Solar Radiation Management and Comparative Climate Justice

Toby Svoboda

Solar radiation management (SRM) — that is, any climate engineering technique that would reduce the fraction of incoming solar radiation absorbed by the planet — is a very interesting subject for distributive justice, or the type of justice that concerns how benefits and burdens should be apportioned among various parties. On the one hand, SRM techniques carry risks of substantial injustice to present and future parties, and ethicists interested in climate engineering have tended to focus on these possible injustices. On the other hand, SRM has the potential to manage current and impending injustices due to anthropogenic climate change, including risks of unjust harm to the global poor. This points to the possibility that, for all its potential ethical problems, a climate policy involving deployment of some SRM technique might perform better than other available options in securing distributively just (or minimizing distributively unjust) outcomes, at least in certain future contexts.

In line with Christopher Preston's argument in the introduction to this volume, I argue here that, although it is helpful to identify potential injustices associated with SRM, it is also crucial both to evaluate how SRM compares to other available options and to consider empirical conditions under which deployment might occur. In arguing for this view, I rely on a distinction between two types of questions: (1) whether SRM would produce just or unjust outcomes in some case and (2) whether it would be just to deploy SRM in that same case. The former question pertains to whether some distribution of benefits and burdens is morally good or bad, whereas the latter pertains to whether some action or policy is morally permissible, impermissible or obligatory. Although related, these two uses of justice do not come to the same thing. It may be that some climate policy involving SRM carries risks of substantial distributive injustice and yet is permissible or even obligatory. This is because, as I argue, considering what would be just to do should be comparative, taking into consideration both empirical conditions and the morally valuable and disvaluable features of alternative climate policies. To put this in a more intuitive manner, rightness and goodness can come apart — sometimes the right course of action produces bad outcomes. I will return to this distinction in greater detail below.

I consider a prima facie case that some climate policies involving SRM could come out well on such a comparative perspective, given that a commitment to dangerous climate change due to past emissions may limit the effectiveness of policies relying on mitigation and adaptation alone. Notwithstanding, the Paris agreement reached at COP 21, given the insufficient progress on cutting global emissions to this point, it is plausible to expect that, at some point in the future, all available climate policies will exhibit substantial inadequacies when it comes to securing just outcomes. In such cases, the morally disvaluable features of SRM might not be decisive in counting against the permissibility of deployment. In one sense of the term, we might think of this as a 'lesser of two evils' argument, for my claim is that SRM, despite serious problems, could be morally permissible in cases in which it compares favourably to all the alternatives. However, although not technically incorrect, using this language of 'lesser evils' potentially invites misunderstanding. Usually, 'lesser of two evils' arguments are broadly consequentialist in nature, claiming that some policy is to be favoured despite serious costs or harms, and this because its ratio of benefits to costs or harms is better than the ratios of the alternatives. My argument is quite different, because it does not involve merely weighing up the aggregate costs and benefits of various climate policies. Instead, my focus is on the distributions of such costs (or burdens) and benefits, and I argue that some policy involving SRM can be a just thing to do if its distribution of burdens and benefits is better than that of any alternative policy. In order to avoid the false impression that my argument hinges on aggregate costs and benefits, I will forego using the 'lesser of two evils' language.

DISTRIBUTIVE JUSTICE AND CLIMATE CHANGE

Anthropogenic climate change raises important questions of distributive justice, because climate change will involve substantial benefits and burdens, as will any policy meant to deal with it. Importantly, these benefits and burdens will be differentially distributed on each policy, with some parties enjoying a greater share of benefits or suffering a greater share of burdens. Moreover, specific distributions will vary depending on what responses are adopted. Potential climate-related burdens are driven by many factors: an increased frequency of extreme weather events, sea-level rise, the spread of disease to new regions and so on. Potential benefits of various climate policies include curbing these burdens and perhaps avoiding them altogether. This could be achieved through mitigation of greenhouse gas emissions, adaptation to changing climatic conditions, climate engineering through either carbon dioxide removal (CDR) or SRM techniques or some combination of these responses.

Anthropogenic climate change and climate policy are matters of justice because, unlike natural phenomena, they are driven by human activity, such as the emission of greenhouse gases and the...