Ranchers, who raise their animals outdoors on pasture, often find themselves attacked from two very different sides of what sometimes seems like a binary debate. (It isn’t). On one side, there’s an industry that wants to maintain an industrial system of production. This system of production has a lot of vested interests (meat packers, pharmaceutical companies, agro-chemical /seed companies) who want to maintain the status quo. On the complete opposite side is a very small, but vociferous, abolitionist vegan community that will use any rational or irrational argument to further their fundamentalist foodie jihad. When arguing against pastured based systems, one of the bigger ironies is that these fundamentalist vegans will borrow arguments and statistics from industrial producers to further their own vegan agenda. Thus understanding the industrial perspective is key to finding fallacy in both of these opposing sides arguments.
One such paper that takes an industrial perspective was titled “Future of Meat.” After reading this paper on the supposed “Future of Meat,” specifically in regards to extensive systems, I immediately had to wonder whether this effort was a sincere effort to look at this topic from different perspectives or simply one intended to reinforce a perspective intent on “intensification” (the chickenization of the beef industry). I’m left wondering because whose papers the author chose to cite, and whose research the author failed to acknowledge or wasn’t aware of when reaching her conclusions.
By only looking at certain viewpoints and not fully understanding the genesis of the data used to formulate these viewpoints, the author makes a number of erroneous deductions. This is particularly true about carbon sequestration, enteric emissions and water use. In her analysis, the author failed to explore any of the current and evolving soil science research that includes more detailed in field calibration.
Swain cites Kamali et al 2014 (1) to exclude carbon sequestration from net emissions. Yes soil carbon sinks will eventually reach equilibrium, as well as have diminishing returns. But after 10,000 years of plowing including the past 100 years of chemical inputs, there still is significant potential for carbon sequestration over extended periods. Paustian et al (2) discuss this potential in their meta-analysis of the current state of soil carbon science. Wang, Teague et al 2015 (3) have shown that change in grazing management from continuous grazing to AMP managed grazing can significantly increase carbon sequestration for periods over 100 years. In restored or desertified area, there is even greater potential for longer periods of carbon sequestration. Rowntree et al 2016 (4) have shown that accounting for this carbon sequestration in LCA’s for different management systems, enough carbon can be sequestered to create carbon sinks in pasture offsetting all the enteric emissions as measured by SF6 tracers apparatus on cattle. This is Rowntree’s equation: GHGnet = GHGecosystem + GHGfeed + GHGenergy – GHGseq
In this equation the GHGecosystem includes the enteric methane which is the primary driver of GHG emissions. So it really is useful to look at how enteric methane is calculated. Both of Swain’s primary sources Capper (5) and Kamali (1) model previously generated data rather than doing any actual field measurements. Capper cites a dairy study from 1979 (6) and Kamali cites a study from 2007- Ellis, JL et al (7) for their respective methane data and calcs. Kamali’s data is better in that it cites more sources for info and more current data. For both Capper and Kamali all methane data is based on SF6 tracer, mask or whole body calibration (chamber measurements). Enteric measurements gathered this way only look at nose and tail emissions of methane. These are probably fine for assessing the impacts of different feed on methanogenesis, but these methodologies don’t provide a true ECOSYSTEM context where methane oxidizing bacteria (MOB aka methanotrophs) in the soil have the potential to offset the enteric emissions from methanogens in the rumen. Through better grazing management and soil regeneration, more methanotrophic activity can be created in soils which helps provide an ecosystem offset to the enteric methane (8,9,10) from methanogenesis. There is no soil benefit in feedlots. Feedlot poo and pee is also full of excreted antibiotics that undermine any beneficial soil microbes that could possibly live in that hostile dirt environment.
(Editorial note, my understanding of methane sinks has evolved with further inquiry, so the ideas in the following paragraph and excerpt has been superseded by ideas in a more recent blog entry -“Methane Math and Context“).
