In this study we investigated the climate impact of beef production, including changes in soil organic carbon and using two different climate metrics, GWP100 and AGTP. For the later, a time-dependent life cycle assessment was performed in which yearly fluxes of greenhouse gases were considered and the climate impact in terms of temperature response over time was calculated. Two hypothetical suckler cow systems located in south-east of Sweden were studied. The systems differed in intensity; in one the animals were fed exclusively grass (pasture and silage) while in the other the offspring were also fed barley, resulting in them reaching their slaughtering weight quicker (slaughtered at 15 months instead of 20 months). The ICBM was used for modelling yearly soil organic carbon changes from land use. The results showed an average carbon sequestrationrate of 0.2 Mg C ha−1 and yr−1, so carbon sequestration could potentially counteract 15–22% of emissions arising from beef production (see figure below). The temperature response, which showed a high initial increase due to methane emissions from enteric fermentation, started to level off after around 50 years due to the short atmospheric lifetime of methane. It should be noted however that sustained methane emissions maintains the temperature response and contribute to climate damage. The more intensive systems had lower climate impact than the more extensive grass-only system due to lower slaughtering age and hence lower methane emissions, even though more carbon was sequestered in the grass-only system.
Hammar T, Hansson PA, Röös E. Time-dependent climate impact of beef production – can carbon sequestration in soil offset enteric methane emissions? Journal of Cleaner Production 331,129948. https://doi.org/10.1016/j.jclepro.2021.129948.