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FRENCHMANS BAYOU, Ark. — Will Tipton's farm, not far from the Mississippi River, has been in his family since 1836. For the past eight generations, his family mostly planted one crop per field per year — and that was it. "Straight soybean, soybean, soybean," Tipton says.
In recent years, Tipton's been trying something new. He leans over the field and picks up a mass of green leaves. "This is definitely a turnip," he says, and then picks up a white flowering vegetable. "Daikon radish out here as well."
These are cover crops. Tipton now plants them instead of letting his fields lie fallow after the harvest. Tipton lets some soil come apart in his hands. Inside is a pink earthworm.
"It's a sign of life," he says. "They're growing around, happy, got plenty to eat."
Worms can be a sign of healthy soil — and a sign of carbon in soil. When carbon dioxide is in the atmosphere, it heats the planet. When plants and their roots pull in that carbon dioxide, or CO2, they help turn soil into a big carbon reservoir. "That CO2 is no longer in the atmosphere where we don't want it," says Matthew Hayek, professor in environmental studies at New York University.
Tipton's farm is part of something bigger. A push by businesses and governments into something called "regenerative agriculture." That's a term used for farming practices, like cover crops, that proponents say are good for the environment and the climate.
Modern agriculture is a big driver of climate change. Powerful warming gases are released from cows and fertilized soils, and deforestation that's driven by rising food demand.
Many food businesses now promote regenerative farming practices as a climate solution. Whether it's the corn in PepsiCo's Doritos or the potatoes in its Frito-Lay chips, Margaret Henry, PepsiCo's vice president of sustainable and regenerative agriculture, says her company is encouraging its farmers to integrate these practices on 7 million acres worldwide by 2030.
The U.S. government is also encouraging many of these practices with farmers. The Biden administration's 2022 climate legislation provided $19.5 billion to the USDA's Natural Resources Conservation Service to largely support "climate-smart agriculture." "Climate-smart agriculture" as interpreted by the USDA includes many common regenerative agriculture practices like cover crops.
But many farming practices supported by companies and the U.S. government may not reduce as much climate pollution as they claim, says Timothy Searchinger, a senior research scholar at Princeton University and technical director of agriculture and forestry at the World Resources Institute. He worries that the focus on certain regenerative farming practices can distract from solutions that can make faster, deeper cuts in climate pollution. "It becomes an excuse for claiming you're dealing with the climate when you're really not," he says.
With corporations and governments making big climate promises about what regenerative agriculture can achieve, researchers say it's important to know what's supported by science and what can be misleading. Here are answers to questions about the regenerative agriculture claims food companies and governments make.
Can any regenerative agriculture practices actually reduce climate pollution?
Some practices that are sometimes called "regenerative agriculture" can directly reduce pollution that causes climate change, says Ken Giller, agriculture professor at Wageningen University in the Netherlands.
Take fertilizer. A lot of fossil fuels go into making fertilizer, and fertilizer releases nitrous oxide, a gas that heats the planet nearly 300 times more than carbon dioxide over 100 years. If farms can reduce fossil fuel-based fertilizer use, that can be a climate solution. "It's an absolute reduction in the release of gases which contribute to global warming," Giller says.
Another practice, "no-till" farming, eliminates the plowing of soil before planting, often done with diesel-fueled tractors. Giller says if no-till farming can reduce the use of diesel fuel, that can be a climate solution.
But a lot of the enthusiasm in regenerative agriculture involves the idea of storing more carbon in soil to slow global warming. That makes many soil scientists wary. "That's when one's Spidey senses ought to tingle, because those claims are challenging to back up," says Eric Slessarev, professor of ecology at Yale University.
When can climate claims about regenerative agriculture get overstated?
Some food and agriculture companies say that certain regenerative farming practices, like cover crops and no-till agriculture, can make the soil store more carbon. This is called soil carbon sequestration.
The USDA is paying farmers to adopt regenerative practices with the idea that adding more carbon to soils can, in part, help the U.S. achieve its climate goal of reducing greenhouse gas emissions 50-52% under 2005 levels by 2030.
But researchers tell NPR there are three big problems with claims that regenerative practices add more carbon to soil. The first involves measurements. Grayson Badgley, research scientist at Carbon Plan, a climate nonprofit, says there isn't a lot of consistency when measuring soil carbon on farms. Measurements are often taken at different depths, which can lead to overestimates of how much extra carbon is in the soil because of these practices, he says.
"If you measure just the first few centimeters of the soil versus measuring a meter," Badgley says, "you can get really, really different answers about how much carbon has actually been gained."
