On 23 July 2025, the International Court of Justice (“ICJ”) handed down its long awaited Advisory Opinion on climate change (“the Opinion”).1There has already been a considerable volume of ink spilled over the international, political and policy dimensions.2 Much of this writing considers whether the Opinion represents a sea change in the approach to climate change and, the ramifications of the declaration of an “existential” crisis”3 in an action brought by the Global South, in particular the island and coastal nations, against the actions of the developed North.
This paper has a different focus. In it we set out, in headline terms, what the Opinion says and does and then the possible results with a particular emphasis on the impacts on the energy, commercial and infrastructure sectors. In so doing, the focus is not on the inter-State operation of treaties but on how climate change may directly impact domestically and on the private sector.4 The paper further addresses the instinctive reaction of many private lawyers: what does public international law have to do with me? As well as the chequered history of the practical effect of public international law and ICJ advisory opinions in a domestic context. It is the third in a series of papers written by one of the authors on this point – “Stranger Things? New Obligations and Jurisdictions in International Investment Treaties and Arbitrations”5 and “Big Oil’s Terrible, Horrible, No Good, Very Bad Day”.6 Those papers combined with the present paper show the clear direction of travel in this area towards a wider application of what used to be called “soft” law to commercial disputes.
Background
On 29 March 2023, the United Nations General Assembly framed questions to be put to the ICJ for an advisory opinion.7 The ability to make such a request is written into the UN Charter8 and the power to consider that request is written into the ICJ’s Statute.9 It is fair to say, however, that to date, whilst advisory opinions have advanced the law, they have not had significant political impact.10
The questions were, put crudely, (a) what obligations do states owe in relation to climate change; and (b) what happens if the States breach those obligations.11 Unsurprisingly, due to the nature of the questions and the potential impacts of the answers,12 the ICJ sought representations and submissions from a wide range of countries and entities and these were duly provided.13
Based on all of that the ICJ issued the Opinion.14
The Opinion15
The ICJ started by outlining the expanding concerns at the international level including at the UN and the Intergovernmental Panel on Climate Change.16
The ICJ then went on to consider the science of climate change and said this:
72. …As explained further in this section, it is scientifically established that the climate system has undergone widespread and rapid changes, including, in particular, an increase in global surface temperatures, or global warming. Climate change is caused by the accumulation of certain gases in the atmosphere that trap the sun’s radiation around the Earth, leading to a greenhouse warming effect. While certain GHGs occur naturally, it is scientifically established that the increase in concentration of GHGs in the atmosphere is primarily due to human activities, whether as a result of GHG emissions, including by the burning of fossil fuels, or as a result of the weakening or destruction of carbon reservoirs and sinks, such as forests and the ocean, which store or remove GHGs from the atmosphere.
73. The consequences of climate change are severe and far-reaching; they affect both natural ecosystems and human populations. Rising temperatures are causing the melting of ice sheets and glaciers, leading to sea level rise and threatening coastal communities with unprecedented flooding. Extreme weather events, such as hurricanes, droughts and heatwaves, are becoming more frequent and intense, devastating agriculture, displacing populations and exacerbating water shortages. Furthermore, the disruption of natural habitats is pushing certain species toward extinction and leading to irreversible loss of biodiversity. Human life and health are also at risk, with an increased incidence of heat-related illnesses and the spread of climate-related diseases. These consequences underscore the urgent and existential threat posed by climate change.
The ICJ therefore found as scientific fact that anthropogenic climate change17 is real and is occurring. Arguments to the contrary were given no shrift.18
The ICJ then moved on to consider the questions. The ICJ did so adopting the following approach:
the Court is further of the view that the relevant conduct for the purposes of these advisory proceedings is not limited to conduct that, itself, directly results in GHG emissions, but rather comprises all actions or omissions of States which result in the climate system and other parts of the environment being adversely affected by anthropogenic GHG emissions. The Court considers that the material scope of its inquiry encompasses the full range of human activities that contribute to climate change as a result of the emission of GHGs, including both consumption and production activities. This interpretation is confirmed by the understanding of most of the participants that replied to the question posed by a Member of the Court concerning “the specific obligations under international law of States within whose jurisdiction fossil fuels are produced”. These participants submitted that obligations pertaining to the protection of the climate system do not rest exclusively with consumers and end users, but also include activities such as ongoing production, licensing and subsidizing of fossil fuels.19
Question (a) – what are the obligations?
