Isometric Standard

The Isometric Registry records Verified Certificates that represent emission impacts which satisfy the latest Version of the Isometric Standard. This includes net Removals of atmospheric carbon dioxide equivalent (CO₂e), Reductions of specified greenhouse gas emissions, and Environmental Attributes, representing an environmental attribute of a certified product. The Isometric Standard, detailed in this document, lists the requirements that ensure Delivered Certificates have measurable environmental impact. In summary, Certificates must represent a Removal, Reduction, or Environmental Attribute, be Additional and be calculated using the latest scientific techniques. This includes a scientifically robust Uncertainty quantification meeting at minimum with the requirements outlined in the Standard.

Isometric coordinates quantification and Verification necessary to Issue Certificates on the Isometric Registry. All data, calculations and evidence associated with Certificates are publicly available.

This Isometric Standard sets out the duties and obligations of stakeholders in relation to the Isometric Registry. Its purpose is also to provide for a consistent and predictable experience for all parties engaging with the Isometric Registry.

This Standard and the rules contained herein were designed and developed by Isometric HQ Limited.

Throughout this Standard, and throughout Isometric Protocols, the words below are to be interpreted as follows:

• “Must” indicates a requirement.
• “Should” indicates a recommendation.
• “May” indicates a permissible course of action.
• “Will” indicates standard operating procedures implemented by Isometric.

The Isometric Crediting Program is guided by the Isometric Standard, and exists to:

• provide guidance, transparent infrastructure and to set a high scientific caliber that fosters high quality climate action in the form of durable net Removals of CO₂e, Reductions of greenhouse gas emissions, and Environmental Attributes; and
• Issue Verified Certificates that can be used as an evidentiary statement of their ownership for Removal, Reduction or Environmental Attribute claims and reporting purposes.

The Isometric Standard sets requirements that all Isometric Protocols must meet at a minimum.

The Isometric Crediting Program adheres to the following principles:

Collaboration

• Isometric engages with relevant governmental and Non-Governmental Organizations (NGOs) to facilitate equitable representation of stakeholders in a predominantly private industry and advance the creation of high quality industry standards.
• Isometric engages the scientific community and collaborates with experts in areas such as sensor development, physical inspection, auditing, earth-system modeling and data analysis to Verify Deliveries.
• Where appropriate and practicable, Isometric Systems may be integrated with similar tracking systems to help ensure full and accurate information for Buyers of Removals and Reductions and minimize the potential for Double Counting.

Incentive Alignment

• Isometric does not sell or broker the sale of Certificates.
• Isometric charges Buyers – not Project Proponents – a single flat fee per Offtake or purchase which is based on effort required for monitoring, reporting, and verification of a specific pathway/process. This price structure is independent from the number of Certificates issued and thus reduces incentives for overcrediting.
• Isometric does not receive payments from Project Proponents to Verify the delivery of tonnes and adherence to Certified Protocols.
• Isometric undertakes the cost of third-party Verification to ensure neither Buyers nor Project Proponents can have undue influence over this process.
• Isometric independently and impartially chooses third-party Validation and Verification Bodies (VVBs) for Projects.

Scientific Rigor

• Isometric uses the latest science to quantify net Removal or Reduction, Environmental Attributes, Durability, Uncertainty and Additionality across a variety of heterogeneous Removal, Reduction and Environmental Attribute Pathways.
• Isometric will review and update Protocols without a penalty on previously Issued Certificates in order to incentivize continued investigation of underlying scientific questions – through which Removal, Reduction or Environmental Attribute estimates can be further constrained.
• Isometric quantifies all Carbon Fluxes and Greenhouse Gasses related to the Removal, Reduction or Environmental Attribute activity taken by the Project Proponent in a Conservative manner that incorporates uncertainty – including second order effects on leakage.

