Posted by: Tobias | September 23, 2008

Just another air pollution problem?

In the current issue of Slate, Gregg Easterbrook reviews Thomas Friedman’s latest book, Hot, Flat, and Crowded, in which the Pulitzer Prize Winner rings the alarm bells about the danger of global warming.

Several points he makes are well taken, but he goes to far, I think, in his conclusion:

Friedman concludes Hot, Flat, and Crowded by proclaiming greenhouse damage could cause humanity to be "just one more endangered species." Better to consult history on this topic. Greenhouse gases are an air-pollution problem. Smog and acid rain, the two previous serious air-pollution problems, once were viewed as emergency threats. Then federal standards were imposed, and inventions and new business models were devised; now smog and acid rain are way down in the United States and declining in much of the rest of the world. And no international treaty governs smog or acid rain! Nations have adopted smog and acid-rain curbs because it is in their self-interest to do so. The same dynamic will take hold for climate change, not long after the United States finally imposes greenhouse-gas rules. Unquestionably the future is flat and crowded. Hot? Maybe not.

Oh if only this were so. But Easterbrook misses at least two important ways in which the pollutants in the case of global warming (CO2, methane, ozone, chlorofluorocarbons and some others) differ from those resposible for acid rain and smog.

For one, acid rain and smog were relatively localized phenomena. True, aerosols released into the air by factories in the Ruhr area did cross the borders into Belgium, the Netherlands and France if the wind was right, but they were fairly unlikely to end up in Spain or even Brazil. This means that countries already had fairly strong incentives to reduce these emissions for their own good. In addition to this the number of parties in any international negotiation on the issue would have been much lower than the full UN panel engaged in the Rio process. And any game theoretician will tell you that the likelihood of coordination falls rapidly with the number of players.

Moreover, while the aerosols which are responsible for smog and the sulfurous and nitrous gasses responsible for acid rain are washed out of the atmosphere by rain relatively quickly, the half-life of a CO2 molecule in the atmosphere is much longer, 38 years to be exact. This means that in the case of acid rain and smog, you basically go back to square one, a clean atmosphere, every time you stop poluting. The same is not true in the case of greenhouse gas concentration which exhibit significantly more inertia. If we all stopped emitting greenhouse gasses tomorrow, the atmospheric concentration of CO2 would still be at 380ppm, about 100ppm above pre-industrial levels, and only very slowly move back towards “natural” levels. What this means is that it’s hard to get rid of the stock of greenhouse gasses we have already accumulated. So even if, say, all OECD and G8 countries decided to cut back drastically on their emissions because they agree with Easterbrook that it is in their own self-interest to do so (a point that’s at least debatable), it would not be enough. As long as the major developing countries and newly-industrialized countries do not follow suit, we would still likely reach atmospheric concentrations which the IPCC would consider dangerous some time in the next century, perhaps even during the current.



  1. I thought that the silence around smog and acid rain were caused by the increased interest into other topics (like greenhouse gases). Furthermore the lack of real hot summers, something in my mind strongly related to the occurrence of smog, seemed to me another reason why the topic hasn’t retuned in the newspapers. And where there has been attention to air being to strongly polluted by car emissions (I remember a street in The Hague scoring the highest within Nl or Eu) the layout of the street was changed which caused traffic to spread more evenly over other roads, rather solving the eminent problem to a certain extend than solving the actual pollution. And although busses are supplied with filters, (new) cars are or will be subject to stronger regulation and industries are restricted in the amount and type of pollution the can sent into the sky I thought that smog and acid rain are actually still a problem.
    I can understand the line of reasoning in the post but where did my idea go wrong?

  2. You may well have a point that the coverage of other issues has displaced smog and acid rain as issues in the news somewhat, but I find it hard to believe that’s all there is to it. After all, London really has much cleaner air these days and it’s been a long time since I’ve heard somebody express the fear that the limestone of the cathedral in Cologne might crumble from acid rain soon, something I heard on a monthly basis in the early 90s. And some of your other assertions, I think aren’t true either. The summers of the late 90s and early 2000s were some of the hottest on record and still the smog was not nearly as severe as it was sometimes in the 70s and 80s. Current pollution of the particulate matter (=Feinstaub) variety almost seem like luxury problems in comparison to the thick smog and soot of the past.

    None of this, of course logically matters for my original argument. If acid rain and smog were still a major problem, the prospects of making headway on climate change would be even dimmer.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


%d bloggers like this: