In his interesting book Beyond Animal Rights, philosopher Tony Milligan considers, among other questions, whether the whole world could be vegetarian (or vegan). If not, this could be considered a strike against these two dietary choices.
The problem, he argues, is that we need to transition to a more ecologically sustainable system of food production, one that relies less on concentrated, industrial methods of farming, extensive use of synthetic pesticides and fertilizers, etc. However, universal vegetarianism would seem to require an industrialized food system since there would be no cows or other farmed animals to provide, for example, natural fertilizer.* In other words, animals seem to be a key part of a healthy and organic farming ecosystem (as Michael Pollan and others have argued). And if raising at least some animals on farms is necessary for a sustainable food-production system, then universal vegetarianism doesn’t seem to be a desirable goal.**
Milligan points out, though, that it’s at least conceivable that we could raise animals on farms without killing them for their flesh. A system of, for example, non-intensive dairy farming seems to be compatible, in theory, with the kind of natural agriculture that sustainability-proponents have in mind. So, he concludes, while universal veganism might not be compatible with a system of ecologically sound and sustainable agriculture, a universal vegetarianism might be. A “mixed community” of vegetarians and vegans is, therefore, at least a hypothetically attainable ideal.
I don’t actually know whether vegan organic (“veganic”) farming is a live, large-scale possiblity, or whether animals are strictly necessary to an environmentally sound mode of farming. It’s clear that the widespread frequent meat-consumption that we currently have (much less the greatly expanded amount we’re likely to see as other nations develop economically) is not sustainable. But what exactly the feasible alternatives are isn’t so clear. I’d like to find out more.
*Milligan considers another possible response by the vegetarian/vegan: even if such diets require industrialized food production, they would require less land to be devoted to such methods for the familiar reason that it takes far fewer resources to produce plant-based food for direct human consumption than for raising animals who are, in turn, consumed by humans.
**Even if that’s true, however, Milligan points out that there may still be good reasons, including ethical ones, for some people to be vegetarians. See this earlier post of mine for a similar point.