The Carbon Cost of Meat

by Steve Bien

The case for vegetarianism has always swung between two arguments. There is the notion that killing and eating animals is morally wrong and there is the idea that being a vegetarian is better for your health. Neither one has been persuasive for me. I think it is possible to treat animals humanely but nevertheless to kill and eat them. And the evidence that a vegetarian diet is intrinsically healthier just isn’t supported in nay medical literature that I have seen. But a new argument has hit the media and one that is harder to dismiss. Eating lower in the food chain, eating less or no meat, is better for the planet. Articles in both Audubon and Scientific American detail this, the former in a fairly shrill fashion and the latter a little more persuasively.

According to Nathan Fiala, an economist, (Scientific American, February 09) the net greenhouse gas (GHG) cost’ of meat production exceeds all forms of transportation combined, 18% of all GHG emitted annually. Further, Fiala turns a widespread myth on its head to show that the transportation of food is the smallest part of its carbon cost of food, dwarfed by the carbon emitted by food production. According to him eating locally is not a solution. His tally includes the nitrogen and carbon inputs in feed grains and the copious methane that ruminants expel in their belchings, fartings, and manure. One half pound of meat, a large hamburger, represents the same CO2 cost as driving a car 10 miles, 18 times the carbon gas generated by the importation of a pound of asparagus from a hot house in Peru. Pork, chicken, and dairy products are a little less ‘expensive’. If a pound of beef generates 15 pounds of CO2, equivalent amounts of pork and chicken involve 3.8 and 1.1 pounds respectively.

Here is another way to think of it: the average motorist might be thought of one who drives a 25 mpg car 12000 miles per year, resulting in 4.4 tons of CO2 per year. If that driver switched to totally local sources of meat, she would save the equivalent of 1000 miles of driving yearly. Shifting from red meat to fish, chicken, eggs, or vegetables for just one meal per week would shave off 700-1000 miles. Total avoidance of red meat would reduce the total by the equivalent of 5000 miles of driving per year.

Now the meat industry is not taking these concerns passively and they are responding by attempting to better control the inputs of feed and the output of manure. For example, they claim that using artificial growth hormones shrinks the carbon foot print by decreasing the feed requirements for weight gain. Manure collection can be made more efficient and contained so that the accompanying methane gas is collected for fuel and the manure recycled in various fashions.

If Fiala and others are correct, where does this put the locavore notion that eating locally is good for the environment? Where does this put the other environmental claims of small scale and organic farming, which are revitalizing and reclaiming agriculture here in Maine?

As I ponder this I wonder if all carbon atoms are equal. Fossil fuels represent sequestered carbon fuels that are pumped from deep underground and burned, whereas grains and grass are part of the everyday carbon cycle that include trees. As such plant carbon, whether in the form of the plant, the animal, or the atmosphere might be thought of as an atom making its usual recycling rounds, quite unlike the carbon of oil sands and coal beds thousands of feet below the earth’s surface? This might be especially true in the case of free range, grazing animals whose manure is recycled back as fertilizer for their forage. How do these considerations change the math?

In addition methane, unlike carbon dioxide, is degraded eventually by sunlight and does not persist indefinitely as carbon dioxide does. . Finally, agricultural methane is itself small compared to the vast amount of methane that is beginning to come out of permafrost as the tundra warms, a process already under way.
Be that as it may, eating lower in the food chain makes sense from a number of points of view. If it takes 5 pounds of corn and soy bean to make a pound of beef, 2.6 pounds for a pound of chicken, and only 2 ounces of grain to make a pound of milk, eating lower in the food chain is a kind of energy conservation. And avoiding feedlot meat also certainly removes our support for the vast amount of deforestation that takes place in the name of hamburgers.

Please note that the interesting columns you find here do not necessarily reflect positions taken by Maine Audubon.