The participation of central banks in the fight against climate change has recently been advanced in several academic articles and policy papers. Since the emerging consensus is that climate change poses financial risks, the envisaged green central banking has a responsibility to address environmental sustainability as a means of promoting financial stability—an increasingly accepted goal of central banks in the post-financial crisis world. Thus far, the pro side of the argument is well represented in the literature, though often the benefits remain implicit: with the help of central banks via monetary and macroprudential policies, a smooth transition to a low-carbon economy would be somehow beneficial to all of us. With this article, we aim to add to this literature by looking at the costs and trade-offs of this course of action in light of the observation that the con side of the proposal has been only marginally addressed. We put forward a framework for the analysis of the costs and trade-offs of green central banking and exemplify the applicability of this framework by studying three cases of central banks for which the transition to green operation has been advanced. We find evidence that if costs and trade-offs are taken into account, the case in favor of greening central banks becomes less straightforward than is currently conveyed in the literature.