Last week, I attended an Edinburgh Skeptics event on arguments for and against vegetarianism. Like Robert Nozick, I’ve always thought that the arguments in favor of being vegetarian are ethical (Nozick’s is quite profound). I was surprised to see people hurting the argument for abjuring meat by making a green case, because environmental arguments don’t help vegetarians’ cause at all. This is because environmentalists have no grasp of agricultural economics (“land economy”), and their evidence is deeply unreliable. Simply put, vegetarians can do better.

Here, for everyone’s edification (not just Skeptics and vegetarians, but libertarians as well), is the land economy stuff environmentalists routinely ignore. You need to be willing to write off a day to read all the links, and some of them are science-y, but by the end, you will know how many green arguments are spurious.

1. All greenie arguments about “eating local”, the environmental benefits of organic farming, and “locavorism” make the problem they are attempting to solve worse. They require more fertilizer, more labor (paid less), more land, or have a larger carbon footprint. Sometimes all four combine, which means that the people advocating them really have no idea. Organic produce is also almost without exception more expensive (thanks to those four factors), which means poor people miss out. People like Michael Pollan are fine with poor people missing out, too. Eating organic also confers no measurable health benefits.

Free trade and agriculture2. Environmentalists simply do not grasp comparative advantage, economies of scale, and gains from trade. They commonly think economic gain is zero sum. Because many of them purport to be lefties and worship at the feet of Paul Krugman, you can (a) remind them that while Krugman may be a Keynesian, he is still an economist, (b) give them a copy of this essay of his (Ricardo’s Difficult Idea), and then (c) stand back and watch their heads explode. Krugman’s paper explains why free trade makes for less intensive agriculture (pic to the left via Tim Harford).

3. All greenie arguments against GMOs are scientifically illiterate nonsense, on a par with anti-vax (or thinking that demand curves slope up, as many environmentalists do). Where libertarians sometimes find themselves (mistakenly) making common cause with greenies on GMOs is over intellectual property, of which many are skeptical. It is of the utmost importance to remember that the two issues are separable–one is scientific, one legal. As part of this process, recall that much greenie vandalism of GMO crops has been directed at not-for-profit trials, not Monsanto.

4. Many “feel good” greenie policies are simply bonkers: take the popular campaign against plastic bags, for example. In 2005, the UK’s Environment Agency commissioned a study on plastic bag use that found, “in order to balance out the tiny impact of each lightweight plastic bag, consumers would have to use the same cotton bag every working day for a year.”

5. Libertarians in particular need to drop their widespread refusal to accept the reality of climate change. It makes us look like wingnuts and diverts attention from the larger number of greenies who spew pseudoscience on a daily basis. That said, don’t confuse real science with greenie catastrophizing. When Matt Ridley pointed out (a) that climate change is real, (b) it is currently having beneficial effects, and (c) is likely to continue to do so for some time, he got a bucket of turds dumped on his head by both sides. Don’t do that.

Finally, most scientists, when presenting their findings, do so with great care. They seldom make policy recommendations: scientists are aware there is this thing called the division of labor and that policy is better developed by others. Indeed, it is economists who are most aware of the problem of intergenerational discounting, where present generations have to give something up in favour of future generations. This is something that doesn’t just affect climate change: it’s the main driver behind pension crises throughout the developed world.

Now, armed with actual evidence, go forth and make lazy greenies defend their case.