ORGANICALLY farmed food has a bigger climate impact than conventionally farmed food, according to a new study by Swedish researchers.

The team from Chalmers University of Technology developed a new method for assessing the climate impact of land-use, and used this, along with other methods, to compare organic and conventional food production. Their results suggest that organic food can result in much greater emissions, primarily due to the greater areas of land it requires.

“Our study shows that organic peas, farmed in Sweden, have around a 50% bigger climate impact than conventionally farmed peas," said Stefan Wirsenius, an associate professor from Chalmers. "For some foodstuffs, there is an even bigger difference – for example, with organic Swedish winter wheat the difference is closer to 70%.”

Organic food has lower yields per hectare, because chemical fertilisers are not used, so to produce the same amount of organic food, you need a bigger area of land which, the Swedes argue, creates a much larger climate impact.

“The greater land-use in organic farming leads indirectly to higher carbon dioxide emissions, thanks to deforestation,” said Mr Wirsenius. “The world’s food production is governed by international trade, so how we farm in Sweden influences deforestation in the tropics. If we use more land for the same amount of food, we contribute indirectly to bigger deforestation elsewhere in the world.”

Even organic meat and dairy products are – from a climate point of view – worse than their conventionally produced equivalents, he claimed: “Because organic meat and milk production uses organic feeds, it also requires more land than conventional production. This means that the findings on organic wheat and peas in principle also apply to meat and milk products. We have not done any specific calculations on meat and milk, however, and have no concrete examples of this in the article,” he conceded.

The Chalmers researchers used a new metric, which they call 'Carbon Opportunity Cost', to evaluate the effect of greater land-use contributing to higher carbon dioxide emissions from deforestation, by taking into account the amount of carbon that is stored in forests, and thus released as carbon dioxide as an effect of deforestation.

“The fact that more land use leads to greater climate impact has not often been taken into account in earlier comparisons between organic and conventional food,” noted Wirsenius. “This is a big oversight, because, as our study shows, this effect can be many times bigger than the greenhouse gas effects, which are normally included. It is also serious because today in Sweden, we have political goals to increase production of organic food. If those goals are implemented, the climate influence from Swedish food production will probably increase a lot.”

But the study's findings do not, he stressed, mean that conscientious consumers should simply switch to buying non-organic food: “The type of food is often much more important," said Wirsenius. "For example, eating organic beans or organic chicken is much better for the climate than to eat conventionally produced beef. Organic food does have several advantages compared with food produced by conventional methods. For example, it is better for farm animal welfare. But when it comes to the climate impact, our study shows that organic food is a much worse alternative, in general.”