Figure 1. Greenhouse gas emissions associated with the production of protein-rich foods. Beef has the highest emissions per kilogram. These emissions data are from Poore & Nemecek (2018), with the exception of "Ruminant meat," which was calculated based on the amount of beef and lamb consumed in 2022.
Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987–992.