Jackdaw Gas Field Approved: Does the UK Defy the ICJ Climate Opinion?

Introduction

The United Kingdom approved production at the Jackdaw gas field on October 21, 2026, despite the International Court of Justice's (ICJ) 2025 advisory opinion identifying circumstances in which governmental support for fossil fuel production may constitute an internationally wrongful act. The authorization does not automatically violate international law. Its legality depends on whether the UK has complied with its obligations under the Paris Agreement, customary international law, and other applicable rules governing climate protection.

The decision follows the Scottish Court of Session's January 2025 judgment quashing Jackdaw's earlier consent because the environmental assessment had excluded emissions from the eventual combustion of extracted hydrocarbons. The renewed authorization considers those downstream emissions, which the government estimates at approximately 35.8 million metric tons of carbon dioxide equivalent. Despite acknowledging significant climate effects, the Secretary of State concluded that production could proceed (Department for Energy Security and Net Zero, 2026).

The international legal controversy extends beyond the environmental consequences of one North Sea development. In the October decision, the UK expressly rejected the ICJ's conclusion that the customary international-law duty to prevent significant environmental harm applies to the climate system. The Court had reached that conclusion in July 2025 and identified fossil fuel production among the activities through which failures of governmental regulation may engage international responsibility. Jackdaw consequently presents a concrete dispute over the legal limits of fossil fuel authorization, the scope of climate due diligence, and the relationship between domestic regulatory approval and international obligations.

1. The Jackdaw Gas Field Approval of October 2026

On October 21, 2026, the North Sea Transition Authority (NSTA) granted consent for development and production at Jackdaw following the Secretary of State for Energy Security and Net Zero's agreement. The underlying ministerial decision was dated October 14, with the authorization announced publicly on October 21. The decision permits development to proceed toward commercial gas production under an existing petroleum license rather than granting new exploration rights (Department for Energy Security and Net Zero, 2026).

Jackdaw is an ultra-high-pressure, high-temperature gas-condensate field in the Central North Sea, approximately 250 kilometers east of Aberdeen and around five kilometers from the maritime median line between the United Kingdom and Norway. The development includes four wells, a wellhead platform, and a subsea pipeline connecting the field to the existing Shearwater installation. Natural gas is intended to reach the St Fergus terminal, while condensate is transported through the Forties Pipeline System.

The project is operated by Adura Operations Limited, a joint venture between Shell and Equinor. Adura became the named developer during the renewed regulatory process.

The wellhead platform was installed in October 2025, and drilling of the four wells was completed in February 2026. Construction had continued under the conditions established by the Scottish court, although extraction remained prohibited pending reconsideration of the original consent.

The government anticipates that Jackdaw could operate for up to 11 years and increase production from the UK Continental Shelf by approximately 6% at peak output. This percentage concerns domestic offshore gas production, not the country's total gas consumption. The October announcement indicated that supplies could begin as early as the end of the month, although consent alone did not establish that commercial production had commenced.

The distinction between an exploration license and development consent is legally significant. A petroleum license provides rights relating to exploration and production within a designated area, but it does not independently authorize a particular development to proceed. Under the Offshore Oil and Gas Exploration, Production, Unloading and Storage (Environmental Impact Assessment) Regulations 2020, the project also requires the relevant regulatory consent, subject to the environmental assessment process.

Regulation 4 establishes the requirement for ministerial agreement and consent from the petroleum regulator. Regulations 14 and 15 govern the Secretary of State's agreement and the regulator's grant of consent. The renewed approval was consequently a fresh governmental decision concerning fossil fuel production, even though the underlying petroleum license already existed.

2. Why the Scottish Court Quashed the Earlier Consent

Jackdaw's earlier authorization was granted in 2022 following revisions to the development proposal. The initial environmental statement had been reconsidered after authorities declined to approve the project in September 2021. A revised statement was submitted in February 2022, ministerial agreement followed on May 27, and the Oil and Gas Authority granted consent on June 1.

Greenpeace challenged the authorization because the environmental assessment had not examined greenhouse gas emissions from the eventual combustion of the extracted hydrocarbons. The omission concerned a substantial category of the project's climate effects, distinct from emissions generated during extraction and processing.

The resulting litigation concerned requirements under domestic environmental assessment legislation. Although these requirements reflect wider principles of international environmental law, the Scottish proceedings were decided under the applicable UK legal framework. They did not determine whether Jackdaw would violate the Paris Agreement or customary international law.

2.1 The Finch Judgment and Downstream Emissions

The decisive judicial development was the UK Supreme Court's June 20, 2024 judgment in R (Finch) v Surrey County Council [2024] UKSC 20. The case concerned proposed oil extraction at Horse Hill in Surrey and the interpretation of environmental impact assessment requirements under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017.

The Supreme Court held, by a majority, that foreseeable greenhouse gas emissions arising from the eventual combustion of extracted oil were indirect environmental effects requiring assessment. The commercial purpose of the project was to produce hydrocarbons that would ultimately be used as fuel. Their combustion was consequently a foreseeable consequence of extraction rather than an unrelated activity (UK Supreme Court, 2024).

The ruling addressed the scope of the environmental assessment, not the substantive permissibility of fossil fuel extraction. Environmental impact assessment requires relevant environmental consequences to be identified, examined, and considered before consent is granted. It does not ordinarily prohibit authorization merely because significant adverse effects have been identified.

