I. Introduction
A fundamental and widely recognized inequity at the core of the existential climate crisis facing the planet today is that those who have contributed the least to climate change are also the most affected. The United States, European Union-28, Russia, Japan, and Canada, according to some accounts, are together responsible for 85 percent of global greenhouse gases (GHG) emissions thus far.Footnote 1 Yet it is the climate vulnerable—least developed countries, low lying, and small island states among others—that are at the frontlines of climate impacts. There is widespread scientific and diplomatic consensus on the multiple causes and devastating impacts of climate change but so far justice for vulnerable states has proven elusive.
States on the frontlines of climate impactsFootnote 2 have advanced claims for climate justice in the United Nations (UN) climate regime, as well as more recently in the International Court of Justice (ICJ). Their claims have taken different forms across negotiating and dispute settlement fora but across these fora international legal doctrine has presented a formidable challenge.
This Article focuses on the claims of vulnerable states for climate justice—and reparations within that broader claim—against major emitting states.Footnote 3 It explores their claims in the UN climate regime—comprising the 1992 UN Framework Convention on Climate Change (UNFCCC),Footnote 4 the 1997 Kyoto Protocol,Footnote 5 and the 2015 Paris AgreementFootnote 6 —for the last three decades, as well as more recently before the ICJ. It traces the arc of the legal narrative that major emitters have deployed to avoid claims for reparations from vulnerable states. It tests and challenges that narrative and the formalistic vision of international law in which the narrative is embedded, and offers an alternative purpose-driven, progressive, and emancipatory approach to international law that is better tailored to address global existential challenges and deliver the glimmerings of climate justice.
This Article uses the categories of “major-emitting states”Footnote 7 and “vulnerable states”Footnote 8 because these better reflect the politics of climate justice and reparations compared to the categories of “developed” and “developing” states,Footnote 9 given some developing states have emerged as major emitters. There are neither multilaterally agreed lists or definitions of states in these categories, nor are these watertight categories. Major emitters, such as India, have low per capita emissions and significant vulnerability concerns, given their relative lack of development. Further, these categories do not lend themselves to legal proceedings aimed at securing reparations,Footnote 10 which turn on the satisfaction of specific legal requirements and differ from state to state.Footnote 11 These broad categories nevertheless offer a useful framework to understand the politics—and legal arguments shaped by these politics—surrounding climate justice.
Part II of this Article sets out the compelling case that vulnerable states have for climate justice and reparations. It outlines the extent of current and future climate harms for vulnerable states, and their limited contribution to climate change. Part III examines the efforts by vulnerable states to advance claims for climate justice and reparations in the UN climate regime. This part finds that the UN climate regime has allowed major emitting states to deflect such claims by basing treatment of issues relating to loss and damage on “cooperation and facilitation” and excluding consideration of “compensation and liability.” It finds that there is limited “cooperation and facilitation,” however, and that the available support is radically inadequate. This has led vulnerable states to seek accountability and redress for climate harms elsewhere. In their submissions in the proceedings for the ICJ’s advisory opinion on climate change, vulnerable states have sought to engage the law of state responsibility to establish their claims for climate justice and reparation. Part IV explores contestations over a key element of state responsibility—“an internationally wrongful act”—and challenges the limited and limiting account of international law that enables major emitting states to distort compelling claims for reparations from vulnerable states. Part V argues for an approach that reclaims and empowers international law to address the civilizational challenges we face. Part VI concludes.
