John Broome has long been a central figure at the intersection of philosophy and economics. Broome has also been an expert on climate change, and has been named as a lead author on the Intergovernmental Panel on Climate Change's Fifth Assessment Report, Working Group III. With his Counting the Cost of Global Warming (1992), Broome gave the first book-length treatment of the issue of climate change from a philosophical perspective. Now that climate change is more broadly recognized as one of the most significant issues of our time, Broome has revisited the topic in Climate Matters: Ethics in a Warming World. Those familiar with Broome's other work will not be surprised by the tempered manner of his writing and high quality of his argumentation. Although the book is targeted towards a general audience, and does not make an effort to confront the existing philosophical literature on climate change, it is nonetheless essential reading for anyone interested in the ethics or economics of climate change.
Broome's aim in Climate Matters is limited; as he says, ‘[i]n this book, I do not claim to give you definitively correct views about the morality of climate change’ (9). Rather, the book is intended as ‘food for thought . . . ideas and arguments to think about’ (192). On the one hand, in several places, one wishes that Broome had gone further than he does in the book in solving some of the problems he raises. On the other hand, Broome carefully sets out specific areas for further philosophical inquiry on climate change, and admirably never lets his conclusions get ahead of his arguments.
After an introductory Chapter 1, Chapter 2 is a sober presentation of the science of climate change. Broome explicates the consensus view amongst climate scientists that due to anthropogenic greenhouse gas (GHG) emissions, it is highly likely that climate change will ensue, and that the effects on human beings will be very bad. Broome emphasizes, rightly, that ‘each reduction [in GHG emissions] is well worthwhile’ (35), and it is not the case that only a global agreement on climate change will make any difference. As Broome hopes, this should be taken as ‘an antidote to the despair or apathy that descends on some people when they contemplate the horror of climate change’ (35).
Chapter 3 concerns climate economics. Broome discusses the notions of externalities and of economic efficiency in characteristically lucid and concise fashion. The key facet of Broome's discussion is his support of the strategy he calls efficiency without sacrifice. The idea, stemming from work by Duncan Foley (Reference Foley, Harris and Goodwin2009), is that harms caused by GHG emissions should be viewed as externalities, but that we can achieve efficiency by borrowing money or other resources from future generations in order to finance present-day emission mitigation strategies. If we do this, then we will be at least as well off as we otherwise would be, since we will be using not our own money to finance a change in our energy systems and infrastructure. And people in the future will of course benefit by not being harmed by climate change even though that benefit will come at a cost to them. But the benefits that will accrue to future people from a present reduction in GHG emissions will exceed the harm caused by our taking their money or resources. Thus, in principle, efficiency can be achieved by the present generation without any sacrifice on its part.
Broome does regard efficiency without sacrifice as an imperfect solution, since it would be even better if the current generation were to indeed sacrifice in order to limit our own emissions. For it is unjust for the current generation to inflict harm on future generations – in this case, by depleting resources or incurring debt. However, Broome believes that if it were broadly recognized that we could reduce GHG emissions without any sacrifice, then it would become politically feasible to do so, and he thus supports a popularization of the efficiency without sacrifice strategy. Broome's case for this approach is strong, and gives us reason for optimism that it may be possible to get our GHG emissions under control. Still, one may wonder exactly how the transfer of wealth and resources between generations is supposed to occur. And it is also unclear how politically feasible the strategy really is, given the degree to which deficit reduction has come to dominate mainstream economic discussion, at least in the EU and the USA.
Broome turns in Chapter 4 to the ethics of climate change. The centrepiece of his analysis is a distinction between justice and goodness. He argues, using Judith Jarvis Thomson's famous transplant surgeon example (in her 1985), in favour of the view that there are cases where justice demands that one not act in a way which promotes the most overall good. (Broome's discussion on this point is fairly brief and will likely not be persuasive to those already familiar with these issues.) Broome accepts the result of Derek Parfit's famed non-identity problem (1984, Part IV): even though the lives of future people if climate change occurs will be worse than the lives of future people if climate change does not occur, the people who will live under conditions of climate change would not have lived if there were no climate change. It thus cannot be said that the primary long-term impact of large-scale government actions regarding climate change is harm to specific individuals. Broome concludes that the primary duties of governments with regard to climate change policies are thus duties not of justice, but duties to promote the good. Chapters 6 to 10 of the book discuss these duties in more detail.
