Trading Beef for Chicken Could Cut Global Food Emissions by a Third

Replacing beef and lamb with poultry across 181 countries would cut the world's food-related greenhouse gas emissions by 37% over the rest of this century and still leave the 1.5 °C climate target out of reach, according to a modeling study published Sept. 8 in Environmental Research Letters.

Yaling Li of Anhui Agricultural University, with Fujin Yi and Xiaoxi Wang of Zhejiang University, set out to test how much of the Paris Agreement's temperature goals a change in diet can deliver on its own, without taking food away from countries where people already eat too little.

Against a business-as-usual baseline of 1,768 billion metric tons of carbon dioxide equivalent from food, the study modeled three paths. If every country moves to its own national dietary recommendations, the total falls to 1,411 billion metric tons, which the paper describes as only marginal alignment with the 2 °C limit. Swapping high-emission meat for lower-emission protein brings it to 1,113 billion metric tons, the deepest cut and the only path the authors call robustly compatible with that limit. A third path, in which countries move toward higher-emission foods, ends above the baseline.

Even on that best path, the emissions budget left for everything that is not food narrows to between 407 and 818 billion metric tons, a constraint that "renders the 1.5 °C target unattainable through dietary shifts alone."

The authors also propose a way to divide the effort, setting obligations and allowances by how far a country's intake departs from its own dietary guidelines. Countries eating well above their guidelines, particularly of animal-source foods, take on obligations under that rule; countries eating below them are allocated protected allowances scaled to population. The study names the United States and China as examples of the first case, Nigeria and Ethiopia of the second.

It is a proposal in a research paper, not an adopted policy. The study is open access.