Jackdaw was subject to a different statutory instrument: the Offshore Oil and Gas Exploration, Production, Unloading and Storage (Environmental Impact Assessment) Regulations 2020. The Scottish court applied the consequences of Finch to that offshore framework, under which the Secretary of State and the petroleum regulator exercise their respective functions.

The legal defect in Jackdaw's original approval was the absence of an adequate assessment of downstream combustion emissions. The Supreme Court's reasoning meant that the authorities could no longer treat those emissions as outside the relevant environmental consequences of extracting hydrocarbons intended for commercial use.

2.2 The January 2025 Judgment and Suspended Quashing

On January 29, 2025, the Outer House of the Scottish Court of Session delivered its judgment in Petitions by Greenpeace Limited and Uplift for Judicial Review [2025] CSOH 10. The proceedings concerned the Jackdaw gas development and the separate Rosebank oil project.

Following Finch, the parties accepted that the earlier decisions were unlawful because their environmental impact assessments had omitted downstream emissions. The central contested issue was the appropriate judicial remedy, particularly whether the consents should be quashed or allowed to remain effective despite their acknowledged unlawfulness.

Lord Ericht concluded that the public interest in lawful decision-making and the climate-related interests at stake justified quashing the defective authorizations. The developers' substantial investments and commercial interests did not warrant permitting the unlawful decisions to stand. Paragraphs 151–152 of the judgment established that the authorities could reconsider the projects and issue fresh decisions after taking downstream emissions into account.

The court nevertheless suspended the effect of quashing while reconsideration took place. Offshore developments involve complex engineering schedules, specialized equipment, contractual commitments, and periods when weather conditions permit construction. An immediate halt could have produced considerable disruption even if consent were later granted again.

Under paragraphs 158–160, the developers could continue preparatory construction at their own commercial risk. Extraction and production, however, could not begin before the authorities reached fresh decisions. The court considered that allowing hydrocarbons to be extracted before their combustion emissions had been assessed would defeat a fundamental purpose of the environmental assessment regime (Court of Session, 2025).

The judgment did not permanently prohibit Jackdaw. It required renewed consideration of the development through a legally adequate procedure. The October 2026 approval followed that process, including additional environmental information, consultation, and a revised assessment of greenhouse gas emissions.

Addressing the omission identified by the Scottish court does not settle the project's status under international law. A domestic authority may complete the assessment required by national legislation while leaving unresolved whether its ultimate authorization satisfies separate international obligations governing climate protection.

3. The Climate Effects Acknowledged in the New Decision

The October 2026 decision examined a substantially broader range of greenhouse gas emissions than the assessment underlying the original consent. The Secretary of State considered emissions from extraction, downstream combustion, associated lifecycle activities, and the project's cumulative contribution to climate change.

The government accepted that Jackdaw would have likely significant environmental effects from greenhouse gas emissions under the domestic environmental impact assessment regime. This finding was reached despite the developer's assessment that the project's effects were not significant.

The Secretary of State ultimately assigned moderate adverse weight to the greenhouse gas effects while concluding that other considerations justified approval. The decision consequently recognized substantial climate consequences rather than treating the project's emissions as scientifically negligible (Department for Energy Security and Net Zero, 2026, paras. 173–183).

3.1 Jackdaw's 36.6 Million Tonnes of Projected Emissions

The government's decision estimates Jackdaw's total lifetime greenhouse gas emissions at approximately 36.6 million metric tons of carbon dioxide equivalent (MtCO₂e).

Approximately 35.8 MtCO₂e falls within Scope 3, while direct project emissions account for approximately 0.81 MtCO₂e (Department for Energy Security and Net Zero, 2026, paras. 40–44).

Scope 1 comprises direct greenhouse gas emissions associated with project activities. Scope 3 covers emissions arising elsewhere in the value chain, including processing, transportation, and the eventual combustion of produced hydrocarbons. For Jackdaw, downstream activities account for approximately 98% of the total assessed emissions.

The government estimated that combustion alone would generate approximately 30.5 MtCO₂e. The larger Scope 3 figure includes additional emissions associated with processing and transportation before final consumption. The combustion estimate is already included within the broader lifecycle assessment and cannot be added to it without double counting.

These estimates were calculated using the P10 production scenario, representing a higher-production case with a 10% probability that the forecast volume will be equaled or exceeded. The government selected this scenario to avoid understating potential environmental effects, rather than relying solely on the more probable P50 forecast.

The assessment also assumed that all extracted hydrocarbons would ultimately be combusted. This precautionary assumption does not establish that every quantity of condensate or natural gas liquids will necessarily be burned. Some products could be used as industrial feedstocks, but the government declined to rely on uncertain noncombustion uses to reduce its emissions estimate.

The figures represent projected lifetime emissions, not emissions already released. Actual quantities will depend on production volumes, operational performance, transportation, and the eventual use of the hydrocarbons.

Nevertheless, the predominance of Scope 3 emissions illustrates why the original environmental assessment was inadequate. An examination restricted to the offshore platform would exclude most of the climate effects associated with producing and consuming Jackdaw's gas and condensate.

3.2 Cumulative Climate Effects and the Global Carbon Budget

Greenhouse gas emissions contribute to climate change through their cumulative effect on atmospheric concentrations. The significance of an individual project cannot be determined solely by comparing its emissions with worldwide annual totals.

The Intergovernmental Panel on Climate Change's Climate Change 2023: Synthesis Report identifies the relationship between cumulative anthropogenic carbon dioxide emissions and global temperature increases. Limiting warming requires substantial and sustained reductions in emissions, with the remaining carbon budget becoming increasingly constrained as emissions continue (IPCC, 2023).