Another problem has to do with something called "permanence." Even if farming practices can increase carbon in the soil, droughts, heat waves and things like having to switch crops can cause that soil to leak carbon back into the atmosphere, where it heats the planet again.
"In my mind, that is the biggest uncertainty. How long is that carbon going to stay out of the atmosphere if it ends up in the soil?" Slessarev says.
And there's still uncertainty over whether some regenerative farming practices like no-till actually lead to more carbon getting stored in the soil in the first place, says Shelby McClelland, soil scientist at NYU.
While there is evidence that some regenerative farming practices can preserve carbon that's already in soil, Searchinger says that with practices like no-till there's still "a fundamental question of [whether] this is doable physically" to add more carbon to soil.
"Is it even possible to build soil carbon in large quantities and significant quantities on working agricultural land? That's the question," he says.
In an emailed statement, a USDA spokesperson writes that federal climate legislation "provided needed funding to help us drive measuring, monitoring, reporting and verification efforts … to quantify the impact of [farming] practices on greenhouse gas emissions and carbon sequestration, and ensure that future resources are directed to the most effective practices."
There's also "regenerative grazing" — what's that and does it reduce climate pollution?
Cows are one of the biggest sources of climate pollution in food, largely because their burps and manure release the potent planet heating gas, methane. In the search for solutions for cows' climate pollution, some companies and governments have embraced "regenerative grazing," or "rotational grazing." Instead of cows grazing in one place, with rotational grazing farmers deliberately move cows from one place to another.
Some food companies claim that rotational grazing can make the soil store enough extra carbon that it can negate cows' methane pollution and make beef "climate-smart" or "carbon neutral."
But Hayek says this is another example of the climate benefits of soil carbon being oversold. "Folks have claimed that [regenerative grazing] pulls so much carbon out of the atmosphere and into the soils through healthier soil that it completely offsets or negates cattle's methane emissions," Hayek says. "That's not correct."
Also, research finds that cows doing regenerative grazing on grasslands can use up to 2.5 times more land, which could lead to the loss of ecosystems that store carbon.
Last month the USDA issued new guidance for environmental claims made on food company labels. The new guidance says it "strongly encourages" food companies to use third-party certification to back up environment-related claims, including claims that beef is "raised using regenerative agriculture practices."
Giller worries that some poorly implemented regenerative farming practices could end up increasing climate pollution. "I think proponents of regen ag are really overselling the positive without necessarily really grappling with what the negatives could be," Giller says.
Why is it important that regenerative agriculture might not have as big a climate impact as it claims?
A lot of money is at stake, Hayek says, both for companies and governments. Billions of dollars from the 2022 climate legislation, the Inflation Reduction Act, are going to U.S. farmers to — in theory — reduce planet-heating pollution on their farms. If the USDA promotes regenerative farming practices like regenerative grazing and cover crops where some climate benefits are unclear, Hayek says that money may not have its intended climate impact. "We need to think pretty smartly about how we distribute literally billions in taxpayer money," Hayek says.
Some companies, like Indigo Ag, are selling millions of carbon offsets based on the idea that some of these regenerative farming practices can reduce climate emissions. Tipton's farm is part of Indigo Ag's carbon offset program. If these farming practices aren't reducing as much emissions as claimed, then companies buying those offsets might not have the climate impact they thought.
In an email, A.J. Kumar, vice president of sustainability sciences at Indigo Ag, writes, "While there are many [soil carbon offset] programs today with different design and approaches, we have gone to great lengths to engage the scientific community and address issues that others may have had in the past."
Kumar also notes: "We continuously update our programs as science advances."
Is it still worth it to do regenerative agriculture if it might not have as big a climate impact?
Emily Oldfield, a soil scientist at the Environmental Defense Fund, says for many of these practices, the answer is still yes. She says regenerative farming practices like cover crops and no-till can increase soil health and reduce erosion, water runoff and water pollution.
When NPR visited Tipton in Arkansas, there was a huge storm. Tipton drove by a neighbor's farm, which wasn't using cover crops and no-till agriculture. Wet soil was washing off his neighbor's field into a muddy ditch. Tipton's fields were absorbing the moisture.
For Tipton, keeping his soils healthy and storing water is the main reason he's doing regenerative agriculture. "Drought tolerance is a key issue for us 'cause our farm is 100% dry land, nonirrigated crops," Tipton says. "Any time, the rain can quit. You're not guaranteed the rain when you need it."
Searchinger says he "enthusiastically" supports many of these regenerative farming practices to address water pollution and help farms adapt to a changing climate. As droughts and heat waves become more common with global warming, scientists say regenerative agriculture practices that improve soil health will be key for resilience.
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