The ICJ’s Advisory Opinion on Obligations of States in respect of Climate Change is one of a string of recent cases which has brought the ICJ to the centre of public discussions of international law (see coverage of proceedings on the BBC, the Guardian, and Forbes), and academic commentators have already noted the significance of the case for procedural rules on the participation of small island developing states and amicus curiae from NGOs, the establishing of obligations erga omnes, and the Court’s use of experts fantômes. In this short post, I want to focus on a different aspect of the Advisory Opinion: namely, its temporal significance, as a decision over when climate change began, how it manifests in our present, and how it will develop in the future.
Time may seem a marginal issue for understanding climate change. Yet across the submissions of the 96 states and 11 international organisations participating in the case, different histories, presents, and future expectations are again and again put before the ICJ to guide its decision. For some states, climate change has a long history, its origins stretching back decades to the emergence of scientific consensus on climate change in the 1960s, or even further back to colonial possession of natural resources and the Industrial Revolution (see, for example, Kenya’s submissions that carbon dioxide emissions should be measured from 1850). This creates a differentiated present: while some states have historically made the largest contributions to climate change, it is others that have been forced to bare its brunt. Accordingly, the history of climate change alters expectations about its future regulation. With the pollution of some states already threatening the existence of others, the ICJ must recognise legal obligations between these states which can halt and rectify the existing damage caused by climate change and restore the right of those states to self-determination over their future (see, among many passing citations by other states, the detailed submissions on self-determination by the Melanesian Spearhead Group, the Republic of Fiji, the Marshall Islands, Papua New Guinea, Kiribati, Liechtenstein, Micronesia, Namibia, Nauru, Palau, Saint Vincent and the Grenadines, Samoa, and Tuvalu).
In contrast, other states see the regulation of climate change as a primarily anticipatory measure, with the only relevant obligations being those designed to prevent global harms in the future. These states downplay the historical inequality of climate change and instead seek to frame its regulation as a collective, global threat, governed exclusively by the climate regime that has arisen over the past three decades (see, for example, Australia’s framing of climate change as ‘the greatest shared threat to all nations’; Russia’s statement that ‘[g]lobal challenges require global solutions’, with climate change obligations existing ‘exclusively’ within the framework of the UNFCCC and excluding treaties ‘adopted long before the global problem of climate change was recognized by science and the international community’; and the submissions of the USA, discussed below). Repositioned in this way, historic obligations between states are deprioritised, with climate change characterised as a ‘novel’ challenge with no legal precedent. Compare, for example, the treatment of transboundary harm between these two types of state: Australia characterises the cumulative, global build-up of greenhouses gases over a large period of time as presenting ‘novel challenges in applying the requirement of causation’ for transboundary harm; while the Melanesian Spearhead Group states that:
‘[m]ajor emitters and producers…have tried to hide behind the enormity of the problem, overstating the complexity of the legal question…if an isolated incident of transboundary pollution is unlawful, it is unthinkable that the ultimate form of pollution is not’.
The task facing the ICJ, then, is not merely to establish which legal obligations apply to a discrete set of facts, but rather to harmonise a single global time of climate change, privileging certain pasts, presents, and futures while discarding others as legally irrelevant. Set out in this way, this sounds like a lofty question—but international law regularly deals with time. The formation of customary international law, the entry into force and changing interpretation of treaties in line with subsequent agreements and subsequent practice, the doctrine of intertemporal law—all of these rules regularly enact and reproduce the kinds of time law is able to see. Understanding how the ICJ will apply these rules to climate change, and how this will produce a ‘time’ of climate change separate from, say, the quantitative measurements of science or moral and ethical questions of global and generational solidarity, helps make visible the distinct and ever-present relationship between law and time generally.