The October decision acknowledged that Jackdaw's projected emissions were relatively small when considered separately against global emissions and the remaining carbon budget. However, paragraph 176 recognized that accounting for emissions from existing and approved projects left little, if any, remaining global budget within the assessment considered by the Secretary of State.

This finding is significant because assessing developments individually may obscure their collective climate consequences. A project can represent a small fraction of worldwide emissions while still contributing to the cumulative increase in greenhouse gas concentrations.

The International Energy Agency's net-zero scenarios provide additional context. Its Net Zero by 2050 pathway envisages declining fossil fuel demand and does not require approval of new long-lead-time conventional oil and gas developments. The government distinguished Jackdaw from those projects because much of its infrastructure was already completed and production could begin relatively quickly.

That distinction concerns the factual applicability of an energy-system scenario. It does not independently establish compliance with international law. The IEA's modeling is relevant scientific and policy evidence, but it does not impose a binding prohibition on individual petroleum developments.

The Secretary of State also acknowledged that no project-specific measures had been proposed to mitigate Scope 3 emissions for environmental assessment purposes. Measures intended to reduce operational emissions do not eliminate the carbon dioxide released when extracted gas is ultimately burned (Department for Energy Security and Net Zero, 2026, para. 177).

The government assessed gross projected emissions rather than subtracting an assumed benefit from displaced foreign production. This precautionary approach reflects uncertainty about whether other gas would otherwise be extracted, where that production might occur, and how worldwide consumption would respond.

Gross emissions are not necessarily identical to the net increase that would occur relative to every possible scenario without Jackdaw. Establishing that difference would require credible evidence about displaced production and changes in demand. The decision did not establish a reliable quantity of avoided foreign emissions.

The remaining global carbon budget does not constitute a legally assigned emissions allowance for Jackdaw. International climate law contains no specific project-level quota allocating the field a fixed proportion of permissible worldwide emissions. The scientific evidence remains relevant because it informs the seriousness and foreseeability of climate risks against which governmental due diligence must be assessed.

4. What the ICJ Climate Advisory Opinion Requires

On July 23, 2025, the International Court of Justice delivered its advisory opinion in Obligations of States in Respect of Climate Change. The proceedings followed a request from the United Nations General Assembly concerning states' obligations to protect the climate system and the legal consequences of conduct inconsistent with those obligations.

The opinion identified relevant duties under climate treaties, customary international law, and other applicable international legal instruments. It also addressed the general rules governing state responsibility for internationally wrongful acts.

An advisory opinion is not a binding judgment between disputing states. Its significance lies in the Court's authoritative interpretation of international law, including obligations that may independently bind states through treaties or custom. The legal status and effects of ICJ advisory opinions must consequently be distinguished from the binding character of the rules they interpret.

The Court did not examine Jackdaw or decide that every new fossil fuel development is unlawful. Its reasoning nevertheless provides standards for assessing governmental decisions that permit activities contributing to greenhouse gas emissions.

4.1 The Paris Agreement and National Mitigation Duties

The Paris Agreement, adopted in 2015, establishes the principal treaty framework governing international climate mitigation. Article 2(1)(a) sets the collective objective of holding global warming well below 2°C above preindustrial levels and pursuing efforts to limit the increase to 1.5°C.

In paragraph 224 of its advisory opinion, the ICJ interpreted 1.5°C as the parties' agreed primary temperature goal, taking account of scientific developments and subsequent decisions under the climate regime. The Court treated this objective as central to understanding the obligations established by the Agreement.

Article 4(2) requires parties to prepare, communicate, and maintain successive nationally determined contributions (NDCs). States must pursue domestic mitigation measures aimed at achieving the objectives of those contributions.

Article 4(3) requires successive contributions to represent progression and reflect each party's highest possible ambition, taking account of common but differentiated responsibilities and respective capabilities.

These obligations form the legal foundation of the Paris Agreement's system of nationally determined climate commitments. Parties retain discretion over the measures selected to pursue their national objectives, but that discretion operates within binding treaty requirements.

The ICJ emphasized that preparing NDCs requires stringent due diligence. In paragraphs 245–246, the Court examined the legal expectations governing national ambition. Paragraph 253 addressed the duty to pursue domestic mitigation measures reasonably capable of achieving the objectives of a state's contribution (ICJ, 2025).

The Paris Agreement does not ordinarily make achievement of every NDC emissions target an unconditional legal guarantee. The obligation to pursue domestic mitigation measures nevertheless requires substantive efforts directed toward the agreed objectives.

The treaty contains no express universal prohibition on authorizing an individual gas development. Whether a particular decision is compatible with Article 4 depends on the applicable duties and the relationship between the authorization and the state's mitigation conduct.

For Jackdaw, the relevant inquiry concerns whether the UK is pursuing the measures required by its international commitments while authorizing additional fossil fuel production. The existence of a nationally determined target is relevant, but it cannot independently establish the adequacy of every decision affecting future emissions.

4.2 The Customary Duty to Prevent Significant Climate Harm

The ICJ concluded that the customary international-law duty to prevent significant environmental harm applies to the climate system. Paragraph 273 of the advisory opinion places climate change within the protection afforded by the established preventive obligations of international environmental law.

The duty has a substantial judicial history. In Pulp Mills on the River Uruguay (Argentina v. Uruguay), the ICJ recognized the obligation to exercise due diligence to prevent activities within a state's jurisdiction from causing significant environmental harm beyond its borders (ICJ, 2010, para. 101).