Treaty law
Unsurprisingly given Articles 2620 and 2721 of the 1969 Vienna Convention on the Law of Treaties, the ICJ found that the various environmental Treaties were binding on the States.22 Obviously, such obligations are imposed at the State-to-State level.
Customary International Law
For present purposes, however, it is the introduction of customary international law (“CIL”) that deserves attention.23Indeed, the ICJ regarded this as key to dealing with climate change.24
The ICJ identified two types of CIL – the duty to prevent harm to the environment and the duty to cooperate.
In relation to the duty to cooperate, the ICJ stated that without cooperation, it was difficult to achieve meaningful results in preventing harm. Again the duty to cooperate operates at the international level – i.e. State-to-State.25
On the duty to prevent harm, the ICJ made two more significant statements.
First the ICJ rejected the argument that this duty was confined to narrow and direct cross border harm. The ICJ stated that the duty applied generally to the global environment.26 This has implications for those States that might wish to raise sovereignty objections to defend against allegations of breach.27
Second, the “duty to prevent significant harm to the environment is an obligation to act with due diligence”28 saying further:
the Court recognizes that the standard of due diligence for preventing significant harm to the climate system is stringent (see Climate Change, Advisory Opinion, ITLOS Reports 2024, pp. 91-92, para. 241, pp. 92-93, para. 243, p. 94, para. 248, pp. 137-138, paras. 398-400, and pp. 152-158, para. 441). Moreover, as the Court has explained, due diligence “entails not only the adoption of appropriate rules and measures, but also a certain level of vigilance in their enforcement and the exercise of administrative control” (Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment, I.C.J. Reports 2010 (I), p. 79, para. 197). As concerns climate change, a heightened degree of vigilance and prevention is required.29
And
The conduct required by due diligence has several elements. These elements include States taking, to the best of their ability, appropriate and, if necessary, precautionary measures, which take account of scientific and technological information, as well as relevant rules and international standards, and which vary depending on each State’s respective capabilities. Other elements of the required conduct include undertaking risk assessments and notifying and consulting other States, as appropriate.30
The ICJ then sought to give content to the due diligence obligations. Critically, the ICJ said:31
States must
“put in place a national system, including legislation, administrative procedures and an enforcement mechanism necessary to regulate the activities in question, and . . . exercise adequate vigilance to make such a system function efficiently, with a view to achieving the intended objective
As far as climate change is concerned, such appropriate rules and measures include, but are not limited to, regulatory mitigation mechanisms that are designed to achieve the deep, rapid, and sustained reductions of GHG emissions that are necessary for the prevention of significant harm to the climate system. Adaptation measures reduce the risk of significant harm occurring and are therefore also relevant for assessing whether a State is fulfilling its customary obligations with due diligence. These rules and measures must regulate the conduct of public and private operators within the States’ jurisdiction or control and be accompanied by effective enforcement and monitoring mechanisms to ensure their implementation.
(emphasis added)
Thus, what the ICJ is saying is the due diligence obligation does not sit at an inter-state, public international law level but sits in domestic actions against public and private bodies. The ICJ is in essence saying that where climate change and GHGs are concerned, private bodies are now to be regulated.
The ICJ then went to consider international human rights law;32 sustainable development; responsibilities and capabilities;33 equity; intergenerational equity34 and the precautionary principle were all guiding principles in deciding the obligations owed.35 Again all of these, traditionally soft law concepts have, arguably, been turned into hard law principles.
Question (b) – consequences of breach
Treaty law
In terms of breach of the various treaties, again this is dealt with at the State level and as per the obligations and procedures in the treaties.36
Customary International Law
Before turning to the consequences of breach, the ICJ considered three questions: attribution; causation and erga omnes. These are important. Attribution and causation both relate to the fact that climate change is a global phenomenon which is also cumulative. Therefore it may be difficult to attribute blame to any one Defendant or Respondent. These are arguments with which any English litigator will be very familiar: how to prove that one entity’s emissions were causative of the flood/famine/fire at issue?
Erga omnes relates to the fora in which one may sue for environmental damage.
The ICJ gave attribution short shrift.
