The Nimanic carnivore's dilemma

I haven't seen much discussion of the NY Times Op-Ed by Nicolette Niman of former Niman Ranch fame, arguing "that a conscientious meat eater may have a more environmentally friendly diet than your average vegetarian."

Call it highly unproven at this point, even accepting that she's talking about the tiny percent of beef in the US that's grass-fed. Typical grass-fed cattle aren't much better for greenhouse gas emissions than typical factory farmed. Niman has to resort to discussing techniques for reducing methane that are experimental or not widely adopted even among the small percent of cattle that's grass-fed.

She does have an interesting argument that one study shows a 19% increase in soil carbon sequestration from pasturing cattle instead of raising crops. My one-study rule applies though (one study's result isn't proof of anything, it might just show the need for lots of study to confirm the result). And I didn't know that turkeys could be grass-fed.

She left out the issue that most everyone does as well, that ranching provides an alternative land use to sprawl. She also left out the argument that lands that have been pastured for decades/centuries at the current rate of use are carbon neutral for that time period.

Finally, here in California the grass would have been originally grazed by elk and deer, while in the Midwest it would have been grazed by buffalo. It would be interesting to compare emissions on that basis.

Unrelated bonus blogging: Tim "Slob Hunter" Pawlenty may have gut-shot his reputation among the hunting community by abandoning a wounded deer in the field. This may well cause him more trouble in running for the Republican nomination than all the deaths from that bridge collapse in 2007.

Grass-fed beef and greenhouse gas - now with data! (Some data, anyway.)

My business plan, by the way, is to overtake the Huffington Post in traffic counts by focusing on greenhouse gas emissions from cattle. Should take about a month, I figure.

In that Grist article I talked about earlier, someone named CL Weber showed up with data:

J Environ Qual 35:231-239 (2006) compared different types of suckler beef production, while Casey, J. W. and N. M. Holden. 2006. Quantification of GHG Emissions from Sucker-beef Production in Ireland. Agricultural Systems 90: 79-98 .... The JEQ article does indeed show (slightly) lower GHG emissions from organic production, at 11.2 kg CO2eq/kg-yr vs. 12.2-13 kg CO2eq/kg-yr for the conventional production schemes, which is still higher than the 10.8 kg CO2/kg-yr mean value calclulated in the Agricultural Systems piece....

However, again, my point is not that grass-fed is substantially worse than grain-fed but that they're pretty much in the same ball-park GHG-wise, and that the difference between them is in the noise when compared to the difference between beef and chicken (1.4 kg CO2e/kg in the US, according to Pelletier, N. 2008. Environmental performance in the US broiler poultry sector: Life cycle energy use and greenhouse gas, ozone depleting, acidifying and eutrophying emissions. Agricultural Systems 98(2): 67-73.)

Obviously pastured beef can have much better impacts on many other things, like water and air quality, than CAFO beef, but a substantial GHG advantage can't be had without assuming large amounts of C sequestration and no land use impacts despite the large amounts of land needed.

Not looking good for grass-fed beef. Story's not completely over, though. The commenter acknowledges earlier that indirect land use changes aren't accounted for. He or she thinks that could make cattle effects worse, but not necessarily. The main alternative use I'd expect of ranchlands in the San Francisco Bay Area in lieu of cattle would be sprawl. Also it doesn't include soil carbon, which would be a significant benefit I'd expect (maybe) from switching from tilled agriculture to pasturage.

Without those effects, beef is nearly ten times worse than chicken, which in turn is probably three times worse than vegetarian (my somewhat-eductated guess). It will take a heck of a lot to make up the difference between beef and vegetarian calories. Some interesting high-tech suggestions on page 120 of this UN FAO publication could be a start, if consumers will tolerate changing cattle's internal biota. Could be a split between the hippie and techno sides of the environmental movement.

Grass-Fed Beef and Methane, Part Deux: Still More Armwaving

I've written several times about grass-fed beef not being the climate nightmare that grain-fed beef is, and possibly a better alternative than eating plants. In the comments to one post, Michael Tobis and I engaged in much speculating about whether the methane emissions from cattle were worse than the carbon emissions involved in agricultural production of the same amount of calories. (And I never answered his final point that on already-cleared (regularly plowed) land, farming should be carbon neutral - the response is that it still takes energy inputs to farm, transport, and process the production, and soil carbon is not neutral relative to the possibility of converting the land to pasturage.)

Anyway, it was a data-free discussion, which is fine for what it's worth. Now comes a cattle rancher to make the same argument at Grist. To his credit he raises the methane issue, but after asking questions as to ways that, maybe, somewhat reduce methane emissions, concludes as to whether the methane is a problem, "The fact is clear. It is not the livestock; it is the way they are raised."

I may have been guilty of armwaving in my discussion with Michael, but at least I didn't jump from that to a conclusion. I left a comment saying as much, and a later commenter said it better:

It is conceivable to me that a steer that eats only grass from naturally fertilized pasture could have a negative carbon footprint. Root structures of grasses can be quite large, and soil can become a carbon sink, so the pasture could possibly sequester enough carbon to make up for the methane emitted by a steer during digestion. I'm also open to the idea that manure decomposes differently on pasture than at the feedlot. But someone needs to demonstrate it with some actual measurements and some real science.