What must I do as one of many uncoordinated holidaymakers faced with a drowning child whose rescue would require most of us to act together? Or as one of hundreds of people crowding onto a bridge that can only hold fifty and will, if it collapses, injure children swimming below (or all of us, or both)? Such dilemmas, where no individual in isolation can change the outcome and there has been no coordinated collective action but is huge aggregate potential for harm or good, are forced onto the moral agenda by anthropogenic climate change. However, they have traditionally been neglected by theories of individual moral responsibility. This paper starts from the assumption that most of us, as a collectivity or potential collectivity, have a collective moral duty to tackle climate change but that collective action has not been taken to fulfil this duty. It considers three possible individual duties: Promotional (to promote the necessary collective endeavour); Mimicking (to mimic the individual actions that would fairly have been assigned as part of such collective action); and Direct (to act directly to protect the interests at stake or mitigate the harm, oneself or with a like---minded subset). The paper defends Promotional Duties as primary, supplemented by Direct Duties. However, Mimicking actions are those standardly considered part of a “green” lifestyle. Accordingly, it is first considered how they might philosophically be defended. It is argued that such arguments either fail altogether or fail to make a case for such duties as primary or exclusive. Rather, where Mimicking actions are appropriate it is generally as means of fulfilling Promotional or Direct duties. Promotional duties are then defended as primary, on the grounds of efficiency, fairness and effectiveness. Finally, it is indicated when individuals might, nonetheless, be required to fulfil Direct duties.
