most significant legal questions the ICJ sidestepped was whether historic GHG emissions can give rise to State responsibility today. By refusing to define the temporal scope of climate-related obligations, the Court effectively excluded the crucial issue of retroactive liability—an omission that substantially weakens the opinion’s legal weight, particularly for climate justice for the Global South.
The principle of non-retroactivity has not been definitively recognised as a general principle of law, or an established customary rule. While Article 28 of the Vienna Convention on the Law of Treaties (VLCT) codifies this principle in the treaty context, a similar logic appears in Article 13 of the ILC’s Articles on State Responsibility (ARSIWA) through the doctrine of intertemporal law, since juridical facts can only be assessed with the law contemporary to it, and not the law (not restricted to treaty) at the time when the dispute arises.
Some States raised arguments about non-retroactivity in the advisory opinion hearings (see e.g. USA (para 5.4), Canada (para 32), France (para 186)). Presented with the opportunity to clarify the non-derogable nature of this principle in light of historic emissions (para 97), the Court remained silent. As such, the issueremains effectively untested, and in the meantime, the ICJ’s silence may imply that historical emissions cannot trigger State responsibility, as no obligation—treaty or otherwise—existed at the time.
GHG emissions can be characterised as a composite wrongful act, as argued by various states, including Vanuatu (para 530-535) and Albania (para 130); this posits that a series of actions or omissions, can be defined in the aggregate as wrongful.. GHG emissions since the pre-industrial period, taken collectively, have driven the current climate crisis, with impacts from centuries ago still being felt. This legal characterisation opens an alternative avenue for attributing responsibility to historical emitters. International investment cases applying the rules of the VCLT may be able to assist. For example, in Société Générale v Dominican Republic the LCIA arbitral tribunal held that where conduct spans both before and after a treaty’s critical date, non-retroactivity does not bar attribution (para 88). Applying that principle to the climate regime would catch emissions that began before the UNFCCC regime but continued after 1992. But, as above, the Court was did not answer this particular legal question.
Beyond doctrinal analysis, the ICJ also declined to engage with a deeper normative issue. Scholars such as Lauterpacht have argued that an ‘irresistible need for justice’ may justify derogations from strict non-retroactivity. Climate change is precisely such a case. Without attributing historical emissions, those most responsible will evade liability, while specially affected States in the Global South continue to suffer disproportionate harm for a crisis they did not create (on the irrelevance of specially affectation for legal consequences, see advisory opinion, para 110, which treated disproportionate harm as a matter for primary rules rather than for legal consequences).
Admittedly, applying this reasoning would push the boundaries of existing international legal interpretation. But climate change is an unprecedented global crisis, indeed, as the Court recognised (para 421). No other legal issue has affected as many people, with such stark asymmetries in responsibility and harm. Cautious, incremental interpretation may suit ordinary disputes—but climate change demands more.
Implications for the Global South
The Court’s failure to define the temporal scope of obligations disproportionately affects the Global South. The Global North, including countries such as the USA, Germany and other industrialised nations, had been the major emitters of GHG before the 1980s, a period during which the ICJ identified no binding legal obligation. This historical gap could be exploited under the doctrine of intertemporal law, as articulated in the Island of Palmas case: ‘A juridical fact must be appreciated in the light of the law contemporary with it, and not of the law in force at the time when a dispute in regard to it arises or falls to be settled’. Without temporal clarity, the ICJ leaves open a loophole through which developed Global North states could evade accountability for their historic emissions.
In contrast, developing countries such as India significantly increased their emissions only after the UNFCCC was adopted, as part of their development, while developed countries have since reduced emissions to a certain extent through access to cleaner technologies and policy changes—having already benefited from decades of unrestricted emissions. In any future proceedings, developing nations may face the dual burden of demonstrating that historical emissions by Global North States constitute internationally wrongful acts, while also justifying their own current emissions.
Compensation from such proceedings could be pivotal for climate adaptation efforts in the Global South (para 39). However, the limits of the advisory process mean that the burden of proof of the Global North’s climate harm lies with Global South. The legal clarity achieved is not as clear as it looks, and may undermine the Global South’s quest for climate justice. In refusing to define when obligations began—and sidestepping related questions—the ICJ handed the Global South a promise of climate accountability, while giving the Global North a legal escape route that undermines accountability for climate harm.
Conclusion
In sum, the ICJ’s failure to define the temporal scope of climate obligations presents a significant lacuna that allows the Global North to evade responsibility. In declining to engage with the attribution of historical emissions, the Court missed a critical opportunity to lay the groundwork for climate accountability. An examination of the principle of non-retroactivity, at a doctrinal level, could have clarified the question of attribution in regard to climate change. As a result of this oversight, the Global South may once again find itself bearing the burdens of a crisis it did not cause.
Subhiksha S K is a third-year undergraduate law student at Hidayatullah National Law University, Raipur.