Voluntary GHG Registries

American Carbon Registry (ACR)

The American Carbon Registry (ACR), an enterprise of Winrock International, is the first private voluntary GHG registry in the U.S.  Founded in 1996 as the Greenhouse Gas Registry by Environmental Resources Trust, ACR has over 15 years of experience in development of rigorous, science-based carbon offset standards and methodologies as well as operational experience in high quality carbon offset issuance, serialization and transparent on-line transaction and retirement reporting.

Approval of ACR as an OPR by ARB
The approval of ACR as a Offset Project Registry (OPR) signals that ACR has met stringent regulatory requirements including technical expertise in carbon offset protocols; extensive experience in the oversight of offset project listing, registration, independent verification and issuance; operational know-how in offset registry management; and a solid understanding of the regulation underpinning the compliance offset program.

ACR has several approved and pending methodologies related to agricultural offset activities, including:

Approved ACR Methodologies

N2O Emissions Reductions through Reduced Use of Fertilizer on Agricultural Crops
The ACR Methodology for Quantifying Nitrous Oxide (N2O) Emissions Reductions from Reduced Use of Nitrogen Fertilizer on Agricultural Crops details requirements for quantifying greenhouse gas (GHG) emission reductions by reducing the amount of nitrogen used to fertilize crops. The methodology was jointly developed by Michigan State University (MSU) and the Electric Power Research Institute (EPRI).  The methodology is applicable to the Agriculture, Forestry and Other Land Use (AFOLU) sector, and is specific to Agricultural Land Management (ALM) project activities. The scope of this methodology is limited to on-farm reductions in N fertilizer rate associated with the management of N-containing synthetic and organic fertilizers that reduce net N2O emissions from annual or perennial cropping systems. Emissions reductions and crediting for project activities occur by reducing the N fertilizer rate during the crediting period, when compared to the baseline (pre-project) period.

Emissions Reductions in Rice Management Systems
The ACR Methodology for Emissions Reductions in Rice Management Systems was developed by Environmental Defense Fund (EDF) in partnership with the California Rice Commission (CRC), Applied Geosolutions, LLC, and Terra Global Capital LLC.  The modular nature of the parent methodology makes it applicable to Agricultural Land Management (ALM) project activities around the world that involve a change in rice cultivation practices. Approved activities under this version of the methodology include (1) reducing the duration and frequency of winter flooding, (2) removal of rice straw from the field after harvest and before winter flooding, and (3) replacing water seeding with dry seeding.

In addition to the parent methodology, ACR also approved two regional calibration modules for California and the Mid-South region of the U.S. The eligible activities for each module differ. Eligible activities in California include (1) removal of rice straw from the field after harvest, (2) replacing water seeding with dry seeding, and (3) early drainage at the end of the growing season. Eligible activities under the Mid-South module include: 1) removal of rice straw from the field after harvest, 2) early drainage at the end of the growing season, 3) intermittent flooding during the growing season, and 4) increased water and/or energy use efficiency, achieved through measures including but not limited to: convert contour levees to precision or zero grade; use of side inlet/poly piping systems; use of more efficient diesel pumps; switch from diesel to electric pumps; use of soil moisture sensors to tailor flood to water needs.

Avoided Conversion of Grasslands and Shrublands to Crop Production (ACoGS)
The methodology was developed by Ducks Unlimited, The Nature Conservancy, The Climate Trust, Environmental Defense Fund, and Terra Global Capital LLC. The methodology estimates the emissions avoided from preventing the conversion of grasslands and shrublands to commodity crop production. Grassland and shrubland soils are significant reservoirs of organic carbon that, if left uncultivated, will continue to store this carbon below ground. Grassland and shrubland ecosystems may also support greater plant biomass than annual cropland, especially below ground. In addition to the avoided cultivation and oxidation of soil organic carbon, several crop production practices, such as fertilizer application, may also be avoided. Livestock, primarily cattle, are anticipated to be common in the project scenario and their associated emissions from enteric fermentation and manure deposition are accounted for. The methodology includes two Avoided Planned Conversion baseline scenarios: where the conversion agent is identified and where unidentified. Projects that can identify the conversion agent are required to demonstrate proof of intent to convert by the identified agent. Where the specific conversion agent cannot be identified but a class of likely agents can, the Avoided Planned Conversion – Unidentified Agent baseline approach is used to determine the probability of conversion. This approach is based on the relative ratio of the property’s appraised value in the baseline and project scenarios. The removal of project lands from the supply of potential cropland is expected to create leakage effects in the form of market leakage. A default market leakage estimate is proposed to account for these effects. Standardized values for leakage and baseline determination are specific to the United States and Canada. Projects using this methodology must comply with all requirements of the ACR Standard, submit a GHG Project Plan for certification by ACR, and secure independent validation and verification by an ACR-approved third-party verifier.

