While states have agreed to substantial reduction of emissions in the Paris Agreement, the success of the Agreement strongly depends on the cooperation of large Multinational Corporations. Short of legal obligations, we discuss the effectiveness and moral legitimacy of voluntary approaches based on naming and shaming. We argue that effectiveness and legitimacy are closely tied together; as voluntary approaches are the only alternative to legally imposed duties, they are most morally defensible particularly if they would be the most effective in reducing the harmful greenhouse gases. Shaming could be made effective if states could prompt more corporations to accept voluntary cuts with high gains-such as public acknowledgements-and high losses, such as reporting on noncompliance and public exposure (naming), along with some kind of condemnation (shaming). An important challenge of such voluntary approaches is how to ensure compliance with the agreed upon commitments, while avoiding greenwashing or selective disclosure. Certain institutional arrangements are inevitable, including an independent measurement, monitoring and verification mechanism. In this paper, we discuss the potentials and ethical pitfalls of shaming as a strategy when corporations have a direct relationship with consumers, but also when they are in a relationship with governments and other corporations.