Despite it may seem better for the planet, switching to fully organic food production would actually mean an increase in greenhouse gas emissions, according to a new study, which claimed that an organic production would require more land to produce the same amount of food.

The study, published at Nature Communications, said a 100% organic food production in England and Wales would mean a 21% increase in emissions compared to the conventional approach on farming, now responsible for about 9% of UK’s overall emissions.

Organic farming avoids the use of synthetic fertilizers, pesticides, and genetically modified organisms, all of which can boost the number of crops produced per acre. Instead, organic farmers rely on things like animal manure and compost, and practices such as crop rotation, which involves growing different plants throughout the year.

Implementing such practices on a larger scale would see a drop in emissions of about 20% for crops and around 4% for livestock. However, the study predicts significant drops in food production by using organic standards, by around 40% compared to conventional farming.

Researchers said that organic production means smaller crop yields and the introduction of nitrogen-fixing legumes into crop rotations, reducing the amount of land available for production. So, crops like wheat would see falls in production and the volume of meat would go down.

To meet the demand for food, the shortfall would have to be made up of imports. The researchers assume that a proportion of these imports would have to come from changing land use overseas. Due to significantly lower productivity in other countries, this would require five times the amount of land that is currently used.

Converting grassland overseas to arable uses also reduces the amount of carbon stored in the soil. In the best-case scenario, with the least amount of land change, then overall emissions are comparable to those under conventional agriculture. However, if half the land is changed from grassland, then overall emissions from UK food production would go up by 21%.

“We estimate that, were organic farming to be adopted wholesale without any change in diet, we would need nearly six million more hectares of land,” said one of the authors, Philip Jones. “Much of which would need to come from Europe. This has an associated impact on the environment, adding potentially unnecessary food miles and greenhouse gas emissions to our food systems.”

There would be significant benefits for cleaner air and water and improved biodiversity under a fully organic farming future, the authors claimed. But critics of the study have focused on the fact that it presumes that there will be no change in people’s diets.

“The assumptions behind the study’s conclusion that there will be a net increase in greenhouse gas emissions under organic are fundamentally flawed,” said Rob Percival of the Soil Association. “The study assumes no change in diet, which is clearly untenable given the global dietary health crisis.”

The researchers involved in the study responded to these criticisms by underlining the fact that that wasn’t the goal of this piece of research.

“The assumption about diets is crucial: today’s organic consumers are a self-selecting group and not typical of the nation,” said co-author Dr. Adrian Williams from Cranfield University.