Why Superfreakonomics' authors are wrong on geo-engineering

A fierce debate has been raging between climatologists and Superfreakonomics authors Stephen J Dubner and Steven Levitt, culminating in an impassioned New York Times blogpost yesterday by Dubner.
From RealClimate, part of the Guardian Environment Network
guardian.co.uk, Monday 19 October 2009 11.50 BST
Many commentators have already pointed out dozens of misquotes, misrepresentations and mistakes in the 'Global Cooling' chapter of the new book SuperFreakonomics by Ste[ph/v]ens Levitt and Dubner (see Joe Romm (parts I, II, III, IV, Stoat, Deltoid, UCS and Paul Krugman for details. Michael Tobis has a good piece on the difference between adaptation and geo-engineering). Unfortunately, Amazon has now turned off the 'search inside' function for this book, but you can read the relevant chapter for yourself here (via Brad DeLong). However, instead of simply listing errors already found by others, I'll focus on why this chapter was possibly written in the first place. (For some background on geo-engineering, read our previous pieces: Climate Change methadone? and Geo-engineering in vogue, Also the Atlantic Monthly "Re-Engineering the Earth" article had a lot of quotes from our own Raypierre).
Paul Krugman probably has the main issue right:
…it looks like is that Levitt and Dubner have fallen into the trap of counterintuitiveness. For a long time, there's been an accepted way for commentators on politics and to some extent economics to distinguish themselves: by shocking the bourgeoisie, in ways that of course aren't really dangerous.
and
Clever snark like this can get you a long way in career terms — but the trick is knowing when to stop. It's one thing to do this on relatively inconsequential media or cultural issues. But if you're going to get into issues that are both important and the subject of serious study, like the fate of the planet, you'd better be very careful not to stray over the line between being counter-intuitive and being just plain, unforgivably wrong.
Levitt was on NPR at the weekend discussing this chapter (though not defending himself against any of the criticisms leveled above). He made the following two points which I think go to the heart of his thinking on this issue: "Why would anyone be against a cheap fix?" and "No problem has ever been solved by changing human behaviour" (possibly not exact quotes, but close enough). He also alluded to the switch over from horse-driven transport to internal combustion engines a hundred years ago as an example of a 'cheap technological fix' to the horse manure problem. I deal with each of these points in turn.
Is geo-engineering cheap?
The geo-engineering option that is being talked about here is the addition of SO2 to the stratosphere where it oxidises to SO4 (sulphate) aerosols which, since they are reflective, reduce the amount of sunlight reaching the ground. The zeroth order demonstration of this possibility is shown by the response of the climate to the eruption of Mt. Pinatubo in 1991 which caused a maximum 0.5ºC cooling a year or so later. Under business-as-usual scenarios, the radiative forcing we can expect from increasing CO2 by the end of the century are on the order of 4 to 8 W/m2 – requiring the equivalent to one to two Pinatubo's every year if this kind of geo-engineering was the only response. And of course, you couldn't stop until CO2 levels came back down (hundreds, if not thousands of years later) without hugely disruptive and rapid temperature rises. As Deltoid neatly puts it: "What could possibly go wrong?".
The answer is plenty. Alan Robock discussed some of the issues here the last time this came up (umm… weeks ago). The basic issues over and above the costs of delivering the SO2 to the stratosphere are that a) once started you can't stop without much more serious consequences so you are setting up a multi-centennial commitment to continually increasing spending (of course, if you want to stop because of huge disruption that geo-engineering might be causing, then you are pretty much toast), b) there would be a huge need for increased monitoring from the ground and space, c) who would be responsible for any unanticipated or anticipated side effects and how much would that cost?, and d) who decides when, where and how much this is used. For point 'd', consider how difficult it is now to come up with an international agreement on reducing emissions and then ponder the additional issues involved if India or China are concerned that geo-engineering will cause a persistent failure of the monsoon? None of these issues are trivial or cheap to deal with, and yet few are being accounted for in most popular discussions of the issue (including the chapter we are discussing here).
Is geo-engineering a fix?
