What if we got rid of all livestock? Would that reduce greenhouse gases? And what would we eat instead?
Those are some of the questions that authors Robin White and Mary Beth Hall tried to answer. To see what would happen they modeled a United States where no livestock existed, and we ate only plant-based diets. Their conclusion, published in their paper, “Nutritional and greenhouse gas impacts of removing animals from US agriculture,” is that the total US greenhouse gas emissions would only be reduced by 2.6% and that this decrease would come at a high cost.
First, with a plant only diet, it would be much more difficult for people to meet their nutritional requirements. Animals are our only non-pill form of calcium, 3 fatty acids, and vitamin B12. Two of these fatty acids reduce heart disease and are critical for the visual and mental development of infants. The authors found that, “Even though it is possible to balance plant- based diets for individual humans, it may be a challenge for these diets to scale well within the US food production system because of the types of crops that can be grown in the available climates and soils.” They pointed out that animals convert energy-dense, micronutrient-poor foods like grain into micro-nutrient dense foods like meat, milk, and eggs, making it possible for the U.S. to meet the population’s nutritional requirements.
We might also have to import more food. Current U.S. fruit and vegetable consumption is 203% and 164% of what we produce domestically. The authors point out that given this high demand, if it was viable to produce more of these high-value crops in the U.S., it would already be occurring. They concluded that limitations on production may be a result of suitable land, climate and infrastructure to grow these crops.
According to the authors, we’d face other challenges as well in a no-livestock world. Assuming we kept our pets, how would we replace the almost 1.5 billion pounds of protein and almost 300 million pounds of fat we need to feed our cats and dogs every year? How would we get rid of the inedible vegetable waste that we currently feed to animals? We’d also have to produce more synthetic fertilizers to replace animal manures. Finally, with no animal agriculture, 1.6 million people would need to find new jobs, and we’d need to replace a $32 billion hit to our exports.
One of the reasons for suggesting getting rid of livestock is their role in greenhouse gas emissions. Past models of a shift to a plants-only diets have shown reductions in a household’s carbon footprint when people ate less meat. But these Life Cycle Assessments did not consider all the changes that White and Hall realized would have to be made in the food system as a result. That’s why their numbers have come out so differently.
In the end, after subtracting out greenhouse gas emissions for livestock, and adding in increases to synthetic fertilizer production, disposal of inedible waste, and changes in land use, agricultural emissions were reduced from 622.6 CO2 equivalents to 446. Since agriculture makes up only 9% of U.S. greenhouse gas emissions, this change meant a reduction of only 2.6% in total U.S emissions.
Based on their results, White and Hall concluded, “Overall, the removal of animals resulted in diets that are nonviable in the long or short term to support the nutritional needs of the U.S. population without nutrient supplementation.” They recommend that any discussion of our food system should include the kinds of direct and indirect effects they considered in their paper so we can properly evaluate impacts of potential changes.
Thanks to Jon Previant for inspiring us to follow up on this article!