It’s a sunny weekday afternoon and Chris Tolles, CEO of the Boston-area startup Yard Stick, is standing in a sprawling farm field in the middle of Ohio holding what looks like a drill. The tool, with a long probe, has a tiny camera embedded in the tip. As Tolles holds it above the ground, it begins to turn gently, pulling itself into the soil. The goal: to measure the carbon underground.
A spectral sensor on the tool gathers data about the soil that can be analyzed using artificial intelligence. “Organic carbon has a spectral signature,” Tolles says. Using the images from the camera and some software, he explains, can reveal how much carbon is in the soil.
It’s one way to address a question that both food companies and governments want to answer: How much can farming help tackle climate change? Could shifting to a variety of so-called regenerative practices (for example, rotating between different crops) enable farms to capture more carbon in soil? By one estimate, implementing the idea could sequester more than a billion tons of carbon per year globally, more than the emissions of the entire airline industry. In the U.S. alone, a National Academy of Sciences study estimated that farms may be able to sequester as much as 250 million tons of carbon per year, or 4% of national emissions.
The potential for regenerative agriculture, also sometimes called carbon farming or climate-smart agriculture, has spawned a growing wave of support. Food companies, from McDonald’s to PepsiCo and General Mills, are pouring money into the space. Nestlé is investing more than $1 billion over five years to increase the use of regenerative agriculture in its supply chain. Consumer goods giant Unilever partnered with insurer Axa earlier this year to create a billion-euro private equity fund to invest in regenerative projects.
Additionally, the recently passed Inflation Reduction Act includes around $20 billion to support regenerative farming. Pitchbook estimates that startups in the space raised more than $700 million globally last year. Some companies are starting to help farmers sell voluntary carbon credits—certificates of greenhouse gas emissions reductions that other companies buy to offset their own emissions—even before there’s concrete evidence of exactly how much the amount of carbon in their fields has changed. And it’s now possible to buy “climate-friendly” crackers and “carbon-negative” beef jerky.
But as carbon farming grows, critics question whether it may be overhyped as a climate solution. Some scientists argue that it’s unlikely to achieve large-scale emissions reductions; others disagree. Estimating how much carbon is in the soil can be challenging, and arguably may not always be accurate enough for companies to sell carbon credits, which are often what is paying to transition to these practices in the first place.
There are also questions about how long the carbon will stay in the ground if it is ever put there. But even if some of the carbon claims turn out to be overblown, “regenerative” farming methods can also benefit the environment in several other ways. And the potential to sequester carbon in soil may still be large, even if it’s too complex a calculation upon which to base a simple carbon credit market. How should farmers and food companies approach the idea—and how can consumers know when claims are greenwashing or legitimate?
Getting carbon back into the soil where it belongs
The top meter of the earth’s soil contains around three times as much carbon as the atmosphere. Traditional farming sends large amounts of that carbon back into the air as fields are plowed and then left fallow. By one estimate, since agriculture began around 133 billion metric tons of carbon may have been lost from the top 6 feet of soil.
Regenerative agriculture aims to add some of that carbon back, through a variety of techniques that help hold on to the carbon that plants capture naturally through photosynthesis and then transfer underground via their roots. (The same thing could happen, at a larger scale, if current farmland were allowed to return to a natural state as forests or prairies.) While there’s no official definition for regenerative agriculture, it’s used to describe several different methods.
For example, perennial crops like Kernza, a grain that Patagonia has recently used to brew beer, have long roots that can add more carbon underground as the plants grow. Planting “cover” crops between cash crops, when a field would otherwise be bare, can store more carbon. So can adding compost or manure to fields. Rotating between different crops can help add carbon. Managing how cattle graze, so they rotate between fields and grass stays at a specific length, can also potentially store more carbon. Switching to no-till farming, so crops are planted without disturbing the soil, may help—though, like other techniques, the details are complicated, and it doesn’t work the same way on every farm. (Some also use the term regenerative more broadly to describe technologies that reduce emissions, such as sensors that can shrink the amount of fertilizer used on a field.)