II. Climate Harms
A. Devastating Impacts
There is an incontrovertible record of scientific consensus that climate change caused by human conduct is occurring with devastating impacts for people and the planet. Global surface temperatures are already at 1.1°CFootnote 12 –1.28°CFootnote 13 above 1850–1900, and each of the last four decades has been warmer than any decade before it since 1850.Footnote 14 2024 was the warmest year on record with temperature exceeding 1.5°C above pre-industrial level for the first time.Footnote 15 Human influence has warmed the atmosphere, ocean, and land.Footnote 16 It has driven global retreat of glaciers,Footnote 17 decrease in Arctic Sea ice,Footnote 18 warming of the upper ocean,Footnote 19 global acidification of surface open ocean,Footnote 20 sea level rise,Footnote 21 and increased the frequency and intensity of heatwaves.Footnote 22
Such climate change has caused widespread adverse, even irreversible impacts, and loss and damage to nature and people.Footnote 23 Adverse impacts for human populations and natural systems are unevenly distributed across regions, and while physical exposure is an important aspect of vulnerability, lack of adaptive capacity is crucial in determining the extent of vulnerability.Footnote 24 The Intergovernmental Panel on Climate Change (IPCC) identified a list of “[g]lobal hotspots of high human vulnerability” that includes West, Central, and East Africa, South Asia, Central and South America, small island developing states, and the Arctic,Footnote 25 and it records that “[v]ulnerable communities who have historically contributed the least to current climate change are disproportionately affected.”Footnote 26 Millions have been exposed to “acute food insecurity and reduced water security” with the largest impacts observed in Africa, Asia, Central and South America, small islands, and the Arctic.Footnote 27 There is climate-induced displacement across the world, but with the small island states “disproportionately affected.”Footnote 28
People who are development-constrained, poor, face governance challenges, and lack access to basic services and resources are far more vulnerable to climate hazardsFootnote 29 —a further devastating inequity. The IPCC finds, tellingly, that between 2010 and 2020 “human mortality from floods, droughts and storms was fifteen times higher in highly vulnerable regions.”Footnote 30 Such vulnerability is exacerbated by “inequity and marginalization linked to gender, ethnicity, low income or combinations thereof … especially for many Indigenous Peoples and local communities.”Footnote 31
Even in this landscape of acute impacts for vulnerable states, the effects on small island states are catastrophic. Small islands states, mostly remote, surrounded by rapidly rising seas, with comparatively small land areas, and limited global connectivity, are particularly vulnerable and suffer from amplified climate risks.Footnote 32 These risks include “tropical cyclones (TCs), storm surges, droughts, changing precipitation patterns, sea level rise (SLR), coral bleaching and invasive species, all of which are already detectable across both natural and human systems.”Footnote 33 Intense tropical cyclones, in particular, have devastated small island states, threatening human life and destroying building and infrastructure.Footnote 34
A host of internationally protected rights are at risk from such climate impacts.Footnote 35 Human rights treaty bodiesFootnote 36 and special procedures mandate holders have cautioned that climate harms threaten the enjoyment of human rights to life,Footnote 37 health, food,Footnote 38 water and sanitation,Footnote 39 and adequate housing,Footnote 40 and that it has particularly severe consequences for women,Footnote 41 children,Footnote 42 vulnerable and marginalized groups including migrants,Footnote 43 Indigenous communities,Footnote 44 the internally displaced,Footnote 45 and those living in extreme poverty.Footnote 46
And, much worse is to come.Footnote 47 Entire island nations, their culture, traditions, identities, will likely be swallowed up by the rising seas in the decades ahead as GHG emissions continue to rise,Footnote 48 states’ mitigation ambition remains insufficient,Footnote 49 and the world continues to warm at an alarming pace.Footnote 50 At the levels of predicted temperature rise, there will be grave, pervasive, and irreversible changes, crossing many natural tipping points, the impacts of which will be faced primarily by vulnerable states.
B. Disparate Contributions
Yet these highly vulnerable states and peoples on the frontlines of climate impacts, have done little to cause climate change. There are many ways of parsing the historical emissions data (resulting in differing rankings for countries in terms of contributions), but across all of them, the majority of historical emissions have come from industrialized countries,Footnote 51 as acknowledged in the UNFCCC preamble. The United States leads in historical emissions among industrialized countries, accounting for a quarter.Footnote 52 However, emissions in developing countries such as China, India, and Brazil have grown rapidly, with China’s total CO2 emissions exceeding those of the advanced economies combined in 2020, and is now also above the world per capita average.Footnote 53 There is variance among major emitting developing countries; per capita emissions are still low for India and BrazilFootnote 54 that continue to struggle with energy poverty and developmental challenges. The shift in emissions profiles of large developing countries, especially China, has influenced their positions in the UN climate negotiations and judicial proceedings. China and India too, as we shall see, are beginning to instrumentalize narrow technical interpretations of relevant international legal norms to pre-empt claims for climate reparations. There is tellingly limited overlap between the IPCC’s identified hotspots of vulnerability and the top ten major emitters that collectively account for two-thirds of current global GHG emissions.Footnote 55
All available evidence thus underscores the fact that vulnerable states are facing significant climate harms that they have played little part in causing, either historically or currently, that the acts causing the harm continue at pace, and that the resulting emissions are likely to escalate the harm in future.Footnote 56 Vulnerable states thus have a compelling moral case for reparations—at its most basic that those who have caused the harm remedy the situation and make amends.
Yet, international law has thus far lent itself to systematic efforts by major emitting states to deny and dismantle claims for climate reparations. As a first port of call, vulnerable states sought to address their claims for reparations in the UN climate negotiations.