The ICJ held that whilst the question was difficult:37
in principle, the rules on State responsibility under customary international law are capable of addressing a situation in which there exists a plurality of injured or responsible States…the rules on State responsibility are capable of addressing situations where damage is caused by multiple States engaging in wrongful conduct, and that the responsibility of a single State for damage may be invoked without invoking the responsibility of all States that may be responsible.38
Therefore, a single state or several responsible states could be liable.39
In relation to causation, the ICJ stated that the direct causal nexus test was to be flexible in this context40 and the question of causation could be resolved purely by the science41 – albeit the ICJ ultimately dodged any definitive answer to the question.42
The ICJ’s reasoning on attribution is, however, instructive. The ICJ said:
Failure of a State to take appropriate action to protect the climate system from GHG emissions — including through fossil fuel production, fossil fuel consumption, the granting of fossil fuel exploration licences or the provision of fossil fuel subsidies — may constitute an internationally wrongful act which is attributable to that State. The Court also emphasizes that the internationally wrongful act in question is not the emission of GHGs per se, but the breach of conventional and customary obligations identified under question (a)pertaining to the protection of the climate system from significant harm resulting from anthropogenic emissions of such gases.
Some participants also argued that the conduct of private actors resulting in emissions of GHGs is not attributable to States. In relation to private actors, the Court observes that the obligations it has identified under question (a) include the obligation of States to regulate the activities of private actors as a matter of due diligence. Therefore, attribution in this context involves attaching to a State its own actions or omissions that constitute a failure to exercise regulatory due diligence. In such circumstances, the question of attributing the conduct of private actors to a State does not arise. The legal standard to assess compliance with the obligation to regulate, as well as the nature of the actions or omissions that lead to attribution, has been set out by the Court in several cases (Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment, I.C.J. Reports 2010 (I), pp. 79-80, para. 197; United States Diplomatic and Consular Staff in Tehran (United States of America v. Iran), Judgment, I.C.J. Reports 1980, p. 31, para. 63). Thus, a State may be responsible where, for example, it has failed to exercise due diligence by not taking the necessary regulatory and legislative measures to limit the quantity of emissions caused by private actors under its jurisdiction.43
Thus, the ICJ does two things. First, it is not the pure emission of GHGs that is the issue, it is everything related to that emission – including licences, consumption, production and subsidies. Second, passing the risks associated with climate change off to the private sector is not an answer – the State must retain control by regulation and enforcement. Thus, the ICJ again moves the issues surrounding climate out of the realm of State-to-State interaction.
Erga omnes is the principle that any State may sue another State for breach of that State’s obligations. The ability to claim is not limited to a State that has suffered harm. The ICJ put it this way:
the Court considers that all States have a common interest in the protection of global environmental commons like the atmosphere and the high seas. Consequently, States’ obligations pertaining to the protection of the climate system and other parts of the environment from anthropogenic GHG emissions, in particular the obligation to prevent significant transboundary harm under customary international law, are obligations erga omnes.
that responsibility for breaches of such obligations, such as climate change mitigation obligations, may be invoked by any State when such obligations arise under customary international law. When such obligations arise under the climate change treaties, all parties to the treaty may invoke such responsibility, since every party is deemed to have a legal interest in the protection of these obligations.44
This, needless to say, is important. It is a standard reaction to claims under public international law that they are rarified and are heard between two states in the ICJ and are therefore of academic interest only. Erga omnes is in part the answer to that. Allowing any State to sue raises substantive and forum issues. Substantively, it is well known that some states are far more aggressive on the issue of climate change. Those states and others either directly incorporate or may explicitly incorporate public international law into their domestic systems. This may well give their courts jurisdiction. Thus, although company A may reside in state B – and both of them are antipathetic to the GHG issue, that can be no answer to claims made in another state.
