Remove meat from your plate one day a week. Halve what ends up in the garbage unnecessarily. Eat less beef, replacing part of it with meat with a lower climate footprint. Three rather earthly changes that, combined, could reduce meat-related emissions in US cities by 51%.
The calculations are based on a study published on Nature Climate Changewhich followed the supply chain of beef, chicken and pork consumed in 3,531 U.S. urban areas, from feed crops to primary animal processing. And no, the famous one Meatless Monday alone it doesn’t halve anything: it’s worth around -14%. 51% arrive by combining multiple interventions. Monday, poor thing, can only do so much.
Overall, according to the researchers’ model, the meat consumed in the cities analyzed generates approximately 329 million tons of CO2 equivalent every year. The authors called this enormous entanglement of emissions carbon hoofprinta clog variant of the best known carbon footprint.
Beef takes up a third of the plate and almost three-quarters of the emissions
The cities considered consume around 11 million tonnes of meat every year: 4.6 million tonnes of chicken, 3.7 million tonnes of beef and 2.7 million tonnes of pork. The proportions change a lot when you go from the weight of the meat to the weight on the climate. Beef represents approximately 34% of consumption, yet it accounts for 73% of the climate footprint calculated in the study. Above all, emissions related to cattle breeding, feed production, fertilizers, manure management and changes in land use have an impact. And where and how that meat is produced also matters a lot.
The authors have in fact reconstructed supply chains that cross hundreds of counties. For beef consumed in Los Angeles, for example, the model links ten processing counties to cattle from 469 counties and to feed crops spread across 828 counties. The steak stays still on the plate. Behind, however, there is half a geographical map.
A day without meat is worth 14%, halving waste is 16%
Once this system was reconstructed, the researchers began to move the pieces. If consumers and retailers halved the waste of still-edible meat, emissions would decrease by about 16%. Eliminate meat for one day every seven, the model of Meatless Mondaywould instead lead to a cut of 14%. The day chosen is irrelevant: no particular climatic properties have so far been attributed to Monday.
The most consistent result comes from working on the beef. Replacing half of it with a combination of chicken and pork would reduce the footprint by about 28-29%; using only chicken the decrease would reach approximately 33%. Combining waste reduction, a weekly meat-free day and replacing part of the beef, the most extreme scenario developed by the authors leads to an overall cut of 51%.
A clarification is needed, because that number is very inviting: the study does not demonstrate that a specific public policy would automatically produce this result. The scientists built modeling scenarios by modifying consumption and waste within their reconstruction of supply chains.
The same meat can have very different fingerprints
Then there is a less immediate result than “meatless Monday” and probably more interesting. Among the cities analyzed, per capita consumption changes relatively little. The emissions associated with that consumption, however, range from approximately 500 to 1,731 kilograms of CO2 equivalent per person per year.
The authors identified 868 cities that consume more meat than average while showing a lower-than-average climate footprint. In another 931 the opposite happens. The quantity on the plate therefore only tells a piece of the story. The rest is found in the fields where feed is produced, on farms, in manure management and in the structure of the supply chains that feed cities.
It is also why the authors invite urban administrations to look beyond their borders. Much of the emissions associated with what is eaten in the city occurs several kilometers away, often in rural areas that obviously do not appear on the grocery receipt.
We are talking about US cities, with a significant margin of uncertainty
Before transforming meatless Monday into the new unit of measurement of climate salvation, it is best to define the study carefully.
The analysis covers 3,531 cities in the continental United States and only considers beef, pork and chicken. Consumption was estimated using five rounds of the American national survey NHANES, which overall included 51,623 participants, and subsequently integrated into the reconstruction of supply chains.
The same researchers also report an average absolute percentage error of 26% for the basic urban estimates. The scenarios therefore serve above all to understand the size and direction of possible interventions, rather than to promise percentage point reductions.
There is also another complication. A decrease in U.S. demand could change prices, exports and the destination of the meat produced. A portion of the emissions could therefore move elsewhere. To follow these effects as well, broader economic and commercial models would be needed.
However, the work remains rather eloquent on one thing: among the three meats analysed, beef is by far the one on which interventions produce the greatest effect. And to achieve significant reductions you don’t necessarily need to imagine millions of people becoming vegetarians overnight.
Just shift some habits. A day without meat, less wasted food and a few less steaks. However, let’s leave the 51% to the complete package: attributing it all to poor Monday would be asking too much of him.
