Life Cycle Assessment of mitigation measures of greenhouse gas emissions from beef production in England

British and Northern Irish agri-food systems are faced with the challenge of reducing their supply-chain emissions of greenhouse gases (GHGs) such as nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) in line with the UK’s ambition of achieving a cross-sector ‘net zero’ economy by 2050. Approximately 10% of the GHG emissions are generated by agriculture, and approximately 56% of these GHGs are generated by livestock in the form of CH₄ from enteric fermentation (eructation primarily) and manure management (i.e., storage and subsequent application as an organic fertiliser). Numerous mitigation strategies, both extant and at prototype stage, are being proposed to reduce GHG emissions from ruminants, with many aimed at reducing enteric CH₄ (e.g., methane inhibitors such as 3NOP and ‘wearables’ which break CH₄ down into CO₂ and water vapour during respiration). Before implementing such practices, it is critical to evaluate their net impact on primary production GHG emissions (i.e., farm-level losses). Thus, a cradle-to-farm gate scale modelling framework combining a process-based model, the RothC Model, with Life Cycle Assessment (LCA) was conducted to explore the benefits and trade-offs of a range of intervention strategies for grazing beef systems in UK.

Mitigation interventions were applied to a baseline ‘business as usual’ scenario using the UK Research Council’s (UKRI) National Capability, the North Wyke Farm Platform utilising high resolution data collected on the world’s most instrumented research fam. Mitigation effects on net GHG emissions were subsequently assessed through an LCA scenario analysis with a view to identifying the most feasible, cost-effective strategies. The interventions assessed included: (i) grazing management (e.g., decreasing inputs of synthetic fertilisers and optimising stocking densities); (ii) manure management practices (e.g., adopting anaerobic digestion technology); (iii) livestock feeding regimes (e.g., dietary modification such as inhibitory supplementation) and breeding practices (, for instance, identifying high-performing breeding animals which have been shown to generate fewer GHGs whilst increasing both throughput and financial provision). Although the results to be presented in this work are currently preliminary, some notable findings with implications for policymakers have been observed already; for example, including carbon uptake from soils in a cradle-to-farmgate analysis can reduce system-wide emissions by ~10% in certain circumstances including climate, soil type, and manure management.