Rebuttal arguments dealt with by the ICJ
It has become common place in some quarters to say that if they disagree with a particular obligation, they will withdraw from or renounce the applicable treaty. Even assuming that so doing is compatible with the 1969 Vienna Convention, the ICJ has closed that argument down. Put simply, the ICJ held that if a State were not a party to any given treaty, CIL would still apply:
Customary obligations are the same for all States and exist independently regardless of whether a State is a party to the climate change treaties. On this basis, the Court considers that it is possible that a non-party State which co-operates with the community of States parties to the three climate change treaties in a way that is equivalent to that of a State party, may, in certain instances, be considered to fulfil its customary obligations through practice that comports with the required conduct of States under the climate change treaties. However, if a non-party State does not co-operate in such a way, it has the full burden of demonstrating that its policies and practices are in conformity with its customary obligations.45
Withdrawal or renunciation would therefore, in reality, be a futile gesture.46
Ramifications
General
The Opinion is advisory and advisory Opinions are, as the label suggests, technically non-binding. There are after all no States in actual dispute before the ICJ – yet – and the request comes via the United Nations General Assembly. Thus, even as a matter of public international law (and without the cynicism that term attracts in some quarters), the Opinion does not immediately impact on any given state. That said the language of the Opinion is clear and the ICJ also makes it clear that in its view there are a panoply of binding obligations in relation to climate change. Further, once any claims are brought on the back of the Opinion – those claims, if successful, will inevitably be binding. Thus saying that the Opinion is non-binding is at best a pro tem response.
It is clear that the ICJ intended all stages in the GHG emission chain to be caught one way or another – from licensing to exploration to development to production and emission. It is also clear that the ICJ intended that the private sector was not to be free of the consequences of being involved in those stages of the GHG emission chain. This development, which is novel, is the expansion of public international law outwith its usual bounds and in particular to the private sector. It is this to which we turn.
As the Opinion makes clear, the primary focus is on any given state and it is for that state to act on private entities.47 Therefore, as far as a private entity is concerned, the primary exposure is any given state taking action in response to the Opinion. That action could relate to licensing, exploration, development, production and sale of fossil fuels. As will be developed below, this means that not only are those actually involved in the extraction of fossil fuels exposed but all those associated with that extraction – the constructors and suppliers of hulls, rigs and pipelines.48 The question then becomes: what issues will arise where the state takes action to alter or stop any of the stages in the GHG emission chain? That change could be voluntary or as a result, in England and Wales, of judicial review claims49 or planning claims50 brought against the state. That raises – as SARS-CoV-2 did – the possibility of force majeure and/or change in law claims.
There is a secondary issue, however, is there a possibility of direct claims against private entities? It is reasonable to expect that those involved in the GHG emission chain will be joined to judicial review claims – not least because they have a direct interest in whether their projects51 are slowed, suspended or terminated. There is, however, the increasing risk of private law claims in negligence or more likely nuisance. There are indications here that the Courts in England & Wales may play an increasing role. Lord Sales in a Key Note Address on 9 May 202552 (and so pre the Opinion) having reviewed the case law concluded:
…it is likely that we will see interventions from both institutions, courts and legislature, with each playing a role in responding to the systemic risks and expanding range of losses arising from climate change. As so often in the law, a balance might have to be struck between development of the common law and statutory intervention, with questions of institutional competence and institutional legitimacy at the forefront of how that balance should be approached.
If that were the case before the Opinion, it must be even more likely after the Opinion. Further, as indicated above, the Opinion opens the prospect of exposure to claims outwith England and Wales and in various alternate fora.
The Energy Sector53
Tritely, field development moves in stages: the grant of a licence over a block or blocks; exploration; development; exploitation; transport; storage and sale for consumption. Also tritely, the costs involved are considerable. The Opinion makes it clear that each stage is a legitimate target for litigation.
It is highly likely that further licensing by the UK Government will be subject to challenge – as this has already happened.54 It is fair to say, however, that the success rate of such challenges has been low. This is because the UK Government (in its various manifestations) has been able successfully to contend that in making the decision the UK Government had the various environmental treaties in mind and decided for various reasons to grant the licence. Further, where the UK government’s reasons involve socio-economic policy or complex economic issues (as in the grant of energy licences), the Courts have been unwilling to date to intervene.55 It must, however, now be an open question as to whether the risks associated with climate change are now sufficient to overcome the historical judicial deference. Whether one takes Lord Sales’ PEBA Keynote56 or the ICJ reference to existential crisis,57 there are clear judicial and extra-judicial statements that that might be the case.
In terms of the impact of a quashed licensing decision, it is unlikely that – at this stage – the various field contracts would have been entered into. Further the financial costs lost will, presumably, be the lost costs of obtaining the licence. It is therefore questionable whether any form of claim could be made against the state by a private entity or how that would be framed.