Climate change differs from conventional transboundary pollution because its causes and effects are cumulative, geographically dispersed, and dependent on emissions from many sources. The ICJ concluded that these characteristics do not exclude the climate system from customary prevention obligations.

Due diligence requires appropriate conduct in response to foreseeable risks. Relevant considerations include available scientific evidence, the magnitude and severity of potential harm, the state's regulatory capabilities, and the measures reasonably available to it.

The obligation does not guarantee that no environmental harm will occur. Its content is determined by the precautions and regulatory efforts required in the particular circumstances. A failure to achieve a desired environmental outcome does not automatically establish a breach, but inadequate preventive conduct may do so (ICJ, 2025, paras. 273–282).

Environmental impact assessment forms part of this legal framework. The Court recognized the importance of evaluating activities capable of causing significant environmental harm, while allowing states some discretion concerning assessment procedures and methodologies.

For offshore developments, additional obligations arise under the United Nations Convention on the Law of the Sea (UNCLOS). Article 192 establishes the general obligation to protect and preserve the marine environment, while Article 194 requires states to take measures to prevent, reduce, and control pollution of that environment.

In its May 21, 2024 advisory opinion, the International Tribunal for the Law of the Sea concluded that anthropogenic greenhouse gas emissions can constitute marine pollution under UNCLOS. It identified stringent due diligence obligations concerning the prevention, reduction, and control of such pollution, taking account of scientific evidence and the seriousness of climate-related marine harm (ITLOS, 2024).

These duties are potentially relevant to Jackdaw because the development concerns offshore fossil fuel production and the wider climate effects of greenhouse gases on the marine environment. Neither the ITLOS opinion nor UNCLOS establishes an automatic prohibition on the field's production. Their significance lies in identifying additional obligations whose application must be assessed according to their own terms.

The Paris Agreement does not necessarily exhaust these obligations. In paragraph 314, the ICJ explained that good-faith compliance with climate treaties may indicate substantial compliance with customary duties, while recognizing that treaty and customary obligations remain legally independent.

A state may consequently satisfy particular procedural requirements under the Paris Agreement without conclusively establishing compliance with every applicable international obligation concerning climate protection.

4.3 Fossil Fuel Production and State Responsibility

Paragraph 427 of the ICJ advisory opinion directly addresses the relationship between fossil fuel activities and internationally wrongful conduct. The Court identified failures to take appropriate climate-protective action in connection with fossil fuel production, consumption, exploration licensing, and subsidies as conduct that may engage state responsibility.

The Court did not characterize greenhouse gas emissions themselves as automatically unlawful. The relevant internationally wrongful act consists of a breach of an applicable treaty or customary obligation attributable to the state (ICJ, 2025, para. 427).

Jackdaw's existing petroleum license does not remove the production decision from this reasoning. The Court's formulation expressly includes fossil fuel production, not exclusively the issuance of new exploration licenses.

Paragraph 428 addresses emissions generated by private enterprises. Their commercial activities are not automatically attributable to the state merely because they occur within its jurisdiction.

International responsibility may instead arise from the state's own actions or omissions, including failure to adopt or implement regulatory measures required by its obligations. The relevant conduct may concern legislative decisions, regulatory supervision, or inadequate restrictions on emissions-producing activities.

The ICJ's approach requires assessment of governmental conduct against the applicable legal duty. A finding that a project will produce emissions establishes a relevant factual consequence, but not necessarily an internationally wrongful act.

5. The UK's Express Rejection of the ICJ's Climate Duty

The October 2026 Jackdaw decision contains an explicit governmental response to the ICJ advisory opinion. In Annex A, the Department for Energy Security and Net Zero addressed representations arguing that authorization would be inconsistent with the Court's conclusions concerning climate obligations.

The government acknowledged the ICJ's finding that the customary duty to prevent significant environmental harm applies to the climate system. It nevertheless stated that the United Kingdom did not accept that interpretation. The decision explained that the duty articulated by the Court would be considered as a matter of policy rather than as an accepted legal obligation (Department for Energy Security and Net Zero, 2026, Annex A).

This position was consistent with the UK's explanation of vote delivered at the United Nations General Assembly on June 3, 2026. Ambassador Archie Young expressed support for the resolution concerning the advisory opinion and welcomed several findings, including stringent diligence in preparing NDCs and the importance of international cooperation.

The UK also stated that it disagreed with certain conclusions and maintained reservations concerning the application of customary international law to climate protection (Foreign, Commonwealth & Development Office, 2026).

A government's disagreement with an advisory opinion does not independently establish a breach of international law. Equally, the nonbinding status of the opinion does not make customary international law optional.

Customary obligations arise through general state practice accepted as law. A state cannot establish exemption from an existing customary rule merely by rejecting a judicial interpretation of it. The legal question concerns whether the relevant obligation exists, its applicable content, and whether the state's conduct complies with it.

The October decision also distinguishes significant environmental effects under domestic environmental impact assessment law from significant harm under customary international law.

These standards perform different functions. Domestic environmental assessment requirements govern the identification and consideration of specified effects before authorization. The customary duty of prevention concerns the conduct reasonably required of states to prevent significant environmental harm.

A finding of likely significant effects under domestic legislation does not automatically establish breach of the customary obligation. The reverse proposition is equally important: completing an environmental assessment does not, by itself, establish that the substantive authorization satisfies international preventive duties.

