“We are as gods, and might as well get good at it.” – Stewart Brand

There seem to be two movements under the banner “environmentalism”. One, which we might call old environmentalism, is mainly about wanting everyone to have a high quality of life. Living in a polluted city, drinking dirty water, or having all the forests turned into parking lots would suck, and we can mostly all agree on that.

Of course, there’s still a lot to do, but we’ve largely succeeded at cleaning up the Western world. Leaded gasoline is out, catalytic converters are in, and London is cleaner than it’s been in centuries. (To get an idea of how it was when the US was industrializing, one might look at China, whose rich are moving out to escape vast clouds of smog.)

But the other movement, new environmentalism, seems to be based on the purity/contamination moral axis. From this perspective, nature is “pure”, and humans are “contaminating”. Any change we make to nature is ipso facto bad, not because it has bad consequences (either for us or for animals), but because it damages nature’s purity.

The trouble with this view is that it doesn’t allow for tradeoffs, or expected utility calculations. If we want to clean up the local park, we can figure out how much we value a clean park, how much the cleanup will cost, and then decide if it’s worth it. Should we pay a thousand dollars? Probably. Should we pay a billion dollars? Probably not. The worse a problem is, the more we should pay to fix it. Standard economics.

But purity/contamination morality doesn’t allow for that kind of math. Purity must be preserved. Any contamination, however minor or harmless, is unacceptable. One bizarre result of this is that places we should care least about often have the most environmental protections, because they are implicitly seen as “pure”. For example, Antarctica has some of the world’s strongest environmental laws – all mining is outright banned, and “environmental assessment” must be conducted for all activities, even things like tourism. Now, the majority of Antarctica is a deserted moonscape, with no humans, animals, plants, or even microbes. You could dump a billion tons of garbage there, and no one would even notice for years – it’d have basically no bad consequences. So why are people worried about it? Why would anyone worry about something as small as a single candy bar wrapper, especially in such a place? Because, I think, any human activity feels contaminating, and we dislike contamination.

The same principle applies to global warming. Rapid, unplanned change is usually bad, since animals (including us) have implicitly planned for current conditions, whatever those may be. But it’s unlikely the current climate is optimal. After all, no one decided the weather – it just happened by accident. I haven’t done out the math, but it seems likely that – if it’s slow and well-planned enough for us and nature to adapt – warmer weather and more CO2 in the air would be net beneficial. It would open up vast areas of the planet that are now basically unused for more natural life, more people, and more agriculture. But from the purity/contamination perspective, altering the climate in any direction is sinful.

One standard justification for new environmentalism is the law of unintended consequences. We can’t plan out the future perfectly – hence, any change will have some unplanned bad effects – hence (so the reasoning goes) any change, any contamination, must be bad. This rests on the silly assumption that imperfect planning, even if it’s quite thorough, must be worse than no planning at all. (See also The Fallacy Of Complexity.)

After all, if we don’t control the climate or the distribution of species or the allocation of water, these things get decided by asteroids and storms and volcanoes. A volcano doesn’t care that it will have unknown subtle effects on the downwind ecosystem a century hence. It just erupts and destroys stuff. The real motivation isn’t that anyone thinks humans are worse planners than volcanoes, but that any human activity is assumed to be contaminating, and therefore bad.

The lesson here isn’t that we should destroy the environment, or save the environment. The lesson is that any decision, whether to act or not to act, should be judged by analysis of its costs and benefits. Just like anything else, some human activities are good, and some bad; some really matter, others we can ignore. Real decisions must be based on real numbers, not blanket conceptions of “good” and “evil”.