The phrase regenerative agriculture was first used at least three decades ago by the organic farming nonprofit Rodale Institute, but it got little attention until the last five or six years. The basic ideas are not new: Critics point out that some companies touting “regenerative” ingredients are just rebranding practices that have been used by Native Americans for centuries, such as no-till farming. Other techniques, like planting cover crops, were more common on farms before the widespread use of synthetic fertilizer. Some startups are also pioneering solutions, like Loam Bio, an Australian biotech company that makes a microbial seed coating that it describes as “supercharg[ing] a plant’s natural ability to store carbon in soil.”
The practices, all aimed at protecting the land, stand in contrast to typical industrial agriculture, which strives to maximize production at any cost. The conventional approach of overgrazing, intensive tillage, and growing huge swaths of a single crop has made soil less healthy. But the mainstream food and ag industry is starting to change—or at least change its rhetoric—including some companies that aren’t necessarily known for their focus on the environment.
Cargill, the global food corporation whose practices have been linked to deforestation, recently introduced a regenerative agriculture platform to help farmers make money from carbon credits. BASF, the chemical giant, is marketing some of its products as a fit for “climate-smart” agriculture. McDonald’s is investing in research on regenerative agriculture. General Mills plans to deploy regenerative agriculture on 1 million acres of farmland by 2030; PepsiCo wants to increase regenerative practices to 7 million acres of cultivated land by the same year. Heineken is testing regenerative practices in barley grown for its beer. And the list goes on.
Multiple factors are driving the commitments as part of larger climate strategies. “They’re getting pressure from investors and shareholders,” says Ben Lilliston, director of rural strategies and climate change at the nonprofit Institute for Agriculture and Trade Policy. “They’re also very aware of the impact climate is having on their supply chains.”
In some cases, there’s a risk of greenwashing. “When you start to look under the hood of some of the companies’ various climate pledges, there’s not very much there,” Lilliston says. He points to the example of JBS, the world’s largest meat producer, which plans to use regenerative agriculture in its goal to reach net zero by 2040. But the plan is arguably weak. The company has failed to meet past goals to stop illegal deforestation, and in previous estimates of its carbon footprint, it’s chosen not to include emissions from cattle burps and manure. It also has set goals to reduce “emissions intensity,” or the emissions per piece of meat, meaning that its total emissions can continue to grow.
Companies need to reduce emissions directly, Lilliston says, rather than rely on regenerative agriculture to offset those emissions. Still, the picture is nuanced. For field crops, for example, regenerative techniques can reduce the use of fertilizer, another direct source of emissions. And the methods have other environmental benefits, including making farms more resilient in the face of drought.
As demand grows from big food corporations, more farmers are beginning to make changes, both out of an interest in helping the environment and soil health, and because new incentives will pay them to switch.
“We can be within 20% of the truth 90% of the time”
When the pandemic lockdown began in early 2020, Will Drucker, who runs a craft distillery in Vermont, temporarily headed home to his family farm in Illinois. For six months, his parents and brother joined him. Their land, on 660 rolling acres with a view of the Mississippi River, is partly leased out to other farmers, since the family now lives elsewhere. But as COVID-19 brought them together, they started talking about how they could take a more active role to make the farm sustainable.
They decided to try something they hadn’t done before: planting cover crops. They also stopped tilling some fields.
“We were realizing, okay, we can do these things, and if we do them right, not only is it good for our soil, but there’s an economic benefit from sequestering carbon and the sale of those carbon credits,” Drucker says. Earlier this year, the family got the first payment for their efforts. After making changes on 95 acres of land, they earned around $1,000 from Indigo Ag, a “carbon farming” program that monitors changes on farms and then sells carbon credits to companies like JPMorgan Chase and the North Face that want to use them to offset their own emissions.
Measuring how soil carbon is changing is challenging to do at a large scale. “From a scientific standpoint, we know how to measure really well—it’s just that it’s too expensive for carbon market applications,” says Jonathan Sanderman, a senior scientist at the Massachusetts-based Woodwell Climate Research Center. The traditional method of measuring soil carbon involves hammering a steel cylinder into the ground, pulling out pounds of dirt, and mailing it to a lab, where a scientist evaluates it. That’s expensive and cumbersome enough that it rarely happens.
