Eric has an interesting post commenting on John Tierney’s recent column on wealth and the environment. Eric notes that Tierney’s argument is overly simplistic, and that basic arguments about the correlation between economic growth and environmental performance may not apply in the context of global climate change. Fair enough, but I would also like to qualify some of Eric’s remarks.
First, I think it is important to note that one of Tierney’s primary claims is that the formula of environmental impact advanced by Paul Ehrlich, John Holdren, and others — the so-called I-PAT formula — is incorrect. Ehrlich, et al., asserted that overall environmental impact (I) is a function of population (P), affluence (A), and technology (T), such that increasing P, A or T leads to an increase in I (and impact is presumed to be negative. Thus, as Tierney summarizes, “protecting the planet seemed to require fewer people, less wealth and simpler technology.” Yet, as Tierney notes, wealthier societies are more able and willing to pay for environmental protections. Moreover, technology can enable us to satisfy human wants and needs with less environmental impact, as occurs when technology increases agricultural productivity, enabling us to feed more people on less land (and set aside more land for nature).
What about population? Is the relationship between population and environmental impact still a positive one? Not necessarily. As economist Seth Norton has shown, economic institutions have a greater effect on some measures of environmental quality and human well-being than does population growth. Specifically, Norton looked at measures like access to safe drinking water, water pollution, and deforestation rates. As Norton found, “compared with other forces, the purely adverse effects of population are very small.” Moreover, as it happens, the institutional arrangements which improved environmental performance in Norton’s study (and tend to correlate with, although almost certainly do not explain, reduced fertility rates), are also those that tend to encourage economic growth.
In his post, Eric makes the important point that the Environmental Kuznets Curve (EKC) depends upon “legal institutions to translate people