Organic agriculture is not as good for the environment as commonly believed, according to a new scientific study reviewing multiple lines of evidence over more than two decades.
The study, conducted by German researchers Eva-Marie Meemken and Matin Qaim from the University of Goettingen and published in the journal Annual Review of Resource Economics, challenges many beliefs that have helped the organic food industry grow into an $82 billion global market.
However, Meemken and Qaim also make clear that the scientific evidence shows that organic is better in some specific situations, and that the best strategy overall may be to combine conventional and organic approaches.
In general, the study concludes that while organic farming is more environmentally friendly per unit of land than conventional approaches, it is not better for the environment when assessed in terms of units of output.
This is because organic farming generally has lower yields — between 19-25 percent, on average — although the picture is complicated between different crops and locations.
The lower land-use efficiency of organic systems means that “large-scale conversion to organic would likely require bringing more natural habitats into agricultural production,” with a potentially severe impact on global biodiversity due to the loss of rainforests and other currently wild areas.
Although organic farms tend to have lower nitrogen inputs and better carbon sequestration, more use of fuel and animal manures counterbalances this effect, Meemken and Qaim conclude.
“Overall, the evidence does not support the widely held notion that organic agriculture is more climate friendly than conventional agriculture,” they write.
Nutrient leaching, leading to eutrophication and dead zones in lakes, rivers and coastal seas, is acknowledged as a serious agricultural problem, and is often ascribed solely to the use of synthetic fertilizers.
“Organic farming is not the paradigm for sustainable agriculture and food security”
However, as with biodiversity and climate, “leaching under organic management was found to be lower per unit of land but not per unit of output.” This is because organic systems rely heavily on animal manures, which also leak nitrogen and phosphorus into streams and rivers.
However, the news is not all bad for organic. Because organic practices emphasize the application of organic matter — either green or animal manures — and more diverse crop rotations, “organically managed fields have higher contents of organic matter and larger and more active soil microbial communities,” the researchers conclude.
In addition, because synthetic pesticides are banned in organic farming, “the risk of pesticide pollution of water bodies is lower,” Meemken and Qaim state. However, non-synthetic pesticides — such as copper sulphate for the control of fungal plant diseases — are used in organic farming and can also have negative impacts on aquatic life.
In general, the researchers suggest, organic agriculture may be more suitable to address specific local environmental concerns, such as soil degradation, than global problems like land-use change and greenhouse gas emissions.
Meemken and Qaim also reviewed the economic impacts of conventional versus organic farming. For developing countries, organic agriculture may jeopardize food security, they found, because higher food prices have a disproportionate impact on the poor.
Furthermore, “organic farming is typically more labor intensive, as manual labor is needed for weeding, application of organic fertilizers, and other operations,” which may rely on unpaid family labor. It may also negatively affect women, who often carry out the lion’s share of manual labor on smallholder farms.
The researchers also point out that “most organic farmers in developing countries so far produce cash crops for the export market,” so their results should not be extrapolated into the production of food crops for domestic consumption.
This is because although some “high-income consumers in developing countries are willing and able to pay more for organic foods, many domestic consumers are poor and unable to pay significant price premiums.”
Consumers in rich countries pay hefty premiums for food produced under organic certification schemes, while government policies in some developed countries promote organic methods both with subsidies and other support schemes.
Although the global organic retail industry reached $82 billion in 2015 and has seen rapid growth in recent decades, overall organic agriculture only accounts for 1 percent of total agricultural land worldwide.
The researchers conclude that while “organic farming is not the paradigm for sustainable agriculture and food security” as is often promoted in rich countries, this “does not mean that organic methods cannot be useful in specific situations.”
They warn, however, that while a “smart integration of both types of agriculture” might be most desirable overall, “ideological barriers between supporters and opponents of organic agriculture need to be overcome to pave the way for developing and implementing more sustainable forms of farming.”
Meemken and Qaim declare no competing interests in their paper. Their research was supported by the German Research Foundation, which is funded from German federal and state governments.