About 2/3 of global agricultural land is used for beef production, between pasture and feed and forage production. Yet this land use produces less than 5% of global protein consumption and less than 2% of global calorie consumption. Nonetheless it results in large greenhouse gas emissions, both directly from ruminant methane and indirectly as a leading driver of tropical deforestation.
I used FAO-FAOStats and USDA-PSD (Production, Supply and Distribution) data to model potential reductions in global greenhouse gas emissions from switching diets towards consuming less beef and more of other animal products, such as chicken. This was based on the extensive peer-reviewed literature showing that emissions per gram of protein are several times as high for beef as they are for chicken, pork, dairy and eggs. The diet shift involved both reductions in consumption to levels recommended on the basis of health considerations, for high-consuming countries, and increases concentratedon non-beef sources for lower-consuming countries.
Results/Conclusions
The potential savings in greenhouse gas emissions from such a diet shift are quite large and comparable in terms of mitigation to prospective changes in the transport, electricity and manufacturing sectors. Although the contribution from reduced methane emissions is appreciable, an even larger contribution comes from two indirect results: reductions in emissions from deforestation, especially in Latin America, and carbon sequestration as former pasture land is revegetated. Although a somewhat greater decrease in emissions could be achieved by shifting diets toward plant sources of protein rather than alternative animal sources, this is socially and economically more challenging since it goes counter to the trend of diet change in developing countries in the last several decades. Shifting towards alternative sources such as chicken, on the other hand, is much more feasible since it is consistent with patterns of change already underway in both developed and developing countries.