The IPAT equation (environmental Impact = Population * Affluence * Technology) isn’t really wrong. My objections to it, in the main, are based on my impression that it conceals at least as much truth as it reveals. Technology (at least in our consumerist society) facilitates Affluence to the point of disappearing into it. Population simply cancels itself out, since Affluence is defined in per capita terms. And Affluence, itself, is merely a euphemism for consumption.
So what we’re left with is that Impact = Consumption, which verges on being a tautology. Our impact on the environment increases every time we consume materials which exist in it, and every time we consume its absorptive capacity by exhausting wastes. I = C. To reduce I, reduce C. Period.
So why IPAT? Why has that formula been embedded into the brains of so many Environmental Studies students? Several possible reasons suggest themselves.
First, there’s the fact that I = C is just too simple a formula to build a substantial discipline around. In a sense, IPAT is an attempt at a first-level decomposition, an identification of potentially independent factors, each of which can be analyzed independently. Such an approach is consistent with a basic understanding of the scientific method, so it’s something that fits well into modern academe. The problem, as I hope I’ve demonstrated, is that the terms aren’t really independent of one another. Rather, they interact profoundly in ways that are shaped by a society’s values and expectations. Focusing on either Population or Technology independently leads down a wrong road, and I rarely meet students who are interested in focusing on Affluence (at least, not that are interested in reducing it). IPAT offers the opportunity to apply multiple analytic techniques to multiple contributory factors – to be a fox who knows (and can apply) many things. I = C offers only the opportunity to be a hedgehog, who knows one big thing.
Second, there’s the fact that Environmental Studies needed, at its inception on any campus, to fold itself into a universe of more established, more influential disciplines. As such, it couldn’t afford to step on too many toes, or too hard on any toes at all. The IPAT equation has the advantage of not offending any other discipline and, potentially, of allowing for alliances with disciplines like engineering and sociology. I = C, properly understood, almost guarantees that disciplines like marketing, advertising and economics will take offence. No campus I’ve ever been on would want to create a new department that’s overwhelmingly likely to start a shooting war with the established players.
And finally, any discipline based on I = C would (1) have trouble recruiting students – beyond the occasional dedicated iconoclast – and (2) have even more trouble getting its graduates employed in an economy which arranges itself to keep nominal costs of both natural resources and ecosystem services artificially low. It’s one thing to be able to demonstrate and teach that virtually unrestricted consumption of the ecosphere is, like war, “unhealthy for children and other living things”. It’s quite another to find a way for our graduates to get paid a living wage for understanding that fact.
I can see how and why the IPAT formulation took hold. I can even sympathize with many of the reasons. But I worry that, by making study of the environment palatable in a social system organized to consume that environment, we’ve created a discipline somewhat akin to the 19th-century forms of sociology and geography that proudly served their imperial masters.