This article is part of Food Tank’s primer series, “Food Tank Explains.” Each installment unpacks the ideas, innovations, and challenges shaping today’s food and agriculture systems, offering clear insights into complex topics. To explore more articles in the series, click here.
Carbon farming refers to agricultural practices designed to remove carbon from the atmosphere and store it in soils and plants. By increasing carbon sequestration, carbon farming aims to reduce greenhouse gas (GHG) emissions while improving soil health and adaptability.
Human activities have increased GHG emissions—particularly carbon dioxide, the primary GHG emitted through human activity—intensifying the greenhouse effect and raising global temperatures.
Agriculture and land-use change are major drivers, and global food systems are responsible for about one-third of annual GHG emissions.
One of the agrifood system’s largest contributions to carbon emissions is soil organic carbon (SOC) loss. Soils have a tremendous capacity to store carbon and can function as either carbon sinks or carbon sources. “If soil is a bank account, soil organic carbon is the currency,” Rattan Lal, Distinguished University Professor of Soil Science at the Ohio State University and a Goodwill Ambassador for the Inter-American Institute for Cooperation on Agriculture, tells Food Tank.
But modern agricultural practices have caused soils to emit more carbon than they retain. Soil organic carbon levels hover between 0.05 percent and 0.10 percent, well under the roughly 2 percent threshold that Lal identifies as necessary to sustain healthy, productive soils.
Converting forests or grasslands to farmland, and practices like over tillage, monocropping, heavy machinery use, overgrazing, and removing crop residues disturb soil structure, expose SOC to water and oxygen, and lead to SOC loss. Lower SOC levels weaken soil structure and diminish microbial activity and biodiversity.
Over the past 12,000 years and particularly in the last two centuries, agriculture has released about 133 billion metric tons of carbon dioxide from soils, and in some areas, soils have lost up to 70 percent of their original SOC. Soils emit around ten times more carbon dioxide than fossil fuels.
Because of their capacity to store carbon, soils also have significant potential to help mitigate climate change. Research suggests that improved land management could enable croplands to sequester up to 1.85 gigatons of carbon per year, roughly equivalent to the annual emissions of the global transportation sector.
And soils in good condition could capture a meaningful share of the emissions reductions needed to keep global warming below 2°C. What we have taken from the land, Rattan Lal says, we can put back.
By increasing soil carbon storage and reducing the release of carbon into the atmosphere, carbon farming aims to shift soils from carbon sources to carbon solutions.
Carbon farmers earn credits for sequestering carbon, with each credit representing a measurable reduction or removal of GHGs. Carbon credits can be sold in carbon markets to companies or other buyers seeking to offset their emissions and meet climate goals. Companies like Grassroots Carbon are helping operationalize this model, recently delivering 1.9 million tons of verified carbon removals. Ranchers participating in these programs report generating meaningful new income streams and reducing operational costs while also improving soil health.
One common carbon farming approach involves adding organic materials to the soil, such as compost or biochar, increasing soil organic matter which in turn increases soils’ carbon storage capacity.
Planting perennial crops, which remain in the ground year after year, can also help store carbon. Their deeper and longer-lasting root systems allow more carbon to accumulate in the soil compared with annual crops that are replanted each season.
Another widely used practice is cover cropping. Farmers plant crops during periods when, or in areas where, fields would otherwise remain bare. These plants not only protect soils from water and air erosion, but they also capture carbon dioxide and transfer some of that carbon into the soil through their roots and plant residue. Cover crops add additional organic matter to soils when they decompose.
Other carbon farming strategies focus on minimizing the carbon that is released into the atmosphere by reducing soil disturbance, particularly through practices that minimize plowing or tilling.
In addition to mitigating GHG emissions, practices that increase or maintain SOC levels enhance soil structure, fuel microbial activity, and improve fertility. By improving overall soil health, these practices can increase agricultural yields while reducing the need for agricultural inputs.
And carbon-rich soils are generally more resilient to environmental pressures. Higher levels of soil organic carbon improve water holding capacity and infiltration, helping farmland better withstand both drought and flooding. “If your neighbor’s land has twice as much carbon as yours, their land will sequester twice the amount of water as your land,” Peter Byck, Arizona State University Professor and Director, Producer, and Writer of Carbon Nation, tells Food Tank.
They also support more active microbial communities, boosting biomass by 40 to 70 percent, and stronger soil structure, enabling soils to absorb shocks and sustain productivity under stress.
Despite its potential to reduce emissions and nourish soils, carbon farming remains the subject of ongoing debate among scientists and policymakers. There is currently no universally accepted system for measuring, reporting, and verifying soil carbon credits, creating confusion for farmers entering carbon markets.
And significant uncertainty remains about how much carbon agricultural soils can store and how accurately sequestration can be measured. Because soil carbon levels can change quickly in response to management practices or weather, stored carbon may also be released back into the atmosphere, complicating efforts to treat soil carbon as a long-term or permanent climate solution.
Concerns about carbon farming also include rebound effects: if certain practices reduce yields, farmland expansion elsewhere could generate emissions that offset the original climate gains. Evidence also shows that widely used no-till systems often rely on herbicides for weed control, accounting for roughly one-third of U.S. pesticide use in corn and soy production.
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Photo courtesy of Sohail Shaikh
