At first this sounds like some PETA press release, but it’s right there in the current issue of WorldWatch: “Livestock and Climate Change,” by Robert Goodland and Jeff Anhang. The key conclusion: livestock-related greenhouse gas (GHG) emissions are 51%, or more, of all human-caused GHG emissions.

What?

If this stands up, it completely changes the politics of fighting global warming. It means that all the alternative energy in the world is still less effective than a vegan diet in combating global warming.

When the FAO report Livestock’s Long Shadow appeared a few years ago, they put the greenhouse gas (GHG) emissions of livestock agriculture at 18% of all GHG emissions. PETA latched onto this report and proclaimed meat to be the “#1 cause” of global warming. This was a bit premature, as it relies on statistical trickery — by putting all other causes in separate categories so that each other category, by itself, is less than 18%. But now it could turn out that PETA was right all along, even though for the wrong reasons.  In case it’s not obvious, let’s be clear: the thoughtful and reasoned analysis of this WorldWatch article is totally different from that typically adopted by PETA.

So how did we go from 18% to 51%? The authors point out uncounted land use changes, undercounted methane, the fact that meat-eating has gone up since 2002, and some other things, in reaching this point.

The most interesting category, though, is breathing by livestock (!), which amounts to 13.7% of the GHG total. Evidently plants extract carbon from the ground, and then livestock eat the plants and turn this carbon dioxide into the air, making livestock a sort of carbon sequestration system in reverse.

There’s a possible conceptual problem here I’d like to see someone address. Without livestock, there would surely be other animals that would replace them: prairie dogs, deer, whatever. These other animals would also breathe, wouldn’t they?  My response would be that even if we turned this extra land used by livestock back to wilderness (which we wouldn’t have to do), the biomass of these wild animals would be only a small fraction of that of livestock.

This article is of critical importance, and I’ll be following the debate over this with great interest.

(Slightly updated Oct. 26)