Causal responsibility for (possibly) overdetermined climate harms

When it comes to climate change, some people may think that they bear no responsibility for climate change-related harms because their own behaviour does not make any difference to these harms – they will happen whatever they do or omit doing. In climate ethics, this issue is known as the problem of ‘inconsequentialism’: it seems that no emitter can make a morally relevant difference to climate harms by emitting greenhouse gases (GHG) – or by not emitting. If this is true, then it means that climate change is a case of causal overdetermination: no emitter's GHG emissions are sufficient nor necessary to bring about climate harms. In this article I explore the implications of climate overdetermination for the causal responsibility of GHG emitters: are they exempt from any such responsibility if they make no difference to climate harms? Provided a causal account meeting certain criteria can be identified, I will argue that this is not the case: a moral agent, whether individual or collective such as a company, contributing inconsequentially to climate change can be held causally responsible for the harms climate change brings about. These criteria – namely, being able to account for overdetermination and to differentiate degrees of responsibility without committing the pie fallacy – are intuitively plausible, and any causal account must satisfy them, especially when dealing with collective action cases such as climate change. I will make use of the NESS (Necessary Element of a Sufficient Set) account of causation as adequate for assigning responsibility in cases of overdetermination, since this account does meet both criteria. Its implication is that causal responsibility for climate harms is not contingent on whether emitters make a difference to climate harms or not. Since causal responsibility is, however, only a necessary but not sufficient condition for moral responsibility, this article merely paves the way for a fuller account of the latter.