UN livestock emissions report distorted our work, say experts
A flagship UN report on livestock emissions is facing calls for retraction from two experts who say the paper “seriously distorted” their work.
The UN Food and Agricultural Organisation (FAO) misused their research to underestimate the potential of reduced meat intake to cut agricultural emissions, according to a letter sent to the FAO.
In the letter Paul Behrens, an associate professor at Leiden University, and Matthew Hayek, an assistant professor at New York University, accused the FAO study of systematic errors, poor framing, and highly inappropriate use of source data.
Hayek said: “The FAO’s errors were multiple, egregious, conceptual and all had the consequence of reducing the emissions mitigation possibilities from dietary change.”
Agriculture accounts for 23% of global greenhouse gas emissions, most of which are attributable to livestock in the form of methane from burps and manure, and deforestation for grazing and feed crops.
At the Cop28 climate summit in December, the FAO published the third in a series livestock emissions studies. As well as reducing the FAO’s estimate of livestock’s contribution to global heating for a third consecutive time, it used a paper written by Behrens and others in 2017 to argue that shifts away from meat-eating could only reduce global agrifood emissions by between 2% and 5%.
Behrens’s 2017 paper assessed the environmental impacts of nationally recommended diets (NRDs) of the time. Many countries such as China and Denmark have drastically cut their recommended meat intake since then, while Germany now proposes a 75% plant-based diet in its NRD. The letter said “voluminous evidence” from larger environmental reports recommending reductions in meat content, such as the Eat-Lancet Planetary Health Diet, were ignored.
“The scientific consensus at the moment is that dietary shifts are the biggest leverage we have to reduce emissions and other damage caused by our food system,” Behrens told the Guardian. “But the FAO chose the roughest and most inappropriate approach to their estimates.”
Of more than 200 climate scientists surveyed by Behrens and Hayek for a recent paper, 78% said it was important for livestock herd sizes to peak by 2025 to halt dangerous global heating.
Behrens and Hayek said the FAO report “systematically underestimates” the emissions-cutting potential of dietary shifts through methodological errors including double-counting meat emissions until 2050, mixing different baseline years in analyses and channelling data inputs that inappropriately favoured diets allowing increased global meat consumption.
Hayek said the FAO inappropriately cited a report he co-authored that measured all agrifood emissions, and applied it to livestock emissions alone. “It was like comparing really small apples to really big oranges.” Correspondingly, the mitigation potential from farming less livestock had been underestimated by a factor of between six and 40, he said.
The FAO said it was committed to accuracy and integrity and its report had undergone rigorous review. “FAO will look into the issues raised by the academics and undertake a technical exchange of views with them,” it said.