The Secretary of State concluded that granting Jackdaw consent would not cause significant harm in the relevant international-law sense or breach the preventive duty described by the Court. This conclusion represents the government's legal assessment rather than a determination by an international tribunal.

There is also a question concerning the government's treatment of cumulative harm. Under the ICJ's reasoning, the relevance of a state's preventive duty cannot be assessed solely by asking whether one project independently causes identifiable global climate damage. The standard concerns the adequacy of governmental conduct in response to significant, foreseeable environmental risks.

The disagreement over Jackdaw consequently has two components. The first concerns the UK's rejection of the ICJ's customary-law interpretation. The second concerns whether the production authorization would satisfy the preventive standard even if the Court's interpretation were applied.

The existence and content of an international obligation must be distinguished from the factual assessment of compliance. The government's position does not conclusively determine either question.

6. The Government's Justification for Approving Jackdaw

The Secretary of State approved Jackdaw after weighing its anticipated benefits against the environmental consequences identified in the renewed assessment. Energy security received significant positive weight, while certain employment and infrastructure benefits received moderate positive weight.

The government assigned moderate adverse weight to the project's greenhouse gas emissions. It also acknowledged that continued domestic fossil fuel production could adversely affect the UK's international climate credibility.

These considerations were part of the domestic authorization process. Their international legal significance depends on the applicable obligations and the standard of conduct required. Economic benefits or energy-security interests do not automatically excuse a breach of an international obligation.

6.1 Energy Security, Domestic Supply, and Consumer Prices

The government's principal justification was Jackdaw's expected contribution to domestic gas supply during the energy transition. The UK anticipates continuing demand for natural gas as electricity generation, domestic heating, industrial processes, and transport move toward lower-emissions technologies.

At peak output, Jackdaw could produce approximately four million cubic meters of gas per day. Government analysis estimated that this quantity could supply the equivalent of approximately 350,000 homes during a rare cold winter day (Department for Energy Security and Net Zero, 2026, para. 191).

This estimate differs from the developer's annual-average comparison of approximately 1.4 million homes. The Secretary of State considered the peak-day calculation more appropriate for assessing energy-system resilience.

The field's contribution is considerably smaller when measured against all available gas supplies. The government's decision estimated that Jackdaw would account for less than 1% of total gas available from domestic production, imports, and other sources on a peak-demand day.

Jackdaw would not eliminate British reliance on imported gas. Nor would it materially reduce household energy bills, given that gas prices are influenced by international markets. The Secretary of State accepted that the field's security contribution would be small but meaningful.

The development may also extend the operational life of existing infrastructure, including the Shearwater installation. The developer estimated that Jackdaw would create 27 new direct jobs and safeguard 273 existing positions associated with continued infrastructure operations.

Employment and infrastructure considerations help explain the government's decision. They do not establish that production from this particular field is legally indispensable to national energy security.

The government's reasoning reflects the wider relationship between energy dependence, infrastructure resilience, and climate change as a security risk. Continued reliance on fossil fuels can create exposure to international price fluctuations even where domestic production provides some protection against supply disruption.

From an international-law perspective, the question is how these circumstances affect the assessment of reasonable preventive conduct. They are not an independent legal defense that automatically permits conduct contrary to binding climate obligations.

6.2 Domestic Gas and the Uncertain Displacement of Emissions

The government argues that producing gas at Jackdaw may involve lower production-stage greenhouse gas emissions than obtaining some imported alternatives, particularly liquefied natural gas.

Liquefied natural gas requires additional processing to cool and transport the fuel before it reaches consumers. These activities can increase lifecycle emissions, although comparisons depend on the source of the imported gas, methane leakage, transportation distances, and production methods.

Gas transported by pipeline from Norway, for example, does not necessarily have a higher emissions intensity than gas produced at Jackdaw. The environmental comparison cannot be reduced to a general assumption that all domestic gas is cleaner than all imports.

Lower production emissions do not eliminate the carbon dioxide released when natural gas is burned. The climate effects of downstream combustion remain substantial regardless of where extraction occurs.

The possibility of displacement introduces further uncertainty. Additional British gas production could replace some foreign production, reducing upstream emissions if the displaced supply were more carbon intensive.

However, such an outcome depends on market behavior. It is uncertain which suppliers would reduce production, whether gas consumption would change, and how alternative energy technologies would respond to the availability of additional supply.

The government did not establish a definitive quantity of global emissions that would be avoided through Jackdaw. Its environmental assessment adopted a precautionary approach by counting gross projected emissions without deducting an assumed displacement benefit (Department for Energy Security and Net Zero, 2026, paras. 45–46).

This accounting approach does not prove that the project's net global emissions effect will equal the gross estimate under every possible counterfactual. It reflects the absence of sufficiently reliable evidence to quantify the emissions that would otherwise occur.

The distinction is relevant to climate due diligence. A possible reduction in foreign production emissions can inform the factual assessment, but a government cannot treat an uncertain substitution effect as an established environmental benefit.

6.3 UK Carbon Budgets and the 2035 Climate Commitment

The Climate Change Act 2008 establishes the principal statutory framework governing the United Kingdom's domestic emissions reduction obligations.

Section 1 provides the legal basis for the 2050 net-zero target, while Section 4 requires five-year carbon budgets. Section 13 requires the Secretary of State to prepare proposals and policies considered capable of meeting those budgets.

These obligations operate at an economy-wide level. The legislation does not assign Jackdaw a separate statutory share of the remaining global carbon budget.

