I’m not often inclined to retreat behind the veil of ignorance to decide policy questions, but every now and again it makes sense to take out one’s less-favored philosophical tools and see how they handle a difficult problem. Today, we’re going to take global warming behind the veil of ignorance, and see where it gets us.
Why do I want to retreat behind the veil of ignorance on this problem in particular? Mostly because I think the two big moral accounting methodologies being brought to bear by the two sides in the debate – the Precautionary Principle on the one side and Cost-Benefit Analysis on the other side – each have serious deficiencies. So I thought it might be interesting to come at the problem from a different direction.
The Precautionary Principle (PP) has some very fundamental problems. The most fundamental, I think, is its inability to define what constitutes an action. Stated most simply, PP dictates that there should be a strong presumption against taking actions that have extremely severe negative consequences out in the tails of the distribution of possible outcomes. But you can only apply this rule if you know what constitutes taking an action as opposed to refusing to take action.
Sometimes this is an easy question to sort out. If, for example, we decide not to build a superconducting supercollider for fear of destroying the universe, we might be making a stupid decision – this particular risk is really far out on the tails – but we’re pretty clearly applying PP correctly. But sometimes it’s not so clear what constitutes an action, as opposed to a refusal to take an action.
Here’s an example to illustrate what I mean. We are involved in a war in Iraq. Somewhere out on the tails of the distribution of events that could follow a pullout from Iraq are some pretty bad consequences. It’s also true, though, that out on the tails of teh distribution of events that could follow continuing the war in Iraq are some pretty bad consequences. This kind of thing – dueling nuclear war scenarios at the ends of long chains of causation – should be familiar to high school debaters. Assuming that both pulling out and not pulling out are actions then PP would dictate that you must both pull out and not pull out. The only way to resolve this is either to weigh the tails against each other (which, as should also be familiar to high school debaters, is extremely difficult to do; at the end of a long chain of causation, the massive uncertainty about both probability and impact swamp any attempt at comparison), or to identify something as the status quo that gets presumption.
But this second option is also not easy to do. Which is the action: leaving Iraq or staying? Leaving means an end to a host of actions that we have to take by staying; it is a decision that, at a certain level, puts an end to the need to make decisions. As such, the presumptive posture should be: leave, unless there is a clear benefit to staying. But as we are currently engaged in a war in Iraq, the decision to stay is a decision to maintain the status quo; the presumptive posture should be: stay, unless there is a clear benefit to leaving.
Of course, we could decide the Iraq question without reference to PP, and just look at the expected costs of staying or going (as best we can calculate them) and make the call. But we can do that for global warming as well. PP is invoked because cost-benefit analysis doesn’t weight more remote scenarios very heavily, and under many cost-benefit analyses drastic action to stop global warming doesn’t appear to be worth the cost. Jim Manzi has written a great deal about this kind of analysis; see here and here and here among other places. (I’m not endorsing his analysis here, just citing it.) So how does PP work out applied to global warming?
I think it has the same kinds of problems as my Iraq example above. Advocates of the PP approach argue that we must not continue burning fossil fuels because we shouldn’t radically alter the earth’s environment when it’s so unpredictable what the consequences could be; out at the tails of the distribution, human civilization itself is imperiled, and not quite so far out there is massive death and destruction. Now, this might be a plausible line of argument if we didn’t currently have a fossil fuel-based economy. But we do currently have a fossil-fuel based economy. And drastically curtailing economic growth also has very severe consequences way out at the tails of the distribution. Where does presumption lie? Which is a positive action – burning fossil fuels, or taking legislative action to end the burning of fossil fuels?
Again, this is not the only problem with PP. PP would probably dictate not building more nuclear power plants. That, however, might mean greater dependence on fossil fuels for a longer period of time. But this would be a perverse consequence of correctly applying PP, not a fundamental problem with applying PP itself. I think there are fundamental problems with applying PP itself when you talk about global warming, because global warming is believed to be the result of pervasive and ongoing activities of our economy, and drastic action to change the nature of our economy is, I would argue, a significant action which itself would need to pass PP to be justified. And it probably can’t be.
So much for PP. What’s the problem with cost-benefit analysis (CBA)?
