Supreme Court Clarifies Duties of Public Bodies Under National Climate Policy

Supreme Court judgment provides welcome clarity for public bodies on their obligations arising from national climate policy  

On 4 February 2026, the Supreme Court issued judgment in Coolglass Wind Farm Limited v An Coimisiún Pleanála [2026] IESC 5*, upholding on different and narrower grounds the decision of the High Court to quash a decision of An Coimisiún Pleanála (the Commission) for failure to comply with its obligations under Section 15 of the Climate Action and Low Carbon Development Act 2015 (as amended) (the 2015 Act). Byrne Wallace Shields LLP acted for the Commission in this case of systemic importance which is the first time the Supreme Court has had the opportunity to consider the implications of Section 15 of the 2015 Act.  The measured judgment from the Court provides welcome clarity for public bodies on their obligations arising from national climate policy.    

Legislation

The core focus of the decisions of the High Court and Supreme Court was the interpretation of Section 15 of the 2015 Act as amended by Section 17 of the Climate Action and Low Carbon Development (Amendment) Act 2021 (the 2021 Act). Section 15(1) of the 2015 Act requires all public and prescribed bodies (as defined in the FOI Acts), in so far as practicable, to perform their functions in line with approved climate action plans, national long term climate action strategies and overall national climate objectives.    

Background

In 2024, the Commission refused an application from Coolglass Wind Farm Limited (the Respondent) for the construction of a 13-turbine wind farm and associated works in County Laois on the grounds that the proposed development was manifestly at odds with the Laois County Development Plan (the CDP). The Respondent challenged the decision of the Commission before the High Court on seven Core Grounds. 

Mr Justice Richard Humphreys in the High Court quashed the Commission’s decision on a number of these grounds, the most significant being his finding that the Commission had failed in its obligations under Section 15(1) of the 2015 Act. Mr Justice Humphreys held that Section 15 the 2015 Act required public bodies to comply with their obligations unless it was not possible or practicable for them to do so, which would effectively require the Commission, unless legally precluded, to use its discretionary powers to favour climate-positive outcomes. That approach, if upheld, would have had far-reaching implications for Irish planning law. The Supreme Court unanimously rejected this interpretation, finding that the climate objectives set out in Section 15 cannot be converted into a simple formula.

Judgment of the Supreme Court 

The Commission appealed the High Court Judgment to the Supreme Court and leave to appeal was granted on 16 May 2025. 

The Supreme Court upheld the Commission’s appeal on all of the grounds that proceeded before it** save for Core Ground 1, which turned on the proper interpretation of Section 15 of the 2015 Act. 

Judgment on Section 15

While ultimately the Supreme Court upheld the lower Court’s finding that the Commission failed to comply with its obligations under Section 15, it did so on fact-specific grounds. The Supreme Court disagreed with the High Court’s interpretation of the meaning and effect of Section 15 set out above, and firmly rejected that formulaic, outcome-based approach,  instead finding that “the question of consistency of an individual planning decision with the s. 15(1) objectives, is much more complex than a traffic light system of climate friendly (go) (unless impracticable) and climate unfriendly (stop)”.

The Supreme Court noted that Section 15(1) required public bodies to positively engage with climate objectives, but did not impose or create additional obligations on public bodies outside of their statutory functions. The Court set out that the legal test to determine compliance with Section 15(1) is “whether the performance of the functions of the relevant body in that regard falls within the spectrum of possible outcomes that could be said to be consistent, in so far as is practicable, with the objective of s. 15.”***

The Supreme Court found that Section 15 is very far from being the sole or primary mechanism for ensuring that the planning process generally, and any individual planning decision, is consistent with climate change policy. On the contrary, it found that climate considerations permeate the planning process, meaning that a planning authority such as the Commission “is entitled to approach its task on a presumption that any strategy or development plan adopted is consistent with climate objectives, and that any decision consistent with such a plan and strategy will itself be consistent with those objectives, and therefore in compliance with s. 15(1)”. 