Transparency

• Isometric provides Buyers and Beneficiaries with access to full traceability of Carbon Fluxes involved in the quantification of Removals, Reductions and Environmental Attributes, alongside the evidence gathered for the Validation and Verification Process. For Reductions, gross reduction is reported in CO₂e and broken down into avoided fossil CO₂ and avoided non-CO₂ greenhouse gasses.
• Protocols and quantification Models are transparently versioned, allowing for public tracking of changes, and public consultation after major updates.
• Each Certificate Issued by Isometric is publicly accessible – allowing for inspection of the information used to quantify Removals, Reductions and Environmental Attributes.

Isometric works with Projects conforming to a Protocol which has undergone or will undergo the Isometric Certification Process. Projects are not eligible if:

• The applicable Protocol or Module sets a minimum Durability Threshold for The Project's underlying emission impact, and The Project does not meet the conditions to justify it, or
• Project activities lead to Enhanced Hydrocarbon Recovery (EHR).

Isometric Issues three Types of Certificates:

• Carbon Dioxide Removal Certificates, for the net removal or one metric tonne of CO₂e,
• Emission Reduction Certificates, for the net reduction of one metric tonne of CO₂e of specified greenhouse gasses generated by an existing emitter, and
• Environmental Attribute Certificates (EACs), representing the environmental attributes of one functional unit of a certified product or service.

Projects can issue multiple Types of Certificate.

Isometric works with Projects worldwide. Isometric works in English. Additional languages may be considered given translation by a trusted source.

In some instances, Modules within Protocols may be tailored for Projects which have geographical specificities. In this circumstance, geography-specific alterations to utilized Modules will be made clear in order to maintain transparency amongst Project Proponents.

Isometric issues Removal, Reduction and Environmental Attribute Certificates. The following greenhouse gasses (GHGs) are relevant:

• For Carbon Dioxide Removal Certificates, the removal of atmospheric CO₂,
• For Emission Reduction Certificates and EACs, reductions of specified greenhouse gasses generated by an existing greenhouse gas emitting source or activity, as defined in the relevant Protocol.

In evaluating the comprehensive greenhouse gas (GHG) emissions of a Project, all GHGs are considered. Isometric uses the United States Environmental Protection Agency definition of GHGs¹, which includes: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and fluorinated gases such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and nitrogen trifluoride (NF₃).

This Isometric Standard was first published 4th October 2023.

This document will be updated on an ongoing basis to reflect changes in the operation, governance and/or rules that apply to either Projects on, or activity described by, the Registry.

Any proposed material changes to the Standard will be put forward for review by the independent Science Network. Following any amendments resulting from that process, the draft changes will be put out for public comment. After having incorporated any further amendments, the final changes will be published in an updated version of the Standard, alongside a clear explanation of the stakeholder input received and how this informed the final changes that were made.

Version numbers follow the MAJOR.MINOR.PATCH format, where three non-negative integers denote the version of the Standard.

Incrementing each number signifies a different type and magnitude of change:

• Major – Material changes significantly altering the scope, applicability, or foundational framework of the Standard.
• Minor – Material changes that may have significant impact on Project eligibility, Verification practices, or Certificate issuance.
• Patch – Improvements without introducing material changes, such as fixing typographic errors, clarifying wording, or adding examples.

A full changelog, along with all previously published versions and their dates of publication, is publicly available on Isometric’s website.

Requirements that govern Isometric's own conduct, as well as requirements which VVBs follow (i.e. those framed as "Isometric will…" or “the VVB will…”) are always those set out in the most recent Certified version of the Standard.

A Project adheres to a specific minor version of the Isometric Standard (the “Project’s Standard version”).

Projects must validate against the most recent certified version of the Standard. Projects may qualify for an earlier version by commencing Validation or initiating Project registration on the Registry prior to the new version's certification.

Projects must adhere to Requirements (e.g. those framed as "Projects must…") from The Project’s Standard version, but may choose to upgrade to a later version of the Standard.

Upon renewal of a Crediting Period, Projects must be re-Validated against the most recent Certified version of the Standard.

Isometric reserves the right to issue a mandatory adoption schedule in exceptional circumstances in order to resolve a substantive vulnerability, or due to material changes in realms such as scientific knowledge, technology and/or regulatory frameworks. Any requirements made mandatory in this way will be clearly marked in the Standard.

