FEATURE: What are the options when considering a project to sequester carbon in the soil?
Quantum Commodity Intelligence – The agriculture sector is becoming an increasing focus for voluntary carbon market projects, with ways to sequester carbon in the soil through regenerative agriculture practices, such as no till farming or cover crops, a particular area of growth.
Here Quantum takes a look at some of the methodologies and protocols out there that can be used by developers for soil carbon projects, or developments that include sequestration as part of wider measures.
ACR
Version 2.0 of the 'Avoided Conversion of Grasslands and Shrublands to Crop Production' methodology under US-based standard ACR, formerly known as American Carbon Registry, includes sequestration of carbon in soils as one of several ways to generate carbon credits. It was published in October 2019, replacing an earlier version, which had been approved in 2013.
Australian Carbon Credit Units
In Australia, the Australian Carbon Credit Units (ACCUs) scheme has two methodologies that cover soil carbon. They are the 'Estimating sequestration of carbon in soil using default values method' and the 'Estimation of soil organic carbon sequestration using measurement and models method'.
The first methodology, as its name suggests, provides the rules for crediting carbon stored in soil resulting from altered management practices under pasture, crops or mixed farming systems using default abatement values.
The second one covers soil carbon sequestered under pasture, crops, horticultural or mixed farming systems and provides both a measurement-only approach and a hybrid approach that combines soil carbon model estimates with soil sampling to calculate soil carbon changes.
Verra
The main methodology for soil carbon projects under US-based Verra's Verified Carbon Standard (VCS) is 'VM0042 Methodology for Improved Agricultural Land Management, v2.0', which has been active since May 2023.
VM0042 quantifies the greenhouse gas (GHG) emission reductions and soil organic carbon (SOC) removals resulting from the adoption of improved agricultural land management practices.
These practices include reduced tillage and improvements in fertiliser application, biomass residue and water management, cash and cover crop planting and harvesting practices, and grazing practices.
In May, Verra launched a major revision of the methodology to strengthen a range of measurement, reporting, and verification elements with a view to accelerating the scaling up of regenerative agriculture project activities. The registry said it plans to begin the formal public consultation on the draft of VM0042, v3.0 in the fourth quarter of this year, with publication of the final version expected for the first half of 2025.
The revisions include enhancing standardisation for land stratification, soil sampling procedures, and soil sample processing and laboratory analysis when determining changes in soil organic carbon stocks, and introducing a baseline approach that can accommodate flexible crop rotations by averaging baseline data for multiple crops.
They also include bringing woody biomass quantification into alignment with VCS Methodology VM0047 Afforestation, Reforestation, and Revegetation, v1.0; and clarifying the purpose of repeated measurements when following a "measure and model" approach to quantifying SOC stock changes.
In the nearer term, Verra also plans to consolidate two existing sustainable grassland methodologies to ensure consistency.
The consolidation of the grassland methodologies aims to ensure that all VCS projects boosting SOC stocks in native grassland systems consistently follow the same methodology requirements and quantification procedures to generate high-quality carbon credits, Verra said.
While VM0042 covers a range of agricultural land management activities, a standalone methodology for grasslands is "essential to addressing the complexity and scale of grasslands, as well as the limited availability of measured data to calibrate and validate biogeochemical models", Verra said.
"Such a methodology will include the necessary guidance and quantifications for the specific conditions of carbon projects in native grazing systems in different geographies including savannas, bushlands, and rangelands," the registry added.
To create the consolidated methodology, Verra inactivated VM0026 Methodology for Sustainable Grassland Management (SGM), v1.1 at the end of May and is updating VM0032 Methodology for the Adoption of Sustainable Grasslands through Adjustment of Fire and Grazing, v1.0.
Verra is currently reviewing a proposed revision to VM0032 submitted by Soils for the Future, key focus areas of which are the inclusion of a dynamic baseline approach, as well as the expansion of guidance on the use of biogeochemical models for SOC stock quantification.
Upon completion of its review, Verra will run a public consultation on the planned updates to VM0032. The updates will also be considered in the revision to VM0043 "to ensure both methodologies have clear purposes and are neither duplicative nor contradictory", the registry said.
Validated projects under VM0026, v1.1 may continue to apply the version of the methodology under which they were validated until the next baseline reassessment or crediting period renewal, whichever comes, after which they must transition to the latest version of VM0032 or VM0042.
Label Bas Carbone
Label Bas Carbone (LBC), a domestic standard set up by French authorities in late 2018, approved the CarbonAgri methodology, proposed by the Livestock Institute (Idele), in 2019. LBC describes it as a "multi-lever method aimed at accounting for the emission reductions made possible by the implementation of practices allowing the mitigation of greenhouse gas emissions as well as the increase in carbon storage in the soil and biomass in agricultural operations involving cattle breeding and large crops located" in mainland France.
Carbon storage is one of 10 so-called emissions reductions "levers" within the methodology, with project developers having a choice between a specific reference scenario determined by individual assessments of the farms involved, and a generic scenario determined by production system and geographical area.
LBC currently lists 11 projects having been developed using the methodology, out of 1,168 listed projects in its registry.
Pure Sky
North America-based blockchain registry Pure Sky last December approved Canadian developer Carbon RX's RX Regenerative Agriculture Protocol, which is a methodology for creating carbon credits from regenerative agriculture related to food production, with a particular focus on farms in Western Canada. Carbon RX has since had its first project using the methodology approved by Pure Sky.
"We wanted to design something that reflected the Canadian farming system with deliberate metrics on nitrogen use, fuel efficiency, crop yield, and a series of other parameters that takes into account the way a modern farm looks at sustainability," said Tristan Skolrud, an associate professor at the University of Saskatchewan's College of Agriculture and Bioresources who worked with Carbon RX on developing the protocol.
Nori
US-based carbon marketplace Nori offers a platform for selling so-called 'Regenerative Tonnes', which represents approximately 1 tonne of carbon removed from the atmosphere and stored in the soil for 10-plus years.
The carbon is verified by an independent verification party, then Regenerative Tonnes are issued in accordance with Nori's US Croplands methodology.
A new version of the methodology (Version 1.6) was completed in January and became effective from April 1 this year.
Noris says the methodology relies on Soil Metric's platform, which is a commercial version of a Greenhouse Gas Implementation Tool (GGIT ) model, which is in line with US Department of Agriculture (USDA) greenhouse gas and carbon stock and flux estimation guidance – often referred to as "Blue Book" standards.
The tool on which GGIT is based was developed by CSU [Colorado State University] staff and students, with funding from and under the guidance of the USDA Natural Resources Conservation Service.
Earlier this month, Noris announced the issuance of 125,000 Regenerative Tonnes using the methodology under German chemical giant Bayer's carbon programme in the US, with a further 240,000 in the pipeline.
The Bayer Carbon Program encourages farmers to enrol and pays them for implementing carbon-smart farming practices that generate carbon credits. It has also been implemented in Europe.
Climate Action Reserve
The latest version of the US-based Climate Action Reserve's (CAR's) Soil Enrichment Protocol (Version 1.1) was adopted in May 2022 – the first version having been released in September 2020 – but is currently being updated.
A workgroup is working on the revised methodology with a public comment period expected later in the summer or the autumn, with the aim to submit to CAR's board for approval by year-end.
Stakeholders involved in the workgroup include AgriCapture, Regrow, ATOA Carbon, Nutrien, Environmental Defense Fund, Soil Health Institute, Indigo Ag, and Truterra, among others. However, CAR invites stakeholders not in the working group to participate as 'observers'.
"Observers may attend workgroup meetings in listen-only mode, submit written comments on the draft methodology when it is available for public comment, and attend the public webinar(s) held during the public comment period," CAR said.
BCarbon
The US-based BCarbon registry, which originated from Rice University's Baker Institute for Public Policy, released the second version of its Soil Carbon Protocol in October 2022.
The protocol defines a six-step process, addressing site selection and stratification, quantification of the accrued carbon mass, and interim credit estimates, according to BCarbon.
This is based upon measurement of the initial soil organic carbon content at the start of the project, a second round of measurements at the end of the 'true-up' period, and a statistical analysis of the net carbon mass accrued over that period of time.
Social Carbon
Brazil-based carbon standard Social Carbon's Methodology for Regenerative Land Management (SCM0005) went live in 2022, with latest version (2.0) issued in August last year. The methodology uses Social Carbon's Standard (version 6.0) and its "standard definitions", as well as VM0042 under Verra's VCS as sources.
SCM0005 offers three approaches to quantifying removals from regenerative land management: measure and model; measure and re-measure; and modelled.
Social Carbon says the methodology has been designed to "facilitate the implementation of regenerative agricultural practices internationally, supporting both small and large landowners".
Gold Standard
In February, Switzerland-based Gold Standard unveiled an expansion of its Soil Organic Carbon Framework Methodology, which was first released in in 2020, including a module for zero tillage and 30-day consultations for cover crops and managed pasture modules.
The framework is described as an 'umbrella methodology' defining "requirements and guidance to ensure consistent quality across different SOC activities used by project developers, and sets the requirements for the development of activity modules".
Gold Standard says the way the framework is structured "allows for a broad range of applicability from small scale, low tech land use to industrialised, large scale land management, using a variety of SOC improvement approaches, including improved tillage practices, application of organic soil improvers from pulp and paper mill sludges, and biostimulants for soil revitalisation".
Plan Vivo
Scotland-based carbon standard Plan Vivo released its 'Agriculture and Forestry Carbon Benefit Assessment Methodology V1.0' (PM001) in November last year.
It provides carbon accounting procedures that can be used in smallholder agriculture and community forestry projects to generate Plan Vivo Certificates (PVCs) – which each represent sequestration or mitigation of one tonne of carbon dioxide equivalent, as well as co-benefits such as biodiversity enhancement or poverty reduction.
Plan Vivo describes PM001 as modular allowing "project coordinators, or other parties, may submit modules or tools for inclusion in the methodology following the Plan Vivo methodology approval process". The standard will also consider additions or amendments to the methodology proposed by developers or other parties.
Regen Network
Blockchain-based carbon marketplace Regen Network offers carbon and biodiversity credits known as 'Ecocredits' generated by what the company calls "ecological regeneration projects" that use its Regen registry's standards. There are a number of methods related to soil carbon sequestration.
The 'GHG Benefits in Managed Crop and Grassland Systems Credit Class' focusses on regenerative cropping and managed grassland agricultural systems.
The 'CarbonPlus Grasslands Credit Class' aims to increase the amount of hectares under managed grazing globally focusses on soil carbon sequestration in grassland ecosystems. Regen says the 'Plus' relates to co-benefits thus creating credits that account "for more than just carbon".
The 'Ruuts Credit Class for Soil Carbon Sequestration through Regenerative Grazing' aims to "provide farmers with a measuring and monitoring process for soil organic carbon sequestration in regenerative grazing systems, enabling them to generate carbon credits that also include robust ecological co-benefits such as water infiltration and biodiversity".
The 'CarbonPlus Grasslands' credit aims to increase the number of hectares regeneratively grazed worldwide, but relies on "remote sensing to substantially reduce the cost of monitoring carbon sequestration".
Others
In 2020, the UN's Food and Agriculture Organization (FAO) released the 'GSOC MRV Protocol: A protocol for measurement, monitoring, reporting and verification of soil organic carbon in agricultural landscapes'.
As the name suggests it aims to "provide a framework and standard methodologies for the measuring, monitoring, reporting and verifying changes in SOC stocks and GHG emission removals from agricultural projects that adopt sustainable soil management practices at the farm level", FAO said at its launch.
Colombia-based carbon standard Cercarbono's 'Methodology to Implement GHG Removal Projects Through Reforestation, Forest Restoration and the Establishment of Woody Crops', includes an option to include soil organic carbon in calculations, but it is not the main focus of the method.