III. Deflecting Claims for Climate Reparations in the UN Climate Regime
A. Addressing “Loss and Damage” in the UN Climate Regime
Given the significant and escalating climate harms that impact vulnerable states, unsurprisingly the issue of “loss and damage” has underpinned the UN climate negotiations from its start.Footnote 57 The term “loss and damage” is not defined in the UNFCCC, Kyoto Protocol, or Paris Agreement, and only finds explicit mention in the Paris Agreement. But it has acquired distinct meaning in the climate negotiations. The term “loss and damage” refers to the impacts of climate change that have negative effects on human and natural systems.Footnote 58 “Loss” is associated with negative impacts for which reparation or restoration is impossible, such as disappearance of islands, and “damage” with negative impacts for which reparation or restoration is possible, such as destruction of roads.Footnote 59
In the negotiations for the UNFCCC, the Alliance of Small Island States (AOSIS) tabled a proposal in 1991 for an insurance mechanism to compensate vulnerable small island and low-lying coastal developing countries for loss and damage resulting from sea level rise.Footnote 60 Although the UNFCCC does not include a compensation mechanism, it recognizes the specific needs and concerns of developing countries arising from the adverse effects of climate change, and requires parties to take actions to meet these needs.Footnote 61 In the first decade of the climate negotiations, however, parties focused on mitigation, and it took considerable negotiating prowess from vulnerable countries to bring the issue of adaptation and then loss and damage forward. The term “loss and damage” first appeared in the 2007 Bali Action Plan,Footnote 62 followed in 2010 by the launch of a work program on loss and damage,Footnote 63 and in 2012 by the establishment of institutional arrangements for loss and damage.Footnote 64 In their submissions for these institutional arrangements, many vulnerable countries stressed the crucial importance of “redress” and “compensation” for climate harms. AOSIS sought “redress for loss and damage that is unavoidable and unrecoverable,” and proposed a “rehabilitation and/or compensat[ory]” component to the proposed mechanism.Footnote 65 The Africa groupFootnote 66 and Bolivia, Ecuador, China, El Salvador, Guatemala, Thailand, Philippines, and NicaraguaFootnote 67 echoed the AOSIS proposal and asked also for “compensation for lost development opportunities.”Footnote 68
The United States, amongst other major emitters, rejected such calls, arguing that compensation would place “a monetary value on the lives, livelihoods and assets of the most vulnerable countries and populations” and that the international community did not have “the capacity to make a normative judgment, on a centralized basis, of what gets valued and what does not.”Footnote 69 Displaying concern for vulnerable communities, they argued that such “centralized decision about valuation would very likely result in undervaluing poorer communities, cheaper land, and subsistence livelihoods.”Footnote 70 The 2013 Warsaw International Mechanism on Loss and Damage established at the end of this process did not contain a compensatory component.Footnote 71
A key related issue at the time was whether loss and damage should be addressed as part of adaptation or as a distinct issue. While vulnerable countries believe that loss and damage engages issues of liability and compensation, major emitting states preferred to keep loss and damage contained within the less contentious and more limiting adaptation framework. The decision establishing the Warsaw International Mechanism recognized that loss and damage “in some cases involves more than, that which can be reduced by adaptation”Footnote 72 leaving the door open for subsequent distinct treatment of loss and damage. Such distinct treatment is first seen, twenty-five years into the climate negotiations, in the Paris Agreement.
B. Loss and Damage in the 2015 Paris Agreement
The Paris Agreement addresses “loss and damage” in its free-standing Article 8, separating loss and damage from adaptation, as vulnerable countries had sought. The United States, however, conditioned its acceptance of this article on the inclusion of text in the Conference of Parties (COP) decision accompanying the Paris Agreement stating that “Article 8 … does not involve or provide a basis for any liability or compensation.”Footnote 73 Arguably this paragraph is not legally consequential, given that it features in a non-legally binding COP decision, the decision was adopted under the UNFCCC rather than the Paris Agreement, and the exclusion of liability and compensation is limited to Article 8.Footnote 74 Regardless, the language and content of Article 8, a product of careful negotiation between radically divergent positions, is anodyne, and does not lend itself to claims of liability and compensation. The explicit focus, basis, and approach of Article 8 is “cooperation and facilitation” “to enhance understanding, action and support” relating to loss and damage.Footnote 75
C. Funding Loss and Damage
The next milestone in the treatment of “loss and damage” in the climate negotiations is the 2022 decision on funding arrangements.Footnote 76 Parties agreed on “the urgent and immediate need” for financial resources to assist vulnerable developing countries in responding to loss and damage.Footnote 77 Although hailed as a “historic” decisionFootnote 78 acknowledging climate inequities, the fraught negotiations and the decision text signals a more limited win for vulnerable states. The issue was included in the agenda for the 2022 Sharm-el-Sheik conference only after parties agreed that “its outcomes would be based on cooperation and facilitation and would not involve liability or compensation.”Footnote 79 This understanding is reiterated in the 2023 decision operationalizing the funding arrangements for loss and damage.Footnote 80 In addition to these express threshold exclusions of “compensation and liability,” the content of these 2022 and 2023 decisions blur the basis for compensation and liability. Crucially, they obfuscate who is responsible to pay, to whom, and on what basis.