Broome also discusses the contentious issue of fairness between countries in distributing GHG emissions. He suggests that emissions ‘should be divided between countries in proportion to their populations at some well-chosen date’ (71), which allows for equity between individuals in different countries and also provides a disincentive to increase population. Broome's discussion on this point is rather quick; for instance, one may wonder whether an individual born in a country with a growing population, and who thereby has rights to less GHG emissions, is treated fairly in such a scenario. Still, his solution is a highly plausible one.
Interestingly, Broome's view regarding the duties of individuals in light of the non-identity problem differs from his view regarding the duties of governments. He claims that the impacts from individuals’ GHG emissions will not have an effect on the identities of people across the world in less than several generations. At the same time, he believes that the impacts of reductions in GHG emissions will have beneficial effects starting almost immediately. For this reason, Broome believes that individuals do have duties of justice not to harm others with their GHG emissions. However, Broome writes that ‘[i]f, as an individual, you aim to improve the world, reducing your emissions of greenhouse gases is a poor way to do it’ (65). This is because, even though one can do a small amount of good by reducing one's emissions, one can much more easily do good by other means. Thus while Broome does not believe, as does Walter Sinnott-Armstrong (Reference Sinnott-Armstrong, Sinnott-Armstrong and Howarth2005), that an individual's GHG emissions make no difference whatsoever, he still accepts that the good one promotes by reducing one's emissions is small in comparison to the good one can just as easily promote.
Chapter 5 continues the discussion of the ethics of individual decisions. Broome estimates that one's lifetime GHG emissions ‘will wipe out more than six months of healthy human life. Each year, your annual emissions destroy a few days of healthy life in total. These are serious harms’ (74). It is difficult to see how Broome has calculated these numbers, and John Nolt (Reference Nolt2011) has attempted to estimate the same total, and has come up with a number many times as large as Broome's – Nolt argues that the average American is responsible, through his or her lifetime emissions, for the severe suffering or death of one to two people. Although Nolt's own estimate has its own problems, the disparity between the estimates shows that further research in estimating the harms associated with climate change (aside from its effects estimated through purely economic measures) is needed.
It is certainly not Broome's aim to minimize the effects of individual actions. Since he believes that six months of harm is morally significant on its own, he does argue that individuals have a duty of justice not to cause such harm. However, he goes on to argue that it is relatively inexpensive to discharge one's duties to not emit GHGs. His discussion here is once again clear and provocative. He makes the useful point that if one is in a country which has in place a cap and trade system, there will be no benefit to reducing one's own emissions. This is because, in countries which operate under a cap, if one individual reduces her own GHG emissions, others’ emissions will rise to make up the difference. Interestingly, he then says: ‘However, even though switching to green energy does not reduce overall emissions, one important thing remains true. When you reduce your emissions, you move closer to meeting your duty of justice not to cause emissions yourself. You move closer to justice, even though you do no good’ (83). Some may regard this as a nice feature of Broome's view regarding individual duties while others with consequentialist leanings will likely regard it as a reductio.
Broome then discusses offsetting of emissions. Surprisingly, given what he has just said regarding a situation in which one has a duty to not emit GHGs even if one's refraining from doing so will make no difference in the total amount of GHGs emitted, Broome supports carbon offsetting – the practice of paying others to reduce their emissions to compensate for one's own emissions. It is surprising because offsetting sounds an awful lot like causing a harm oneself but preventing others from causing an equivalent harm. Although Broome does an excellent job responding to several practical objections against offsetting – specifically, objections which claim that offsetting delays progress in reducing emissions – he does not address the objection to offsetting which is perhaps most common, namely, that it is akin to buying an indulgence. For it would be wrong to commit child abuse while at the same time paying money to the child abuse prevention fund which prevents an equivalent amount of abuse (as argued, for instance, in Kinsley Reference Kinsley2007). Maximizing consequentialists as well will likely object to the idea that one is obligated to offset the precise amount of one's own emissions – though it might be the case that giving money to offsetting programmes would be part of a maximizing strategy, it would be a grand coincidence if the amount of money one should optimally give to offsetting programmes would reduce others’ emissions by the exact same amount of one's own emissions.
The second half of the book is occupied with questions about public morality. Since Broome believes that governments have a duty to promote goodness, the focus is on goodness and how to aggregate it. Those familiar with Broome's past work will find less in these chapters which is new, but his arguments here are still of value. Broome argues persuasively in Chapter 6 that ethical considerations must be incorporated within any analysis of climate change: ‘Ethics is everywhere in the debate about climate change; it is just that scientists and economists sometimes do not recognize their own ethical judgments when they make them’ (104).