The appropriate citation for the document is the Isometric Standard (2026), version 2.2.

This section outlines the requirements for all Isometric Certified Protocols including Isometric Certified Modules.

An Isometric Certified Protocol is a Protocol developed by Isometric that has undergone Public Consultation, and is listed as Certified on the Isometric Registry. Protocols may incorporate Modules, using the Isometric Modular Framework.

Isometric will not list multiple Protocols or Modules as Certified where they pertain to the same or essentially the same underlying carbon removal, reduction, or Environmental Attribute activities.

A Protocol can incorporate an existing Isometric Certified Module. Modules are developed by Isometric and follow the same Certification process.

Each Protocol minor version specifies and locks in the exact minor versions of all Modules which it incorporates. Once certified, this combination never changes, so the Protocol minor version number alone specifies which Module versions apply.

All Reduction and Removal Protocols will incorporate the same Modules for GHG accounting, in order to create a consistent accounting framework across all Projects. Environmental Attribute Protocols will provide guidance on GHG accounting in relation to the practices inherited from underlying product certifications.

Isometric will review individual Modules annually and be responsible for version changes in accordance with our Updates to Protocols policy.

The external Consultation process will be as follows:

1. Expert review through the Isometric Science Network
2. Public Consultation

Expert review will be conducted through the Isometric Science Network. Expert review is the process in which the internal Isometric Science Team invites individuals with deep subject matter expertise to submit feedback on a Protocol or Module. Isometric generously compensates experts for their detailed review with a flat hourly fee paid upon feedback submission.

Public Consultation will be announced on the Isometric Registry and to the Isometric Science Network. Protocols and Modules are open for public commenting for a minimum of 30 days. All relevant stakeholder comments are considered and responded to by the internal Isometric Science Team, and the results of the Consultation will be published on the Registry. All anonymized comments and reviews will be made available upon request.

Typically, at least 5-10 scientific experts are engaged for a given Module or Protocol via the combination of the above processes.

When a Protocol is updated and the changes to it are limited to introducing, upgrading, or removing Modules that have already undergone Consultation, the Module Consultations fulfill the Protocol Consultation requirement. A Module Consultation must address the impact of the Module on any Protocol that will incorporate it.

The internal Isometric Science Team will review a Protocol or Module if Isometric deems it necessary due to material changes in realms such as scientific knowledge, technology and/or regulatory frameworks. This review will be completed within a period of 6 months from the date an issue is raised. If the review results in substantial changes to a Protocol or Module such that a new version is required, these changes will adhere to the Protocol Certification process.

In addition to the triggers for review outlined above, each Protocol will be reviewed at the sooner of the following criteria:

• after 2 years have passed since the original Certification; or
• whenever the number of Certificates Issued under a Protocol passes the following milestones: 100,000 Certificates Issued; 500,000 Certificates Issued; 1,000,000 Certificates Issued; 5,000,000 Certificates Issued.

Major and minor changes will be documented on the Isometric Registry and published alongside the results of a public commenting period of a minimum duration of 30 days. All versions of Protocols and Modules will be documented, archived and made publicly available. All revisions and updates will be systematically versioned according to the Protocol version number format.

Isometric reserves the right to suspend and/or withdraw a Protocol if deemed necessary due to credible, evidence-based concerns that carbon removal or reduction activities, or Environmental Attributes, are being overestimated or that Additionality may not be ensured. In such exceptional cases, Isometric may take immediate action to suspend and/or withdraw a Protocol. The Protocol may then be re-introduced following the usual period of public consultation in the case of any material change.

Certificates issued against a previous Protocol version are not affected by Protocol updates, unless otherwise specified with justification in the updated Protocol. Projects must update to newer Protocol versions according to Protocol adoption requirements, with continuity of operations protected by Protocol backward compatibility mechanisms.

For the purposes of Protocol versioning, material changes are defined as those which affect how Validations and Verifications are conducted, or their outcomes. If a change requires Validation and Verification Bodies to modify their approach, methods, or decisions, it is considered material.