Grazingland and Livestock Management (GLLM)
The ACR modular Grazing Land and Livestock Management (GLLM) GHG Methodology is designed to ensure the complete, consistent, transparent, accurate and conservative quantification of GHG emission reductions associated with a GLLM project. The methodology focuses on five primary GHG sources, sinks and reservoirs (SSRs) affected by livestock production – enteric methane, manure methane, nitrous oxide from fertilizer use, fossil fuel emissions, and biotic sequestration in above- and below-ground biomass and soils – and provides accounting modules for each of these, leaving producers the flexibility to design their emission reduction activity. The modular structure allows Project Proponents (livestock producers or the project developers/aggregators representing them) to select the modules relevant to their particular baseline and project activities. To improve usability and cost effectiveness, the methodology also provides a graduated approach in which the complexity and data requirements of the required GHG accounting methods correspond to the scale of impacts expected in a particular SSR; for micro- and small impacts, simplified accounting methods are provided.

Methodology for Greenhouse Gas Emission Reductions from Compost Additions to Grazed Grasslands (Version 1.0)
This methodology accounts for the carbon sequestration and avoided GHG emissions related to compost additions to grazed grasslands. The methodology was developed by Terra Global Capital with support from the Environmental Defense Fund, Silver Lab at the University of California Berkeley, and the Marin Carbon Project. Adding compost to grazed grasslands has been demonstrated to be an effective way to increase soil carbon sequestration and avoid emissions related to the anaerobic decomposition of organic waste material in landfills. Grazed grasslands represent a large portion of agricultural working lands, and a number of recent studies have highlighted that, globally, grasslands are in a state of degradation.

The methodology provides a quantification framework for emissions reductions from a number of activities including avoiding anaerobic decomposition of organic material used in compost production, directly increasing soil organic carbon (SOC) content by applying compost to grazed fields, and indirectly increasing SOC sequestration through enhanced plant growth in amended fields. Apart from the economic benefit of increased forage production, applying compost to grazed grasslands also has many environmental co-benefits such as improved soil quality, decreased risk of water and wind erosion by increasing soil aggregation, and increased nutrient and water availability for vegetation.

Pending ACR Methodologies

N2O Emissions Reductions through Changes in Fertilizer Management (Version 2.0)
(Public comment period closed; undergoing scientific peer review for version 2.1)

The ACR Methodology for N2O Emissions Reductions from Changes in Fertilizer Management details requirements for quantification of GHG emissions reductions in the agriculture sector resulting from changes in how fertilizer is applied and used.  The methodology incorporates site specific data into a peer-reviewed, tested and highly parameterized model, the Denitrification-Decomposition (DNDC) model, to quantify direct N2O emissions as well as indirect emissions from leaching and ammonia volatilization. This methodology is applicable to Agricultural Land Management (ALM) ACR project activities that involve a change in fertilizer management, including changes in fertilizer rate, type, placement, timing, use of timed-release fertilizers, use of nitrification inhibitors, and other factors.

ACR Methodologies Under Development

There are no agriculture methodologies currently under development.

ACR Inactive Methodologies

Methodology for Emissions Reductions from Biochar Projects
The methodology was prepared by The Climate Trust, The Prasino Group, the International Biochar Initiative, and Carbon Consulting.  Biochar is produced through the pyrolysis of biomass. The methodology quantifies and credits both the avoided emissions from combustion or decomposition of biomass in the baseline and enhanced carbon sequestration at sites where biochar is applied. In the baseline scenario, biochar feedstocks would be combusted or decompose, releasing carbon dioxide and/or methane. In the project scenario, pyrolysis physically and chemically transforms the feedstocks into a more recalcitrant form that can be applied to soil for long-term sequestration.

Under this methodology, biochar may be produced from any biomass residues from forestry and agriculture, municipal solid wastes, and other biomass-based materials approved for use under the International Biochar Initiative’s IBI Biochar Standards (2013) provided such feedstocks also meet sustainability criteria specified in the methodology.

Quantification Methodology for Reduced Carbon Intensity of Fed Cattle
The methodology was prepared by a Protocol Scientific Adaptation Team convened under the USDA Greenhouse Gas (GHG) Conservation Innovation Grant (CIG) entitled Bovine Innovative Greenhouse Gas Solutions (BIGGS). This methodology addresses both GHG emissions including enteric methane (CH4) from digestion of feed in the rumen, and methane and nitrous oxide (N2O) from manure storage and handling. GHG reductions arise from alterations in feeding strategies and other technologies that reduce the carbon intensity, per kg of fed cattle, at feedyards in the United States.