The decision establishing the fund does not specify who is responsible for paying, merely directing that efforts are made to consider “identifying and expanding the sources of funding.”Footnote 81 The subsequent decisions operationalizing the fund “urge” developed countries to “continue to provide support” and “encourage” other parties to voluntarily provide support.Footnote 82 Even this cautious reference to developed countries providing support is caveated in a footnote that reads: “[t]his paragraph is without prejudice to any future funding arrangements, any positions of Parties in current or future negotiations, or understandings and interpretations of the Convention and the Paris Agreement.”Footnote 83 Regarding who is eligible to receive funding, these decisions identify “developing countries particularly vulnerable to the adverse effects of climate change” as beneficiaries of support.Footnote 84 Neither are the terms “developed countries” and “developing countries particularly vulnerable to the adverse effects of climate change” defined, nor is there a list of countries in each category, leaving states to identify themselves as one or the other. The basis on which such “assistance” is provided to “developing countries particularly vulnerable to climate change” is “cooperation and facilitation.”Footnote 85
D. Setting Loss and Damage in the Context of Climate Finance
Moreover, the broader context of climate finance suggests the need to temper expectations of the loss and damage fund. The UN climate regime has thus far only offered targeted and partial support to vulnerable developing countries. The overall pot of climate finance is a fraction of estimated need, and only a small proportion of it goes toward meeting adaptation or loss and damage needs of vulnerable countries, the rest going toward mitigation.
The Paris Agreement obliges developed countries to provide financial resources to developing countries “in continuation of their existing obligations under the Convention,”Footnote 86 and to lead in “mobilizing climate finance from a wide variety of sources ….”Footnote 87 An earlier agreement to mobilize US$100 billion per year by 2020,Footnote 88 was finally achieved in 2022.Footnote 89 In Baku in 2024, parties set a goal of US$300 billion per year by 2035,Footnote 90 and called on “all actors” to scale up financing to at least US$1.3trillion per year by 2030.Footnote 91 This is far short of the estimated need and widens the net of those expected to scale up finance to developing countries. The IPCC estimates the estimated need to be between US$1.6 trillion to US$3.8 trillion annually until 2030,Footnote 92 and the UN Standing Committee on Finance estimates the need to be US$ 28.2 trillion.Footnote 93 The IPCC also found that the flow of finance is three to six times below what is needed to reach the Paris Agreement’s temperature goal.Footnote 94
Of the climate finance available, only an estimated 20–25 percent flows to adaptation, with the majority flowing to mitigation.Footnote 95 The dedicated funds under the UN climate regime—the Special Climate Change Fund (SCCF), Least Developed Countries (LDC) Fund, and Adaptation Fund (AF)—channel part of the available finance for adaptation, with a significant proportion dedicated to assisting vulnerable countries prepare national adaptation plans,Footnote 96 with less available for implementing adaptation and addressing loss and damage. Even the 2024 Baku decision by parties “to pursue efforts to at least triple annual outflows” from those Funds from 2022 levels by 2030,Footnote 97 will not make a significant dent in meeting the estimated need.
Yet, the climate harms already being faced by vulnerable states at 1.1°C–1.3°C of temperature rise, is extensive and existential, and their need for support is significant. Global costs of extreme weather attributable to climate change in the last twenty years have been estimated as US$143 billion per year,Footnote 98 and the broader costs of loss and damage are estimated to rise to US$425 billion in 2020 and US$671 billion in 2030.Footnote 99 The loss and damage fund has thus far attracted pledges of about US$741 million.Footnote 100 The 2023 UAE Consensus acknowledged that there are “significant gaps, including finance, that remain” in responding to loss and damage.Footnote 101
E. Beyond the UN Climate Regime
As a result of three decades of impassioned advocacy from vulnerable states, the issue of “loss and damage” is addressed in a binding treaty, and there are dedicated institutional mechanisms to address it, including a fund. However, the issue is addressed on the basis of “cooperation and facilitation” rather than “compensation and liability,” it is not anchored in a binding obligation to provide support, and what is available is a fraction of estimated needed.
Many vulnerable island states entered declarations when ratifying the Paris Agreement to clarify that their ratification did not “constitute a renunciation of any rights under international law concerning State responsibility for the adverse effects of climate change” and that “no provision in the Paris Agreement can be interpreted as derogating from principles of general international law or any claims or rights concerning compensation due to the impacts of climate change.”Footnote 102 There is ample support for the position that the treaties comprising the UN climate regime do not preclude the operation of general international law. On the contrary, general international law complements and strengthens the obligations in these treaties.Footnote 103
It is in this context and fueled by a frustration with the glacial and unsatisfactory treatment of this issue in the UN climate negotiations that vulnerable states, led by Vanuatu, convinced the General Assembly to approach the ICJ.Footnote 104 Since many major emitters, in particular the United States, China, and Russia,Footnote 105 have not consented to the compulsory jurisdiction of the Court, a contentious case is not an option, itself an indication of the limits of international law in the climate context. In his statement to the General Assembly, Vanuatu’s Prime Minister Alatoi Ishmael Kalsakau Maau’koro noted that while the UNFCCC and Paris Agreement have provided “an invaluable platform for cooperation and action on climate change,” the level of ambition is still far adequate, and thus the need for an ICJ advisory opinion “to clarify the rights and obligations of States under international law in relation to the adverse effects of climate change” and “importantly to achieve climate justice.”Footnote 106
Is the faith in international law, especially the law of state responsibility, to “achieve climate justice” justified? The next part explores contestations over a crucial element of state responsibility for the adverse effects of climate change—the existence (or lack thereof) of an internationally wrongful act.