Version numbers follow the MAJOR.MINOR.PATCH format, where three non-negative integers denote the version of the Protocol or Module. Incrementing each number signifies a different type and magnitude of change:

• Major – A significant departure from a previous version, introducing material changes to validation and verification rules. Typically used to remove support for old practices.
• Minor – An evolution from a previous version, introducing material changes to validation and verification rules. Typically used to introduce support for new practices, adapt to scientific or legal developments, or systematize existing rules.
• Patch – An improvement without introducing material changes. For example – fixing typographic errors, clarifying wording, or adding examples.

A full changelog for each Protocol, along with all previously published versions and their dates of publication, is publicly available on Isometric's website.

New Projects must validate against the most recent certified major and minor version of the relevant Protocol. Projects may qualify for an earlier version by commencing Validation or initiating Project registration on the Registry prior to the new version's certification. Isometric may also, at its discretion, permit a Project Proponent to validate a Project against an earlier Protocol version in other scenarios; for example if the most recent version has not been approved by ICVCM or CORSIA.

The adoption requirements upon release of a new Protocol version are as follows:

• Major – Projects are not required to adopt a new major version until they seek renewal of their Crediting Period.
• Minor – Same as Major: Projects are not required to adopt a new minor version until they seek renewal of their Crediting Period.
• Patch – Take effect automatically upon release. Projects operate under the latest patch version of their current Protocol minor version.

Isometric reserves the right to issue a mandatory adoption schedule in exceptional circumstances in order to resolve a substantive vulnerability, or due to material changes in realms such as scientific knowledge, technology and/or regulatory frameworks.

When new Protocol versions are Certified, Projects can continue operating uninterrupted through the use of the following backward compatibility mechanisms:

• No forced major and minor version upgrades – Projects are not required to adopt a new Protocol major or minor version until they seek renewal of their Crediting Period, or an exceptional mandatory adoption schedule was issued.
• Legacy exemptions – Project Proponents may voluntarily adopt a new version and request exemptions against new requirements introduced after the Protocol minor version used for initial Validation in the current Crediting Period. Where a Project Proponent seeks such an exemption against specific requirements, the Project Proponent must demonstrate that said requirements create non-trivial operational difficulty or cost. Where granted, such exemptions remain valid until the end of the current Crediting Period.
• Retained validation status – Projects do not require revalidation when adopting a new Protocol minor version.

All Protocols must include an Applicability section.

The Applicability section must, at a minimum, outline the activities to which the Protocol applies and whether Removal Certificates, Reduction Certificates, EACs, or a combination are generated from applicable Projects.

The Applicability section may also set out conditions that a project must meet in order to be eligible for crediting under the Protocol, including specific baseline requirements.

The system boundary for GHG accounting sets out the GHG Sources, Sinks, and Reservoirs associated with the project boundary and to be considered in the GHG Statement. The system boundary is specified by the relevant Protocol and must include at a minimum all GHG SSRs from:

For an EAC, the boundary for GHG accounting is defined by the relevant standard for the underlying product certification, as specified by the relevant Protocol.

Every EAC issued under a Book and Claim chain of custody must also have a defined Book and Claim Boundary: a physical region, or an otherwise delineated network or market.[^ISO-22095-3:2026]

The relevant Protocol defines the Book and Claim Boundary, and must specify, at a minimum, in accordance with ISO 22095-3:

• the geographic boundary within which EACs are valid;
• which materials or products can generate an EAC, and any restrictions on temporal or geographic eligibility; and
• what a Retired EAC can be claimed against, and any restrictions arising from location, sector, product, or applicable law.

Establishment of the Baseline scenario will differ between Project types and will be specified in the relevant Protocol.

Projects will only be Credited for Removals or Reductions above and beyond what was likely to have occurred in the Baseline scenario.

Projects must reassess and validate the Baseline scenario whenever they request a Crediting Period renewal.

For Environmental Attributes, the Baseline is the carbon intensity of the conventional product or service that the low-carbon alternative displaces. It is used to determine the Emission Reduction Value, including any minimum Emission Reduction Value thresholds where relevant. The methodology for quantifying the Baseline for an EAC is set by the relevant Protocol.

