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Organic corn. Photo credit: Marco Verch Professional /Flickr (CC BY 2.0)

A new study raises questions about the impact of organic farming on climate change.

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Organic farming has long been considered healthier for the consumer and better for the planet than conventional farming. But a new study by a team of researchers at Cranfield University in the United Kingdom is now challenging that green doctrine. 

The researchers include, among others, Dr. Adrian Williams, who studies greenhouse gas emissions, and Dr. Laurence G. Smith, who studies environmental policy and development. The funding for both this study and Smith’s PhD program in Agricultural Systems Modeling was donated by The Ratcliff Foundation and the Engineering and Physical Sciences Research Council

Smith started off his career in agriculture working on organic farms around New Zealand and later moved back to England and joined the organic research sector.

The researchers examined all crops grown in England and Wales and — using Optimal Land Use Modeling (OLUM), a linear programming model — suggested that if all the conventional agriculture were converted to organic methods, the low crop yield of the latter would lead to more land dedicated to agriculture, which in turn could increase greenhouse gases.  

The authors of the study, published in the peer-reviewed Nature Communications, predicted greenhouse gas emissions would increase by 21 percent.  

Organic farming initially reduces emissions through decreased farm inputs, such as fertilizers, and increased carbon storage. However, according to this study, it also reduces crop and livestock yields by around 40 percent. To produce the same amount of food, a lot more land is needed. 

Clearing additional land to make up for yield loss produces more greenhouse gases than are reduced through the initial organic farming practices, the study finds. 

Smith was surprised by the extent of yield loss found in the study. He deemed the research all the more important because of that. “It is my role to challenge assumptions we have and to see what extent they are grounded in fact or reality,” Smith told WhoWhatWhy.

For crops, conventional farming uses fertilizers, pesticides, and genetically modified organisms. Organic farming depends on natural materials and methods — such as the use of animal manure and compost as fertilizer, and crop rotation with legumes (which provide nitrogen). 

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Freshly picked strawberries. Photo credit: Susy Morris / Flickr (CC BY-NC 2.0)

The organic method produces less greenhouse gas than the synthetic fertilizers used in conventional farming.

For livestock, conventional farming uses hormones, supplements, and feeds that increase yields. Organic methods allow animals to graze over a longer period of time. 

Grazing cuts emissions associated with conventional feed and prompts plant growth and subsequent carbon storage. 

Although in the fledgling phase organic methods produce lower emissions, according to the Cranfields University study, the problem still stands — yields are lower and more land is needed. 1.5 times more land, to be exact. 

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But other experts in organic farming point out the limitations of the study’s statistical model. For example, the study fails to include the environmental impact of creating, distributing, and using fertilizers, or their residual impact on the land and the food chain, said Abby Youngblood, the executive director of the National Organic Coalition. “Fertilizers release nitrous oxide, which is a greenhouse gas three times more potent than carbon dioxide,” said Youngblood.

And another expert says there are flawed assumptions baked into the study. Dr. Yichao Rui, a soil scientist at the Rodale Institute, claims that the major finding of this study, that yields will drop 40 percent if there is a large-scale shift from conventional to organic methods, is not true. 

The Farming Systems Trial, an almost forty-year longitudinal study which compares outcomes for 12 acres of side-by-side of organic and conventional agricultural methods, shows that there is no statistical difference between organic and conventional yields, explained Dr. Rui. 

“In arid years — climate change scenarios — organic farming can produce 50 percent more wheat and 100 percent more soybeans,” he told WhoWhatWhy

The Farming Systems Trial — which began in 1981 — showed that, in the first five years of transitioning from conventional to organic, yields decline. “You need some time for the soil biology and biological activity to be restored.”

After the initial five years, organic farming systems produce equal or better yields than conventional methods.

“This paper is single-sided,” said Dr. Rui. “It does not take a holistic perspective of what is needed to fundamentally transition to a sustainable system.” 

The competing viewpoints show that this issue is not clear-cut and deserves more study. Time is running out, however, as solutions are urgently needed to address this looming crisis. 

Related front page panorama photo credit: Adapted by WhoWhatWhy from Sethoscope / Flickr (CC BY-SA 2.0)


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