Comment on Sabine Hohl and Dominic Roser: Stepping in for the Polluters? Climate Justice under Partial Compliance

Sabine Hohl and Dominic Roser argue that states that emit their fair share of greenhouse gases have a duty to step in for states that emit more than their fair share. In this comment I ask two questions: First, given that Hohl and Roser are right, how relevant is the duty to step in for the polluters in practice? Second, is there such a duty on more non-ideal approaches than the one taken by Hohl and Roser as well? I argue that the duty to step in for the polluters is not very relevant (because of considerations of demandingness and fairness) and that on more extremely non-ideal approaches there may be only a limited duty to take up the slack, or no such duty at all (because the duty must be weighed against other duties, and because states are poorly motivated to act in conformity with it).