Protocols can use Default Emission Factors, Standards, Proxies and Models to quantify Removals or Reductions, demonstrate Additionality and/or establish Baselines. In metered systems, the preference is for direct measurement of required variables.

Proxies and Models will only be permitted for use under circumstances which are justifiable, such as for reasons of practicality, reliability, and for gap filling in variable un-metered systems.

Proxy measurements are secondarily preferred, and models may be used when neither Proxy or direct measurements are viable.

When used, Models and Proxy measurements must apply Conservative Uncertainty factors and make Conservative assumptions.

Assumptions and estimations must be disclosed and justified.

When Models and Proxy measurements are used, Uncertainty must be assessed and clearly outlined in the Protocol.

Further requirements and guidance for the use of Default Emission Factors, Standards, Proxies and Models in Protocols are outlined below, and requirements describing Project use of Proxies and Models are given in Section 3.2.1 Documentation of Proxies and Models.

The Protocol must appropriately cite and describe the source of any third-party Default Emission Factor, Standard, Model or Proxy. Third-party Default Emission Factors and Standards must be either internationally recognized or derived from a Reputable Source.

Where a newly established Default Emission Factor is used in a Protocol, the reasoning behind this choice and documentation of Default Emission Factor calculations must be clearly outlined and will be subject to review in accordance with the Consultation Requirements.

Protocols must identify Default Emission Factors that are likely subject to future changes. Default Emission Factors can be subject to updates and revisions given the Isometric Updates to Protocols policy.

All calculations must use consistent, standardized factors, including the following:

Global Warming Potential (GWP): Unless otherwise stated in a Protocol or Module, calculations must use the 100-yr GWP for the GHG of interest, based on the most recent volume of the IPCC Assessment Report, currently the Sixth Assessment Report².

Uncertainty is due to factors such as inability to precisely measure certain physical phenomena and/or assumptions in Models or GHG accounting. Protocols must set up frameworks that allow for the reduction of uncertainties with time as measurements, models, and scientific understanding improves.

Emission impacts can have a Risk of Reversal and a finite durability associated with them. Alternatively, some emissions impacts are permanent with no risk of reversal, for example when a high GWP gas is permanently converted to a low GWP gas.

Protocols and Modules will specify if an emission impact has a risk of reversal and finite durability with one or more Durability Threshold(s), or in the case of some Reductions or Environmental Attributes if it is permanent. Where a Protocol or Module does not explicitly specify a Durability Threshold or that the emission impact is permanent, the default Durability Threshold for the Protocol or Module is 1,000 years.

Removals, Reductions or Environmental Attributes will only be Credited for their emission impact in excess of the specified Project Durability Threshold.

Where Projects generating Removals or Reductions cause additional storage or reduction below The Project Durability Threshold for The Project, this storage or reduction cannot count positively towards the end number of Certificates, but can be used to offset losses in Counterfactual storage or reduction below The Project Durability Threshold, as outlined in the relevant Certified Protocol.

Protocols and Modules crediting non-permanent emission impacts will set requirements which Projects must meet in order to justify the claimed Project Durability Threshold.

Where the emission impact relies on the storage of carbon, a full risk assessment must be undertaken to identify all possible mechanisms that will lead to Reversals of crediting non-permanent emission impacts and subsequent decreases in Durability.

The duration of storage monitoring required is process and location specific and requirements will be specified in the relevant Protocol.

The answers to the Protocol or Module specific risk assessment, or the default risk questionnaire, are used to support the Risk of Reversal and Buffer Pool Size.

The Risk of Reversal and the corresponding Buffer Pool Size are meant to compensate for the risk of Reversals that may be observed as a result of monitoring. The Buffer Pool is not meant to compensate for reversals of greenhouse gasses that are stored in an open system (e.g., the ocean) and direct observation of reversals would not be possible. In open systems, storage risks must be assessed as part of the Uncertainty assessment and accounted for in the Conservative estimate of Removal or Reduction. As such, Protocols that store carbon in open systems typically fall into the “No observable risk” Risk of Reversal category, and correspondingly are not required to make buffer pool contributions, or to complete a reversal risk questionnaire. This also applies to Reductions with a permanent emission impact. See Buffer Pools for further information.