Post grant of a licence, there will be the various field contracts – the Production Sharing Contracts; the Joint Operating Agreements; Farm In and Farm Out Agreements; and Sale Agreements. There will also be charterparties for vessels and contracts for the design and construction of rigs; hulls and pipelines. The number of parties and the costs will increase considerably. Here it is worth recalling not only that the Opinion states that the regulation and administration of GHG emission chain is ongoing but also, as per Erga omnes, challengeable by states other than the one(s) in which the field sits. Thus, the Opinion envisages that there would be an ongoing review of that which a State is doing in relation to GHG emissions.58 That could mean either that a licence granted historically was no longer appropriate or should not be extended or that associated, necessary licences should not be granted. In any of those circumstances, the exploitation etc of the field would come to an immediate stop.59 At this point, there could be expensive ongoing charterparties, hulls or infrastructure being laid down and the question will inevitably arise as to whom bears those expenses.
The private entities will in those circumstances inevitably turn to force majeure and there will inevitably be force majeure clauses in the contracts.60 Reliance on a force majeure clause in the energy arena is, however, fraught with difficulty.61 To take an example, suppose a private entity, X, has entered into a charterparty for an FPSO as operator of field A. The state in which field A sits follows the Opinion and terminates activities in field A. X, however, is the operator on other fields in other states where activities are ongoing. There will be no force majeure because X can move and use the FPSO in those other fields and performance the charterparty is not impossible and X, in any event, usually has to mitigate the effects of force majeure.
Two points flow.
First, there is a strong possibility that the Operator will be left with any liabilities flowing from the field either solely or with an attempt to recover from the other parties under the Joint Operating Agreement.
Second, some might turn to thoughts of obtaining indemnities from the relevant states. There could, however, be an issue that a state provided indemnity could be viewed as a subsidy which would be caught by the Opinion.
There is one final point here. Manifestly many of the “players” in the energy sector are multinationals. As Milieudefensie v Royal Dutch Shell62 shows multinationals are attractive targets for direct claims which – as discussed above – are distinctly possible.63
Construction and Infrastructure Sectors
The focus here must be on the in progress design and construction of hulls, rigs, pipelines and offshore and onshore infrastructure which sit in the GHG emissions chain.64 As any claim in these sectors will require contracts and contracts will only be let once a licence is issued, claims here will be for subsequent legal changes and supervening illegality.
Both sectors are no strangers to supervening illegality. A project may be licensed and then there is a change in the licensing provisions.65 Most recently there were and continue to be extensive debates over the impact of SARS-CoV-2 and government responses to the pandemic on projects.66 As with the Energy Sector there may be frustration or force majeure claims.67 These will face the same difficulties as in the Energy Sector. What is different about these sectors, however, is the widespread use of standard forms which contain explicit provisions seeking to address the issues.
NEC4 (as well as NEC3) does not contain an expressly labelled ‘force majeure’ clause. Instead it defines as a “compensation event” those events that i) neither party could prevent ii) that an experienced contractor (or subcontractor etc as the case may be) would have judged at the contract date to have such a small chance of occurring that it would have been unreasonable to have allowed for it, and iii) that stop the contractor (or subcontractor etc) from completing the works.68 In theory, therefore, that clause could be available to recoup as a compensation event damages arising from actions resulting from the Opinion.
Turning to FIDIC, the 2017 suite discusses force majeure in terms of “exceptional events”.69 Similar to NEC’s compensation event discussed above, “exceptional events” are defined expressly as i) events beyond a party’s control and ii) that a party could not reasonably have provided against. The FIDIC suite goes further than NEC and expressly states that “exceptional events” only include iii) those events that, having arisen, the Party could not reasonably70 have avoided or overcome and iv) that is not substantially attributable to the other Party. Since arbitration is the default dispute resolution forum for FIDIC, there is very limited publicly available material on the proper construction of this clause.71 In circumstances proposed by the Opinion, where the conduct of private operators within the States’ jurisdiction is to be controlled and monitored, again it appears in theory at least that such activity could constitute an “exceptional event” under FIDIC. On the occurrence of an exceptional event, the contractor is excused from performance, and may be entitled to additional time and potentially even termination.72
In contrast to the above, for those NEC and FIDIC contracts entered into after the Opinion, it may, however, become increasingly difficult for a contractor/subcontractor to argue that any ramifications of the Opinion were not preventable or were reasonably considered to be unlikely. The result is that it would be more difficult to establish the ramifications of the Opinion as a compensation event (NEC) or exceptional event (FIDIC). The NEC4 suite does of course make express provision for the possibility of adding bespoke additional compensation events. Bespoke amendments could also be contemplated as part of FIDIC. As with all contract negotiations, the appetite for inclusion of these items would depend on the relative bargaining power of the parties. Future contracts may well need to consider (at the very least), and potentially expressly address, who takes the risk for carbon-emission related events and losses.