The methodology allows any feeding practice or management strategy that decreases carbon intensity. The metrics for both baseline and project are intensity-based, using a functionally equivalent unit of kg CO2 equivalent emissions per kg of carcass weight.  It does not prescribe any particular feeding practice because it is recognized that different feedyard operators will use different techniques and several techniques may be used at once and may vary over time. GHG reductions are quantified by comparing actual project performance to a performance standard baseline, based on national datasets analyzed by Colorado State University, representing typical feedyard performance in the United States. Reductions in carbon intensity of fed cattle, provided they are not mandated by any applicable regulation, are recognized as additional and credited relative to the performance standard baseline.

Climate Action Reserve (CAR)

The Climate Action Reserve (CAR) encourages action to reduce GHG emissions by ensuring the environmental integrity and financial benefit of emissions reduction projects.  The reserve establishes high quality standards for carbon offset projects, oversees independent third-party verification bodies, issues carbon credits generated from such projects, and tracks the transaction of credits over time in a transparent, publicly-accessible system. CAR has developed and approved several protocols for agricultural offset project types. To review all CAR protocols and their development status click here.

Agricultural Protocols

Nitrogen Management Project Protocol (Version 1.1)
(Note:  the Minimum Data Standard is currently under revision) CAR’s Nitrogen Management Project Protocol provides guidance on how to quantify, monitor, and verify GHG emissions reductions from improving nitrogen use efficiency in crop production. To access a one-page Nitrogen Management Project Protocol Summary in pdf form click here.

Grassland Project Protocol (Version 1.0)
CAR's Grassland Project Protocol (GPP) provides guidance to account for, report, and verify greenhouse gas (GHG) emission reductions associated with projects that avoid the loss of soil carbon due to conversion of grasslands to cropland, as well as other associated GHG emissions.

Rice Cultivation Project Protocol (Version 1.1)
CAR’s Rice Cultivation Project Protocol provides guidance on how to quantify, monitor, and verify GHG emissions reductions from changes in water and residue management in rice cultivation.  Version 1.0 of the Rice Cultivation Project Protocol uses the DNDC biogeochemical process model to quantify emissions reductions achieved through the application of approved rice cultivation project activities in California.  CAR provides guidance in applying an accuracy deduction for structural uncertainty associated with the use of the DNDC model in a guidance paper available in pdf format at the above link.

US Livestock Project Protocol (biogas/methane digesters) (Version 4.0)
CAR’s US Livestock Project Protocol provides guidance to calculate, report, and verify GHG emissions reductions associated with installing a manure biogas control system for livestock operations, such as dairy cattle and swine farms.

Agricultural Sector Protocol Presentations

CAR has has a number of presentations related to the development of agriculture sector protocols. These documents are intended to provide a basis for discussions about key methodological issues, including additionality determinations, quantification methods, and managing the risk of CO2 reversals.

Verified Carbon Standard (VCS)

Verified Carbon Standard (VCS) is a GHG accounting program used by projects around the world to verify and issue carbon credits in voluntary markets. VCS was founded in 2005 by business and environmental leaders who identified a need for greater quality assurance in voluntary markets. The VCS founding partners - the Climate Group, the International Emissions Trading Association (IETA) and the World Economic Forum - convened a team of global carbon market experts to draft the first VCS requirements. The World Business Council for Sustainable Development (WBCSD) joined the effort soon after. One of several project categories credited by VCS is Agriculture and Forestry (AFOLU) projects. A complete listing of VCS methodologies (including non-AFOLU project methodologies) can be accessed by clicking here.

VCS currently credits two relevant project types within AFOLU: 
• Agricultural land management projects (ALM), and
• Avoided Conversion of Grasslands and Shrublands projects (ACOGs).

VCS requirements for AFOLU Projects can be accessed on their website.

The following relevant AFOLU methodologies have been approved by VCS, and are available for use by project developers:

VM0017: Adoption of Sustainable Agricultural Land Management, Version 1.0
(Methodology developer: BioCarbon Fund, World Bank)
This methodology quantifies the GHG emission reductions of sustainable land management practice activities that enhance aboveground, belowground and soil-based carbon stocks of agricultural areas. The methodology applies input parameters to analytic, peer-reviewed models to estimate the organic soil carbon density at equilibrium for each of the identified management practices in each land use category. This methodology is applicable to projects that introduce sustainable management practices to an agricultural landscape where the soil organic carbon would have remained constant or decreased in time without the intervention of the project.

VM0021: Soil Carbon Quantification Methodology Version 1.0
(Methodology developer: The Earth Partners)
This modular methodology is designed to be applicable to ALM projects, including changes to agricultural practices, grassland and rangeland restorations, soil carbon protection and accrual benefits from reductions in erosion, grassland protection projects and treatments designed to improve diversity and productivity of grassland and savanna plant communities. The associated modules provide methods for quantifying and monitoring changes in carbon accrual in and emissions from soils as well as from other GHG pools and sources that may be affected by AFOLU projects.