When you solely rely on nose & tail measurements for CH4 measurements, without any context, of course you’ll get larger enteric CH4 sum amounts for animals with longer lifespans simply because the total sum, without any offsets, is greater the longer ruminant animals live. The equation in this case is essentially X (Tracer or Chamber emission value) * LS (life spans- days of life) * number of ruminants = Total enteric CH4 emissions. The whole industrial premise (echoed by DEFRA and Long Shadow’s authors) with this equation is that however you shorten the LS through feedlots, hormones and genetics, the less total enteric CH4 emissions you get and this therefore is an environmental benefit. The whole fallacy is that when you put the ruminants in feedlots, you lose the mitigation through MOB’s you’d get by leaving the ruminants on pasture. You disregard or ignore the soil science. Soil Scientist Dr. Christie Jones notes this disconnect in this interview, “Save our Soils — Dr. Christine Jones Explains the Life-Giving Link between Carbon and Healthy Topsoil.” (11) Here she notes the following,
“…we’ve gone from free-ranging herds to animals in confinement. That changes everything. Firstly, we’re growing feed for these animals using fossil-fuel intensive methods and secondly, confinement feeding creates a disconnect between ruminants and methanotrophs. Methanotrophic bacteria use methane as their sole energy source. They live in a wide variety of habitats, including surface soils. If a cow has her head down eating grass, the methane she breathes out is rapidly metabolized by methanotrophs. There’s an analogous situation with termites. Termites produce methane during enteric fermentation, as happens in the rumen of a cow. But due to the presence of methanotrophic bacteria, methane levels around a termite mound are actually lower than in the general atmosphere. In nature, everything is in balance…”
At the beginning of the 1980’s some scientists thought termites emitted up to as much as 30% of atmospheric methane based on laboratory experiments. However when termite emissions were looked at in the context of their ecosystems. Methane emissions were NEGATIVE.
The way you can get a more accurate comparison of systems is to use open path lasers (or better yet eddy covariance ‘flux towers)’ in the field to get enteric CH4 measurements. So what you really want to see is a comparison of enteric CH4 emitted from the same breed and number of head of cattle in a feedlot versus the same and number of head in a well-managed [AMP/HM] paddock with healthy well aerated soils. I strongly suspect that when you compare these two systems this way, what you’ll see is a lot greater sum of enteric CH4 from the feedlot system despite the shorter ruminant lifespans. This would be more accurate than solely relying on mathematical models interpolating previously generated data that doesn’t account for any of this current and evolving soil science. In field analysis of AMP systems is currently being done as part of this Soil Carbon Curious Project a collaboration between scientists at Michigan State University, Texas A& M University and Arizona State University. Here are two videos- https://vimeo.com/130721684 + https://vimeo.com/181861077 documenting some of this research though not specifically the evolving methane flux measurement portion of this research.
Capper’s analysis is wrong because of others assumptions as well. One big variable is average daily gain, which she uses as 1.35 lbs./day for pastured cattle. That’s not a bad assumption for a typical grazer, but in adaptive multi-paddock management systems, the ranchers that know what they’re doing can do much better than that with their grazer’s gains (~2lbs/day). This has a huge effect because GHG for enteric emissions is driven by days in pasture, and it takes 2x as many days to finish at 1.35 lbs./day as 2.7 lbs./day. Average daily also impacts land utilization on output productivity per acre as noted in Rowntree et al 2016(4)
Anyway, on a completely different front regarding enteric methane, here’s a good video https://youtu.be/nPMdtmQMud8 showing how enteric methane can be further mitigated through feed and supplements. There’s a lot of research going on in Australia, India, Canada and other places looking at how to mitigate enteric methane through supplemental feeds one of which is red algae grown in aquaculture systems. So that’s a completely different strategy to reduce enteric methane that can be used in ADDITION to regenerating soil conditions more favorable to methanotrophs. Thus such land restoration, in conjunction with other mitigating strategies via supplementation (or simply better feed) to reduce methanogensis in cattle rumen, really has the potential to make the issue of enteric methane a red herring in these well managed (AMP/HM) systems. With rumen mitigation/better diets, a lot less enteric CH4 has to be offset in a pastured system. This is a both/and strategy.
There’s a whole other discussion about water including what more soil carbon means to water infiltration and retention. More soil carbon drastically improves water retention. Better management improves infiltration. When water infiltration and retention are improved through better grazing management, rain fall (green water) is more effective which means very little to no blue water is required for irrigation. This increasing grass/forage amount and quality improves land holding capacity allowing for higher stocking rates, many well managed holistically managed ranches don’t require any irrigation. So for their water footprints, 98% of the water is the water required to grow grasses, and 98% of that 98% is green (rain) water. Feedlot systems aren’t anywhere near as efficient. They typically require three to four more times (around 6 to 8%) the amount of blue water for corn/soy/other crop growth. I’ve discuss water, water footprint modeling (water balance models) limitations and effective rain fall more in another previous post: Understanding Numbers. Capper’s analysis is outright shameful on water (assumes 50% irrigated pastures), so again she demonstrates a propensity to figure figures in such a way to reinforce her confirmation biases.