Can local movements grow global solutions?
The international community has focused concerted efforts to negotiate consensus on reducing global greenhouse gas emissions through the Paris climate agreement in recent years. This tremendously optimistic undertaking has been paralleled by growing conversations among farming communities, researchers and agricultural networks about the potential for agriculture to draw down atmospheric carbon. While the Paris agreement is focused on emission reductions to address climate change, this “carbon farming solution” promises to sequester atmospheric carbon and store it in the soil. Last year the state of California piloted an ambitious new program to incentivize carbon farming practices on farms.
The idea is to take advantage of carbon cycling by plants in agriculture and ensure that more carbon ends up in the soil than is released (1). Plants use sunlight and water to convert carbon dioxide into oxygen and organic carbon compounds. These plant-based carbon compounds feed the soil food web and become a diversity of things that constitute what’s called soil organic matter (decaying plant parts, enzymes, bacteria, fungi, mites and other soil fauna).
Advocates of carbon farming emphasize that agricultural soils can be a significant sink for atmospheric carbon dioxide if managed properly (2). Some agricultural management practices, like incorporating cover crops, are proven to increase soil organic matter. Other practices, such as tillage, are widely accepted as destroying soil organic matter, much of which is released as greenhouse gasses. Many of the practices that promise to capture carbon have other benefits to farm productivity and society, including increased yields, increased water holding capacity, reduced erosion, and increased pest defenses.
Farmer perspectives: co-benefits
It’s not just more carbon in the soil that California farmer John Wick (3) is motivated by, but additional benefits of holding more water moisture in his soils. This is especially important in the face of California’s chronic drought patterns. Wick also recognizes that more moisture holding capacity in soil could help draw down atmospheric water vapor, which is a powerful greenhouse gas in its own right.
The potential for agriculture to capture atmospheric CO2 while increasing productivity is not a new tune, but it’s one that’s catching on in a big way right now. Books and workshops on the topic are popping up in every kind of farmer network, under titles such as “regenerative agriculture”, “carbon farming”, “climate change mitigation”, “carbon sequestration” and more (4). The catchy part of this story is the invitation to re-envision human activity on the planet as beneficial. Regenerative, carbon sequestering agriculture in theory reduces greenhouse gas emissions, grows food better and supports agricultural economies all at once. Doesn’t that sound great?
Benefits of carbon farming asserted by the California Healthy Soils Initiative:
Many strategies that are advocated as effective in capturing carbon are contested in the body of scientific studies that have been evaluating them (5). Well-known conservation practices, such as no-till and cover cropping, are included in the advocated practices for carbon farming. While there is consensus on the short-term gains these practices offer to top soils, there is conflicting information about their impact on soil carbon at greater depths. As well, the long-term improvements of cover cropping and no till are easily undone and released by one tilling event.
On the other end of the spectrum of practices lie innovative agroforestry systems which take long-term monitoring to confirm and are challenging to replicate. Despite the challenges, “scientists have estimated the potential of agroforestry systems to increase soil carbon to be approximately 95 times greater than the conservation practices of no-till, cover crops and crop rotations” (6).
For many farmers these promising strategies are so knowledge intensive, that they feel unrealistic to production-based farmers who grow substantial amounts of food. Many practices require investments that are also cost prohibitive to farms that are barely making ends meets. The major challenge for this opportunity is not that its unrealistic for agriculture to transition towards valuing sequestering carbon. The challenge is more that the transition to carbon farming is slow to catch on, and there is a sense of urgency to addressing climate change.
California leads the country in agricultural production and last year made a big move to lead the nation in pushing for carbon farming solutions that support farms too. In 2016, the California legislature passed two bills which established the Healthy Soils Program. The program “provides financial assistance for incentivizing and demonstrating the implementation of conservation agricultural management practices that sequester carbon, reduce atmospheric greenhouse gases and improve soil health” (7). Drawing together collaboration from state and municipal agencies, the initiative put out a bold agenda for action based on the multiple benefits of increasing soil carbon. And through strategic funding the program is making big waves in the farming community.
Primary Actions of the California Healthy Soils Initiative:
In the last year, the program funded 22 demonstration projects administered by research and municipal bodies, and 64 cost-share grants to help farmers implement practices that reduce CO2 emissions. In fact, each project has an estimated emissions reduction in tonnes of CO2 per year. One can actually do the math on how much CO2 is being captured due to this program. Carbon trading schemes are likely cheering about this. This information is based on models called “COMET-planner” and “Compost-Planner” (8), which trace their origins to development at Colorado State University.
The state also has an aggressive climate change strategy (9), which feels like a satisfying flip of the bird to Trump and his decision to pull from the Paris agreement. If they reach their goal, by 2030, California will have reduced their greenhouse gas emissions to 40% less than 1990 levels.
Does California’s commitment to soil carbon, farm resilience and climate mitigation pave the way for other states in the US? With federal policy on climate change in a Trump Era free fall, its hopeful to see that local and state level initiatives can lead the way in taking responsibility for action. And in this case, the Healthy Soil funding incentives created significant amount of management changes on farms that both prove farmers are willing to change if they have the financial capability, and that it’s possible to accelerate the adoption of mitigation practices.
The state has created a standardized soil carbon testing procedure due to this program, but there is still a need for more science to confirm and quantify the carbon dioxide offset of many potential carbon farming practices, and how weather and site conditions interact with carbon cycling. It’s also important to note that the program is only focused on carbon dioxide. Nitrous oxide and methane are stronger greenhouse gasses, and agricultural management practices makes significant contributions to these emissions. The California Healthy Soils initiative is certainly a piece of climate optimism, but in the long-term, it should include accounting of these gasses too. I’m hopeful about the growth of this initiative and those that follow in other states.