The UK's nationally determined contribution submitted in January 2025 commits to reducing greenhouse gas emissions by at least 81% by 2035 relative to 1990 levels, excluding international aviation and shipping emissions from that particular target (United Kingdom, 2025).

The October 2026 decision concluded that Jackdaw would not materially affect the UK's ability to meet its carbon budgets or NDC objectives. The government relied partly on projections of declining national gas demand and its wider policies for reducing emissions across the economy.

The relationship between production and territorial emissions accounting is relevant here. Under international greenhouse gas inventory arrangements, emissions are generally recorded in the country where fuel combustion occurs.

If Jackdaw gas is burned in the United Kingdom, the resulting territorial emissions will ordinarily appear in the British inventory. Where hydrocarbons are consumed abroad, the corresponding combustion emissions will generally be accounted for by the country of consumption.

These rules govern national emissions accounting. They do not conclusively determine the international obligations of a state authorizing extraction within its jurisdiction.

The ICJ's analysis of climate due diligence concerns governmental regulation and the prevention of significant environmental harm. Responsibility for recording emissions in a national inventory is consequently a different question from responsibility for exercising appropriate regulatory care.

The Climate Change Committee's Progress in Reducing Emissions: 2026 Report to Parliament provides independent context. It recognizes the UK's substantial historical emissions reductions while identifying the need for faster progress in electrification, implementation, and the delivery of policies required to meet future targets (Climate Change Committee, 2026).

The government's climate commitments support its argument that Jackdaw forms part of a regulated transition rather than an unrestricted expansion of fossil fuel production. Their legal significance nevertheless depends on whether the measures adopted and implemented meet the relevant international obligations.

The existence of national targets does not independently establish compliance with every international duty concerning fossil fuel authorization.

7. Does Jackdaw Constitute an Internationally Wrongful Act?

The legality of Jackdaw under international law must be assessed through the general rules governing state responsibility. The International Law Commission's 2001 Articles on Responsibility of States for Internationally Wrongful Acts provide the principal framework.

Article 2 identifies the essential elements of an internationally wrongful act: conduct attributable to the state and a breach of an international obligation binding on that state. These requirements are central to state responsibility in international law.

The Articles are not a universally binding treaty. They articulate general rules of international responsibility, many of which reflect customary international law and have been relied upon by international courts.

Article 3 establishes that the international characterization of state conduct is governed by international law. A determination that the same conduct is lawful under domestic law does not prevent it from being internationally wrongful.

For Jackdaw, this means that domestic authorization cannot conclusively establish international compliance. The decisive questions concern the UK's attributable conduct and whether that conduct breaches an applicable obligation.

7.1 Attribution of the UK's Production Decision

Article 4 of the International Law Commission's Articles provides that the conduct of state organs is attributable to the state under international law.

The Secretary of State's agreement to Jackdaw and the North Sea Transition Authority's grant of consent are exercises of public authority attributable to the United Kingdom. Establishing attribution of these official decisions does not present the same difficulties that may arise when considering conduct undertaken independently by private enterprises.

Adura's commercial operations and the eventual combustion of hydrocarbons by consumers must be distinguished from the government's own decisions. Private emissions are not automatically attributable to the British state merely because extraction occurs under a UK petroleum license.

The ICJ addressed this issue in paragraph 428 of its 2025 advisory opinion. Where private enterprises contribute to greenhouse gas emissions, the relevant internationally wrongful conduct may arise from a state's failure to adopt or implement appropriate regulatory measures.

For Jackdaw, the legally attributable conduct includes the authorization decision and potentially relevant governmental acts or omissions concerning the regulation of emissions-producing activities.

Attribution alone does not establish wrongfulness. The existence of an internationally wrongful act depends on whether the identified governmental conduct breaches a legal obligation applicable to the United Kingdom.

7.2 The Competing Assessments of Legal Compliance

The government's argument for the lawfulness of Jackdaw rests on the distinction between authorizing fossil fuel production and failing to exercise adequate climate due diligence.

International law does not presently establish an express universal prohibition on every additional gas development. The ICJ's reasoning requires examination of the state's conduct against applicable treaty and customary obligations rather than treating production itself as automatically unlawful.

The UK can point to its renewed environmental assessment, statutory carbon budgets, mitigation policies, 2035 NDC, and 2050 net-zero commitment. It also relies on the field's advanced development stage, anticipated short production period, and contribution to domestic energy security.

Under this interpretation, the government has evaluated the project's foreseeable emissions within an economy-wide mitigation framework. The relevant duty concerns reasonable preventive action rather than an absolute guarantee that no emissions will occur.

The opposing interpretation emphasizes the stringent nature of climate due diligence identified by the ICJ and the environmental findings contained in the government's own decision.

Jackdaw's projected lifetime emissions reach approximately 36.6 MtCO₂e. The Secretary of State acknowledged their cumulative contribution to climate change, recognized the severe constraints on the remaining global carbon budget, and accepted that no project-specific mitigation had been proposed for Scope 3 emissions.

These findings raise questions about the adequacy of the regulatory response. Identifying significant climate effects is relevant evidence of environmental assessment, but the international duty of prevention may require further measures depending on the applicable legal standard and circumstances.

The UK's capabilities are relevant to this assessment. The ICJ recognized that due diligence is stringent and must be evaluated in light of factors including available scientific knowledge, the seriousness of foreseeable harm, and a state's capacity to take preventive action.

