Comparison of two methods for assessing land footprint

Agricultural land used to produce our food is a limited resource and must be preserved both in quantity and in quality. French ADEME (Barbier et al., 2020a; 2020b) and Australian (Ridoutt et al., 2020; Ridoutt and Garcia 2020) studies have developed methods for assessing land footprint of vegetal and animal agricultural production. We inferred the land footprint of typical French and Australian diets. These studies provide contrasting images regarding the footprint of different types of meat. In this article, we seek to understand and analyze reasons for differences. The ADEME study does not differentiate the different types of agricultural land; it brings out beef and sheep meats, produced mostly from grassland systems, with the largest footprint. Conversely, Australian studies accounts for agricultural land according to their potential yield; they do account for permanent grasslands, and therefore highlight monogastric meats (pork, poultry) as the most impacting ones. Thus, Ridoutt method leads to a relatively limited footprint of extensive livestock farming, mostly linked to grass consumption, and more broadly of ruminant meats, compared to meats from monogastric breeding that essentially feed on cereals and therefore use arable land. In terms of diets, those methodological differences lead to large differences in the meat share (all types of meat combined) of diet land footprint: it is three times less for Australian diets with a comparable meat consumption with respect to the French diet. Considering the many ecosystem services provided by grazeland, we therefore recommend the use of the Ridoutt methodology for the calculation of agricultural land footprint.