IV. Distorting Claims for Climate Reparations in International Judicial Proceedings
The starting point for the engagement of state responsibility is an “internationally wrongful act.”Footnote 107 An internationally wrongful act consists of conduct that is “attributable to the State under international law” and constitutes “a breach of an international legal obligation” in force for that state at that time.Footnote 108 And, if this can be established, legal consequences flow, and the “responsible State is under an obligation to make full reparation for the injury caused by the internationally wrongful act.”Footnote 109 These elements of state responsibility for climate harms have been extensively discussed in the literature,Footnote 110 and will not be rehashed here. This part focuses on the existence (or lack thereof) of an internationally wrongful act—a crucial precondition to the engagement of responsibility—to illustrate the extent to which formalistic approaches to international law lend themselves to dismantling claims for climate reparations.
An internationally wrongful act arises from the breach of an international legal obligation, whether such an obligation is contained in a treaty or is part of customary international law. In relation to climate harms, the Paris Agreement, and the customary international law principle of harm prevention are the most directly relevant. Most major emitters—whether developed or developing—argue that the UN climate regime (and particularly the Paris Agreement) is the principal source of climate-related obligations for states and that customary international law, particularly the harm prevention principle,Footnote 111 is not applicable to climate change. In their telling, because the Paris Agreement’s procedural obligations have not been breached, and the harm prevention principle is not engaged, notwithstanding past and continuing harmful emissions of GHGs from major emitters, no internationally wrongful act has occurred. This two-step argument leads them to the conclusion that state responsibility is not engaged, claims for reparation are baseless, and that diplomatic processes, and the UN climate regime, premised on “cooperation and facilitation,” will ultimately deliver a safe climate. Each of these steps in the argument is presented, contextualized and tested below.
A. The 2015 Paris Agreement
The 2015 Paris Agreement, with 196 parties, is the international community’s dedicated legal response to the climate crisis. The “purpose” of this Agreement is to limit global average temperature to “well below 2°C” and “pursue efforts” toward 1.5°C above pre-industrial levels.Footnote 112 In order to achieve this goal, the Agreement requires parties to achieve a balance between GHG emissions by sources and removals by sinksFootnote 113 —popularly characterized as “net zero”—in the second half of this century. Toward this end, the Paris Agreement requires parties to communicate a “nationally determined contribution” (NDC)Footnote 114 every five years,Footnote 115 accompanied by ex-ante information,Footnote 116 and to account for it ex-post.Footnote 117 Parties’ contributions are neither internationally negotiated nor subject to obligations of result. Parties are obliged to submit NDCs but not to achieve their targets.Footnote 118 Parties are obliged, however, to participate in an ambition cycle, which comprises several elements. Parties are to provide information to track progress in implementing and achieving their NDCs.Footnote 119 Such information flows into a “global stocktake” scheduled every five years,Footnote 120 and into a facilitative implementation and compliance process.Footnote 121 Although parties’ contributions are nationally determined, there is a normative expectation that every successive NDC represents a “progression” on the previous, and their “highest possible ambition” and differentiated responsibility.Footnote 122 Developed countries are also expected to advance NDCs that reflect their leadership.Footnote 123 Developed countries carefully circumscribed obligations to provide financial support under the UNFCCC are continued under the Paris Agreement.Footnote 124
Although there are profound differences between them in their interpretations of the Paris Agreement—in particular on differentiation between states—there is remarkable unity among the major emitters that the Paris Agreement, characterized as the product of “engaged, protracted negotiations and careful compromise between States”Footnote 125 and “embodying the clearest, most specific, and most current expression of states’ consent to be bound by international law in respect of climate change,”Footnote 126 is the last word on the obligations of states to avert climate harms. China in its submissions to the International Tribunal for the Law of the Sea (ITLOS), stressed the primacy of the UN climate regime in order to argue that if states meet their obligations under this regime they also satisfy their obligations to protect and preserve the marine environment under Part XII of the United Nations Convention on the Law of the Sea (UNCLOS).Footnote 127 India in a similar vein argued that the UN climate regime deals with “issues arising from and pertaining to climate change, with the customary law principle of CBDR-RC as its cornerstone,” and since the question is “to determine the obligation of States Parties to the UNCLOS in relation to climate change” … “the question should be addressed within the UNFCCC framework.”Footnote 128 Crucially, China argued, citing Article 55 of the Articles on State Responsibility,Footnote 129 that because the UN climate regime is “fundamental and primary” (i.e., lex specialis) in addressing climate change, state responsibility for internationally wrongful acts “cannot be resorted to.”Footnote 130 Most major emitters have also adopted this position in their submissions to the ICJ for the advisory opinion on climate change. The United States argues that “ongoing diplomatic efforts” in the UN climate regime and especially the Paris Agreement, offer “the best means for achieving the international community’s shared climate goals and protecting the climate system for the benefit of present and future generations.”Footnote 131