Broome defends cost-benefit analysis in Chapter 7 and argues against the use of the precautionary principle in dealing with climate change. However, his discussion here is fairly brief and again is likely unpersuasive for those who already have views on the topics. In Chapter 8, Broome discusses future discounting, and argues convincingly that the discount rate should be below market rates. One of the most illuminating aspects of Broome's discussion is that those who favour a relatively high discount rate (say, 5.5%) on the grounds that future people will be better off than present people and that we have less duties to those who are better off typically neglect the fact that such prioritarian considerations also lead to a strong duty for those in wealthy countries to help those in need at present.
In Chapters 9 and 10, Broome writes lucidly about the value of human lives and population ethics; Broome has covered much of this ground in his previous books. In accord with his earlier discussion (2004: Ch. 10), Broome argues against what he calls the ‘intuition of neutrality’ – the idea that additional people are negligible in making comparisons about value. However, in contrast to his discussion in Chapter 7 (though in accord with his discussion in his 1992: 19–22), Broome concludes that cost-benefit analysis is fatally flawed in its application to climate ethics, for two reasons. First, although poor individuals have less money, and thus less money to put towards their own wellbeing, it is not the case that their lives are worth less than those with more money. Even though this is a familiar problem and proponents of cost-benefit analysis have developed mechanisms to overcome this issue, none has been successful, according to Broome. Second, there are deep and unresolved questions about aggregating the value of lives. This may be surprising since Broome does not here endorse the aggregative view he supports in his (2004). I myself would have found it more illuminating had Broome simply put forth the ramifications of his own view on the topic of climate cost-benefit analysis. But Broome instead, given the lack of consensus amongst philosophers on population ethics, claims that population ethics requires further study and that until a point is reached where there is consensus, ‘democratic public debate is at present the only means we have of coping with this sort of uncertainty’ (191).
Although there are many worthwhile arguments in the book, there are also three omissions which stand out. Broome's goal was to write a short and accessible book. Nevertheless, the following issues are at the centre of climate ethics, and the outcomes of each of these issues have the potential to affect, in a significant way, ethical views and policies on climate change.
First, the book contains virtually no discussion of the effects of climate change on non-humans. Given certain highly plausible assumptions that all sentient beings deserve some degree of moral consideration and that very many sentient non-human animals will be severely impacted by climate change, it follows that the effects on non-human animals are morally significant. Furthermore, given that there is some level of public approval for wilderness preservation and of the value of biodiversity, some discussion of the value of these wholes is in order. Of course, it is extremely difficult to determine both the facts concerning the impacts of climate change on non-human animals and ecosystems and the values to be attributed to those things. But it is unlike Broome to shy away from difficulties; indeed, one of his goals is to shed light on the difficulties in arriving at a solution to climate change.
Second, Broome gives no consideration to the science and ethics of geoengineering. Given that, as estimates of climate harms continue to escalate in severity, geoengineering will invariably be seen as a potential solution to the problem, it is an important component of any thoroughgoing analysis of climate change solutions. Since geoengineering also raises its own ethical and economic concerns, one is left wondering how Broome's views would extend to decision-making about different geoengineering measures.
Third, Broome's final view as expressed in the book rests heavily upon the practicality and legitimacy of democratic political systems in making decisions about climate action. There are a number of problems for this approach. It is an irony of the climate ethics literature that many argue that because individual emissions reductions don't make a significant difference with regard to climate change, we should focus our energies instead on changing the political system. But of course, the efficacy of individual actions in creating political change is famously limited. Additionally, though Broome's emphasis on open political discussion is noble, we are far from having the global democratic structures in place to make a well-reasoned political solution to climate change work. And even within individual democracies, for various reasons there has been very limited success in enacting programmes which properly limit GHG emissions. Of course this is not a problem one would expect Broome to solve. But given the weight Broome attaches to the democratic process, the book would have benefited from a greater discussion of how to overcome the obstacles it faces.
Despite these shortcomings, the book is a significant contribution to the literature, and is to be admired for its combination of quality of argumentation and clarity of presentation. It is typical for book reviewers to recommend the book to those who are interested in the topic, as I do with this book. However, as is implied by the book's title, the book makes the case that those who are not interested in climate change and the ethics thereof, ought to be. As Broome shows, climate indeed matters, or should, to ethicists and to the world. The book could have also been aptly titled Morality Matters: Ethics in a Warming World. For one of the book's most compelling themes is that climate policy discussion must include the views of ethicists in addition to economists. It is those who are unconvinced of that point to whom I most highly recommend the book.
