A recent editorial in The Guardian outlined some of the difficulties with measuring soil carbon sequestration, in reference to climate mitigation efforts:
“The reality of soil carbon is that it is highly variable, hard to measure, hard to shift and easy to lose.”
This is indeed true. Many opponents of emerging agriculture carbon markets point to these issues as reasons to devalue carbon markets. In doing this, they create confusion for parties working to scale carbon removals in working lands. Perhaps the loudest criticism of efforts to scale soil carbon is that it will not solve the climate crisis.
Of course, soil carbon alone will not solve climate change. As with every climate mitigation plan, efforts must be combined across industries to holistically address climate change.
How to Sequester Carbon in the Soil
In order to increase our soil carbon, we must increase our agricultural soil health by adopting sustainable, resilient farming practices. These practices include crop rotation, planting of cover crops, reduced- or no-till farming, and precision nutrient management, to name a few. These practices help keep organic matter and nutrients in the soil, which allows it to maintain vitality for agricultural purposes. Healthy soil also sequesters carbon — carbon which would otherwise exist in our atmosphere as GHG emissions.
The benefits of increasing soil health have been well-studied.
In addition to sequestering more carbon, healthy soil has higher water holding capacity, increased nutrient retention, improvements in soil organism diversity, ground and surface water quality improvements, and increased crop resilience.
All of these help us build stronger, more resilient and sustainable ecosystems and food systems in addition to removing GHG emissions from our atmosphere.
Transitioning to New Practices
While the management practices and tools used to sequester soil carbon are simple to list, they are not always accessible or financially viable for American farmers.
Over the last decade, The USDA found that acres under reduced tillage in the US has increased by approximately 28% while no-till acres increased by almost 10%. This demonstrates a notable trend of adoption on American farmland. Other practices however, like planting cover crops, have not seen the same broad uptake in adoption. This is likely due to the costs associated with implementing these practices.
For this reason, many stakeholders in the agrifood value chain have begun incentivizing farmers and landowners to adopt practices that result in soil carbon sequestration.
These incentives help reduce the economic barriers to adopting sustainable farming practices, while providing companies the opportunity to reduce their carbon footprint, generate insets and meet corporate ESG and net-zero targets.
Why the Debate?
Some industry stakeholders believe that the variabilities associated with measuring soil carbon make it an unreliable metric for measuring the impact of certain practices on our climate. In truth, unreliable or uncertain data devalues the metric or incentive that is associated with it.
These uncertainties may cause some decision makers to dismiss soil carbon measurements in an effort to avoid reputational risk, misrepresenting data or accusations of greenwashing.
At Regrow, we believe this practice is incorrect. While soil carbon has historically been difficult to quantify, the validity of measurement practices will improve as science progresses. Indeed, it already has begun to do so.
DNDC: A Scientific Model for Soil Carbon Estimation
At Regrow, we use a scientific model called DeNitrification - DeComposition (DNDC) to estimate soil carbon levels and to predict how they may change with the adoption of new farming practices. This model, developed by soil scientists at the University of New Hampshire and shared with a global research community, has appeared in more than 500 peer-reviewed studies.
This model is validated with ground-truth data and calibrated at a global scale. It allows us to estimate the impact of our efforts with a scientifically rigorous level of accuracy: our validation indicates that our model estimates are within 0.05 tons of Carbon per acre (+/-) of measured soil carbon changed, at 95% confidence level (for a project with 100 fields).
As we continue to utilize, calibrate and validate this model — and indeed, as other models in the industry evolve — soil carbon measurements will continue to become more accessible, more scalable and more holistically reliable.
In short, yes — soil carbon is hard. It’s a nuanced practice that changes as our farm management practices change, and as science improves. However, the difficulty of the practice does not make it impossible or unreliable. On the contrary: soil carbon modeling is the only practice that can scale to meet our climate change mitigation goals. The science behind soil carbon modeling is progressing quickly, and research continues to underscore its value in the future of our food systems. In fact, it is the difficulty of soil carbon that makes its case for increased research and support.
Support for Better Research
Efforts for this have already begun. Carbon180, an NGO “with a vision to remove legacy carbon emissions from the atmosphere and create a livable climate in which current and future generations can thrive,” has proposed a Soil Carbon Moonshot effort to increase research and knowledge in this field.
Carbon180 has proposed an interagency, coordinated $2.3 billion investment, centered at the United States Department of Agriculture (USDA), over five years, and across five key categories:
- Fundamental research
- Measurement, reporting and verification efforts for ecosystem markets (MRV)
- Data collection and management
- Adoption of soil carbon practices
- Soil carbon demonstration trials.
This Moonshot effort would significantly increase our research base for carbon soil science, and build validity for the field with regard to climate mitigation. This research is absolutely necessary in our efforts to mitigate climate change.
Carbon-rich soil does more than just reduce atmospheric carbon. It is the foundation for healthier ecosystems, more sustainable food systems and a planet that can maintain vitality for generations to come.
The more carbon we can sequester in our soils, the fewer harmful emissions we’ll have in our atmosphere. And with climate change, every tonne of gas, every acre of land, every corporation, every consumer, and every farmer can make a difference.