From PBS

By —Courtney Vinopal

Science Updated on Oct 23, 2019 10:00 AM EDT — Published on Oct 22, 2019 3:56 PM EDT

For decades, the conventional wisdom surrounding organic farming has been that it produces crops that are healthier and better for the environment as a whole.

In the U.S., where organic food sales totaled nearly $50 billion last year and made up 5.7 percent of total food sales, companies such as Annie’s and Organic Valley market their products as leaving a low carbon footprint. They remind consumers that their ingredients “matter…to the planet we all share,” or that their farming practices “remove excess carbon dioxide from the air.” The International Federation of Agriculture Movements promises in its literature that organic farming can “help reduce greenhouse gas emissions within the agricultural sector of the European Union and beyond.”

But a new study out this week challenges this narrative, predicting that a wholesale shift to organic farming could increase net greenhouse gas emissions by as much as 21 percent.

“We’re not saying that organic is wrong,” said Adrian Williams, an associate professor of environmental systems at Cranfield University in the U.K., but that consumers and environmental organizations would be wise to consider what these farming practices would look like on a much larger scale before making assumptions about the environmental impacts. Williams worked on the study published in Nature Communications on Tuesday.

While it’s unlikely that any country will pursue a complete, 100 percent transition to organic farming anytime soon, the study falls in line with others that raise questions about the degree to which these practices can mitigate the effects of climate change — and how market forces limit their ability to do so.

What would a shift to 100 percent organic look like?

Much research has been done about the link between organic farming and greenhouse gas emissions in smaller, niche settings, from grassland farms in Southern Germany to suckler-beef producers in Ireland. Results have been varied — while organic farming practices lowered greenhouse gases in some scenarios, in others, emissions grew or remained constant.

A team at Cranfield University sought to expand this scope of research by predicting how far the food supply would carry if England and Wales made a switch to 100 percent organic farming.

“The question was, how much could we produce using only organic methods?” Williams said.

Forty percent less, it turns out. Organic farming typically produces lower crop yields due to factors such as the lower potency fertilizers used in the soil, which are limited to natural sources such as beans and other legumes. Williams’ model found that a 100 percent organic farming system in England and Wales would mean much smaller crop yields. For wheat and barley, for example, their production would be halved relative to conventional farming.

“Having established that there would be a shortfall in massive production, the gap would be filled by increased imports, ” Williams said.

If we try to have the same diet and convert to organic, we can’t really do it without expanding agricultural land demands.

This outcome could lead to a 21 percent rise in greenhouse gas emissions from England and Wales because those imports would likely be raised overseas through conventional agriculture. Such a transition would render moot the potential reductions in greenhouse gas emissions that would otherwise be achieved by the switch.

Full article here.