Meat consumption in countries around the world varies more than 30-fold, with the US near the top. Our appetite for meat, estimated to be on average 137-250 pounds per person annually, far exceeds nutritional recommendations.    Meanwhile many people in other countries, some long-deprived of meat’s benefits, want more. Some estimates predict a near doubling of global demand by 2050, fueled more by economic than population growth.   This anticipated change in the diet of a dominant planetary species is unprecedented historically in time or scale. Implications for human, ecosystem and planetary health are profound.
Scaling up meat production can take different approaches. An industrial model features production efficiencies, intensive confined animal feeding operations, and externalized costs. Other models incorporate animal agriculture into more context-specific, integrated farming systems that are less destructive and help to restore soil quality, biodiversity, and ecosystem health. Whether or not these can fulfill completely the anticipated meat demand is debatable, but they can be much more sustainable over the long term, providing abundant nutritious diets that will undoubtedly include more plant-based proteins.  Since the consequences of the choices we make among models differ, it’s worth considering how they will be assessed.
Efficiency and economic return on investment are common metrics for evaluating alternative production systems. For example, the concepts of carbon efficiency—greenhouse gas emissions/kg meat—feed conversion efficiency, and water footprint are liberally imbedded in studies of agricultural animal production. But, instead of focusing primarily on efficiency, others begin by asking first about the effectiveness of alternative livestock and crop production systems. What do we want them to do? Produce the most product per dollar input? Rebuild soil? Promote biodiversity? Protect air and water quality? Increase resilience and buffering capacity against climate change, drought, or economic shock? Support community? If we were to clarify what we want agricultural systems to do, we would have a better idea of how to evaluate their costs and benefits and consider alternatives.
This essay at (the link) by SEHN’s Science Director, Ted Schettler looks at this using the examples of climate change and water use linked to animal agriculture. Among the take-home messages:
Analyses of the long-term sustainability of various meat production systems are complex, inconsistent, and sometimes contentious. They deal with assumptions, boundaries, uncertainties, and data gaps differently. For example:
- Greenhouse gas (GHG) emissions related to producing energy-intensive fertilizer used on crops to feed animals are not included in the EPA’s agriculture GHG inventory and often not considered in estimates of the carbon footprint of meat.
- Studies comparing climate-changing impacts of growing animals in intensive, confined animal feeding operations vs. more extensive grazing systems sometimes fail to account for carbon soil sequestration achievable with improved grazing and manure management.
- Studies of water use in animal agriculture often fail to distinguish among water sources and availability. Cattle grazing on rain-fed grass have a very different water footprint than cattle eating forage, silage, and grain grown on irrigated land.
Despite these inconsistencies, in general, producing beef results in far more GHG emissions than equivalent amounts of pork or poultry, although management practices can effectively reduce the total carbon footprint.
Similarly, the water footprint of beef far exceeds that of pork and poultry.
Plant-based sources of proteins such as legumes and pulses have still lower carbon and water footprints than animal proteins.
An emphasis on efficiency in meat production in industrial systems contributes to excessive air and water pollution, climate change, and loss of soil quality and biodiversity. These costs aren’t covered in the price of meat. Tens of millions of acres of cropland in the US planted in corn and soybeans fed to animals are essential to this dominant model of meat production. Much of this land is suitable for growing diverse, nutritious crops for people to eat that could also protect and restore watersheds and soil fertility.
To be sustainable over the long term, the growing global demand for meat should be considered in the context of a goal to provide adequate, culturally-appropriate nutrition to the world’s population, while restoring soil fertility and biodiversity, protecting water, and helping to reduce drivers of climate change. Supply-oriented changes in meat production are unlikely to be sufficient without some constraints on demand.
Strategic incentives, including full-cost accounting for establishing food prices, could encourage more widespread adoption of more ecologically-based agricultural models already proven to produce abundant nutritious food. Where meat consumption is excessive, beyond nutritional recommendations, individuals, families, communities and institutional purchasers—hospitals, schools, universities, businesses, governments—could choose more plant-based protein alternatives and give preference to meat from ecologically integrated systems, produced in more sustainable, context-appropriate ways. In the end, our growing appetite for meat comes with costs that could far outweigh the benefits, depending on how we respond to the unprecedented demand.
 Fehrenbach K, Righter A, Santo R. A critical examination of the available data sources for estimating meat and protein consumption in the USA. Public Health Nutrition. 2015; 19(8):1358–1367.
 Fehrenbach K, Righter A, Santo R. A critical examination of the available data sources for estimating meat and protein consumption in the USA. Public Health Nutr. 2016; 19(8):1358-1367.
 Herrero M, Thornton P. Livestock and global change: emerging issues for sustainable food systems. Proc Natl Acad Sci. USA. 2013; 110(52):20878-81.
 Garnett T, Appleby M, Balmford A, Bateman I, et al. Sustainable Intensification in Agriculture: Premises and Policies, Science, 2013; 34, 6141, 33-34
 Garnett T, Roos E, Little D. Lean, green, mean, obscene…? What is efficiency? And is it sustainable. Animal production and consumption reconsidered. 2015. FCRN publication. Available at http://www.fcrn.org.uk/fcrn-publications