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.