10° 40' N, 61° 30' W

Thursday, February 13, 2003

Swelling Gases?

An article in The Economist points out that the Intergovernmental Panel on Climate Change's forecasts of greenhouse-gas emissions are, in all likelihood, based on questionable assumptions:

The combination of overstated gaps and of built-in assumptions about the extent of convergence in the average incomes of rich and poor countries yields projections of GDP for developing regions which are improbably high. Even the scenarios which give the lowest figures for projected cumulative emissions in the course of the century assume that average incomes in the developing countries as a whole will increase at a much faster rate than has ever been achieved in the past.

The unreality of the assumptions about economic growth in developing countries is highlighted by disaggregated projections which were recently released on the SRES website. These projections imply that, even for the lowest emission scenarios, the average income of South Africans will have overtaken that of Americans by a very wide margin by the end of the century. In fact America's per capita income will then have been surpassed not only by South Africa's, but also by that of other emerging economic powerhouses, including Algeria, Argentina, Libya, Turkey and North Korea.

The projections of climate change and the institutional arrangements designed to address the problem--namely, the Kyoto protocol--have very expensive implications, even though it is becoming increasingly clear that the science is still very, very uncertain. This may justify the skepticism of scicentists like Bjorn Lomborg, and, ultimately, the repudiation of Kyoto by George W. Bush.

Bush, coincidentally, yesterday announced an voluntary initiative on carbon emissions. There are better measures, I think--emissions trading, followed by carbon taxes--but the move is a positive one. This probably shows that Bush's errors in conveying his message to the rest of the world are more ones of style than of substance, as Daniel Drezner writes.