Narratives Behind Livestock Methane Mitigation Studies Matter

Cyrille Rigolot (1)

1 Territoires - Territoires

Livestock production is currently the largest anthropogenic methane source. This represents about a third of the global anthropogenic emissions, but the uncertainties are huge and the estimations vary depending on the methodology used. In their study, Chang et al. (2021) propose a re-assessment based on a robust and sophisticated modeling framework. The authors calculate temporal changes of livestock methane emissions during about two decades (2000-2018), showing that global emissions increased on average by +10 to +18 Tg CH4 yr −1. The authors also simulated future livestock methane emissions up to 2050, using three socioeconomic scenarios ("Business As Usual," "Stratified Societies," and "Toward Sustainability") and two emission intensity change pathways: "Constant emission intensity" per kg protein and "improving efficiency" with decreasing emission intensity per kg protein. They found that the differences in the projections among different socioeconomic scenarios were small, compared to the continuation of the past decreases in emission intensity. In the discussion, importantly, the authors acknowledge that the emission intensity per kg of protein in developed countries might increase, at the opposite of their methodological assumption, as a result of a move toward more extensive livestock systems (grass-fed beef...). Also, they stress that the largest potential lies in developing countries where the current efficiency is low. The continuation of efficiency improvement in these countries could be achieved through the transition of livestock production systems from extensive rangeland systems to mixed crop-livestock systems, and better management of existing systems. To conclude, Chang et al. (2021) highlights: (a) that efforts on the demand-side to promote sustainable diets (as in the "Toward Sustainability" scenario), will not be sufficient for mitigation without parallel efforts from the production sides; (b) Such efforts to decrease emission intensity on the production-side should be prioritized in a few developing countries with the largest mitigation potential.

Mots clés: mitigation; narrative; transformation; livestock

Domaines: Sciences de l'environnement

Cyrille Rigolot. Narratives Behind Livestock Methane Mitigation Studies Matter. AGU Advances, 2021, 2 (4), ⟨10.1029/2021AV000526⟩. ⟨hal-03818585⟩