This work employs Elizabeth Cripps’ collectivist account of responsibility for climate change in order to ground an individual duty to reduce one’s GHG emissions. This is significant not only as a critique of Cripps, but also as an indication that even on some collectivist footings, individuals can be assigned primary duties to reduce their emissions. Following Cripps, this work holds the unstructured group of GHG emitters weakly collectively responsible for climate change harms. However, it argues against Cripps that what follows (...) from this is a corresponding collective duty to act qua group to bring about an end to the harm and a derivative duty for each emitter to promote the required organization of a group capable of this. Instead, this work argues that acts of GHG emission, to the extent that they are avoidable and performed with requisite knowledge, make one into a member of a group that is morally responsible for climate-related harms. Thus, individual emitters who can do otherwise should recognize themselves as members of a group that collectively harms. Subsequently, they should take all possible steps in order to renounce their membership (e.g. by reducing their GHG emissions). (shrink)