It's a disappointing conclusion, but surely there are other reasons why Earth-friendly food production is a good idea.
For anyone who cares about health and planet, buying local organic food seems like a no-brainer. It means fewer chemicals entering the body, greater financial support for local farmers who care deeply about the soil, and possibly less reliance on fuel-gulling machinery. That said, the impact on reducing one's carbon footprint by buying organic food may not be so significant as many shoppers think.
An open-access study published in Environmental Research Letters in June 2017 found that, when it comes to measuring carbon footprint, organic agriculture is not much more sustainable than conventional agriculture. The researchers found:
"Organic systems require 25–110 percent more land use, use 15 percent less energy, and have 37 percent higher eutrophication potential than conventional systems per unit of food. In addition, organic and conventional systems did not significantly differ in their greenhouse gas emissions [GHG] or acidification potential."
The study went on to say that GHG emissions are similar between the two styles of agriculture because of the way in which crops are fertilized. Conventional crops use synthetic fertilizers, while organic relies on manure:
"While production of conventional fertilizer is energy- and GHG-intensive, mismatches between nutrient availability and demand in organic systems dependent on manure increase the portion of reactive nitrogen in organic systems that turns into nitrous oxide, a potent greenhouse gas, causing organic and conventional systems to have similar GHG emissions."
There was some variation among food groups, with organic meats having a lower carbon footprint than industrially-raised livestock, and organic vegetables having a higher footprint compared to those that were conventionally produced.
For this devoted organic-eating locavore, the study was puzzling and frustrating to read. Even the study author Michael Clark, who's a vegetarian for health reasons, said he found it surprising. He told CBC:
"There's a …[perception] that organic agriculture is a lot more sustainable than conventional agriculture is, so I guess I was kind of predisposed to believe that too until I looked at the data."
Nevertheless, while reading the study, there were certain paragraphs that seemed to contradict what the research was saying. For example:
"Previous analyses have shown that increasing nutrient application and adopting techniques such as rotational farming, cover cropping, multi-cropping, and polyculture in organic systems can halve the land use difference between organic and conventional systems."
So, if organic farmers are actually using these techniques, it appears one might safely assume that the carbon footprint of organic food would be significantly less. In that case, what kind of organic agriculture is being measured in the study, if it does not use the methods described above?
Also, these findings are the result of comparisons at a local scale only. It's possible that the results would differ "at a regional, national, or global scale." This would meaningful for me, since all produce I buy locally is organic, while conventionally-grown is almost aways imported from far away, i.e. lemons from South Africa.
While I understand the need and desire to quantify all aspects of local organic agriculture and be able to compare it against conventional, I do think that such studies lose sight of the big picture. There are many other benefits to supporting organic farmers that might not be as good when it comes to carbon footprint calculations, but that doesn't mean they don't matter.
Buying from a local organic farmer keeps money in the local economy. It builds up the community, generating income that can be spent on other local businesses, especially those that prioritize caring for the environment. (Those types of people tend to stick together.)
Buying organic says we don't want synthetic chemicals contaminating our soil and water, that it's entirely possible to grow fabulous food without it, even if it's not as efficient. The long-term effects of saturating our food with synthetic chemicals must be weighed, too. (Watch "Modified," a new documentary in which large-scale organic farmers say they have yields that are comparable to those of conventional farmers and far more resilient in drought.)
What about the whole question of waste and how that factors into measuring food's carbon footprint? If people are spending more money to buy organic, local food, one could argue they're more careful to use it all up. The cheaper and more accessible food is, the more is likely to end up in the trash -- hence our massive North American problem with throwing away 40 percent of food grown for human consumption.
The researchers admit that organic agriculture has benefits that conventional does not, such as higher micronutrient concentrations, lower pesticide residues, higher soil carbon retention, and better biodiversity around farms. But it argues that because conventional uses considerably less land for the same yields (which some would challenge), it has less impact on biodiversity and releases less carbon from the soil.
"Developing production systems that integrate the benefits of conventional, organic, and other agricultural systems is necessary for creating a more sustainable agricultural future."
It sounds a bit ambiguous, but fair.