Land Requirements and Carrying Capacity Implications of Consuming Livestock Products.

Growing global demand for livestock products drives increased demand for feed grains, forages, and grazing resources. Producing this feed biomass places increasing pressure on the availability of land. This is a concern from both the perspectives of ensuring food security and of supplying ecosystem services. Land requirements of complete diets were calculated using a spreadsheet model that accounts for food intake; losses at consumer, retail, and processing levels; crop yields, grazing land productivity, livestock feed requirements, and land availability. The model was parameterized to represent productivity and land availability for the U.S. as a unit of analysis. Multiple scenarios were examined to examine the overall land impact of varying the amount of meat, dairy, and eggs in the diet. Preliminary results indicate that large differences exist in the total area and quality of land required among different diets. Estimates of carrying capacity were most sensitive to requirements for land used for production of annual crop production. Interestingly, preliminary results suggest that lacto-vegetarian and ovo-lacto vegetarian diets support higher potential carrying capacity than do vegan diets, in part because of the reliance on land suitable only for perennial crop production. Findings suggest that while consumption of livestock products clearly increases land requirements, the implications for national food security depend on the quality of available land. Compared to current diets, substantial room exists to increase carrying capacity with more modest reductions in meat consumption. Inclusion of dairy and eggs may even enhance food security.