Halting biodiversity loss and especially extinctions arising from agriculture is thus a key policy concern11,12. Effective mitigation hinges on the robust quantification of the impacts of different foods, how these vary spatially and how they might be reduced by changes in consumption patterns, provenance or production methods. Spatial layers and summary metrics can inform the efficacy of candidate interventions across diverse scales and actors: from individuals to governments and from personal dietary choices to national trade policies.
Variation in the opportunity cost of food production
Animal products generally have substantially greater impacts on species extinction risk than staple vegetal products. This is a result of the inherently inefficient nature of these products28,29: producing a unit of animal product requires grazing land and/or cropland for feed production, which when combined with the intrinsic feed conversion efficiency of animals leads to high land use and hence extinction impacts.
In India, where approximately one-third of the population are lacto-vegetarian and cattle slaughter is banned in many states39, ruminant meats (mainly sheep and goat meat) contribute of 40% of the impact of people’s diets on speciesʼ extinctions.
The full ranges of poultry meat and eggs sat within the boundaries of the legumes and pulses group, indicating that well-performing poultry meat might be less damaging than the very worst legumes, though the median impacts are still around five times higher.
In contrast staple crops have relatively low impacts on the opportunity cost to speciesʼ extinctions
Conversely, ‘luxury’ crops (those with little to no calorific benefit but generally commanding a high price) such as coffee, cocoa, tea and spices are all towards the higher end of the impact distribution per kilogram—although, of course, these commodities are typically consumed in relatively modest amounts.
Two findings in particular stand out
- While it is recognized that malnutrition remains a salient problem in many parts of the world, clearly governments, corporations, individuals and others in wealthier nations concerned with averting the extinction crisis cannot do so without serious consideration of steps to dramatically reduce consumption of animal products, especially ruminant meat.u
- A second clear conclusion is that great care should be taken by richer countries in relatively low-biodiversity parts of the world to avoid exacerbating the overseas impacts of their food consumption through land-use and trade policies that will increase the offshoring of production of the food they eat to more biodiverse parts of the world. Whereas these may increase biodiversity domestically, it seems very likely that at global scale, they will cause net biodiversity harm46,68. It seems implausible that these two core findings will change as better data become
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