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Authored by Hailey Clarke
Climate change is a pressing global challenge that demands innovative solutions. Over the past 150 years, the amount of carbon in the atmosphere has increased by 30 per cent, leading to rising global temperatures. Amidst the myriad of strategies to reduce greenhouse gas emissions, one often overlooked hero in the battle against climate change is right beneath our feet— soil. Soil, often seen as a silent and sturdy foundation, has the potential to be a powerful ally in carbon storage and climate change mitigation. One of the most powerful ways that soil can mitigate climate change is through a process known as carbon sequestration. Carbon sequestration is “the long-term storage of carbon in oceans, soils, vegetation (especially forests), and geologic formations.” While the majority of Earth's carbon is stored in the oceans, soils house about 75% of the carbon reservoir on land, which is three times greater than the quantity found in living plants and animals.
Carbon is primarily stored in the soil as soil organic matter (SOM). SOM constitutes a intricate blend of carbon compounds, encompassing decomposing plant and animal matter, microorganisms (such as protozoa, nematodes, fungi, and bacteria), and carbon linked with soil minerals. An increase in SOM not only promotes carbon sequestration, but also enhances soil quality by augmenting water and nutrient retention, thereby fostering heightened plant productivity in both natural landscapes and agricultural contexts. In addition, SOM contributes to improved soil structure, minimizing erosion and subsequently enhancing water quality in both groundwater and surface waters. Ultimately, these positive effects contribute to increased food security and a reduction in adverse impacts on ecosystems.
Scientists have estimated that soils—mostly, agricultural ones—could sequester “over a billion additional tons of carbon each year.” However, while the retention of carbon in soils can extend for thousands of years, it can also be swiftly reintroduced into the atmosphere. Factors such as climatic conditions, the type of natural vegetation, soil texture, and drainage collectively influence both the quantity and duration of carbon storage in the soil.6 Today, global warming and climate change are significant factors impacting carbon storage in the soil by speeding up the decay of soil organic matter. Particularly, industrialisation—such as “converting natural ecosystems like forests and grasslands to farmland”—are major disruptors to the capability of soil to retain carbon. To combat this, scientists, policymakers, and environmental corporations in recent years have initiated projects around the world to increase carbon capture and storage in both the soil and through long-lasting products and materials.
Carbon storage in soil—also known as “soil carbon sequestration”—is one of the key means to help fight against climate change. While soil carbon sequestration projects are not a particularly new method to remove carbon from the atmosphere, corporations and policymakers have increasingly shown interest in soil carbon credits as a means to achieve ‘net-zero’ emissions targets. As per the Commonwealth Scientific and Industrial Research Organization of Australia, carbon sequestration initiatives rooted in nature, particularly those related to soil carbon, stand out as the most economically efficient approaches to carbon storage.
Beyond their role as a cost-effective means of reducing emissions in agriculture, soil carbon sequestration projects also serve as a lasting investment and income source for farmers. Farmers, who typically navigate the challenges of seasonal living and often rely on off-farm employment, can engage in "carbon farming" as an avenue to be compensated for adopting more sustainable agricultural practices. The adoption of these practices not only helps address climate change but also improves soil health, enhances productivity, and aids in the adaptation to climate change. For instance, one U.S.-based project developer notes that American farmers can potentially earn up to $30 per acre per year by participating in soil carbon projects.
Ecosecurities, a Swiss nature-based solutions carbon market firm, has developed a project in partnership with Desde el Suelo, in Paraguayan Chaco, to increase carbon capture in the soil, reduce GHG emissions, and increase the biodiversity of native vegetation and endangered species through rotation on grasslands and restoration and enrichment of degraded pastures. Additionally, in Northeastern Argentina, the Carbono Rural project is also helping ranchers to adopt sustainable farming practices that not only enhance their productivity but also promote biodiversity and improve the quality of life for rural communities. Soil carbon sequestration projects such as these ensure that community-based sustainable economic development is achieved in addition to fighting climate change and protecting local environments.
However, while soil carbon sequestration projects are on the rise, limitations and skepticism remains. For example, historically, there have “been limited finance and policy options” to successfully implement soil carbon sequestration projects. For example, the Kyoto mechanisms did not effectively tackle soil carbon sequestration interventions. Following the global economic recession in 2008, carbon prices (the payment per ton of CO2 equivalent) experienced a significant decline. Additionally, the Copenhagen summit in 2009 and 2010 proved unsuccessful in establishing a new agreement. Despite these concerns, scientists such as Bossio et. al. (2020) agree that soil carbon sequestration can “be an important way to increase carbon sinks and reduce emissions… [soil carbon sequestration] is not an alternative to emission reductions in other sectors, but rather an additional opportunity for increasing currently insufficient ambition in existing NDCs to the Paris Agreement.”13 As with all strategies to fight climate change, best practices must be put in place to ensure that soil carbon sequestration projects have permanence, are socially and economically fair for all parties involved, and successfully remove CO2 from the atmosphere. Ultimately, fighting global warming requires combining initiatives such as soil carbon sequestration with a global effort to substantially reduce greenhouse gas emissions.
Works Cited
198 new facilities – Global CCS Institute. (2022). https://status23.globalccsinstitute.com/new-facilities/
Bossio, D. A., Cook-Patton, S. C., Ellis, P. W., Fargione, J., Sanderman, J., Smith, P., Wood, S., Zomer, R. J., von Unger, M., Emmer, I. M., & Griscom, B. W. (2020). The role of soil carbon in natural climate solutions. Nature Sustainability, 3(5), Article 5. https://doi.org/10.1038/s41893-020-0491-z
Carbon Capture Projects See Meteoric Growth in 2022. (2022). Yale E360. https://e360.yale.edu/digest/carbon-capture-storage-ccs-growth
Ecological Society of America. (2000). Carbon Sequestration. https://www.esa.org/esa/wp-content/uploads/2012/12/carbonsequestrationinsoils.pdf
Créditos de Carbono, una oportunidad más a la sustentabilidad de la ganadería. (2023). https://www.campoagropecuario.com.py/notas/3407/creditos-de-carbono-una-oportunidad-mas-a-la-sustentabilidad-de-la-ganaderia
Melillo & Gribkoff. (2021). Soil-Based Carbon Sequestration. https://climate.mit.edu/explainers/soil-based-carbon-sequestration
Ontl, T. A. & Schulte, L. A. (2012). Soil Carbon Storage. https://www.nature.com/scitable/knowledge/library/soil-carbon-storage-84223790/
Raymond, H. (2023, February 23). Soil carbon credits: Opportunities and challenges ahead. https://www.spglobal.com/commodityinsights/en/market-insights/blogs/agriculture/022323-soil-carbon-credits-opportunities-and-challenges-ahead
Stockmann, U., Adams, M. A., Crawford, J. W., Field, D. J., Henakaarchchi, N., Jenkins, M., Minasny, B., McBratney, A. B., Courcelles, V. de R. de, Singh, K., Wheeler, I., Abbott, L., Angers, D. A., Baldock, J., Bird, M., Brookes, P. C., Chenu, C., Jastrow, J. D., Lal, R., … Zimmermann, M. (2013). The knowns, known unknowns and unknowns of sequestration of soil organic carbon. Agriculture, Ecosystems & Environment, 164, 80–99. https://doi.org/10.1016/j.agee.2012.10.001