Nutrient provision capacity of alternative livestock farming systems per area of arable farmland required

Abstract

Although climate impacts of ruminant agriculture are a major concern worldwide, using policy instruments to force grazing farms out of the livestock industry may diminish opportunities to produce nutritious food without exacerbating the food-feed competition for fertile and accessible land resources. Here, we present a new set of quantitative evidence to demonstrate that, per unit of overall nutrient value supplied by a given commodity, the demand for land suitable for human-edible crop production is considerably smaller under ruminant systems than monogastric systems, and consistently so at both farm and regional scales. We also demonstrate that imposition of a naïvely designed “red meat tax” has the potential to invite socioeconomic losses far greater than its environmental benefits, due largely to the induced misallocation of resources at the national scale. Our results reiterate the risk inherent in an excessively climate-focused debate on the role of livestock in human society and call for more multidimensional approaches of sustainability assessment to draw better-balanced policy packages.

Are single global warming potential impact assessments adequate for carbon footprints of agri-food systems?

“…Lopes et al 2016 ). Given the importance of farming to international food security, there is no doubt that the sector needs to optimise productivity (McAuliffe et al 2018 , Lee et al 2021 ) whilst minimising energy-intensive inputs such as inorganic fertiliser (McAuliffe et al 2020b ). This importance is demonstrated by the range of GHG impact efficiencies across the globe under various production systems, some of which can be quite inefficient (Poore and Nemecek 2018a , 2018b ).…”

Greenhouse Gas and Ammonia Emission Mitigation Priorities for Uk Policy Targets

“…These secondary effects may be both positive and negative, all of which need to be considered and researched in more detail to fully understand and evaluate the net gains and losses in terms of net-zero targets alongside the socioeconomic implications of such changes. For example, reductions in livestock numbers will have a negative impact on business viability and employment within the agricultural sector, including supporting services, such as feed suppliers, veterinarians, abattoirs and processing facilities [47] . Generally, there needs to be more research on nutrient biogeochemistry, land use and public attitudes in relation to the potential reduction in livestock production.…”

Protein quality as a complementary functional unit in life cycle assessment (LCA)

“…If not, then mass or volume (e.g., kg grain flour or litres of milk leaving the system boundary) may be a more suitable FU. One example of not requiring nLCA is demonstrated by Lee et al ( 2021b ) whose work showed that beef-loin quality from three different pasture-based grazing systems did not differ notably in terms of holistic nutritional composition (including protein). Thus an nLCA would not add value in a comparison of these three systems.…”

“…In addition to the limitations of protein as an nFU, focusing on protein (or even composite nFUs for that matter) omit complexities such as anti-nutritional factors (ANFs), including but not limited, to phytates and oxalates that reduce protein digestibility (Raes et al 2014 ). Some nLCA studies assess ‘nutrient density’ (i.e., a composite of nFUs; McAuliffe et al 2018 , Saarinen et al 2017 ) and also include minerals, vitamins and other bioactive molecules that a consumer might expect to receive from protein-rich foods (McAuliffe et al 2020 ; Lee et al 2021a , b ). However, when protein is adopted as an agri-food system nFU, it should, as a minimum, be contextualised according to IAA quality in order to account for variability in IAA content and composition and ultimately digestibility.…”