A handful of startups like Yard Stick hope to make mass sampling feasible. EarthOptics, an Arlington, Virginia-based startup, is working on sensor technology that can attach to a tractor and analyze the soil as it moves over the field. Scientists are also developing solutions, like a tool that can scan and analyze the ground without digging.
Others use satellite images or a combination of remote sensing, modeling, and some sampling to estimate changes in soil carbon. Some of the methods are flawed, Sanderman says. “Personally, I’m uncomfortable with issuing credits just from the models if I don’t think the models are good enough to do that,” he says. “So I would much rather see a lot of measurements.”
Indigo Ag, which Sanderman has advised in the past, does use satellite imagery and modeling to estimate changes in soil carbon, along with a comparison to actual samples on the ground. It’s difficult to model what’s happening on a particular farm or field, but the company says its approach works because it’s looking at changes over large areas.
“In aggregate, the uncertainties start to diminish once you start adding up all the individual components, so that we can then say, okay, across the program, you have very high certainty,” says A.J. Kumar, the company’s senior director of carbon science and modeling. Soil carbon builds up slowly, and changes in soil samples might not be apparent until five years after a farmer starts farming differently; because it wants to incentivize farmers with faster payments, Indigo Ag estimates carbon after a year, before any physical tests would be able to detect it.
Perennial, a Boulder, Colorado-based startup, also uses remote sensing and models based on on-the-ground samples. “Where we are right now is, we can be within 20% of the truth 90% of the time,” says Jim Kellner, the company’s chief science officer, who is a biology professor at Brown University and a researcher on a NASA mission using satellite images to similarly estimate carbon in forests. The company will continue developing the technology before it begins to sell carbon credits. “We place a lot of emphasis on [the quantification], because we’re talking about a problem here where getting the right answer really matters,” he says.
Even physical samples have to be taken carefully to be accurate. The amount of carbon in the soil could be completely different if you’re standing in one place in a field than another. And if the sample is taken near the surface of the field, you may get a different result than if you dig deeper. Early studies of no-till fields, for example, took samples near the surface and found increases in carbon. But others that took lower samples found that tilling brings carbon deeper underground, and if tilling stops, it may just mean that carbon is redistributed.
The results of a particular intervention can also vary by location. If a farm is in a cold, wet climate, and the farmer stops tilling, that might not be as beneficial as it would be on a hotter, drier farm. It’s not as simple as saying that every farmer who switches to no-till farming is storing more carbon in the ground—though there may be other benefits, including the fact that if a farmer stops tilling fields, they’ll be burning less fuel in a tractor. In other cases, shifting practices might mean that farmers end up using more land, something that could eventually lead to more deforestation or conversion of natural grasslands.
Then there’s the question of how long changes can last. If farmers adopt new methods to store carbon but later abandon them—or if the farm is sold and changes—captured carbon could end up in the atmosphere again. A benefit that might be temporary doesn’t work well as an offset for fossil fuel pollution that has permanent effects.
“When you emit a ton of CO2, it impacts the atmosphere for literally millennia,” says Freya Chay, a project manager at CarbonPlan, a San Francisco-based nonprofit that studies the impact of climate actions. “So the permanence question is not a small piece of this. We know that management practices change, and management practices can change soil carbon content really quickly. So if you are relying on soil to make an offsetting claim, you have to be thinking about how soil carbon is maintained through time and how short-term carbon storage relates to the long-term impact of fossil emissions. And that’s a really hard question that people haven’t figured out how to grapple with yet.”
Big ag buys in
As the urgency of addressing the climate crisis keeps growing (as well as consumer demand for more climate-friendly food), food producers are trying to make changes in their supply chains while simultaneously figuring out how best to make those changes. “No one has this nailed yet, right?” says Britt Lundgren, director of organic and sustainable agriculture at Stonyfield, the organic yogurt and dairy brand. “We’re all trying to fly the plane while we’re building it.”
Because Stonyfield has been an organic brand from the beginning (the company launched as an organic farming school in New Hampshire in 1983, and then started selling yogurt to support the school), the farms that it works with have always been environmentally focused. The company is working to directly reduce emissions in its supply chain as much as possible by switching to renewable electricity, helping farms better manage manure, and testing other potential solutions like feeding cows seaweed. But it also saw an opportunity for farmers to do more for soil health, and for it to begin to quantify the climate benefits. It’s currently working with a dozen farms to see how changes in grazing affect the soil on each farm.
