Organic Eggs Have a Carbon Footprint Nearly Twice as Large

The production of organic, free-range eggs can have a climate impact nearly twice as great as that of eggs produced by caged hens. This is according to a new study published in the scientific journal *Royal Society Open Science*, as reported by the British newspaper *The Guardian*.

The analysis indicates that if the entire egg production sector in the UK were to shift to organic, free-range methods, annual greenhouse gas emissions would reach 2,316,000 tonnes of carbon dioxide (CO₂ equivalent). By comparison, a system based entirely on caged hens would result in 1,184,000 tonnes of emissions—nearly half the amount.

The researchers attribute this difference to the lower productivity of free-range hens. Producing the same quantity of eggs requires a larger number of birds, whereas hens in caged systems utilize feed more efficiently and lay more eggs.

The study further reveals that organic, free-range production performs the worst in terms of the risk of nutrient pollution in water (eutrophication), environmental acidification, and land use. Additionally, this model was found to have the highest mortality rate among the hens.

At the same time, the authors emphasize that the study has certain limitations. The analysis is based on data from British poultry farms covering the 2009–2010 period and does not account for more recent technologies or changes in production methods. Furthermore, it does not address other environmental factors, such as pesticide use or impacts on biodiversity.

“We identified a significant trade-off. Farms generally considered better for animal welfare—such as organic or free-range operations—may require more birds to produce the same quantity of eggs, as they are less efficient and can have a greater environmental impact,” stated Dr. Harriet Bartlett of the University of Oxford, one of the study’s authors.

However, she notes that these findings do not present the full picture. According to her, organic production may perform better in areas such as pesticide toxicity and biodiversity conservation.

A similar view was expressed by Lee Holdstock, Regulatory and Commercial Manager at Soil Association Certification—who was not involved in the study—noting that the lower emissions associated with intensive production represent only one part of the environmental picture.

“A truly sustainable food system must also take into account impacts on nature, soil health, water quality, the use of synthetic substances, and animal welfare,” he points out. The authors estimate that under the current British system—which includes a combination of caged, barn, free-range, and organic free-range farming—annual emissions amount to approximately 1,439,000 tonnes of CO₂ equivalent.

Illustrative photo: pexels-klaus-nielsen-6294164