Making Croplands a Climate Solution
Soil carbon sequestration
As plants photosynthesize, they transfer carbon dioxide from the air into their biomass and root systems in order to grow and replenish their own organic matter, which decomposes over time and a portion of it is sequestered- deposited permanently into the ground- in the form of soil organic carbon. Soil carbon sequestration takes place passively all over the Earth, but climate stakeholders- including Vitidore- have taken particular interest in the process as it relates to agriculture; the world’s 2.3 billion acres of cropland have significant potential as an avenue for carbon removal, but farmers face decisions weighing regenerative soil management practices that enable the expansion of this carbon sink against established, more intensive practices that keep the atmospheric-to-soil carbon interface in a constant flux.
Size of the carbon sink depends on human (farmer) inputs
Soil carbon sequestration is affected by a variety of factors, including water infiltration, erosion, and temperature. On farms, field management decisions and types of vegetation grown alter those variables along with directly disrupting carbon stocks, most notably through tilling practices. Tilling can displace as much as 60% of the carbon stored in the affected layer of soil, re-releasing it back into the atmosphere and undoing the sequestration process- perhaps many years worth- achieved by vegetation on undisturbed soil.
While the benefits of no-till have been documented for years, it is practiced consistently on only a small portion of cropland, likely due in part to the precise and holistic approach needed to take full advantage. Renewed interest in both its agronomic and climate benefits is changing that. Cover crops are often used as a compliment to no-till because they can counteract some of the disadvantages of untilled bare soil, such as weed pressure and erosion.
Numbers in perspective
An acre of cropland contains as much as 200 tons of carbon within the top meter of its soil, and conservative estimates put a figure of a ton of additional 2 tons of carbon removed or avoided per year as a result of switching from till to no-till with a permanent cover crop (including soil carbon sequestration and a reduction in use of fuel and fertilizer). Every 3 farm acres is capable of removing a car’s worth of CO2 from the air per year.
While scientists suggest there may be a point at which the cropland carbon sink becomes “full” after several decades of soil regeneration, the prospect of potentially hundreds of millions- or billions- of acres each increasing soil carbon capacity by even a few tons, is extremely promising. The IPCC projects that an annual 3-4% reduction of our 50 billion tons of annual CO2-equivalent emissions through 2050 would keep us below its warming target of 1.5 degrees C. In theory, a transition to soil-regenerative farming practices across the world’s croplands could fully account for 2-3 years worth of progress toward that goal. 400 million acres of permanent crops- such as nuts and grapes- could cover the agriculture industry’s share (24%) of those emissions reductions.
In reality, global emissions will likely take longer to reach net zero, and we don’t expect a 100% transition to no-till and/or cover cropping. But it is important to know the scale of the impending climate scenario and the full capacity of its potential solutions, serving as motivation for companies like Vitidore to help farmers to bridge economic and environmental sustainability.
