The purpose of this article is to show it is only in light of legal culture that climate change jurisprudence in the European Union can be explained. Examining the case law concerning the EU Emissions Trading Scheme, this article demonstrates that climate change proceedings in the European Union raise questions that stand at the heart of the EU legal order; that is, they demand that the boundaries of the EU's regulatory competences are drawn. In effect, the EU courts focus on ensuring that EU climate change laws are in accord with the rule of law or, in the context of EU law, the borders of the EU's environmental regulatory powers. As such, this article shows that attention needs to be given to the interaction between climate change laws and the constitutional role of the EU judiciary. These interactions are considered here together with the contingency of EU climate change litigation on EU legal culture.