Unpleaded Climate Points Cannot Be Certified; EIA Does Not Require State‑Wide Cumulative Traffic GHG Assessment — Commentary on Friends of Killymooney Lough v An Coimisiún Pleanála (No. 2) [2025] IEHC 576

Introduction

This commentary examines the High Court of Ireland’s decision in Friends of Killymooney Lough v An Coimisiún Pleanála & Ors (No. 2) [2025] IEHC 576, delivered by Humphreys J. on 31 October 2025. The decision arises at the leave-to-appeal stage under sections 50, 50A and 50B of the Planning and Development Act 2000, following the Court’s principal judgment on 16 July 2025 upholding a grant of planning permission for a Tesco retail development in Cavan (ABP-318406-23).

The applicant sought a certificate for leave to appeal on three climate-centric questions, newly framed after the adverse substantive judgment, which purported to raise issues of exceptional public importance: (i) whether, under the EIA Directive, transport-related greenhouse gas (GHG) emissions must be cumulatively assessed with other existing/approved projects against the Climate Action Plan 2024 (CAP24); (ii) whether effects “inconsistent” with the matters in section 15(1)(a)–(e) of the Climate Action and Low Carbon Development Act 2015 are per se significant under the EIA Directive; and (iii) whether, in such circumstances, the planning authority must give specific s.15 reasons for nonetheless granting permission.

The Court refused certification. The judgment is significant for three reasons. First, it emphatically reasserts pleading discipline: appellate courts will not entertain points that were neither pleaded, evidenced, argued, nor decided at first instance, especially in complex, evolving areas such as climate law. Second, it rejects as unworkable an EIA approach that would require State‑wide cumulative assessment of all transport GHG emissions to benchmark significance against CAP targets. Third, while declining to apply them in this case (because unpleaded), the Court sketches a provisional, pragmatic, three‑step framework for assessing “emissions‑causing projects” under the Climate Act regime.

Summary of the Judgment

Certification refused: The applicant’s three proposed questions were not pleaded or argued below and thus did not properly arise for certification under s.50A (paras 19–25, 43(i)).
Workability matters: The Court views as “totally unworkable” the suggestion that the EIA process required the authority to assess “all transport emissions in the State” to determine significance vis‑à‑vis CAP24 (para 43(ii)), invoking Supreme Court guidance rejecting “impossibly onerous and unworkable obligations.”
No “after‑the‑fact” reprogramming: Attempts to retrofit new law points (including detailed s.15 obligations) post‑judgment, or to stimulate a perception of conflicting jurisprudence by introducing new authorities at leave stage, do not meet the “exceptional public importance” threshold (paras 27–33).
Public interest: An appeal was not in the public interest. The emissions here were “very low,” the climate issues were poorly framed and unpleaded, and tangible prejudice to the notice party (jobs, economic impact, and prolonged uncertainty) weighed against certification (paras 36–42).
Obiter guidance: Subject to future clarification by the Supreme Court (notably in pending Coolglass), the Court tentatively outlines three steps for assessing an emissions‑causing project: (i) identify net emissions against a baseline; (ii) evaluate against national/sectoral “headroom” under relevant climate instruments; and (iii) consider the practicability of compliance if headroom would be exceeded (para 17). The Court expressly did not apply this to the case due to pleading deficiencies (para 18).
Order: Leave to appeal refused; conditional costs direction if a leapfrog appeal is sought and granted; otherwise no order as to the leave costs; and the orders to be perfected forthwith (para 44).

Analysis

Precedents Cited and Their Influence

An Taisce v An Bord Pleanála (Kilkenny Cheese) [2022] IESC 8 (Hogan J.): Relied on to reject “impossibly onerous and unworkable obligations” in environmental assessment (para 43(ii)). This case underpins the Court’s refusal to impose a State‑wide cumulative traffic GHG analysis via the EIA significance test.
Connelly v An Bord Pleanála [2018] IESC 31: Cited as the authoritative statement on reasons—no fresh “clarification” was needed for the applicant’s third question (para 43(iv)).
Concerned Residents of Treascon and Clondoolusk v An Bord Pleanála [2024] IESC 28 (Murray J.): The High Court signposts how appellate courts will dispose of poorly framed or procedurally defective issues; a cautionary reminder against propelling half‑developed arguments to appeal (para 37).
Massey v An Bord Pleanála (No. 4) [2025] IEHC 309: Referred to for the general leave principles and for the Court’s earlier critique of manufacturing “conflicts” by adducing new authorities post‑judgment (paras 8, 31).
Carrownagowan (No. 3) [2024] IEHC 549: Cited (via submissions adopted) to reinforce that the mere absence of appellate authority does not itself create uncertainty warranting certification (para 32).
100 Meter Tall Group v An Bord Pleanála [2025] IEHC 42: Employed to illustrate that a broad reference in pleadings (e.g., to “Hen Harrier,” or here, to “climate”) does not authorise raising entirely new, unpleaded points later (para 19).
O’Sullivan v HSE [2023] IESC 11 and O’Sullivan v Sea Fisheries Protection Authority [2017] IESC 75: Quoted for procedural discipline and to emphasise that draft judgment procedures do not open a new litigation phase (paras 6, citing para 39 of O’Sullivan v HSE, and O’Donnell J. in O’Sullivan v SFPA).
External authorities invoked by the applicant (Finch [2024] UKSC 20; EFTA Court Greenpeace Nordic, Case E-18/24; Hassard et al [2025] NIKB 42): The Court accepted submissions that these did not support the applicant’s unworkable EIA thesis and cautioned against contriving “conflicts of jurisprudence” at certification stage (paras 31–32).

