To avoid a climate catastrophe and keep the world’s temperature from rising by more than two degrees Celsius, experts say, it’s not enough to just cut pollution. We’ll also have to pull some carbon emissions from the atmosphere. But how? One idea gaining traction is paying farmers to use regenerative practices to store carbon in the soil.
No one knows the best way to pull carbon dioxide from the atmosphere and safely store it. Plenty of solutions have been proposed, including using sophisticated machines that directly capture carbon dioxide from the air, fertilizing the oceans with iron powder, and spreading rocks that naturally soak up atmospheric carbon. None have proven ready to be rolled out globally, and some haven’t even been demonstrated to work at scale.
Regenerative agriculture, a term popularized in the early 1980s by the Pennsylvania-based farming think tank Rodale Institute, takes advantage of the fact that plants naturally remove carbon dioxide from the air through photosynthesis, convert it into sugars, then store it in leaves, stalks, and roots or excrete it into soil. Regenerative methods can put carbon back in the soil and keep it stored underground by minimizing soil disturbance and by increasing the volume of smaller plants, such as hairy vetch, buckwheat and crimson clover, grown in between the farmable crops. There, it accumulates over time, leading to higher crop yields for farmers and reducing the need for water and fertilizers.
The biggest hurdle is determining whether farms are actually removing and storing increased amounts of carbon dioxide.
Rattan Lal, a soil expert at Ohio State University, says using farms to sequester carbon is “an immediate, cost-effective, and scalable climate mitigation strategy.” He believes incentivizing growers to adopt regenerative techniques is a crucial part of the solution.
That’s the vision guiding the Terraton Initiative. Launched by the Boston-based company Indigo Ag, it aims to pull one trillion tons of carbon dioxide from the atmosphere by rewarding growers with $15 per metric ton sequestered. The company would finance payments through a marketplace where carbon-dioxide emitters — including corporations, local governments and individual households — can meet compulsory or voluntary emissions targets by purchasing offset credits from farmers. As of today, growers working around 18 million acres of farmland have committed to the initiative.
The Seattle-based startup Nori has set up a similar platform. A third one, backed by a consortium of food and agriculture giants that includes General Mills, McDonald’s, and Cargill, is currently running a pilot program that is scheduled to expand across the United States in 2022.
Critics consider the concept unproven. “While farmlands do have the capacity to absorb and store carbon dioxide, the science isn’t robust enough to support carbon markets,” says Mark Bradford, a soil scientist at the Yale School of Forestry and Environmental Studies.
The biggest hurdle is determining whether farms are actually removing and storing increased amounts of carbon dioxide. For their measurements, both Indigo and Nori use sophisticated computer models relying on rivers of data from satellites and sensors. But Bradford says no one knows if this is the right approach.
The lack of reliable data makes for significant disagreements about which techniques work, to what extent, and across which different types of soil, climate conditions, and time periods. It’s unclear whether a massive-scale adoption of the practices over long periods could undercut food production, especially in water-scarce areas, where the added plants might compete with the crops for water or nutrients in the soil.
Such uncertainties have made it difficult to establish reliable carbon offset programs. Critics also argue that polluters can take advantage of these programs to avoid curbing emissions and escape their own climate responsibility.
The big picture
Modern farming methods such as intensive plowing, growing the same crop year after year, and the application of synthetic fertilizers are a major contributor to climate change. By stripping organic matter from the ground, they release vast amounts of carbon into the atmosphere. Regenerative agriculture, by contrast, is “beneficial for food security, water quality, and biodiversity,” says Lal. Many scientists, however, say more research is necessary before using it to fight climate change.