Study shows surprising environmental impact of organic farming

Growing organic crops takes a bigger toll on the environment than growing crops conventionally, according to a study [ https://www.nature.com/articles/s41586-018-0757-z ]  published recently in the journal Nature.
The impact stems from the fact that more land is typically required for organic growing—something that really shouldn’t be all that surprising, according to researcher Stefan Wirsenius, an associate professor at Chalmers University of Technology in Sweden and one of the study’s authors. Still, however, for many, the research results were unexpected and alarming.
“People have been not only surprised, but also rather upset, even angry,” says Wirsenius. “Quite a few have seen it as an ‘attack’ on organic farming. Our research just points out something that should be very obvious: that using more land for the same output, which organic farming does because of its lower yields per area, has consequences in terms of carbon storage.
“Our study,” he continues, “shows that organic peas, farmed in Sweden, have around a 50% bigger climate impact than conventionally farmed peas. For some foodstuffs, there is an even bigger difference. For example, with organic Swedish winter wheat, the difference is closer to 70%.”
The researchers developed a new metric called “Carbon Opportunity Cost” to use in their assessment of environmental impact. Wirsenius explains that when land is converted from forest to farmland, the deforestation means that carbon stored in the previously existing forest is converted to carbon dioxide, which increases atmospheric carbon dioxide levels. What’s more, the researcher says, by continuing to use land for agricultural crops, the opportunity for carbon storage that could be achieved if the land were allowed to revert to forest is lost. According to Wirsenius, existing methods for assessing the climate impacts of different land use fail to consistently account for the effects of carbon storage.
“What I hope that people would take home from this research is that there is almost always a carbon storage cost of using land, regardless of purpose,” he says.