In the interests of word count, this post will focus on two oral submissions—those of the Republic of Vanuatu, which opened the proceedings, and those of the USA, which have received special criticism from climate justice campaigners—to demonstrate the distinct temporal frames upon which each state’s legal arguments rest. By focusing on the different timescales these two states put forward in their oral submissions, the post aims to make visible the ways in which time structures the operation of international law, and in turn calls for a wider reckoning with international law’s complex relationship with time.
Contesting Law through Time
The opening statement by the Republic of Vanuatu (2 December 2024, Verbatim record 2024/35, pages 96-99—all square brackets below refer to specific paragraph numbers) rests on a large timescale. Beginning in the past, Vanuatu casts climate change as an existential threat to its people’s history, one which will destroy ‘vibrant cultures and traditions [built] over millennia’ [2]. Indeed, this existential threat can be expected because climate change ‘has already resulted in injury to Vanuatu’ [3], positioning climate change as a historical process already shaping Vanuatu’s present. The present that has brought forth this Advisory Opinion, then, is cast in wide terms, as a continuous series of harms which have only intensified in recent years. The emergence of new, climate-specific treaties are only part of ‘a range of international obligations’ which should always have rendered unlawful the conduct which has caused climate change [5]. The recent intensification of these harms, with ‘[m]ore than half of all CO2 emissions since 1750…emitted after 1990’, are merely continuous with the failure of states ‘for over a century, despite increasingly dire warnings, to rein in the emissions from their territories’. [4]. ‘Whatever the time frame’, Vanuatu makes clear, ‘there is no excuse’. [4]
Framing climate change in this way makes clear that the contributions of individual states to climate change have not been equal. On one side are ‘a handful of readily identifiable States [that] have produced the vast majority of historic and current greenhouse gas emissions’; on the other are ‘countries, including [Vanuatu], [that] are suffering the brunt of the consequences’ [4]. In this light, the future significance of the Advisory Opinion is equally differentiated, with the Advisory Opinion vital to both ‘the fate of nations like [Vanuatu] and the future of our planet’ [2]. In maintaining this separation between the specific, imminent fate of nations like Vanuatu and the longer future of mankind as a whole, the universal significance of the Advisory Opinion cannot erase the historical inequalities that have produced it. Closing its submissions, Vanuatu is clear: ‘this may well be the most consequential case in the history of humanity. Let us not allow future generations to look back and wonder why the cause of their doom was condoned’ [8]. Latent here is a separation between generations. While all of humanity has a stake in the outcome of this case, some generations will be doomed far sooner than others.
Compare this to the oral submissions of the USA (4 December 2024, Verbatim Record 2024/40, pages 39-51). Here, the request for an Advisory Opinion is cast as ‘a forward-looking response to guide the General Assembly and United Nations Member States on their future conduct’ [34]. As a consequence, climate change’s harms are projected into the future, to be measured against recently-set climate goals—to ‘keep 1.5°C within reach, to achieve global net-zero emissions by 2050, and to avoid the most catastrophic impacts of the climate crisis’ [4]. In this light, climate change is not the product of long-standing violations of international law, as Vanuatu contends, but should be governed only by the more recent climate regime, a novel response ‘collectively designed…to deal with this uniquely complex global problem in a co-operative manner’ [3]. Although the USA’s written observations consider the history of this regime [12], the oral submissions focus exclusively on the 2015 Paris Agreement, foreshortening questions of responsibility for climate change to less than a decade, and with particular emphasis on the Paris Agreement’s ‘“ambition mechanism”, an iterative, five-year process that drives progressively ambitious climate action over time’ [18]—a process which has so far completed only one cycle, in December 2023. On the question of other obligations which might widen the breadth of the ICJ’s consideration, such as the existence of an obligation under customary international law, international human rights law, or the laws of state responsibility for internationally wrongful acts, the USA rejects their application to climate change [22–47].