The Paris Agreement also requires consideration of common but differentiated responsibilities and respective capabilities. Its obligations do not impose identical expectations on every state regardless of development level, resources, or regulatory capacity.

The government's argument that Jackdaw is compatible with national climate targets is material but not necessarily conclusive. The ICJ recognized that treaty obligations and customary prevention duties remain independent, even where compliance with one set of obligations provides evidence relevant to the other.

The domestic environmental assessment also has a limited legal function. Compliance with Finch and the Scottish judgment addresses the requirement to assess downstream emissions before granting consent. It does not automatically establish that authorizing production satisfies every applicable international obligation.

A finding of breach would require identifying the specific primary rule, determining the conduct required by that rule, and assessing whether the UK's actions or omissions fell below the applicable standard.

Under the ICJ's interpretation, this inquiry would include the customary duty to prevent significant climate harm. The UK disputes that interpretation, creating a separate legal disagreement over the content of its obligations.

The government's approval and its disagreement with the ICJ do not independently establish international responsibility. Equally, its national climate commitments and domestic authorization do not provide a conclusive determination of international lawfulness.

The available facts establish the existence of a substantial legal question concerning regulatory due diligence. They do not establish a judicial finding that the October 2026 consent constitutes an internationally wrongful act.

7.3 Causation, Legal Remedies, and Further Proceedings

Climate change presents particular difficulties for the law of state responsibility because greenhouse gas emissions originate from numerous sources and accumulate over extended periods.

The ICJ considered these difficulties in paragraphs 429–438 of its advisory opinion. It concluded that the cumulative nature of climate change does not render the general rules of state responsibility incapable of application.

An essential distinction concerns the relationship between breach and damage. Paragraph 433 explains that causation of damage is not a necessary element of establishing state responsibility in every case. An internationally wrongful act arises where attributable conduct breaches an applicable obligation.

Claims for reparation require further analysis. Where compensation is sought for particular climate-related damage, a sufficiently direct and certain causal connection must be established between the wrongful conduct and the injury for which compensation is claimed (ICJ, 2025, paras. 433–438).

The presence of multiple contributing states does not automatically prevent responsibility from being established. However, neither scientific evidence of global climate change nor the existence of emissions from a particular project independently proves that a state is legally responsible for a specific injury.

The International Law Commission's Articles recognize several possible consequences of internationally wrongful conduct, including cessation of a continuing breach, assurances of non-repetition where appropriate, and reparation for legally attributable injury.

Their availability depends on the nature of the established violation and the applicable rules. A finding that a government failed to exercise due diligence would not automatically determine the extent of compensation for particular climate damage.

The ICJ also addressed obligations protecting collective environmental interests. In paragraphs 440–443, the Court characterized the customary duty to prevent significant climate harm as an obligation owed to the international community as a whole, while identifying the principal climate treaty obligations as obligations owed to all treaty parties.

These legal interests may permit states to invoke responsibility for breaches even when they have not suffered individually identifiable injury. The remedies available to an injured state and those available to a state invoking a collective obligation are not necessarily identical.

The ability to invoke responsibility must also be distinguished from jurisdiction. The ICJ cannot automatically exercise contentious jurisdiction over the United Kingdom merely because another state alleges a breach of climate obligations. A recognized jurisdictional basis is required.

Domestic litigation operates through a separate legal framework. The October authorization could potentially be challenged through judicial review on grounds relating to the environmental assessment, the treatment of relevant considerations, or other requirements governing the decision.

Such proceedings would depend on the applicable procedural rules and grounds advanced. The Scottish court's earlier judgment does not predetermine the legality of the renewed consent, and the possible relevance of international law would depend on the particular legal issues before the domestic court.

The ICJ's advisory opinion provides authoritative guidance on the international obligations relevant to the UK's conduct. It did not decide Jackdaw's legality, establish that a breach had occurred, or determine remedies arising from this particular authorization.

Conclusion

The United Kingdom's October 2026 approval of the Jackdaw gas field creates a genuine dispute concerning the interpretation and application of international climate law. The government authorized production after acknowledging substantial projected downstream emissions and expressly rejecting the ICJ's conclusion that the customary duty to prevent significant environmental harm applies to the climate system.

The advisory opinion does not establish an unconditional prohibition on individual fossil fuel projects. It recognizes that governmental failures to take appropriate climate-protective measures, including in connection with fossil fuel production, may constitute internationally wrongful acts. The Scottish Court of Session's earlier judgment likewise required lawful reassessment rather than permanent cancellation of Jackdaw.

The renewed environmental assessment addressed the principal procedural defect identified in the domestic litigation. It did not conclusively resolve the separate international-law question. The government's climate commitments, regulatory safeguards, and energy-security arguments are relevant to assessing its conduct, but their sufficiency must be evaluated against the applicable international obligations.

The decisive issue is whether the United Kingdom exercised the preventive diligence required by international law when authorizing production in light of foreseeable downstream emissions and cumulative climate risks. The available record does not establish that Jackdaw's approval itself constitutes an internationally wrongful act. It does establish a substantive disagreement between the UK's legal position and the ICJ's interpretation of customary climate obligations, with consequences extending beyond the domestic validity of the production consent.

References

Climate Change Act 2008 (2008) 26 November, c. 27. Available at: https://www.legislation.gov.uk/ukpga/2008/27/contents (Accessed: 21 October 2026).

