When is green nudging ethically permissible?

This review article provides a new perspective on the ethics of green nudging. We advance a new model for assessing the ethical permissibility of green nudges (GNs). On this model, which provides normative guidance for policymakers, a GN is ethically permissible when the intervention is (1) efficacious, (2) cost-effective, and (3) the advantages of the GN (i.e. reducing the environmental harm) are not outweighed by countervailing costs/ harms (i.e. for nudgees). While traditional ethical objections to nudges (paternalism, etc.) remain potential normative costs associated with GNs, any such costs must be weighed against the injunction to reduce environmental harm to third parties.