An additional contractual mechanism that may become relevant following the publication of the Opinion is the standard form treatment of changes in law. The usual approach is for these clauses to shift the risk of changes in law post-contract to the client. For example, in FIDIC 2017 suite, the contract price is adjusted to take account of changes in cost arising from changes in the law of the country as well as any judicial or official governmental interpretation of the laws which affect the contractor’s performance of its obligations.73 The contractor may also be entitled to an EOT.
In contrast to FIDIC, the NEC4 suite treats express consideration of changes in law as optional.74 As a result, the change of law clause, X2, will not have been incorporated into all currently extant NEC4 contracts. If incorporated, the clause operates to treat as a compensation event any change in the law of the country in which the site is located that occurs after the contract (or subcontract etc) date. In other words, like FIDIC, it may trigger entitlement to further time and money.
For those contracts currently operating under FIDIC 2017, or that do currently incorporate Secondary Option Clause X2 of NEC4, the publication of the Opinion itself would not constitute the requisite change in law to trigger any entitlement, principally because the Opinion is expressly guidance. Any legislative and regulatory response by a state to that Opinion, however, may well be capable of triggering such compensation. Whether parties to future NEC4 contracts agree to Option X2 (or, indeed, seek to amend FIDIC) may be influenced by, amongst other things, the heightened potential for responsive legislative changes in this area.
Finally in terms of NEC4, it would be remiss not to mention that the authors of this suite introduced a series of climate change-specific option clauses in 2022 (Option X29).75 The Guidance Notes to Option X29 state, perhaps rather sweepingly, that the clause “is intended to reduce the impact of the creation, operation, maintenance and demolition of the works on climate change”.76 The clause proposes to add to the contractor’s (etc) scope a new set of “Climate Change Requirements”. These are anticipated to be set by the client in the negotiation of the contract. Although the scope of these requirements are to be tailored by the parties, the authors suggest a wide range of items could be considered including, most pertinently in this instance, designs that reduce carbon emissions. Although changes in design to oil and gas extraction may be ‘moving round the deckchairs’ when it comes to reducing carbon emissions, these clauses do act to raise the profile of a topic that is resolutely here to stay. That said, it is unclear to what extent, if at all, this option clause has been taken up by contracting parties or whether it is offered as an aspiration only. It will remain to be seen the impetus created by the Opinion which may generate a trickle down of such “climate” requirements from state to client to contractor to subcontractor.
[1] https://www.icj-cij.org/sites/default/files/case-related/187/187-20250723-adv-01-00-en.pdf
[2] See eg https://www.ft.com/content/8cfdeb7d-9b6a-4f86-990e-05f79370de08; https://www.theguardian.com/environment/climate-crisis; https://www.bbc.co.uk/news/articles/ce379k4v3pwo; https://www.aljazeera.com/news/2025/7/23/world-court-hearing-says-climate-change-is-urgent-and-existential-threat
[3] See [74] and [456]. References in square brackets are to paragraphs of the Opinion
[4] We do not consider therefore the very detailed consideration in the Opinion of the numerous treaties, their interpretation and application
[7] See [1]
[8] Article 96
[9] Article 65
[10] Advisory Opinions were issued, for example, on the legality of nuclear weapons (Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, I.C.J.Reports 1996 (I), p. 237), the Israeli construction of exclusion walls in occupied territory (Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory ICJ Reports 2004 (I) p 179) and Israel’s policies in the Occupied Territories (Legal Consequences arising from the Policies and Practices of Israel in the Occupied Palestinian Territory, including East Jerusalem, Advisory Opinion of 19 July 2024 I.C.J. Reports 2019 (I), p. 113)
[11] See [1]
[12] The South was concerned by “the imminence of the threat it poses to their populations, territories, economies, cultural traditions and, for some, the very existence of their State” at [72]. In that context – see https://www.livescience.com/planet-earth/climate-change/tuvalu-residents-prepare-for-worlds-first-planned-migration-of-an-entire-nation-and-climate-change-is-to-blame. The North by potential liabilities for historic, current and future production of greenhouse gases (“GHGs”)
[13] See pp 14 – 25 for the list of participants and their Counsel.
