Are livestock responsible for 51% of greenhouse gas emissions?
Conventional wisdom has it that meat production is responsible for about 18% of global greenhouse gas emissions — a shocking enough figure as it is. But lately a much higher number has been circulating, with some claiming that meat is responsible for an astonishing 51% of worldwide emissions.
Some skepticism is in order here, so I went looking for the source of the figure. It appears to be this recent report from the Worldwatch Institute. Long story short: I read about 2 pages into the report and then gave up, because its conclusions appear to be hopelessly addled.
Among several “overlooked” sources of emissions, the report attributes a whopping 13.7% of worldwide CO2 to breathing by livestock. This is odd, because breathing is normally considered part of the natural carbon cycle. That is, the CO2 we breathe out is constantly being recycled by plants, which we then ingest, and so on in a cycle that doesn’t add any net CO2 to the atmosphere.
Does the Worldwatch report expose some previously unseen flaw in this reasoning? No:
> Livestock (like automobiles) are a human invention and convenience, not part of pre-human times, and a molecule of CO2 exhaled by livestock is no more natural than one from an auto tailpipe.
Natural doesn’t enter into the picture here. The question is whether the CO2 comes from some previously sequestered source, such as a coal bed, or whether it was in the air to begin with. Cars run on oil. Cows run on plants. Enough said. (Before people rush to point out that industrial agriculture requires the use of lots of fossil fuels, keep in mind that these emissions are already accounted for in previous estimates of emissions from livestock. Adding breathing into the mix just double-counts them.)
> Today, tens of billions more livestock are exhaling CO2 than in pre-industrial days, while Earth’s photosynthetic capacity (its capacity to keep carbon out of the atmosphere by absorbing it in plant mass) has declined sharply as forest has been cleared.
This is a non sequitur. Again, deforestation from livestock production was already accounted for in previous estimates. I took a quick skim through the rest of the report and saw nothing that inspired any greater confidence (in fact, just the opposite). For now, I’ll stick with the 18% figure.
Meanwhile, Nicolette Hahn Niman, of Niman Ranch fame, takes to the pages of the New York Times to launch an equally confused defense of beef — or at least grass-fed beef. The crux of her argument is that the problem isn’t beef so much as how the beef is produced.
Now, this is already a somewhat dubious claim. The greenhouse gas implications of grass-fed beef seem to be fairly difficult to tally, and Niman doesn’t grapple with the numbers in any way that clarifies. But her argument really goes off the rails when she looks askance at vegetarians who eat soy beans of unknown provenance:
> Unfortunately for vegetarians who rely on it for protein, avoiding soy from deforested croplands may be more difficult: as the Organic Consumers Association notes, Brazilian soy is common (and unlabeled) in tofu and soymilk sold in American supermarkets.
Although I happen to think the Niman Ranch does good work, this statement strikes me as almost sleazy in its implication that American grass-fed beef is somehow better for the environment than Brazilian-grown soy. Soy is a commodity traded on a global market. It doesn’t matter where you personally get your tofu from. What matters is the aggregate demand. In this regard, soy is like oil, which is also why it doesn’t really matter whether you buy gasoline that comes from U.S. well fields or from some nasty regime.
So what’s putting pressure on aggregate demand? Livestock, of course. The reason those Brazilian rainforests are getting mowed down is not because of unethical vegetarians, but because so much land is needed in order to feed cattle and pigs and fish.
So, yeah, if you’re in the mood for a burger, the environment is probably better off if it comes from a grass-fed cow. But given the reality of the global meat supply, the planet would probably prefer that you have a salad.