This step of the argument—that the Paris Agreement is lex specialis and occupies the field on climate protection—has been canvassed before the ITLOS and ICJ. The ITLOS rejected this view holding that while the UNFCCC and the Paris Agreement, in particular the Paris Agreement’s temperature goal and timeline for emissions pathways are relevant in interpreting and applying the Convention, the Paris Agreement is not lex specialis to the UNCLOS, and the obligations under the Convention would not be satisfied simply by complying with the Paris Agreement.Footnote 132 It remains to be seen what the ICJ will opine on this issue, but the approach taken by ITLOS offers the glimmerings of a holistic, purpose-driven vision of international law. The interpretative approach taken by ITLOS underscores the importance, in line with the argument advanced here, of interpreting treaties in their normative environment. While the opinion that the Paris Agreement is not lex specialis to the UNCLOS, would also be supported by a straightforward application of the rules of treaty interpretation, ITLOS goes further and incorporates the Paris Agreement benchmarks—the temperature goal and timeline for emissions pathways—in shaping the standard of due diligence required of states.
In any case, if the logic presented by the major emitters is accepted, the primacy of the UN climate regime, and the Paris Agreement in particular means that an internationally wrongful act must be based on the obligations in the Paris Agreement. Yet those obligations are primarily procedural (as for instance submission of an NDC) with some substantive obligations (such as undertaking domestic mitigation measures) linked to obligations of conduct (and associated due diligence) and good faith normative expectations. There are no obligations of result for GHG mitigation, provision of support for loss or damage, or transfer of finance to vulnerable developing countries. On these, the Paris Agreement defers to national circumstances, self-selected targets and goals, and self-justified determinations of fairness, ambition, and progression. Fundamentally, the design logic of the Paris Agreement is premised on “national determination” and privileges national autonomy over centralized prescriptive regulation.Footnote 133 In a provision emblematic of the centrality of national determination to the consensus underpinning the Paris Agreement, the 2023 UAE Consensus “reaffirms the nationally determined nature of nationally determined contributions ….”Footnote 134
The carefully negotiated discretionary language, use of choice auxiliary verbs, and profusion of caveats around each of the core obligations in the Paris AgreementFootnote 135 makes it challenging to identify an international legal obligation that lends itself to assessments of compliance or non-compliance and thus breach. The obligations most likely to lend themselves to such assessments are those that the Paris Agreement’s Implementation and Compliance Committee can initiate consideration on.Footnote 136 These are binding procedural obligations to submit an NDC,Footnote 137 report,Footnote 138 and participate in the “facilitative, multilateral consideration of progress.”Footnote 139 Even if a breach of these binding procedural obligations were found, the conduct that needs to end is the specific conduct that constitutes a breach of the relevant obligation.Footnote 140 And, the reparation due would be based on the injury caused by the internationally wrongful act.Footnote 141 The relevant internationally wrongful act is not excessive GHG emissions but the breach of procedural obligations. This breach would need to end, and reparation would be due for the (limited) injury caused by this breach.
B. Customary International Law: Harm Prevention
The harm prevention principle imposes a responsibility on states “to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction.”Footnote 142 The principle of harm prevention is a binding customary rule,Footnote 143 which imposes on states an obligation of conduct (rather than of result) subject to the exercise of “due diligence.”Footnote 144
Many major emitters argue that the harm prevention principle cannot be extended to the climate context. The United States argues that activities that emit GHGs differ from the point source activities or pollution at issue in the harm prevention principle.Footnote 145 India similarly argues that environmental pollution and climate change differ along “temporal and spatial scales,” and must not be conflated.Footnote 146 China adds that the issue of climate change differs from transboundary harm due to its global, historical, and cumulative nature.Footnote 147 Australia notes that extending the principle to climate change would be inconsistent with the established approach to determining the existence and content of customary rules and fail to account for the unique features of the climate challenge, which is addressed in the climate treaty regime.Footnote 148
The International Law Commission also notes that while in the context of “transboundary atmospheric pollution” the harm prevention principle is “firmly established” as custom, this is “still somewhat unsettled” for global atmospheric degradation.Footnote 149
While there are admittedly differences between the archetypal cases of transboundary environmental harm that led to the emergence of the harm prevention principle and the global commons issue of climate change, the fact that this principle is applicable to and can be adapted to the climate context is evident from the explicit reference to it in the preamble to the UNFCCC.Footnote 150 Further, at its core the harm prevention principle imposes obligations of conduct subject to due diligence requirements, which in the context of climate change, the Paris Agreement also does. The harm prevention principle strengthens the obligations in the Paris Agreement rather than displaces it.
