Is eating less meat better for the environment?
A study published in the Proceedings of the National Academy of Sciences suggests that removing animals from U.S. agriculture would reduce agricultural GHG emissions, but would also create a food supply incapable of supporting the U.S. population’s nutritional requirements.
As a major contributor to agricultural greenhouse gas (GHG) emissions, it has been suggested that reducing animal agriculture or consumption of animal-derived foods may reduce GHGs and enhance food security. A study published in the Proceedings of the National Academy of Sciences suggests that removing animals from U.S. agriculture would reduce agricultural GHG emissions, but would also create a food supply incapable of supporting the U.S. population’s nutritional requirements.
To provide the extreme boundary to potential mitigation options, the researchers explored what would happen if animal products were completely removed from the food system. They quantified the yearly nutritional and GHG impacts of eliminating animals from U.S. agriculture. Animal-derived foods currently provide energy (24% of total), protein (48%), essential fatty acids (23%–100%), and essential amino acids (34%–67%) available for human consumption in the United States.
The U.S. livestock industry employs 1.6 million people and accounts for $31.8 billion in exports. Livestock recycle more than 43.2 billion kg of human-inedible food and fiber processing byproducts, converting them into human-edible food, pet food, industrial products, and 4 billion kg of nitrogen fertilizer.
The researchers found that the plants-only agriculture model produced 23% more food; however, it met fewer of the U.S. population’s requirements for essential nutrients. In addition, although animals now make up some 49% of agricultural GHG (623 million tons/year) in the United States, a plants-only nation would eliminate only 28% of agricultural GHG (446 million tons/year). When nutritional adequacy was evaluated by using least-cost diets produced from foods available, more nutrient deficiencies, a greater excess of energy, and a need to consume a greater amount of food solids were encountered in plants-only diets.