Superfreakonomics- Heating up the global warming debate
Superfreakonomics was a very interesting read. Building on the Freakonomics formula of “this is why the conventional/intuitive view on _____ topic is wrong and here is the data to back up what we view as the correct understanding of _____ phenomenon,” Superfreakonomics continues to look at data in very interesting ways. The most interesting part of these books for me was the ability to use clever naturalistic experiments to examine interesting causal links.
When Superfreakonomics came out it caused a bit of ruckus. When rereading the book, I focused a bit more heavily on the sections that I had read some criticisms about. For instance, Ezra Klein challenges the drunk driving anecdote: arguing that one of the key assumptions in Levitt/Dubner’s calculation “If we assume that 1 out of every 140 of those miles are walked drunk -- the same proportion of miles that are driven drunk” is completely unjustifiable. Ezra goes on to point a number of reasons this statistic might be skewed (more people substitute away from driving drunk towards walking drunk, the sort of miles traveled (rural/urban), and a host of others http://voices.washingtonpost.com/ezra-klein/2009/10/the_shoddy_statistics_of_super.html). While perhaps a justifiable claim, I found this line of criticism a useful reminder not to necessarily be swept up in a statistical story just because it was interesting, but to remember to look closely at both implicit and explicit assumptions in the model. Superfreakonomics is very good at telling interesting stories with data, but it is easy to get swept up and forget to challenge what might be implausible assumptions.
Unsurprisingly, a possibly skewed or misleading assumption in drunk driving was not what caught the media’s attentions. Rather, the passage on global warming raised quite the stir amongst environmental economists and a few global warming advocates. The case Dubner and Levitt seem to be making in the broad sense is that is difficult, if not impossible for a large spectrum of people to change their behaviors with little or no incentives to do so. This is consistent with their broad message, and does a good job of illustrating why the current incentive structure regarding the environment seems suboptimal. Where the critics seem to have taken issue with the work comes through in a few important ways. First, and perhaps most importantly, seems to be a general challenge to the way the facts are presented. While many of them are factually correct, taken together these facts present a misleading picture. For instance, the following sentence received a great deal of criticism: “When Al Gore urges the citizenry to sacrifice... the agnostics grumble that human activity accounts for just 2 percent of global carbon-dioxide emissions, with the remainder generated by natural processes like plant decay...” DeLong and other critics point out that this fact is misleading for a number of reasons. First it underplays the importance of human impact on global warming (http://delong.typepad.com/sdj/2009/10/yet-more-superfreakonomics-blogging-yes-i-know-i-know.html). How the critics would like that sentence to read places more accurate emphasis on human impact: “Of course the agnostics are misleadiing you: the right way to think about it is that already 1/3 of the CO2 molecules in the atmosphere are the products of human actiivity, and the fraction and amount are growing very rapidly indeed…”
Other criticisms focus on misrepresenting scientific studies. Not being an environmental scientist, it is rather difficult to critically say whether these studies were presented fairly. Some certainly seem to claim otherwise: http://thinkprogress.org/climate/2009/10/12/204787/superfreakonomics-errors-levitt-caldeira-myhrvold/ and http://krugman.blogs.nytimes.com/2009/10/17/superfreakonomics-on-climate-part-1/. While, from what I have read many of the general criticisms are a bit overblown and really fall into the category above of being factually correct but at times a little misleading: http://www.freakonomics.com/2009/10/18/global-warming-in-superfreakonomics-the-anatomy-of-a-smear/.
Another area of criticism is drawn around first the criticism of solar panels and the inaccurately rosy picture of geo-engineering. First the solar panels. Superfreakonomics notes that the color of the solar panel makes a difference. For the same reason painting all the roofs white helps to lower the temperature, placing black solar panels all over the place would have the opposite impact. Most of the critics seem to note this as a rather minor impact, and argue that solar power won’t solve the energy crisis for a host of other reasons (http://delong.typepad.com/sdj/2009/10/hoisted-from-comments-nicholas-weaver-on-solar-vs-nuclear-myhrvold-dubner-and-levitt.html). One commentator compared saying the color of solar panels causes global warming in the same way photons from stadium lights cause a curve ball. While it seems solar power is slightly better than the book would have you believe, geo-engineering seems to be a bit worse. There seem to be a host of potential problems with geo-engineering, the least of which being its untested, unknown nature.
The economist criticizes the work by saying: “it contains little in the way of economics, other than a brief discussion of externalities and the observation that the hose system would be much cheaper than building an entirely new low-carbon energy infrastructure for the world.” This quote does a pretty good job of summarizing by feelings on this particular chapter of the book. The economics is generally pretty good; I agree with their thoughts on incentives and the difficulties surrounding policy solutions. I think their focus on one particular plan rather than a market structure aimed at fixing some of the underlying incentives is a bit weak.
For a quick summary of the debate and some of the sources please see: