Over the past few years, carbon markets have experienced an impressive rise in Nature-based Solutions (NbS), with projects ranging from large-scale forest protection to innovative soil-focused programs. While Afforestation, Reforestation and Regeneration (ARR) and Reducing Emissions from Deforestation (REDD+) have long dominated the Voluntary Carbon Market (VCM), a new class of projects is gaining attention: those that tap into the carbon-sequestering power of soil, Improved Agricultural Land Management (ALM) projects.
Soils constitute the largest terrestrial carbon pool, storing nearly three times as much carbon as aboveground biomass and twice the amount of carbon present in the atmosphere, as shown in the image below. Yet, unsustainable land use, especially conventional agriculture and unmanaged grazing, has drastically reduced this storage capacity. Globally, it’s estimated that up to 133 petagrams (Pg) of Soil Organic Carbon (SOC) have been lost due to land-use change and mismanagement (OLIVEIRA et al., 2023).
Figure 1. Schematic representation of the overall perturbation of the global carbon cycle caused by anthropogenic activities, averaged globally for the decade 2013–2022. Earth System Science Data (2023).
Soil Organic Carbon refers to the carbon stored within organic compounds in the soil, originating from decaying plants, roots, and microorganisms. It plays a vital role in soil fertility, multifunctionality and ecosystem services, namely water regulation, nutrient cycling, erosion control, and climate regulation, that arise from the interactions between physical, chemical and biological properties. Recognized as a class of durable carbon removals, SOC is increasingly being monetized through carbon markets driven by significant scientific advancements in large-scale measurement and verification methodologies.
ALM projects lie at the core of this transformation. Practices like no-tillage, cover cropping, manure, diversified crop rotations and managed grazing systems are demonstrating potential to not only limit SOC losses by reducing soil disturbance, but also promote carbon sequestration by enhancing biomass input and microbial activity. For example, cover crops help protect the soil surface, contribute to nutrient cycling, and increase below-ground carbon inputs through root growth. Compost and manure improve soil structure and microbial habitat, accelerating the formation of stable soil aggregates. Rotational grazing, when properly managed, supports plant regrowth, root development, and more uniform organic matter distribution. By tailoring these practices to local conditions and implementing robust monitoring frameworks, ALM is proving essential for restoring degraded soils, improving agricultural resilience, although some challenges still remain.
In the carbon market, these projects can follow different methodologies, each designed to set specific criteria for additionality, permanence, and the quantification of carbon sequestration. Currently, the most widely adopted programs include the Gold Standard (GS), American Carbon Registry (ACR), Climate Action Reserve (CAR), and the Verified Carbon Standard (VCS) by Verra, which we will explore in more detail below.
In the context of projects, VM0042 is currently one of the most widely used frameworks for issuing ALM related carbon credits. It allows carbon accounting via three main pathways:
Among the pathways, the third approach often lacks precision in tropical regions, where global default values tend to underestimate SOC sequestration potential and overestimate N₂O emissions due to complex and region-specific soil–climate dynamics. For example, deeply weathered tropical soils such as Oxisols—common in many tropical ecosystems—exhibit distinctive carbon stabilization mechanisms, which are not fully captured by models developed primarily for temperate conditions. Ongoing research efforts are focused on calibrating emission factors and biogeochemical models to better reflect these tropical soil processes
Regardless of the approach, all of them face the inherent challenge of SOC spatial variability, especially in heterogeneous landscapes common to smallholder systems. To address this, stratified sampling and periodic monitoring (at least every five years) are required, alongside rigorous quality assurance and quality control protocols.
One of the most debated topics in SOC projects is permanence, as the length of carbon storage in soil varies based on the biological, chemical, and physical properties. For that to work, VM0042 addresses this with a minimum 40-year commitment and conservative modeling assumptions. Still, project developers must actively manage these risks through farmer engagement, robust monitoring, and adaptive land management.
This is where effective Monitoring, Reporting, and Verification (MRV) becomes essential. Yet, implementing robust MRV across agricultural landscapes presents several challenges, as SOC changes are subtle, occur belowground, and unfold slowly over time.
Designing a robust MRV system starts with recognizing the variability of soil carbon dynamics. Factors such as soil type, climate, slope, and land use history influence SOC accumulation and loss, making global default values unreliable at the local level. Instead, project-scale assessments must integrate site-specific data through field sampling, modeling, or a hybrid approach.
The World Bank’s MRV framework identifies three main pathways. In practice, combining these approaches enhances both accuracy and feasibility:
Despite the challenges, what makes ALM particularly compelling is its scalability. Unlike REDD+ or ARR projects that often face land tenure issues or a diverse range of deforestation drivers, ALM projects work within existing agricultural systems, minimizing these concerns. Therefore, they can be deployed across millions of hectares with fewer legal and ecological hurdles, sustaining it significant increase in recent years.
As of early 2025, there are 333 ALM projects —discounting the denied— in the pipeline at various stages of development under the following standards: VCS, GS, CAR and ACR. Currently, 32 projects are officially registered, distributed across many countries, such as China, India, South Africa, the United States, Kenya and Brazil, with a growing presence in East Africa and South Asia. Together, these initiatives have issued 13.7 million VCUs so far: China (5,729,980), Kenya (7,188,348), and the United States (848,724).
Figure 2. Top 10 countries with registered ALM projects worldwide.
At hummingbirds, we’ve already integrated SOC quantification and monitoring into several of our projects. If you have any questions or would like to explore this further, feel free to reach us out. Let’s keep the conservation and restoration going!
by Renato Camargo & Vanessa Schetz
Bettiol, W., Silva, C. A., Cerri, C. E. P., Martin Neto, L., & Andrade, C. A. de. (2023). Entendendo a matéria orgânica do solo em ambientes tropical e subtropical. Embrapa Meio Ambiente. Recuperado em 14 de maio de 2025, de https://www.embrapa.br/busca-de-publicacoes/-/publicacao/1153147/entendendo-a-materia-organica-do-solo-em-ambientes-tropical-e-subtropical
Cerri, C. E. P., Cherubin, M. R., Feigl, B. J., & Cerri, C. C. (2016). Brazilian greenhouse gas emissions: The importance of agriculture and livestock. Scientia Agricola, 73(2), 158–166. https://doi.org/10.1590/0103-9016-2015-0167
Cherubin, M. R., Satiro, L. S., Pires, L. F., Feigl, B. J., & Cerri, C. E. P. (2016). Soil greenhouse gas fluxes from different land uses in Brazil: A critical review. Environmental Research Letters, 11(2), 023001. https://doi.org/10.1088/1748-9326/11/2/023001
Oliveira, D. M. S., et al. (2023). Climate-smart agriculture and soil C sequestration in Brazilian Cerrado: A systematic review. Revista Brasileira de Ciência do Solo, 47(nspe), e0220055. https://doi.org/10.36783/18069657rbcs20220055
Tubiello, F. N., Conchedda, G., Karlberg, L., Flammini, A., Mancinelli, G., Federici, S., & Rossi, S. (2023). Greenhouse gas emissions from food systems: Global, regional and country trends, 1990–2020. Earth System Science Data, 15(12), 5301–5338. https://doi.org/10.5194/essd-15-5301-2023
Verra. (2024). VM0042 Improved Agricultural Land Management (Version 2.1). Verra. https://verra.org