In a word, no. To be fair, if the planet was a single column with completely homogeneous properties from the surface to the top of the atmosphere and the only free variable was the surface temperature, it would be fine. Unfortunately, the real world (still) has an ozone layer, winds that depend on temperature gradients that cause European winters to warm after volcanic eruptions, rainfall that depends on the solar heating at the surface of the ocean and decreases dramatically after eruptions, clouds that depend on the presence of condensation nuclei, plants that have specific preferences for direct or diffuse light, and marine life that relies on the fact that the ocean doesn't dissolve calcium carbonate near the surface.
The point is that a planet with increased CO2 and ever-increasing levels of sulphates in the stratosphere is not going to be the same as one without either. The problem is that we don't know more than roughly what such a planet would be like. The issues I listed above are the 'known unknowns' – things we know that we don't know (to quote a recent US defense secretary). These are issues that have been raised in existing (very preliminary) simulations. There would almost certainly be 'unknown unknowns' – things we don't yet know that we don't know. A great example of that was the creation of the Antarctic polar ozone hole as a function of the increased amount of CFCs which was not predicted by any model beforehand because the chemistry involved (heterogeneous reactions on the surface of polar stratospheric cloud particles) hadn't been thought about. There will very likely be 'unknown unknowns' to come under a standard business as usual scenario as well – another reason to avoid that too.
There is one further contradiction in the idea that geo-engineering is a fix. In order to proceed with such an intervention one would clearly need to rely absolutely on climate model simulations and have enormous confidence that they were correct (otherwise the danger of over-compensation is very real even if you decided to start off small). As with early attempts to steer hurricanes, the moment the planet did something unexpected, it is very likely the whole thing would be called off. It is precisely because climate modellers understand that climate models do not provide precise predictions that they have argued for a reduction in the forces driving climate change. The existence of a near-perfect climate model is therefore a sine qua non for responsible geo-engineering, but should such a model exist, it would likely alleviate the need for geo-engineering in the first place since we would know exactly what to prepare for and how to prevent it.
Does reducing global warming imply changing human behaviour and is that possible?
This is a more subtle question and it is sensible to break it down into questions of human nature and human actions. Human nature – the desire to strive for a better life, our inability to think rationally when trying to impress the objects of our desire, our natural selfishness and occasionally altruism, etc – is very unlikely to change anytime soon. But none of those attributes require the emission of fossil fuel-derived CO2 into the atmosphere, just as they don't require us to pollute waterways, have lead in gasoline, use ozone-depleting chemicals in spray cans and fridges or let dogs foul the sidewalk. Nonetheless, societies in the developed world (with the possible exception of Paris) have succeeded in greatly reducing those unfortunate actions and it's instructive to see how that happened.
The first thing to note is that these issues have not been dealt with by forcing people to think about the consequences every time they make a decision. Lead in fuel was reduced because of taxation measures that aligned peoples preferences for cheaper fuel with the societal interest in reducing lead pollution. While some early adopters of unleaded-fuel cars might have done it for environmental reasons, the vast majority of people did it first because it was cheaper, and second, because after a while there was no longer an option. The human action of releasing lead into the atmosphere while driving was very clearly changed.
In the 1980s, there were campaigns to raise awareness of the ozone-depletion problem that encouraged people to switch from CFC-propelled spray cans to cans with other propellants or roll-ons etc. While this may have made some difference to CFC levels, production levels were cut to zero by government mandates embedded in the Montreal Protocols and subsequent amendments. No-one needs to think about their spray can destroying the ozone layer any more.
I could go on, but the fundamental issue is that people's actions can and do change all the time as a function of multiple pressures. Some of these are economic, some are ethical, some are societal (think about our changing attitudes towards smoking, domestic violence and drunk driving). Blanket declarations that human behaviour can't possibly change to fix a problem are therefore just nonsense.
To be a little more charitable, it is possible that what was meant was that you can't expect humans to consciously modify their behaviour all the time based on a desire to limit carbon emissions. This is very likely to be true. However, I am unaware of anyone who has proposed such a plan. Instead, almost all existing mitigation ideas rely on aligning individual self-interest with societal goals to reduce emissions – usually by installing some kind of carbon price or through mandates (such as the CAFE standards).
