Including the agro-economic effects of diet shifts into environmental assessments: Implications for the world's largest red meat eaters

Shifting one's diet towards more plant-based products is seen as one of the most efficient ways to mitigate one's environmental footprint. Yet, associated market adjustments between global demand and supply are rarely considered in environmental assessments and could counterbalance expected environmental benefits. In this context, we used an agro-economic model to predict global production changes following a demand shift towards EAT-Lancet guidelines for red meat and legume intake for the year 2030. We modelled four scenarios which apply to diverse regions, namely, the European Union (EU), EU and China, 40 % of the largest red meat eaters and the whole world. The environmental impact of these subsequent changes was quantified using consequential Life Cycle Assessment. Results show that significant environmental benefits could be achieved already when 40 % of the largest red meat-eating population shifts its diet. For greenhouse gas emissions, it translates into 1.02 GtCO₂ eq and 1.27 GtCO₂ eq saved in the 40 % and global diet shift scenarios, respectively. This latter is equivalent to the annual savings needed to reach net zero in 2050 for the Paris Agreement. Most of the local environmental benefits are linked to the regional specialisation of agricultural production. For example, there would be lower acidification in Asia due to the decrease in livestock production and lower aquatic eutrophication and ecotoxicity in the Americas due to the decrease in feed production. To reach such diet shifts and associated environmental benefits, context-specific solutions should be defined considering cultural and, global and regional physical constraints.