Nevertheless, a finding that the harm prevention principle either does not apply to climate change, i.e., “global atmospheric degradation,” because it is fundamentally different in character to transboundary harm, or that even if it applies, it has not yet attained the status of a custom, would be fatal to a claim for reparation that would need to be premised on a breach of an international obligation.
Some major emitters argue that even if the customary harm prevention principle is engaged by climate change, and represents custom, it operates as lex generalis while the climate treaties operate as lex specialis, and the principle “is applied subsidiarily to the norms of climate treaties.”Footnote 151 Others, even while questioning its applicability to climate change, note that compliance with Parties’ obligations under the UN climate regime should be understood as satisfying a general due diligence standard under customary law.Footnote 152 As the United States notes, “[i]t is those diplomatic efforts that provide the best means for protecting the climate system for the benefit of present and future generations.”Footnote 153 Again, for the major emitters all roads lead to the UN climate treaties.
The tightly constructed legal narrative deployed by major emitters to dismantle claims for reparations by finding no discernible internationally wrongful act is embedded squarely in a formalistic consent-based vision of international law. But there are other approaches to interpreting the UN climate treaties and the customary harm prevention principle that address issues of existential salience to humanity and the planet.
V. Reclaiming and Empowering International Law
The United Nations Human Rights Committee in its path-breaking 2022 case Daniel Billy and Others v. Australia (Torres Strait Islanders Petition) noted that: “[t]reaties should be interpreted in the context of their normative environment.”Footnote 154 In this vein, the Paris Agreement is to be read, interpreted, and applied not in an atomistic fashion, as many major emitters argue, but rather in the light of its rich normative environment, which includes the customary harm prevention principle, widely ratified treaties, such as the core human rights instruments,Footnote 155 other treaties such as the UNCLOS, and a range of principles and standardsFootnote 156 of differing legal character and gravitas. These norms form an intricate tapestry of interlocking obligations and principles within which the UN climate treaties are set. As with the threads that form a tapestry, norms are woven together to create a rich and vibrant vision for the international community, each norm complementing and strengthening others, and maintaining the perfect tension between them to hold the vision aloft. This approach maps on to and is supported by the interpretative framework of the Vienna Convention on the Law of Treaties (VCLT), as discussed below.
The General Assembly resolution seeking an ICJ advisory opinion rests on this premise. It requests that the ICJ have “particular regard to” the UN Charter, International Covenant on Civil and Political Rights, the International Covenant on Economic, Social and Cultural Rights, the UNFCCC, the Paris Agreement, UNCLOS, the duty of due diligence, the rights recognized in the Universal Declaration of Human Rights, the harm prevention principle and the duty to protect and preserve the marine environment.Footnote 157 The use of the language “particular regard to” rather than a formulation limiting the scope to specific instruments, suggests that while these instruments are salient, the entire corpus of international law could be pressed into service, as appropriate.Footnote 158
Flowing from this more holistic interpretative approach, the standard of due diligence in customary law, among other norms, strengthens, bolsters, and enhances the obligations under the Paris Agreement and vice versa.Footnote 159 Customary and treaty norms reinforce each other in this instance. This is in evidence, for instance, in the South China Sea Award where the Arbitral Tribunal held that the harm prevention principle “informs the scope of the general obligation in Article 192” of the UNCLOS.Footnote 160
This approach is supported by the interpretative framework of the VCLT, which provides that while interpreting treaties, “[t]here shall be taken into account” “any relevant rules of international law applicable in the relations between the parties.”Footnote 161 This provision, according to the International Law Commission, reflects the objective of “systemic integration,”Footnote 162 which supports the tapestry of inter-locking obligations and principles approach advanced here. General international law is particularly salient in interpretation when the “treaty rule is unclear or open-textured,”Footnote 163 as is the case with numerous provisions in the UN climate treaties. States such as those of the European Union (EU)Footnote 164 and SwitzerlandFootnote 165 endorse this position, but the United States argues that other rules are either inapplicable, irrelevant, general, or trumped by the Paris Agreement.Footnote 166 The VCLT interpretative framework signals that rules of international law need to be interpreted compatibly to advance systemic integration in international law.Footnote 167 Interpreting the Paris Agreement in its normative environment strengthens such systemic integration.
