Here's an example of the sort of sloppy thinking that plagues environmental punditry, especially when climate is involved. [via Tyler, who bought it uncritically]

The average American household burns through about 8.1 metric tons of greenhouse gases as a result of food consumption. By contrast, if your house has a car that gets 25 mpg and you drive 12,000 miles a year, that produces 4.4 metric tons of greenhouse gases. . .

two Carnegie Mellon researchers recently broke down the carbon footprint of foods, and their findings were a bit surprising. 83 percent of emissions came from the growth and production of the food itself. Only 11 percent came from transportation, and even then, only 4 percent came from the transportation between grower and seller (which is the part that eating local helps cut). . .

the striking takeaway is that "on average, replacing just 21 percent of the red meat in the 'typical' diet with fish or chicken does as much, emissions-wise, as buying everything in that same diet locally." That's not, of course, an argument against eating locally. Taste, farming practices, sustainability, and much else point towards local consumption. But buying locally raised meats doesn't get you off the environmental hook. If you're worried about global warming, changing what you eat is far more important than monitoring where it's produced.

This is the tired old argument that it takes more corn to make a pound of beef than it does a pound of chicken. It's false, since it takes no corn at all to make beef, while it is unavoidable for chicken. Cattle are ruminants evolved to thrive on grass. Chickens are omnivores evolved to thrive on bugs and seeds.

A good deal of the argument for locavorism for red meat is that it is raised without corn, and so does not contribute to the harms caused by growing grain. Substituting fish either contributes to the continuing decline of wild fisheries which are already exploited near to death, or increases the grain drain since farmed fishes are raised on grain too.

The valid part of locavorism is support for growers who do right by the world. When you are close enough to know how they produce their food it's somewhat easier to validate their methods. The invalid part is the transport costs since it is such a small part of the total cost. The important thing is to make sensible and informed choices, which means avoiding the advice of folks like Ezra and Tyler. They have trouble doing the math it seems.

Any thinking environmentalist will consume a fair amount of red meat, not just beef but also goat, mutton, deer etc. Bison is the gold standard. They thrive on grasses, leaves and other greens that people and other omnivores can't digest, and which are grown in environmentally beneficial ways. Pastures don't get plowed up annually, which avoids huge amounts of emissions and other environmental insult such as erosion. Pastures are polycultures which maintain diversity and produce more biomass, and support a host of other species besides the ones being raised as food.

The anti-red meat trope persists due to ignorance, but also because so much effort went into building a consensus among sloppy thinkers, especially paleo-environmentalists. Correcting their factual errors would also require them to disrupt their comfortable consensus. It's a variant of the Concorde fallacy, a sunk-cost effect.