Stonyfield’s biggest opportunity to increase soil carbon on dairy farms may come from managing how cattle graze. One step involves using a grazing stick, a simple measuring device that tracks the height of grass before and after cows eat, and then logging that into a software program. Studies suggest that when cattle graze, the grass grows more roots, which can capture more carbon. But it’s also important that they don’t eat so much of the grass that the plants struggle to survive; grazing sticks show when it’s time for the cows to move to a new pasture.
The collaborators on the project are working to make the tool as simple to use as possible. Farmers “went into farming because they didn’t want to sit at a desk and do spreadsheets,” Lundgren says. “I think our task is to make the record-keeping as simple as possible.” At the same time, the pilot is testing different methods of measuring soil carbon, and evaluating new technology to see how it compares to standard lab tests. So far, they’re still taking baseline measurements. It will likely take a few more years before any changes in the level of soil carbon will be detectable. But Stonyfield plans to eventually pay farmers for the carbon sequestered in fields. (Farmers in the pilot get a stipend now, and Stonyfield is also paying for soil testing.)
General Mills, which has a goal to “advance regenerative agriculture” on 1 million acres of farmland in its supply chain by the end of the decade, is doing some of the same testing. “We’re really trying to make sure all the components of this whole market work, from the soil sampling, to the modeling, to the payment, to the verification of the ecosystem service,” says Steve Rosenzweig, a soil scientist at the company.
Some of its farmers began getting paid for their carbon services in 2021, even as General Mills is still waiting for results, by using modeling to predict how much carbon they’re storing. “We don’t want the farmers to have to wait five years to receive any payments, so we’re going to model those interim years,” Rosenzweig says. The company is also focused on building long-term partnerships—farmers can enroll for 10 years and renew for another 10—and says that it is accounting for the risk of any changes on farms that could result in more emissions as it calculates the climate benefits.
In one program, General Mills offers farmers one-on-one coaching to develop new regenerative management plans, and pays to test soil samples from fields. For farmers, even if changes in carbon levels take time to appear, other benefits may be more readily apparent. Austin Schweizer, a wheat farmer in the program in Kansas, told me last year that he saw one of his fields change after planting a single cover crop.
“That ground was so tight [before] that you could dump water on it and I couldn’t get it into the soil,” he says. The roots from the cover crop made new channels in the dirt, so rain could more easily infiltrate the ground for the next crop of wheat. More earthworms were in the soil, indicating that it was getting healthier.
The benefits beyond carbon sequestration may convince farmers to commit to new practices. “By restoring the fertility of the soil and having a healthy microbial population that can cycle nutrients, farmers can reduce the amount that they have to spend on nitrogen fertilizer, because they’re wasting a lot less,” Rosenzweig says. “And they have that natural fertility, and fertilizer is one of the biggest expenses that farmers have.”
It also means less water pollution from fertilizer running off fields, and a lower carbon footprint from the fertilizer, which creates emissions both when it’s manufactured and when it’s used on a field. Healthier soil can better retain water, making farms more resilient in the face of drought; because water can flow more easily into the soil, it also reduces flooding in heavy storms. Other regenerative practices yield their own benefits. No-till farming, for example, can save money on equipment and fuel and reduce erosion.
PepsiCo, another food company that has been early to invest in the space, is tracking multiple impacts as it aims to help farms in its supply chain bring regenerative practices to 7 million acres of land. Those include soil health, greenhouse gas emissions reductions and removals, watershed health, biodiversity, and the livelihoods of farmers.
“It is an outcomes-based goal, which means that we won’t really count progress towards the goal unless we are able to measure a positive impact,” says Rob Meyers, the company’s VP of agriculture. Farms will have to show progress in at least two areas, one of which is climate.
Though tools for measuring and accounting for soil carbon aren’t perfect, Meyers argues that implementation on farms can’t wait. “Probably the biggest concern that we have is that the lack of available accounting tools creates inertia or a failure to act,” he says. As the company works to convince farmers to make changes—through demonstration farms, incentive payments, and partnering with organizations that farmers already trust to give ag advice—it’s simultaneously working to “advance these tools that we all desperately need to be as accurate as possible,” he says.