Climate Change Committee (2026) Progress in Reducing Emissions: 2026 Report to Parliament. London: Climate Change Committee. Available at: https://www.theccc.org.uk/publication/progress-in-reducing-emissions-2026-report-to-parliament/ (Accessed: 21 October 2026).

Department for Energy Security and Net Zero (2026a) Jackdaw gas field gets green light [online]. Published 21 October 2026. Available at: https://www.gov.uk/government/news/jackdaw-gas-field-gets-green-light (Accessed: 21 October 2026).

Department for Energy Security and Net Zero (2026b) Secretary of State Decision to Agree or Refuse to Agree to OGA Granting Consent: Jackdaw Field Development. Decision dated 14 October 2026, published 21 October 2026. London: Department for Energy Security and Net Zero. Available at: https://assets.publishing.service.gov.uk/media/6ad77f4e13c9ff4fd08ed632/20261014_Jackdaw_decision_doc.pdf (Accessed: 21 October 2026).

Foreign, Commonwealth & Development Office (2026) The UK's explanation of vote on the UN General Assembly resolution on the ICJ's Advisory Opinion on climate change [online]. Statement delivered by Ambassador Archie Young, 3 June 2026.

Published 4 June 2026. Available at: https://www.gov.uk/government/speeches/the-uks-explanation-of-vote-on-the-un-general-assembly-resolution-on-the-icjs-advisory-opinion-on-climate-change (Accessed: 21 October 2026).

International Court of Justice (2010) Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment, 20 April 2010, I.C.J. Reports 2010, p. 14. Available at: https://www.icj-cij.org/case/135/judgments (Accessed: 21 October 2026).

International Court of Justice (2025) Obligations of States in Respect of Climate Change, Advisory Opinion, 23 July 2025, General List No. 187. Available at: https://www.icj-cij.org/case/187/advisory-opinions (Accessed: 21 October 2026).

International Energy Agency (2021) Net Zero by 2050: A Roadmap for the Global Energy Sector. Paris: International Energy Agency. Available at: https://www.iea.org/reports/net-zero-by-2050 (Accessed: 21 October 2026).

International Law Commission (2001) Draft Articles on Responsibility of States for Internationally Wrongful Acts, with Commentaries. Report of the International Law Commission on the Work of Its Fifty-third Session, UN Doc. A/56/10, Chapter IV. Available at: https://legal.un.org/ilc/texts/9_6.shtml (Accessed: 21 October 2026).

Intergovernmental Panel on Climate Change (2023) Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Core Writing Team, H. Lee and J. Romero (eds.). Geneva: IPCC. DOI: 10.59327/IPCC/AR6-9789291691647. Available at: https://www.ipcc.ch/report/ar6/syr/ (Accessed: 21 October 2026).

International Tribunal for the Law of the Sea (2024) Request for an Advisory Opinion Submitted by the Commission of Small Island States on Climate Change and International Law, Advisory Opinion, 21 May 2024, Case No. 31. Available at: https://www.itlos.org/fileadmin/itlos/documents/cases/31/Advisory_Opinion/C31_Adv_Op_21.05.2024_orig.pdf (Accessed: 21 October 2026).

North Sea Transition Authority (2026) NSTA grants consent for Jackdaw [online]. Published 21 October 2026. Available at: https://www.nstauthority.co.uk/news-publications/nsta-grants-consent-for-jackdaw/ (Accessed: 21 October 2026).

Offshore Oil and Gas Exploration, Production, Unloading and Storage (Environmental Impact Assessment) Regulations 2020 (2020) SI 2020/1497. Available at: https://www.legislation.gov.uk/uksi/2020/1497/contents (Accessed: 21 October 2026).

Paris Agreement (2015) Adopted 12 December 2015, entered into force 4 November 2016, 3156 UNTS 79. Available at: https://unfccc.int/sites/default/files/parisagreement_publication.pdf (Accessed: 21 October 2026).

Scottish Court of Session (2025) Petitions by Greenpeace Limited and Uplift for Judicial Review, Opinion of Lord Ericht, 29 January 2025, [2025] CSOH 10. Available at: https://www.scotcourts.gov.uk/media/v0zkbsxy/2025csoh10-petitions-by-greenpeace-limited-and-uplift-for-judicial-review.pdf (Accessed: 21 October 2026).

Town and Country Planning (Environmental Impact Assessment) Regulations 2017 (2017) SI 2017/571. Available at: https://www.legislation.gov.uk/uksi/2017/571/contents (Accessed: 21 October 2026).

UK Supreme Court (2024) R (on the application of Finch on behalf of the Weald Action Group) v Surrey County Council and Others, Judgment, 20 June 2024, [2024] UKSC 20. Available at: https://supremecourt.uk/cases/judgments/uksc-2022-0064 (Accessed: 21 October 2026).

United Kingdom (2025) United Kingdom of Great Britain and Northern Ireland's 2035 Nationally Determined Contribution. Command Paper CP 1250, 30 January 2025. London: Department for Energy Security and Net Zero. Available at: https://www.gov.uk/government/publications/uks-2035-nationally-determined-contribution-ndc-emissions-reduction-target-under-the-paris-agreement/united-kingdom-of-great-britain-and-northern-irelands-2035-nationally-determined-contribution (Accessed: 21 October 2026).

United Nations Convention on the Law of the Sea (1982) Adopted 10 December 1982, entered into force 16 November 1994, 1833 UNTS 3. Available at: https://treaties.un.org/Pages/showDetails.aspx?clang=_en&objid=0800000280043ad5 (Accessed: 21 October 2026).