Charles Kenny makes the case:
The Food & Agriculture Organization of the United Nations reports that in 2012, 966 million pigs, 1.5 billion cattle, and 22 billion chickens were roaming (actually, mostly not roaming) the world’s farms. For cattle, that’s five times the number in 1890 and for pigs about a tenfold increase, according to Clive Ponting’s Green History of the World. That’s one factor behind the growing global obesity epidemic: a British study comparing meat eaters and vegetarians found average differences in weight between meat eaters and vegans of 5.9 kilograms in men and 4.7 kilograms in women—and a recent U.S. study also suggested that meat consumption was positively linked to obesity. …
Yet despite all the reasons for curbing meat consumption, livestock farmers got nearly a third of a billion dollars in subsidies in 2011 from the U.S. Department of Agriculture. Let’s smash that pork barrel and put in place a per-pound meat tax instead, perhaps weighted by the environmental and health footprint of the particular kind of meat and production techniques. A well-cooked steak is one of the greatest achievements of human art and science. It’s time we started paying the true cost of producing it.
According to the baseline projections, by 2070, the agricultural sector alone would be producing more greenhouse gases than would be feasible for a planet with temperatures under control.