If the ICJ were to adopt this holistic purpose-driven approach it would find an ongoing internationally wrongful act. A “stringent”Footnote 168 standard of due diligence attaches both to the obligations of conduct in the Paris Agreement, specifically in Article 4, as well as to the harm prevention principle.Footnote 169 This standard of due diligence is also “objective”Footnote 170 as it does not depend on the subjective will and judgment of the State but is based on concrete benchmarks. In its Advisory Opinion on Climate Change, ITLOS noted that, the “content of an obligation of due diligence should be determined objectively under the circumstances, taking into account relevant factors,”Footnote 171 and that “an obligation of due diligence can be highly demanding.”Footnote 172 The relevant factors in the context of climate change include: the best available science;Footnote 173 the object and purpose of the Paris Agreement, especially its temperature goal;Footnote 174 the normative expectation that states contributions will reflect their highest possible ambition;Footnote 175 states’ human rights obligations;Footnote 176 leadership from those with higher capacity and contribution to harm;Footnote 177 and the nature and degree of harm suffered in the absence of due diligence.Footnote 178 This interpretative approach to the Paris Agreement cannot displace the clear terms of the Paris Agreement, impose obligations where none exist, or replace obligations of conduct with obligations of result. Nevertheless, it is possible to discern a high standard of due diligence that has been breached and continues to be.
The NDCs of major emitters reflect radically inadequate ambition, as discussed in Part II. UNEP reports “that governments plan to produce, in 2030, 110% more fossil fuels than would be consistent with limiting warming to 1.5°C” and “69% more than would be consistent with limiting warming to 2°C.”Footnote 179 And, the International Monetary Fund (IMF) records global fossil fuel subsidies as having reached US$7 trillion in 2022.Footnote 180 Notably, the 2023 UAE Consensus “calls on” Parties to transition away “from fossil fuels in energy systems, in a just, orderly and equitable manner, accelerating action in this critical decade, so as to achieve net zero by 2050.”Footnote 181
If the standard of due diligence required of states has been breached, and an internationally wrongful act is found, a claim for reparations would flow naturally from it.Footnote 182 Although it would be beyond the scope of an advisory opinion for the ICJ to order reparations, even the recognition by the ICJ that such a claim could exist would provide vital steer for cases in other courts. National,Footnote 183 regional,Footnote 184 and internationalFootnote 185 courts, in the context of rights-based climate litigationFootnote 186 have begun to hold states accountable for rights violations stemming from insufficient mitigation or adaptation action that causes or exacerbates climate harms. While these are not state-to state claims, and no claims for reparations have yet been awarded,Footnote 187 the prospects that some compensation might be provided to those on the frontlines of climate impacts would be brighter should the ICJ recognize the compelling claims for climate reparations before it.
VI. Conclusion
Vulnerable states, battered by extreme weather events and watching their lands slip away under rising seas, even as major emitters question climate treaties, exploit loopholes and dilute commitments, have a compelling case for climate reparations, i.e., that the harm caused be remedied. Yet their efforts to advance their claims for reparations in the UN climate regime have been thwarted by major emitters who have deflected these claims by basing the treatment of loss and damage on “cooperation and facilitation” and excluding any consideration of “compensation and liability.” And they are seeking to distort such claims in proceedings before the ICJ by arguing for narrow, formalistic interpretations of core obligations that would lead to the counterintuitive finding that no internationally wrongful act had occurred.
Admittedly, an internationally wrongful act and a case for reparation can only be found against individual states, based on a tailored appreciation of the law and facts that applies in that context, and not on the basis of harms to categories of states. There is also a compelling argument to be made, as Steven Ratner has, that international law does not lend itself to resolving issues that are as morally and political fraught as reparations. International law as currently conceived and applied is indeed a limited tool in addressing the grave existential challenge of climate change, yet it is also the only tool that vulnerable states have, and it is for them to reimagine and repurpose it. Beneath the surface of seemingly technical interpretational differences of the relevant norms of international law lies a fundamental divide between competing visions of international law—a formalistic approach that envisions international law as limited to that which states expressly consent (or not) to, and a purpose-driven, progressive, and emancipatory approach to international law, advanced in this article, that seeks to address global existential challenges and begin to deliver international (climate) justice. The dissonance between these competing visions of international law, at the root, inter alia, of the contestations over climate reparations, has led to a lack of ownership of the climate problem, and created an enduring drag in addressing it. This has not only entrenched a profound sense of unfairness as climate harms ravage vulnerable states; it has also affected the ability of the international community to deliver a climate safe planet. It would take a remarkable leap of legal imagination and political courage for international law to re-orient itself to the challenge of addressing and redressing climate change. It remains to be seen if international law is up to this pressing task.Footnote 188
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