The Supreme Court outlined that, given that climate considerations already permeate the planning process, Section 15 would not normally have decisive impact, but that there could be marginal cases where it could hold a significant impact in planning decisions. A decision which complies with a development plan (which is itself consistent with Section 15 climate objectives) will normally also be consistent with those objectives. However, it this may not always be the case, for example where it is established that the development plan does not meet, or no longer meets, climate objectives, or because of particular features of the specific development. The Court found that the Commission must consider whether it should grant permission in any such case, and where Section 15 objectives are raised, should be able to explain why the decision it has come to is consistent with those objectives. The Court further clarified that a planning authority does not need to address Section 15 of its own motion, but should be able to explain why its decision is consistent with Section 15 climate objectives where they have been relied upon. 

In applying the above findings, the Supreme Court found that, although Coolglass did not place significant emphasis on Section 15 in its planning application, it considered that the Commission’s decision and the report of the Commission Inspector fell short of what was required in the exercise of their functions. The Court, while complimenting the Inspector’s Report generally, held that the Commission and Inspector did not engage with the question of the climate benefits of the proposed development in a real and substantive way. This was an error of law on which the decision of the High Court to quash under CG1 must be upheld (albeit for different reasons to those of the High Court), particularly when the requirements of Section 15(1) were taken into consideration.

The Supreme Court’s judgment reaffirms that decisions by planning authorities are to be made through the structures chosen by the Oireachtas, including the plan-led planning system.  By rejecting an outcome-driven reading of Section 15 in favour of a statutory obligation that informs decision-making, the Court has provided clear guidance that climate obligations under Section 15, though significant, operate within the existing decision-making rubric. For practitioners, developers and public bodies alike, the judgment is a welcome clarification of how climate legislation and planning law properly intersect in Ireland.

Judgment on remaining grounds

The Supreme Court did set aside the findings of the High Court in respect of the remaining core grounds in the appeal. These were Core Ground 3 (which alleged a failure by the Commission to exercise its jurisdiction under Section 37 of the Planning and Development Act 2000 (as amended) (the 2000 Act); Core Ground 4 (which alleged that the Commission had abdicated its Section 15 obligations to the Planning Regulator and/or the Department); Core Ground 5 (which alleged that the Commission had failed to exercise its functions in a manner compatible with the ECHR); and Core Ground 7 (which alleged that the Commission was in breach of the duty of sincere cooperation under EU law). 

In respect of Core Ground 3, O’Donnell CJ held that the fact that neither the Office of the Planning Regulator nor the Department had intervened in relation to the “not open for consideration” designation was not a “manifestly irrelevant consideration” and was not an abdication of the Commission’s functions.

O’Donnell CJ noted, in respect of Core Ground 4, that the Commission’s reference to the incorrect statutory power was a mistake caused by an erroneous submission of the Respondent and did not lead to any failure to consider a ground for material contravention that could have been considered under Section 37G(6). As for Core Ground 5, O’Donnell CJ considered jurisprudence from the Court of Justice of the European Union and ultimately concluded that it was not necessary for the Court to express any view on this Core Ground. Finally, with respect to Core Ground 7, O’Donnell CJ held that there was no evidence that the decision of the Commission was in breach of the TEU and noted that EU law did not require a presumption in favour of granting permission for renewable energy projects.

Key Takeaways 

1. Public bodies are required to engage with their obligations under Section 15 in a “real and substantive” way and this obligation is, in principle, enforced by the courts. 
2. There may be circumstances where it is not practicable for a public body to achieve compliance with Section 15. 
3. The use of the term “in a manner consistent with” under Section 15, implies that there are a range of outcomes available to a public body which would constitute compliance with this provision. 
4. The test for compliance with Section 15 obligations is whether a public body performs their statutory functions in a manner which could be said to be consistent, as far as practicable, with the objectives of Section 15.
5. Section 15(1) obligations are likely to have less impact in planning matters as climate objectives are already a core part of the planning framework in Ireland. 

For more information please contact authors Mona Costelloe, Robert McDermott, Patrick Carty and Art O'Connor. The team at Byrne Wallace Shields LLP acted for An Coimisiún Pleanála.

Footnotes

*    An appeal of the judgment of Humphreys J in [2025] IEHC 1. 
**  Core Ground 2 did not form part of the appeal and Core Ground 6 was withdrawn by Coolglass following the hearing of the appeal. 
*** O’Donnell CJ at Para 118.