Considering Natural Baselines When Calculating Livestock Impacts Point to a Negligible Role of Grass-Fed Livestock Systems in Climate Change

The use of baselines is common in a variety of academic disciplines, including environmental science, but they are subjected to relativity depending on the geographical or historical reference considered. Such considerations are illustrated by how invasive species are evaluated or what reference baselines are considered in biodiversity assessments.

The measurement of livestock effects on climate change has, however, disregarded the use of baselines. Current methodology is based exclusively on greenhouse gas emissions by individual animals, without putting them in their ecological context. As a consequence, current analyses of livestock impacts put grass-fed ruminant systems in the spotlight, because of their high methane emissions. Conversion into intensive, grain-fed chicken and pork systems is recommended to cope with increased meat demand, an approach that is being echoed by media.

In this study we reviewed existing literature on baseline greenhouse gas emissions by wild ruminants, with models available for North America and northern Russia. We also considered the potential of termites in filling herbivore niches in an ungulate-free scenario and reviewed the literature for possible consequences of ensuing wildfires. We found consistent evidence for natural baseline scenarios to be of the same order of magnitude as current livestock scenarios. This implies that the current policy recommendations for tackling climate change through the livestock sector are likely to be much less effective than currently thought.

Other studies on livestock environmental impacts, such as for water or biodiversity, have also not taken into account natural baseline levels from wild herbivores, hence depicting an exaggerated negative image on grass-fed livestock. Policy recommendations should take baseline levels into account, concentrate on reducing intensive use of fossil fuel and focus on double-win strategies for methane emission reduction, such as the use of manure-fed biogas cooking stoves.

This paper uses concepts originally developed at Manzano & White (2019).