Well, the biggest fundamental problem with CBA is how you account for benefits to people who do not currently exist. To take a simple example: I am debating whether to have one or two children. If I have one child, that one child will inherit my entire estate. If I have two, they will split it. Assuming I am not sure whether I would be happier with one child or two, and that I am not sure whether my child will be happier with a sibling or without, and that I am not sure whether the benefit to the world from my brilliant offspring would outweigh the cost to the world of their resource consumption, I can reduce the decision to this one question. Clearly, CBA dictates I should have only one child, so that child gets the undivided benefit of my estate. (Note: this does not pose a problem for PP because PP is structured as a binary decision principle. You don’t need to know how to weigh impacts on future generations against anything; you just need to determine that severe negative consequences are possible.) There are a variety of responses to this problem, none of which I find entirely persuasive, but even granting a solution to this problem I think it is generally agreed that CBA imposes a presentist bias on analysis, since we’re generally debating whether to incur costs in the present to secure benefits in the future, and anything that happens in the future, when discounted back to the present, gets smaller.
Beyond this, there are a variety of other problems attributed to CBA, among the most common cited by folks on the left side of the spectrum is that CBA ignores distribution effects. This can be observed very clearly with respect to global warming. Jim Manzi cites an estimate that global warming could costs as much as 3% of global GDP in the next century. On the one hand, that’s a big number; global GDP now is $66 trillion, and in a century it’ll be much bigger than that. On the other hand, given that the costs of abandoning the fossil fuel economy are enormous, and that those costs are born up-front rather than a century from now, it’s pretty easy to do a calculation that shows that the cost of stopping global warming vastly exceeds the benefit when discounted back to the present. Far better to allow faster economic growth, and divert some of our resources to adaptation strategies and “big bang” solutions to transitioning away from a fossil-fuels based economy (as, indeed, Manzi favors).
But the distribution effects masked by this analysis are potentially huge. Bangladesh, a poor, overpopulated country near the equator and substantially at sea level is a country that is massively vulnerable to the impact of global warming. The Bangladeshi economy is about 0.3% of global GDP, on a purchasing power parity basis. Assuming a static relative position in the world economy over the next century, a forecast of a 3% loss of global GDP is entirely consistent with the complete obliteration of the nation of Bangladesh, ten-times over. We can recall, in this regard, that the economic consequences of Hurrican Katrina were basically negligible, but the failure to prevent the destruction of New Orleans is still viewed rightly as a massive indictment of the relevant public authorities.
For these reasons among others, CBA is rightly viewed as a somewhat suspect tool. It appears most applicable when purely economic questions are being debated; the further afield we go from these sorts of questions, the more suspect CBA appears.
So where am I going with this? Behind the veil of ignorance!
How would a Rawlsian look at the moral question at the heart of the global warming debate? He would say: behind the veil of ignorance, you don’t know who you are. So you should make your decision on a risk-averse basis, as if you are the person most seriously affected by the decision in question.
That person is probably somebody living in Bangladesh. Bangladesh is, as noted above, a country that is exceptionally vulnerable to global warming. But it’s also a country that is very poor (45% below the poverty line, $1,400 GDP per capita on a PPP basis), and hence stands the most to benefit in absolute terms from the continued advance of global economic growth. Conducting a CBA from the perspective of a Bangladeshi answers a lot of the criticisms of CBA. Because Bangladesh is especially vulnerable, the tails of the distribution will be closer to the center for them than they will be for the world at large, so you can avoid a problematic binary rule like PP without feeling like you’ve ignored the severe outlier scenarios. As well, you’ve accounted in a certain fashion for distribution effect questions; by taking the perspective of someone most likely to suffer from downside consequences, you avoid making a decision that will benefit the world on the backs of severe harm to the most vulnerable. Finally, you’re getting the primary benefit of CBA – a serious attempt to account for both sides of the ledger on policy questions – because Bangladesh is especially vulnerable to both downside scenarios, a global economic slowdown and global climate change.
And, to boot, this means we can delegate the entire global warming question to Reihan and his family.
I want to stress one thing in closing: this is not a post about the practical difficulties in attacking global warming. Manzi’s points about the likelihood of regulatory capture, among other things, are very well-taken. All I’m talking about is the moral framework within which we should be making these decisions. Anybody else feel (as I do) like this kind of quasi-Rawlsian framework makes more sense for global warming than it does for, say, setting the level of welfare benefits?