To give a clear example of the difference, let's tackle the problem of leaving lights on in rooms where there is no-one around. This is a clear waste of energy and would be economically beneficial to reduce regardless of the implications for carbon emissions. We can take a direct moralistic approach – strong exhortations to people to always turn the lights off when they leave a room – but this is annoying, possibly only temporary and has only marginal success (in my experience). Alternatively, we can install motion-detectors that turn the lights out if there is no-one around. The cost of these detectors is much lower than cost of the electricity saved and no-one has to consciously worry about the issue any more. No-brainer, right? (As as aside, working out why this isn't done more would be a much better use of Levitt and Dubner's talents). The point is changing outcomes doesn't necessarily mean forcing people to think about the right thing all the time, and that cheap fixes for some problems do indeed exist.
To recap, there is no direct link between what humans actually want to do and the emissions of CO2 or any other pollutant. If given appropriate incentives, people will make decisions that are collectively 'the right thing', while they themselves are often unconscious of that fact. The role of the economist should be to find ways to make that alignment of individual and collective interest easier, not to erroneously declare it can't possibly be done.
What is the real lesson from the horse-to-automobile transition?
Around 1900, horse-drawn transport was the dominant mode of public and private, personal and commercial traffic in most cities. As economic activity was growing, the side-effects of horses' dominance became ever more pressing. People often mention the issue of horse manure – picking it up and disposing of it, it's role in spreading disease, the "intolerable stench" – but as McShane and Tarr explain that the noise and the impact of dead horses in the street were just as troublesome. Add to that the need for so many stables downtown taking up valuable city space, the provisioning of hay etc. it was clear that the benefits of the horse's strength for moving things around came at a great cost.
But in the space of about 20 years all this vanished, to be replaced with electrified trolleys and subways, and internal combustion engine-driven buses and trucks, and cars such as the Model-T Ford. Almost overnight (in societal terms), something that had been at the heart of economic activity had been been relegated to a minority leisure pursuit.
This demonstrates very clearly that assumptions that society must always function the same economic way are false, and that in fact we can change the way we do business and live pretty quickly. This is good news. Of course, this transition was brought about by technological innovations and the switch was decided based on very clear cost-benefit calculations – while cars were initially more expensive than horses, their maintenance costs were less and the side effects (as they were understood at the time) were much less burdensome. Since the city had to tax the productive citizens in order to clear up the consequences of their own economic activity, the costs were being paid by the same people who benefited.
Levitt took this example to imply that technological fixes are therefore the solution to global warming (and the fix he apparently favours is geo-engineering mentioned above), but this is a misreading of the lesson here in at least two ways. Firstly, the switch to cars was not based on a covering up of the manure problem – a fix like that might have involved raised sidewalks, across city perfuming and fly-spraying – but from finding equivalent ways to get the same desired outcome (transport of goods and people) while avoiding undesired side-effects. That is much more analogous to switching to renewable energy sources than implementing geo-engineering.
His second error is in not appreciating the nature of the cost-benefit calculations. Imagine for instance that all of the horse manure and dead carcasses could have been easily swept into the rivers and were only a problem for people significantly downstream who lived in a different state or country. Much of the costs, public health issues, etc. would now be borne by the citizens of the downstream area who would not be benefiting from the economic prosperity of the city. Would the switch to automobiles have been as fast? Of course not. The higher initial cost of cars would only have made sense if the same people who were shelling out for the car would be able to cash in on the benefits of the reduced side effects. This is of course the basic issue we have with CO2. The people benefiting from fossil fuel based energy are not those likely to suffer from the consequences of CO2 emissions.
The correct lesson is in fact the same as the one mentioned above: if costs and benefits can be properly aligned (the 'internalising of the externalities' in economist-speak), societies and individuals can and will make the 'right' decisions, and this can lead to radical changes in very short periods of time. Thus far from being an argument for geo-engineering, this example is an object lesson in how economics might shape future decisions and society.
Finally
To conclude, the reasons why Levitt and Dubner like geo-engineering so much are based on a misreading of the science, a misrepresentation of proposed solutions, and truly bizarre interpretations of how environmental problems have been dealt with in the past. These are, in the end, much worse errors than their careless misquotes and over-eagerness to shock highlighted by the other critiques. Geo-engineering is neither cheap, nor a fix, and the reasons why it is very likely to be a bad idea are ethical and legal, much more than its still-uncertain scientific merits.
• This article was shared by our content partner RealClimate, part of the Guardian Environment Network