VM0026: Methodology for Sustainable Grassland Management (SGM)

(Methodology developer: UN/FAO)

The methodology aims to estimate GHG emission reductions and carbon sequestration in grasslands, by applying sustainable grassland management practices (SGM). Regarding carbon sequestration, carbon stock enhancement within the project boundary in above ground and soil organic carbon (SOC) pools is considered. This methodology is applicable to projects that introduce SGM into a grassland landscape subject to conditions such that SOC would remain constant or decrease in the absence of the project. Where biogeochemical models can be demonstrated to be applicable in the project region, they may be used to estimate SOC pool changes. Where such models are not applicable, the methodology provides for the use of direct measurement methodologies to estimate SOC pool changes.

VM0022: Quantifying N2O Emissions Reductions in US Agricultural Crops through N Fertilizer Rate Reduction

(Methodology developer: Michigan State University)

This methodology quantifies emissions reductions of nitrous oxide from US agriculture, brought about by reductions in the rate of nitrogen fertilization to annual cropping systems. Dependent on which US state the project is located, the methodology utilizes either the generally accepted IPCC Tier 1 default emission factor or an empirically derived, regional emission factor to calculate N2O emissions reductions directly associated with a reduction in the nitrogen application rate from inorganic and organic fertilizers, either singly or in combination. This approach is straightforward and transparent and may be considered as a practical, short- to medium-term solution to help reduce N2O pollution from agriculture and as a pre-cursor to more complex Tier 3 modeling approaches under development.  The methodology encourages the application of economically optimum nitrogen rates that do not deleteriously affect yield and specifies the use of verifiable best management practices for nitrogen application, which are specific to the crop, soil, and environmental conditions encountered. The underlying field research used for methodology development is publicly available in the peer-reviewed literature.

VM0032: Methodology for the Adoption of Sustainable Grasslands through Adjustment of Fire and Grazing

(Methodology developer: Soils for the Future and Jadora International)

This methodology quantifies the GHG emission reductions and removals from activities that introduce sustainable adjustment of the density of grazing animals and the frequency of prescribed fires into an uncultivated grassland landscape. The methodology shows how to determine additional carbon offsets through grassland soil sequestration and/or reduction in methane emissions as a result of reducing fire frequency and altering the density and/or activities of grazing animals.

Relevant AFOLU methodologies currently under first assessment (first of two expert accreditation processes) by VCS include the following:

There are currently no relevant methodologies undergoing a first assessment.

Methodologies Under Development: Second Assessment

There are currently no relevant methodologies undergoing a second assessment.

Inactive Methodologies

General Methodology for Quantifying the Greenhouse Gas Emissions Reductions from the Production and Incorporation of Soil of Biochar in Agricultural and Forest Management Systems
(Methodology developer: Carbon Gold)
This methodology applies to projects that increase the carbon stocks in soils by treating crop residues or other biomass produced as part of agricultural activities or forest management through controlled pyrolysis. The resulting carbon rich residue is applied to soils. Due to the project activity, net GHG emissions from cropland, grassland or managed forest land will be reduced by increasing carbon stocks in soils.

Methodology for Agricultural Land Management: Improved Grassland Management
(Methodology developer: GreenCollar Climate Solutions)
The methodology quantifies the GHG emission reductions resulting from improved grassland management projects. The methodology identifies and accounts carbon stock changes and GHG emissions in the soil carbon, aboveground woody biomass and belowground biomass pools, fossil fuel combustion, enteric emissions, biomass burning, and nitrogen fertilizer application. The methodology is broadly applicable to grass-dominated systems where baseline grassland management activities result primarily in livestock production.

Calculating Emissions Reductions in Rice Management Systems
(Methodology developer: TerraGlobal Capital and Environmental Defense Fund)
This methodology quantifies GHG emission reductions from improving agricultural land management practices in rice cultivation. Flooded rice fields are a key source of atmospheric methane. The methodology proposes an approach to reduce methane emissions from rice cultivation without a significant reduction in rice production by minimizing the duration and frequency of flooding and altering some other aspects of rice cultivation practices. The methodology uses the biogeochemical process model DNDC to quantify N2O and CH4 emissions under the baseline and project scenarios.

Mandatory GHG Emissions Reduction Programs

For up to date information on Mandatory GHG Programs throughout the globe, including the Australian Carbon Farming Initiative (CFI), CA's GHG Cap-and-Trade Program, AB 32, Alberta, Canada, and more, visit our Mandatory GHG Emissions Reduction Programs page.

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