The Real Climate Impact of Organic Farming
Among the general public, the term “organic,” when applied to food, has long been accepted as a sort of shorthand for “healthy and environmentally friendly.”
That reputation is mainly attributable to the fact that organic food is produced without the use of chemical fertilizers and pesticides (despite the fact that it’s about much more than that for dedicated organic farmers), which can damage ecosystems and be harmful to human health at certain levels.
But as the climate crisis has become the defining environmental issue of our time, questions about how organic farming fares specifically when it comes to greenhouse gas (GHG) emissions have started to percolate. And a few recent studies led to surprising headlines like this one: “Sorry, organic farming is actually worse for climate change.”
Of course, it’s not that simple, and even credentialed experts disagree on what current research can tell us. “It’s just not going to be a meaningful part of the climate solution,” says Timothy Searchinger, a research scholar at Princeton University and the lead author of the recent World Resources Institute report “Creating a Sustainable Food Future.” Meanwhile, scientist Yichao Rui, PhD, who oversees soil health research at the Rodale Institute, holds the opposite view. “There’s no doubt that organic systems could reduce greenhouse emissions and improve carbon sequestration,” he says.
Understanding that discrepancy is a matter of digging into the research, analysis, and expert opinions available. It’s also important to ask whether examining GHG emissions isolated from and above all other factors is a productive approach to thinking about the impact of food choices. Given the severity of the climate crisis, is that now necessary? Or will a systematic way of thinking that takes all environmental impacts into account better serve the planet (and its people)?
How Agriculture Contributes to Climate Change
The WRI report estimates that agriculture contributes about 25 percent of annual GHG emissions globally. A little less than half of that results from what researchers call “land-use change,” which mainly refers to clearing vegetation that would otherwise store carbon dioxide. (A good example, covered recently in the news, is the Amazon rainforest being burned to clear land for farming).
A little more than half of those emissions are more directly related to the practice of farming: nitrous oxide that is released from fertilizers and methane released by livestock (both are much more potent greenhouse gases than carbon dioxide) and fossil fuels related to the production and use of inputs (from tractor fuel to pesticides).
Why Some Studies Show Organic Farming Increases GHG Emissions
Criticisms of organic production as a climate solution center on one major factor: land use.
The recent headline-grabbing study, published in Nature Communications, was an analysis of how transitioning agricultural production — from conventional to organic — in England and Wales would impact GHG emissions. It found that the practice of organic farming would reduce emissions compared to conventional farming when it came to factors like livestock and crop production. However, the expected decrease in yields (40%) would be so significant, more land would need to be cleared for production, so emissions would increase overall.
Searchinger said that while he is concerned about the effects of pesticides on the environment, that analysis lined up with the body of research he’s encountered and was an example of the basis for his thinking on the issue. “There have been a lot of different papers on this, and the general rule is that on average, organic production has lower yields,” he said.
Looking at Organic Yields Over the Long Term
At the Rodale Institute, however, studies have shown different results. Started in 1981, the Farming Systems Trial (FST) is the longest-running side-by-side comparison of conventional and organic grain farming in North America. Studies using the data have been published in several major journals including Nature.
Based on the results of that research, Dr. Rui said that yields for organic crops are lower in the first few years of transition as soil biology is restored, but that those decreases don’t continue over the long-term. “Over the 40 years, on average, there’s no statistical difference in yield between conventional and organic,” he said. “Also, in climate change scenarios, like years of drought, organic keeps performing better than conventional. We have found 30% higher yields in organic than conventional in years of drought.”
That difference is attributable to healthy soil that allows water to penetrate and then retains moisture for longer; Rodale’s studies have also shown organic farming builds organic matter in soil over time.
