From “Human Engineering and Climate Change,” by S. Matthew Liao, Anders Sandberg, Rebecca Roache, published last year in Ethics, Policy & Environment.

A widely cited report by the United Nations Food and Agriculture Organization estimates that 18 percent of the world’s greenhouse emissions come from livestock farming, a higher share than from transport. More recently, it has been suggested livestock farming in fact accounts for at least 51 percent of greenhouse emissions. Even a minor (21 to 24 percent) reduction in red-meat consumption would achieve the same reduction in emissions as the total localization of food production — that is, having…