The graph comes from the Environmental Working Group, who describe their findings:
Lamb, beef and cheese have the highest emissions. This is true, in part, because they come from ruminant animals that constantly generate methane through their digestive process, called enteric fermentation. Methane (CH4) – a greenhouse gas 25 times more (CH4) potent than carbon dioxide (CO2), accounts for nearly half the emissions generated in this study’s Nebraska beef production model (see chart below). Pound for pound, ruminants also require significantly more energy-intensive feed and generate more manure than pork or chicken (see figure 2).
* Lamb has the greatest impact, generating 39.3 kg (86.4 lbs) of carbon dioxide equivalents (CO2e) for each kilo eaten – about 50 percent more than beef. While beef and lamb generate comparable amounts of methane and require similar quantities of feed, lamb generates more emissions per kilo in part because it produces less edible meat relative to the sheep’s live weight. Since just one percent of the meat consumed by Americans is lamb, however, it contributes very little to overall U.S. greenhouse gas emissions.
* Beef has the second-highest emissions, generating 27.1 kilos (59.6 lbs) of CO2e per kilo consumed. That’s more than twice the emissions of pork, nearly four times that of chicken and more than 13 times that of vegetable proteins such as beans, lentils and tofu. About 30 percent of the meat consumed in America is beef.
* Cheese generates the third-highest emissions, 13.5 kilos (29.7 lbs) of CO2e per kilo eaten, so vegetarians who eat a lot of dairy aren’t off the hook. Less dense cheese (such as cottage) results in fewer greenhouse gases since it takes less milk to produce it.
My takeaway from this chart: I already don’t eat lamb, so good on that. I had reduced my cheese consumption — not because of greenhouse gases, but because of other gases (i.e., I wanna fart less)1 — but I’ve backslid on that in recent months. So I’ll cut back on cheese again.
I’ve already reduced my beef and pork usage, replacing it mostly with turkey but also with chicken. But I’m still eating beef far too often — it hadn’t penetrated my mind that beef is actually much worse for climate change than pork (27 vs 12.1 kgs). Also, I hadn’t realized that turkey was worse than chicken (10.9 versus 6.9 kgs).
So I’m going to try to turn more of my beef and pork eating into poultry-eating, and more of my turkey-eating into chicken-eating. Also, when I eat a meat other than poultry, I’ll try to have pork. Beef should be a treat food, not a staple.
In the end, it seems like the most important step most meat-eating Americans could take is to cut down on beef, replacing it with pork or poultry or fish. That’s not hard. And marginal changes count — so if you eat beef twenty times a month and you don’t think you can reduce it to once a month, maybe you can reduce it to ten times a month. Or to sixteen a month (that’s changing just one meal a week).
Of course, the best changes are structural, not personal. If the environmental costs of beef were reflected in what we pay at the cash register, than Americans would switch away from beef as a matter of supply and demand.
- I worry that this will be the thing that generates the most discussion in comments, alas. [↩]