Against the background of the differentiated order of competences of primary law, the work examines the European Central Bank's efforts to shape its monetary policy in favour of climate protection. The focus is on understanding monetary policy competence in accordance with Art. 127 TFEU, which ensures the definability and differentiability of the price stability objective, while remaining consistent with the principles of central bank independence, democratic legitimacy, and institutional balance. Furthermore, the analysis considers how price stability can be safeguarded against compromise by either the secondary objective or the environmental horizontal clause.