As such, the task for the ICJ is clear: the Advisory Opinion provides the Court with:
‘an opportunity to reinforce the ongoing negotiations in the UN climate change régime, including the Paris Agreement’s ambition mechanism…by affirming the centrality of States’ obligations, properly understood, under this régime. It is the collective efforts of States through this régime that provide the best means for protecting the climate system for the benefit of present and future generations.’ [50]
In comparison to Vanuatu’s submissions, which maintain differentiated notions of the pasts and futures of different states, the USA anchors its argument around a present collective decision to create a modern climate change regime, erasing the temporal differences between states. The Paris Agreement, for example, ‘requires each party—regardless of its development status—to prepare, submit and maintain successive “nationally determined contributions”…to climate change mitigation’ [13, emphasis original]. As such, historical inequality in development is rendered invisible. By shortening the past and the future of the Advisory Opinion, climate change is rendered as ‘the quintessential collective action problem…[requiring] global action and co-operation by all States’ [3].
Law, Time, and Synchronisation
What insight does a focus on time produce? Comparing the submissions of Vanuatu and the USA, we can see how time enacts very different understandings of climate change, not only centring on different obligations—long-standing rules of customary international law versus recent treaty regimes—but also different responsibilities—Vanuatu’s differentiated historical contributions and existential risks versus the USA’s singular, global present and future. In sum, the notions of time that underpin each submission produce very different legal outcomes.
Over the past three decades, international lawyers have become slowly aware of time as a key component of legal argument. In a 1996 speech, Judge Rosalyn Higgins expressed a ‘general fascination’ with law and time, noting that international law is frequently called upon to make difficult legal and political judgments when determining, say, the jurisdictional limits of a treaty or the retrospective application of amnesty laws in cases of crimes against humanity. Looking back, the question of intergenerational justice has already been debated in environmental law circles since the late-1980s, and more recently Anne Orford and others have called for international law to reckon with its ability to make ‘meaning move across time’, in turn situating international legal history as a vital political intervention in the present.
Despite this growing acknowledgement of international law’s temporal dimensions, the discipline’s understanding of time remains underdeveloped (although see Andrea Gattini and Marco Dimetto’s edited collection on Time and International Adjudication, published just last month, which pursues an approach similar to the one here). If we think of time as merely one indeterminate aspect among many within international legal argument, there is a suggestion that times can be selected strategically, with the right history picked for the right (legal) future. Yet Vanuatu’s submissions make clear that time is a much more significant concept. Vanuatu’s ‘vibrant cultures and traditions’ are ‘intimately [intertwined] with our ancestral lands and seas’ [2], and so the destruction that climate change threatens can only be understood on the scale of centuries, not decades. To downplay this historical span, and argue its case on the terms of the modern climate regime described by the USA, would fundamentally alter the significance of the Advisory Opinion for Vanuatu and other island states. The temporalities put forward by Vanuatu and the USA, then, are not merely competing legal arguments, able to be swapped out and recombined like competing lines of caselaw, but fundamentally incompatible understandings of time that guide the type of legal arguments they are able to make.
As anthropologists, sociologists, historians, and cultural theorists have long argued, people’s experience of time has deep significance, simultaneously shaping and shaped by the social, political, cultural, moral, religious, and economic contexts in which they live. In this light, the ICJ’s Advisory Opinion takes on a new significance. Faced with conflicting times, the ICJ will be called upon to decide which pasts, presents, and futures are relevant to international law, and which lie outside its domain. That makes understanding the temporal work of international law all the more pressing. As historians Helge Jordheim and Espen Ytreberg have recently written, the harmonisation—or ‘synchronisation’, in their phrasing—of conflicting temporalities is a highly political question, ‘deeply implicated in the business of imposing discipline and distributing scarce resources’. Following their lead, we should reflect on the Advisory Opinion as not merely the setting out of legal obligations, but also a wider site of synchronisation, conducted through doctrines not necessarily designed for this purpose. Reckoning with which time we want the ICJ to recognize, then, and the flexibility of our existing doctrines to affirm that time within international law, is a vitally important task for the present.
