The Court of Appeal has dismissed Friends of the Irish Environment’s challenge to Ireland’s Climate Action Plan 2023, while setting out the legal standard future climate plans must meet.
The group argued that CAP23 did not sufficiently quantify, justify and explain how its measures would deliver the emissions reductions required by law, including the statutory target of a 51% reduction in greenhouse gas emissions by 2030 compared with 2018 levels. Its arguments focused particularly on agriculture and measures dependent on changes in farming practices and behaviour.
The High Court rejected the challenge in January 2025, principally because Friends of the Irish Environment had not sufficiently engaged with the detailed plan, its Annex of Actions, modelling and supporting technical material.
On appeal, Ms Justice Butler rejected the group’s argument that the Minister had to possess a very high degree of confidence, equivalent to reasonable scientific certainty, that individual measures would achieve their projected reductions.
The court held instead that measures in a climate action plan must have a realistic evidential foundation and be capable, if fully implemented, of achieving reductions at or close to projected levels. The required degree of specificity is greater for measures in the current carbon-budget period than for measures planned further into the future.
The court also stressed that annual climate plans are iterative. They may include measures dependent on behavioural change, developing science or new technology, while carbon budgets and sectoral ceilings contain mechanisms for correcting future shortfalls.
Friends of the Irish Environment nevertheless bore the burden of proving CAP23 was legally invalid. The court found that it had not adequately engaged with the detailed technical material supporting the plan. For this particular technical challenge, expert evidence was likely necessary, although the court expressly said expert evidence is not required in every challenge to a climate action plan.
The appeal was dismissed. The court proposed making no costs order against the environmental group, subject to further submissions from the State.