Others believe that even if carbon credits for farmers are inexact, they can still be useful. “If you come at it trying to poke holes in the system, there are plenty of holes that you can poke. I fully recognize that,” says Ben Ninio, a partner in the strategy practice at Deloitte who works with food and agriculture companies. “But given the size of the opportunity that we have in ag, and the lack of business models that exist except for carbon credits, I think it’s the only way forward. I think the only thing we can really do is continue to make tactical improvements on both of those fronts until we can start to get more confidence.”
Waiting for an answer
Airly, a new brand selling crackers that it bills as “climate friendly snacking,” believes enough data is available for some crops and regions that it’s possible to use models to predict how much carbon is being sequestered. (The brand is paying for research to continue collecting more direct data separately.) Using modeling, Airly’s scientists studied the carbon footprint of different farms and selected an oat supplier in South Dakota that it says is carbon negative because of its use of no-till farming, cover cropping, and other practices that reduce the farm’s emissions, like the careful application of fertilizer. It also sources from similar Canadian farms.
Location and other conditions matter, including the type of soil and humidity in the area, says Mark Izzo, the chief science officer for Airly, part of Bright Future Foods, a subsidiary of Post Holdings (the company that makes cereals like Honey Bunches of Oats and Fruity Pebbles). “Not all regenerative farms are carbon farms, but all carbon farms are regenerative farms,” he says, adding that any farm that claims to be a carbon farm also needs a careful accounting of its full carbon footprint.
Farms in Michigan growing wheat for the brand were able to tweak some practices to go from low carbon to carbon negative this year, according to the modeling. Airly has tried to minimize other emissions, choosing to make crackers, for example, because they take relatively little energy to produce and they don’t need refrigeration. The brand is exploring ways to reduce emissions further, including recent tests of a zero-emissions oven. Because producing the food (including other ingredients, like the cheese in its cheddar crackers) creates emissions, Airly is paying for forest and agricultural carbon offsets.
Some other companies, like Stonyfield, haven’t yet made claims on their product packaging about the climate benefits of regenerative farming. As the company works to eliminate emissions, it also hopes that there’s potential to use soil carbon sequestration to account for the rest of its carbon footprint. The company wants to reach a point by 2030 that its milk can be carbon neutral, or even have a positive impact on the environment. “If we were to really drive carbon sequestration at a substantial rate, it could offset the rest of the emissions from farms,” Lundgren says. “But no one really knows. Can we get there?’”
The Greenhouse Gas Protocol, which offers companies guidance on how to account for emissions, has spent the past two years working with experts on a framework that companies can use. A final version will come out next year, and some companies are already testing it. The approach includes details like a “principle of permanence,” telling companies that if they’re going to claim that carbon has been removed at a farm, they’ll need to keep tracking it in the future to make sure that the carbon does stay underground.
Some companies “are probably overestimating the benefits that they’re going to get from regenerative ag,” says Matt Ramlow, a research associate at the World Resources Institute who’s working on the protocol. “Really, we’re just trying to bring that into focus: How would you do that analysis, and how could you figure out what the magnitude of that potential is?”
Whatever the climate benefits from soil are ultimately, there’s clear agreement that regenerative techniques can help the environment, from reducing fertilizer use to protecting water quality. “I think relying on soil carbon sequestration to get to net zero is tricky,” says Emily Oldfield, a researcher at the Environmental Defense Fund focused on developing and testing criteria for measuring soil carbon in fields. “That’s not to say companies shouldn’t be prioritizing sustainable land management techniques within the supply chain. . . . There’s no doubt that there are very tangible environmental and agricultural benefits to these practices.”
In a few years, the first results will begin to come back from farms that large companies like General Mills are studying. “That’s kind of a reckoning,” Sanderman says. “I think everyone right now is kind of happy: ‘Oh, let’s let these markets play along and move along. And then let’s see what happens at year five. Let’s see how good these models actually are.’ No one really has worked out exactly what’s going to happen—once that data is collected—if it doesn’t actually match the model estimates.”
Correction: We’ve updated this post to reflect that BASF is not the owner of Monsanto.
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