Legal Reasoning

Humphreys J. organises the decision around the statutory certification test and core principles of appellate procedure, enriched by pragmatism in environmental assessment.

The threshold for certification under s.50A: The Court treated the applicant’s questions as neither properly arising nor suitable for certification. Arguments of “exceptional public importance” must be tied to pleaded and decided issues. Generating new questions post‑judgment is, in the Court’s words, a “hellish legal bingo” strategy that fails the test (paras 27–29, 33, 35).
Pleading discipline and constitutional role allocation: The Court refused to let the appellate courts be turned into courts of first instance on novel climate points “neither pleaded, evidenced, argued, [nor] considered” below, particularly in an evolving, non‑mechanistic area such as climate law (para 1). This underwrites a constitutional separation of functions between trial and appellate courts in complex fact‑sensitive fields.
Workability as a limiting principle: Drawing on Kilkenny Cheese, the Court rejected the applicant’s proposed EIA duty to assess State‑wide cumulative transport emissions to benchmark CAP24 compliance. Such an obligation would be “impossibly onerous,” “unworkable,” and—in context—contrary to the design of EIA significance analysis (paras 30, 43(ii)).
EIA vs climate budgeting: The Court drew a careful distinction between (a) EIA’s project‑level assessment of likely significant effects and (b) the Climate Act’s budgetary tools (carbon budgets, sectoral ceilings, CAP, national objective). If anything, an “overall situation in the State” is assessed at the climate budgeting level (e.g., EPA reporting), not by forcing the EIA process to cumulate and evaluate all State projects (para 34). The applicant’s re-cast EIA theory conflated the two.
Consistency and candour in argument: The Court noted a glaring inconsistency: the applicant both attacked CAP24’s validity and simultaneously wanted to use CAP24 as a significance benchmark—undermining the coherence of its proposed questions (para 21).
Reasons law is settled: The Court declined to “clarify” reasons obligations under s.15 as the more general reasons doctrine is settled (Connelly), and the applicant had not properly raised an s.15 reasons case at first instance (paras 22, 25, 43(iv)).
Provisional guidance for emissions‑causing projects (obiter): While refusing to apply it here due to pleading defects, the Court outlined a pragmatic three-step approach for decision-makers (planning authorities/An Coimisiún Pleanála) confronted with emissions‑causing projects (paras 17–18):
- Step 1: Identify net GHG emissions against a “no‑project” baseline, including indirect emissions (what the judgment analogises to “scope 3” in EIA terms), accounting for mitigation/offsets (including those capable of being conditioned).
- Step 2: Evaluate the net emissions against available national and sectoral “headroom” under relevant climate instruments (carbon budgets, sectoral ceilings, CAP, etc.).
- Step 3: If the project would exceed headroom, determine whether non‑compliance is nonetheless justified by practicability (e.g., imperative needs such as energy security).
The Court expressly deferred full adoption of this framework pending Supreme Court guidance in Coolglass and proper pleading in a suitable case.
Public interest and prejudice: The Court attached weight to the modest, temporary emissions profile in this case, the prolonged timeline (nearly three years since application), and the real-world prejudice to the notice party and community (circa 200 jobs; local economic benefits) against the backdrop of the costs‑protected regime. On balance, an appeal would not serve the public interest (paras 36–42).

Impact

For litigants (especially environmental NGOs): The decision is a firm reminder that climate‑law arguments—particularly those invoking s.15 of the Climate Act, carbon budgets, sectoral ceilings, CAP consistency, and reasons—must be pleaded with precision and supported by evidence at first instance. Reframing a case after an adverse judgment, even in a rapidly evolving field, will not ground certification.
For An Coimisiún Pleanála and planning authorities: While obiter, the Court’s three‑step framework provides a practical orientation for handling emissions‑causing projects. It emphasises quantification against a baseline, evaluation against headroom, and practicability. Authorities should anticipate deepening expectations around quantitative analysis and reasoned evaluation against climate instruments—subject to whatever the Supreme Court decides in Coolglass.
For the EIA practice community: The judgment curtails efforts to transform EIA significance analysis into an all‑projects, State‑wide cumulative carbon budgeting exercise. EIA remains a project‑focused instrument. Climate budgeting comparisons belong to the statutory climate architecture (e.g., EPA reporting on budgets/ceilings), not to a re-invented EIA mandate.
For appellate practice: The Court’s trenchant critique of “legal bingo” at leave stage will likely discourage attempts to stimulate perceived conflicts or novelty by producing new authorities post‑judgment. Certification remains exceptional; absence of on‑point appellate case law does not, without more, create an uncertainty warranting leave.
Systemic development of climate law: Humphreys J. signals that robust climate issues are better aired at first instance with full pleading and evidence, rather than being launched on weak facts through under‑analysed propositions. The Court also hints that stronger test cases are currently in the pipeline, and that the Supreme Court’s decision in Coolglass will be pivotal for s.15 obligations—especially for emissions‑reducing projects, and by inference for emissions‑increasing ones.