Good Soil as a Key to Climate Mitigation
Searchinger agreed that water penetration and retention in soil really matters when considering climate impact, but that there are many farming practices that can improve soil health that are not necessarily only used by organic farmers. Cover crops and no-till farming, for example, have both been shown to improve soil health and therefore moisture retention (and potentially carbon sequestration) over time. “You can get good soil without going organic,” he said. His other criticism is that because Rodale’s fields are part of a research institute, their results might be better than what tends to happen when less careful farmers apply the same techniques in their own fields. “You need a lot more careful management in order to farm without pesticides, and farmers don’t get it right often,” he said.
Still, Dr. Rui said he sees that argument as evidence that more resources need to be dedicated to helping farmers master the transition to organic farming. Plus, he says the question about yield doesn’t take into account the fact that over the long term, intensive monoculture farming with pesticides can destroy soil organic matter.
“If you think about the premise of the [previously discussed] study, they claim that the conventional system of farming can keep producing high amounts of food…but if you keep degrading the soil quality, then there’s no ground to keep providing high productivity. You’re losing your topsoil.” he said. “If you don’t maintain it or improve it, then you are not going to be able to farm in the same way in the next 50 years.”
Urvashi Rangan, a sustainable food systems expert and the chief science advisor for FoodPrint, agrees. “The notion that we may not be able to grow food on soil in the future…it’s real,” she said.
Beyond GHG Emissions: The Bigger Picture
Dr. Rui emphasized that there is a lot of room to improve organic farming practices, which is why more research is crucial. He also pointed out that while looking at yield variations in grains like corn and soy is valuable, it cannot tell the full story of organic farming’s potential benefits. That’s because in its best iterations, organic farming involves complex, diverse systems with varied crop rotations and other soil-building practices, animal integration, and ecosystem preservation. Comparing a diversified organic farm to conventional row cropping in an apples-to-apples way, then, is difficult.
- Regenerative Agriculture
- Regenerative agriculture is a holistic systems approach that starts with the soil, and also includes the health of the animals, farmers, workers and community.
Rodale is also moving towards “regenerative organic” practices that focus not just on the absence of pesticides, but on the many practices that build soil and the climate-friendly reasons to do so. As a proponent of “true cost accounting,” it’s the direction Rangan thinks farming systems should move in to provide maximum environmental benefits across the board.
“It is important to make sure that we are holding the soil onto the ground, physically, and the way you do that is root depth, constant cover cropping, and increased topsoil. So that as inclement weather comes in, for example, as a result of climate impacts, those lands are going to be able to tolerate that disturbance much more easily,” she said. “That’s what we saw in the Midwest this past summer — more resilience on these regenerative farms.”
In other words, measuring environmental impact means considering greenhouse gas emissions but also how chemical inputs impact pollinators, how integrated livestock can impact the ecology of soil, and how keeping soil covered at all times to hold nutrients and carbon in place is integral.
“All those things matter,” she said. “They also have a whole lot of other benefits that we need to be thinking of when we’re thinking about a resilient system overall. Organic gets you started in that direction If you’re practicing it right…and then we can actually sequester carbon in the soil and draw it down. Agriculture can be part of that solution.”
The Path Forward
Research on how much carbon agricultural soils might actually be able to store using regenerative methods and how to measure it is still in its infancy. And forests will always store much more carbon in trees and other vegetation, so no matter how much farmed soil holds, land that can be kept as forest will always be better in terms of GHG emissions.
More studies are necessary to look at how regionality impacts carbon sequestration, Dr. Rui said, and Rodale is in the process of setting up research centers in Iowa, Georgia, and California to apply its methods to different climates and soil types. But results from international studies already look promising. “Most of them agree that organic, or a more regenerative way of farming, has a lot of potential in sequestering carbon,” he said.
The question about land use and yields will continue to be debated, especially if the question of organic farming’s climate impact is applied to simply changing a few variables within the current agricultural system. But Rangan thinks a bolder transformation of that entire system is necessary. “The practices invented in organic are not the only ones that are going to be necessary to deal with the full spectrum of climate impact when it comes to agriculture, but they are central,” she said. “In other words, the best systems will incorporate all of those principles at the end of the day, as we transition to regenerative.”
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