In an excerpt from his forthcoming book, for the Times Magazine annual food issue, Jonathan Safran Foer explains his bumpy practice of vegetarianism. Although most of his qualms run along the lines of not wishing to hurt animals, he also mentions the reason I try to avoid eating terrestrial vertebrates:
According to reports by the Food and Agriculture Organization of the U.N. and others, factory farming has made animal agriculture the No. 1 contributor to global warming (it is significantly more destructive than transportation alone), and one of the Top 2 or 3 causes of all of the most serious environmental problems, both global and local: air and water pollution, deforestation, loss of biodiversity… Eating factory-farmed animals—which is to say virtually every piece of meat sold in supermarkets and prepared in restaurants—is almost certainly the single worst thing that humans do to the environment.