Depending on where you live in the United States, the meat you eat each year could be responsible for a level of greenhouse gas emissions that's similar to what's emitted to power your house.
That's according to new research from the University of Michigan and the University of Minnesota, published in the journal Nature Climate Change. The study provides a first-of-its-kind systematic analysis that digs into the environmental impacts of the sprawling supply chains that the country relies on for its beef, pork and chicken.
Supported in part by the U.S. National Science Foundation, the team calculated and mapped those impacts, which they've dubbed meat's "carbon hoofprint," for every city in the contiguous U.S. While the study does underscore the size of America's urban carbon hoofprint - it's larger than the entire carbon footprint of Italy - it also provides city-specific information that residents and governments can use to make positive changes.
The study found:
- Cities with higher meat consumption were not necessarily correlated with a larger hoofprint. Rather, the link of urban food consumption with rural counties that grow animal feed, raise animals and process animals has the biggest impact on hoofprint size.
- Meat-related emissions vary by location due to differences in feed, land-use change, yield differences, different nitrogen fertilizer application rates and related nitrous oxide emissions.
- Beef is consistently the largest component of the hoofprint, followed by pork and chicken.
- Scenarios show that cities can reduce the hoofprint by 14-51% by implementing strategies to reduce edible food loss and by promoting dietary shifts from beef to poultry.
Each stop and product along the meat supply chain has its own processes with an associated carbon footprint, such as using fertilizer for growing feed and managing manure on farms. That's combined with transporting a variety of goods across the physical extent of the full chains, which can stretch thousands of miles. The team considered these wide-ranging factors in evaluating the carbon hoofprint for more than 3,500 locations.
"There's not a single emissions value for the meat we consume," said Rylie Pelton, co-lead of the study and a research scientist in the University of Minnesota's Institute on the Environment. "That's because the supply chains are different in different locations. And also the impacts of production - the ways that beef, chicken, pork and feed are produced - are different in those different locations. That all matters from an emissions standpoint."
To illustrate this point, consider how the country's second-largest city, Los Angeles, gets its beef, the meat with the largest carbon hoofprint. L.A.'s beef comes from processing facilities in 10 counties. But the meat that's processed in those facilities comes from livestock raised in 469 counties by feed that's sourced from 828 counties.
The study proposed multiple scenarios that could be used to reduce the environmental impact of the meat industry. The scenarios found the largest hoofprint reductions would come from substituting beef with other meats and halving food waste.
"This has huge implications for how we gauge the environmental impact of cities, measure those impacts and ultimately develop policies to reduce those impacts," said Benjamin Goldstein, co-lead of the study and an assistant professor in the University of Michigan's School for Environment and Sustainability. "If you just cut out half of your beef consumption and maybe switch to chicken, you can get similar amounts of greenhouse gas savings depending on where you live. If we can get people to use this type of study to think about how diets in cities impact their environmental impacts, this could have huge effects across the United States."
The team's analysis relied on the Food System Supply-Chain Sustainability - or FoodS3 - platform initially developed at the University of Minnesota to study the country's corn supply chain. Over the course of eight years, the hoofprint team built a framework to apply the platform to a broader set of questions pertaining to meat. The platform is also being used to study other agricultural products, and has the potential to expand to nonagricultural commodities that cities rely on, like steel, as well.
The study concretely demonstrates how to make such opaque urban-rural linkages more transparent. By doing so, how rural and urban livelihoods are intertwined becomes clearer, as does the collective responsibility for cities and rural communities to collaborate in the shared goal of reducing environmental impacts and improving livelihoods.
The researchers hope that their hoofprint study can inspire communities to work together towards creative solutions that will make supply chains more environmentally and economically sustainable.
