This case note examines the 2023 decision handed down by the Irish High Court in Coyne v. An Bord Pleanála, which addresses the evolving role of environmental impact assessments (EIAs) in incorporating climate change considerations within planning decisions. Although the case was dismissed in its entirety, the judgment illuminates how indirect climate effects have been interpreted in Ireland, particularly regarding whether the planning authority lawfully assessed greenhouse gas emissions linked to electricity consumption by a proposed data centre. The Court required the assessment of indirect effects on climate change under the European Union EIA Directive, while emphasizing the practical limits of attributing diffuse, global climate impacts to individual projects. Although energy demand and emissions must be quantified, the Court noted that evaluating broader climate impacts is not feasible. Implications of the judgment for EIA practice in Ireland and beyond, as well as reflections on challenges in integrating climate change into EIAs are offered.