Complex Concepts Simplified

Section 50A certification (Planning and Development Act 2000): In planning judicial reviews, an appeal to the Court of Appeal generally requires a High Court certificate that the decision involves a point of law of exceptional public importance and that an appeal is desirable in the public interest. This is a strict threshold.
EIA “cumulative effects” vs “climate budgeting”:
- EIA cumulative effects are project‑level assessments of how a project’s impacts combine with other projects’ impacts where relevant and reasonably identifiable.
- Climate budgeting (under the Climate Act) is a national/sectoral regime of carbon budgets, sectoral ceilings, a Climate Action Plan (CAP), and a national climate objective, typically monitored at a national policy and EPA‑report level. The judgment resists collapsing the latter into EIA significance assessments.
“Scope 3” analogy: Although “scope 1/2/3” is a GHG inventory concept, the Court alludes to “what would be scope 3 in EIA terms” to capture indirect emissions attributable to the project (e.g., downstream transport). The key point is to identify and, where appropriate, quantify project‑attributable emissions against a baseline.
“Headroom”: This is the remaining allowable emissions capacity within a national or sectoral ceiling/budget under climate policy instruments. A project that consumes headroom may be acceptable or not depending on the climate instruments and the practicability of compliance.
Reasons (Connelly standard): Decision‑makers must give clear, intelligible reasons enabling parties to understand why a decision was taken and enabling a reviewing court to exercise supervision. The Court held that the applicant’s attempt to re‑open “s.15 reasons” at leave stage was not properly pleaded and, in any event, the general law on reasons is settled.
Draft judgment circulation: The Court reminds practitioners that draft judgments are not public domain, are circulated to correct errors, and are not an invitation to re‑argue the case. Submissions are confined to specified matters (paras 5–6).

Further Observations

Applicant’s proposed “seven‑step” s.15/EIA protocol: The applicant put forward an extensive, prescriptive sequence of steps for handling emissions‑causing projects—culminating in a presumption against permission absent CAP consistency and compatibility with budgets/ceilings and the national climate objective. The Court declined to endorse or apply this, describing it as over‑elaborate and unpleaded, and instead offered a more streamlined, provisional three‑step approach (paras 10–13, 17–18).
Not a “companion” to Coolglass: The applicant’s portrayal of the case as “complementary” to the Supreme Court’s pending Coolglass appeal was firmly rejected. The s.15 points were not pleaded here and the facts (very limited, temporary emissions) made the case a poor vehicle for appellate clarification of climate doctrine (paras 1, 17–18, 23, 33, 36–37).
Consistency in litigant positioning: The Court emphasised that the applicant had effectively conceded key climate concepts articulated in the principal judgment, yet attempted to argue that those concepts had not been applied in its favour. Having accepted the principles, a further complaint without proper pleading or factual foundation could not be certified (paras 23–24).
Economic and procedural fairness context: The Court balanced climate concerns with fairness to the notice party and broader public interest considerations: lengthy process history, costs‑protection dynamics (s.50B), significant local employment, and the limited emissions profile of the project (paras 38–42).

Conclusion

Killymooney Lough (No. 2) consolidates three interlocking propositions that will shape Irish climate‑related planning litigation:

Pleading discipline governs certification: New climate arguments, including s.15 Climate Act duties, cannot be retrofitted at the leave stage. The appellate courts will not act as courts of first instance on novel points that were never pleaded, evidenced, or argued below.
Workability limits EIA obligations: EIA significance does not require a State‑wide cumulative assessment of transport GHGs benchmarked against CAP. Attempts to impose “impossibly onerous” obligations on EIA are inconsistent with Supreme Court authority.
Climate budgeting is not EIA by another name: The Court draws a boundary between project‑level environmental assessment and national/sectoral climate accounting. If climate headroom is to be considered, it belongs within the Climate Act framework and must be properly pleaded and evidenced.

Although strictly obiter, the Court’s three-step guidance for emissions‑causing projects—quantify net emissions against a baseline; test them against national/sectoral headroom; and, if necessary, examine the practicability of compliance—will likely inform best practice for decision‑makers pending higher‑court clarification. But the message is unmistakable: climate litigation must proceed with precision, coherence, and procedural integrity. On the facts of this case—limited emissions, extensive delay, and unpleaded climate theories—the High Court rightly refused to certify an appeal.