[14] There are also additional Opinions and variants of the declarations but for present purposes we focus on the main and unanimous document: not least because the additional Opinions go further than the unanimous Opinion particularly in relation to the North – South divide
[15] We consider the background to the ICJ’s approach in the Opinion in some detail: it is a clear indication of the policy drivers in this area
[16] [51] – [71]
[17] It is clear that the ICJ was addressing anthropogenic climate change and we therefore simply use the term climate change
[18] It is outwith the scope of this paper to consider whether the ICJ was wrong to do so – as some have already contended and will contend. We therefore adopt this as the basal finding of fact and do not address climate change denial arguments further.
[19] [94]
[20] Every treaty in force is binding upon the parties to it and must be performed by them in good faith.
[21 ]A party may not invoke the provisions of its internal law as justification for its failure to perform a treaty…
[22] [116] – [130]
[23] [131] ff
[24] [409]. The Court rejected the argument that the treaties in some way circumscribed the application of CIL [418] – if anything, the position was the other way round [420]
[25] See [301] ff
[26] [134]
[27] Such arguments have, however, lacked merit for the last 80 years – see Corfu Channel (United Kingdom v. Albania), Merits, Judgment, I.C.J. Reports 1949, p. 22; Trail Smelter Arbitration (United States/Canada), RIAA, Vol. III (1941), p. 1965. State A may be sovereign to pollute its own territory but that sovereignty does not extent to polluting State B.
[28] [135]
[29] [138]
[30] [136]
[31] [281] - [282]. See also [253]; [347]; [409]
[32] Here the ICJ adopted the same approach (see [403 – 404] as discussed in the context of International Investment Arbitrations in Wilken & McMillan Stranger Things op cit. it is important to note that breaches of human rights law give individuals the ability to sue for damages as the ICJ recognised [449]
[33] In the international law sense of deriving an equitable solution as appropriate from the applicable law – not ex aequo et bono [152 – 3]
[34] “Intergenerational equity is an expression of the idea that present generations are trustees of humanity tasked with preserving dignified living conditions and transmitting them to future generations. [156] and Due regard for the interests of future generations and the long-term implications of conduct are equitable considerations that need to be taken into account where States contemplate, decide on and implement policies and measures in fulfilment of their obligations under the relevant treaties and customary international law [157]
[35] [161]. This is not purely a North – South argument but a reflection of the obligation to take all means at the State’s disposal which is turn reflects national circumstances. The ICJ noted, however, that as State’s economic development and capacity increase so to do the due diligence requirements – see [292]
[36] [408]
[37] [429]
[38] [430]
[39] [431]
[40] [436]
[41] [437]
[42] [438]
[43] [427 – 428]
[44] [440]; [442]
[45] [315]
[46] A similar argument applies to a resort to sovereignty. That a state is sovereign within its own territory does not give it the ability to pollute another state – see Corfu Channel (United Kingdom v. Albania), Merits, Judgment, I.C.J. Reports 1949, p. 22; Trail Smelter Arbitration (United States/Canada), RIAA, Vol. III (1941), p. 1965.
[47] See [427 – 8] supra
[48] This was canvassed as a possibility in Big Oil’s Terrible, Horrible, No Good, Very Bad day op cit last para. That possibility is, as per the Opinion, now a definite probability.
[49] See eg Friends of the Earth Ltd & Ors, R (On the Application Of) v Secretary of State for Business, Energy and Industrial Strategy [2022] EWHC 1841 (Admin); R ((1) Friends of the Earth Limited (2)ClientEarth (3) Good Law Project) v Secretary of State for Energy Security and Net Zero [2024] EWHC 995 (Admin)
[50]R (Finch on behalf of the Weald Action Group) v Surrey County Council [2024] UKSC 20
[51] Eg the construction of a rig or hull or a charterparty for an FSPO
[52]Climate Change and the future of tort law: responding to systemic risk and expanding liability Keynote Address PEBA Annual Conference 9/5/25 at https://www.bailii.org/uk/other/speeches/2025/LVO1B.pdf
[53] We deal mainly with fossil fuels. If one looks at a GHG emission chain, however, renewables can be involved, it is just that nearly no one (see footnote immediately below) would want to or is likely to challenge that – especially if the overall result is net zero.
