Here is quite an interesting paper addressing some of this, including ghg emissions and this weird notion of "teh meat industreez" as if meat production is somehow always similar:
Crosson, P., Shalloo, L., O’brien, D., Lanigan, G.J., Foley, P.A., Boland, T.M. and Kenny, D.A., 2011. A review of whole farm systems models of greenhouse gas emissions from beef and dairy cattle production systems. Animal Feed Science and Technology, 166, pp.29-45.
Expecting ruminant ag to "buy time" for the big polluters (how you remove ruminants from the planet is not clear - rewilding here will just benefit different ruminants, eg deer):
"This is important since methane—the greenhouse gas emitted by ruminant livestock—has become the centre of recent climate mitigation debates (Reisinger et al.,
2021). As a powerful “climate-forcing” gas, methane has major effects on global warming, even though its lifetime in the atmosphere is short relative to carbon dioxide. Livestock production, together with gas pipelines, shale fracking, waste dumps and wet rice agriculture, is a significant emitter of methane.
1 Reducing methane therefore is seen as a “quick win” for climate mitigation due to its significant influence on warming in the short term, and the Global Methane Pledge that commits to reducing methane by 30% by 2030 has over 100 countries as signatories.
2
Efforts to reduce methane emissions will have major implications for livestock production globally, as systems of greenhouse gas measurement, verification, and climate emissions reporting are established. But which livestock, where? What are the uncertainties within the global scientific assessments central to framing mitigation policies? What assumptions and biases may distort, with what consequences? "
And indeed here:
Houzer, E. and Scoones, I., 2021. Are livestock always bad for the planet? Rethinking the protein transition and climate change debate.
"If extensively grazed livestock are removed, what replaces them? Many imagine the return of a ‘wild’ ecosystem, but numerous studies show that wildlife and termites in ‘natural’ systems may produce equivalent emissions, if not more. In many settings where extensive livestock production is central to people’s livelihoods, there are few land use alternatives, as crop farming and tree growing are not feasible."
On the "meat industry" perception:
"The notion of the “livestock sector” presented in many global assessment reports is largely meaningless.
3 There are hugely different livestock production systems in different parts of the world: from contained, industrial factory farming to extensive grazing on open rangelands. Along a long continuum, there are very different emission dynamics and so very different framings of and solutions to the methane mitigation challenge.
Extensive livestock producers make use of rangelands that cover over half the world's land surface, with many millions of producers tending everything from cattle and camels to goats and sheep to yaks, reindeer and llamas (ILRI et al.,
2021). They are frequently marginalized economically and politically and are often seen as “backward” and “destructive” due to their mobile lifestyles. Yet extensive livestock producers, including pastoralists, make use of environments where conventional agriculture is impossible. They contribute to enhancing biodiversity, protecting ecosystem services, preserving cultures and landscapes and contributing high-density protein and other nutrients to diets, often to those who need them most (Manzano et al.,
2021). For obvious reasons, they are very different to large, industrial livestock production systems.
Lumping all livestock systems together in any analysis therefore makes little sense. There are different costs and benefits, different patterns of emissions, and different routes to mitigation. Yet, the way the science is framed in global assessments tends to aggregate and simplify."
On emissions from livestock (which people are still working on methods to accurately measure - some work in my department):
"The aggregate emissions figures are presented in terms of carbon dioxide equivalents, meaning that all greenhouse gases, including methane, must be presented together. However, given the contrasting ways that gases behave in the atmosphere, they have very different “global warming potentials.” Much uncertainty exists around how to treat methane, for example, which has high warming potential in the short-term, but decays rapidly. Some suggest that the effects of methane are overestimated using standard measures, and alternatives for assessing “global warming potential” have been proposed (Allen et al.
2016; Del Prado et al.,
2021). Without going into the technical details, the point is that there is much uncertainty around the seemingly authoritative facts and figures about livestock's methane emissions.
Such uncertainties are compounded when the underlying emissions data on which they are based are examined. Inevitably, global assessments are estimates, but where does the data come from? In large part, livestock emissions data derive from respiratory chamber experiments on large, well-bred animals, mostly in North America and Europe. Such experiments are used to derive emissions factors in national estimates reported to the Intergovernmental Panel on Climate Change (IPCC) and which subsequently are reflected in proposals for “Nationally Determined Commitments” for mitigation. However, a comprehensive review of life-cycle assessments of food production systems highlighted that only 0.4% of these were from Africa (Clark & Tilman,
2017). When empirical studies are undertaken on local animals, very different results emerge to the standard emission estimates. In part, this is because such animals are smaller, but also because they are physiologically adapted and feed selectively on natural range under particular feeding regimes. As a result, such animals produce far fewer emissions than usually assumed in standard models (Goopy et al.,
2021; ILRI,
2018; Ndung'u et al.,
2019). While estimated emissions factors may be necessary while improved data emerges from such local studies, much caution must be applied to the results, since life-cycle analyses may be substantially off the mark due to this chain of compounding uncertainties.
Yet, global assessments that feed into climate policy frequently rely on extrapolations from this type of life-cycle analysis. A widely quoted example was published in Science and used information from an impressive 38,700 production units and 1600 processors as its data source (Poore & Nemecek, 2018). Extrapolating to a global level, the study claimed that reducing consumption of animal-source foods and excluding animal production across 3.1 billion hectares (equivalent to a 19% reduction in arable land) would reduce greenhouse gas emissions by 49% (2018: 991). Without attending to the multiple qualifications and assumptions laid out in the Additional Materials, the media headlines that ensued condemned livestock production and urged major changes in diets, a message reinforced by the much-debated EAT Lancet report (Willett et al., 2019). However, the Science study largely missed out on extensive systems, including as it did only “commercially viable” case studies. It relied on published data, which was mostly from industrial production in North America, Europe and some parts of Latin America and coastal China, and so created a distorted view, now replicated across public and policy debates."
Funny that I'm not the only scientist saying this sort of thing, eh? Apparently not the "lone crazy" that appears to be the attack line used against me on this thread.
And:
"Such biases in the data are in turn exacerbated by a narrow focus on emissions efficiencies per animal or per unit of product, without assessing the system as a whole, including the potential for sequestration. We still know very little about the carbon-nitrogen dynamics in rangeland systems in different parts of the world (Garnett et al.,
2017), but grasslands are a huge global store of carbon, notably in roots and soils (Dass et al.,
2018); part of dynamic “open ecosystems” that have co-evolved with natural herbivory, both domestic and wild, for millennia (Bond,
2019). Depending on the state of such ecosystems, grazing animals can add to such stocks (Conant et al.,
2017; McSherry & Ritchie,
2013). This is especially the case if manure is deposited and incorporated across wide areas, as with mobile systems. More comprehensive life-cycle assessments of mobile, extensive livestock production shows how, if such sequestration potentials are accounted for, then such systems can be in carbon balance, even being net positive under some conditions.
5"
foodrevolution.org
veganuary.com