[54] See eg Thornton, R (On the Application Of) v Oil and Gas Authority [2020] EWHC 2615; Petition of Greenpeace Ltd for Judicial Review [2020] ScotCS CSOH 88 No Gas Caverns Ltd & Anor, Application for Judicial Review (Rev1) [2023] NIKB 84; Petitions by Greenpeace LTD & Uplift for Judicial Review (Court of Session) [2025] CSOH 10. For completeness there also has been one challenge against a renewables licence – see Trump International Gold Club Scotland Ltd & Anor v The Scottish Ministers & Anor [2014] ScotCS CSOH 22
[55] See eg In Re Brewster [2017] UKSC 8 at [49]; [65]; R (London and Continental Stations and Property Ltd) v Rail Regulator [2003] EWHC 2607 at [32]; R (ABS Financial Planning Ltd v FSCS Ltd [2011] EWHC 18 at [65]; Dalston Projects v SST [2025] UKSC 30 at [126 ff]
[56] Op cit - see the opening paragraphs
[57] [456]
[58] See eg [292] which clearly envisages that as a state develops economically, the degree of due diligence required will alter
[59] See eg the facts in Seadrill Ghana Operations Ltd v Tullow Ghana Ltd [2018] EWHC 1640. There a border dispute and a state imposed moratorium brought an immediate end to activities in the field.
[60] See McKendrick (Ed) Force Majeure and Frustration of Contract 2nd Ed at pp 7 ff and Part II for a consideration of force majeure clauses and their drafting
[61] See eg Tullow Ghana supra; Okta Crude Oil Refinery AD v Mamidoil-Jetoil Greek Petroleum Company S.A. & Anor [2003] EWCA Civ 1031; Litasco SA v Der Mond Oil and Gas Africa SA & Anor (Rev1) [2023] EWHC 2866
[62] C/09/571932/HA ZA 19-379
[63] That target becomes all the larger if multinationals begin to adopt an anti-net zero stance
[64] This paper is focussed on the energy sector. It is worth bearing in mind, however, that the production of cement is very productive of GHGs – see eg https://www.scientificamerican.com/article/solving-cements-massive-carbon-problem/
[65] See McKendrick supra at pp 200 – 201 esp fn 36
[66] See eg Wilken It’s Complicated: Deciphering the English Government’s Response to SARS-CoV-2 and its impact on contracts at https://www.keatingchambers.com/wp-content/uploads/2020/05/COVID-19-Government-Advice-and-Construction-Contracts.pdf. See also webinar on Force Majeure at https://www.keatingchambers.com/resources/events/force-majeure-webinar
[67] See Bailey Construction Law I:3.81 – 86 for a general outline. See also McKendrick op cit pp 214 - 216
[68] Clause 60.1(19) of the NEC4
[69] See for example clause 18 of the Silver Book 2nd Ed, 2017 (EPC/Turnkey contracts). The 1999 suite used the phrase “force majeure” but went on to define that as an “exceptional event or circumstance”.
[70] The standard of reasonableness added, presumably, because many events that would otherwise be termed force majeure could be mitigated or reduced if it assumed that the contractor has limitless resources.
[71] Rare examples include JSC Power Machines v. Vietnam Oil and Gas Group and PetroVietnam Technical Service Corporation, SIAC Case No. ARB274/19/AB (30 November 2023) which considered whether US Sanctions constituted force majeure under the 1999 Silver Book, at [475] – [488]
[72] See clauses 18.4 and 18.5 of the Silver Book 2nd Ed, 2017. The authors of FIDIC chose to limit payment of any costs arising to Exceptional Events falling within those events listed in sub-paragraphs 18.1(a)-(e). None of these could realistically be construed to cover matters that might arise from the guidance in the Opinion.
[73] See for example clause 13.6 of the Silver Book 2nd Ed, 2017.
[74] Secondary Option Clauses, at Clause X2 in NEC4
[75] NEC is not the only organisation to broach this subject. See for example the Chancery Lane Project which offers, amongst other things, climate-aligned clauses to be used in commercial and legal documents. https://chancerylaneproject.org/
[76] P 1 pf the X29 Climate Change Guidance Note for NEC4.