Removals, Reductions and Environmental Attributes are conducted and Verified as part of specific Projects. This section describes the requirements for Projects to be compliant with the Isometric Standard.

Contracts must:

• for Environmental Attribute Certificates, demonstrate the right to sever the Environmental Attribute from the associated physical product;

These requirements do not preclude The Project activity from involving multiple underlying entities (e.g., subsidiaries, special purpose entities or site owners).

For a Project to be evaluated for the Isometric Registry, the Project Proponent must document Project characteristics in a Project Design Document (PDD). The document will form the basis for Project Validation and evaluation in accordance with the relevant Certified Protocol. For Projects generating Reductions or Removals, the PDD must be consistent with ISO 14064-2:2019 ³.

For every Project type, the PDD must include:

• Project title, purpose(s) and objective(s);
• R-7X0X-1type of Project, including descriptions of the technologies, products, services and infrastructure to be utilised and how The Project will achieve Removal and/or Reduction, or Environmental Attributes, based on the calculation requirements laid out in the relevant Protocol;
  • G-VCST-0This should include information on facilities and equipment, and all further information essential to understanding how carbon removal or emissions reduction is achieved by The Project.
• R-A5B6-0Projects must submit at least one address and/or specific geo-coordinates for The Project. Projects may submit multiple project locations – please specify what role each location plays in The Project.
• R-XT6V-1anticipated quantity likely to occur from The Project: aggregated net Removals and aggregated Reductions, in tonnes of CO₂e, or aggregated quantity of Environmental Attributes, in Functional units;
• identification of risks that could substantially affect The Project's Removals, Reductions or Environmental Attributes and, if applicable, any measures to manage those risks;
• R-F6R7-0roles and responsibilities, including contact information of the Project Proponent and other Project participants. For each organization, this must include: the organization's name, role in The Project, company number, address, contact person, email address, and phone number;
• a summary environmental impact assessment;
• a chronological plan or actual dates and justification for the following:
  • Project Start Date;
  • Baseline time period;
  • Project Crediting Period; and
• R-GYA1-0a description of the data collection and storage approach taken

For Reductions or Removals, the PDD must also include: 

• conditions prior to Project initiation to support identification of Counterfactual removals or reductions;
• a monitoring plan detailing the elements to be monitored, frequency of monitoring and reporting, including relevant Project activities in each step of The Project cycle, measurement equipment, methods and procedures, details on accuracy and calibration, the clear assignment of responsibilities of parties involved in monitoring and reporting to Isometric, and appropriate measures for quality assurance and quality control; 
• If The Project is crediting an emission impact that is non-permanent, Project Risk of Reversal.
  • Note that project Risk of Reversal must be greater than or equal to the Risk of Reversal outlined in the relevant Protocol. The Risk of Reversal can be increased to account for site-specific considerations that may make a Reversal more likely (e.g., increased risk of a natural disaster). Any increase in Risk of Reversal must be documented, along with its justification, in the PDD;
• an assessment of the compatibility of The Project’s Removal and/or Reduction activities with transition to net zero, by reference to the net zero objectives of the host country;
• The Project’s system boundary and an outline of all GHGs considered across all sources, sinks and reservoirs (SSRs). Robust justification and appropriate evidence must be provided for any GHG SSRs that have been excluded from the project boundary;
• anticipated Uncertainty determination approach;
• description of stakeholder, community, or other interested party Consultations and mechanisms for ongoing communication, and outcomes of any such discussions;

For EACs, the PDD must also include:

• the Functional Unit against which EACs will be Issued;
• anticipated EAC issuance over the Crediting Period, expressed in Functional Units;
• the Product Certification Scheme under which the underlying product is certified, the certified Carbon Intensity, the scope of that certification, and how the certification will be maintained over the Crediting Period;
• conditions prior to Project initiation to support identification of a pre-intervention Baseline;
• the Book and Claim Boundary, and the matching rules that will apply to claims made on Retired EACs;
• how the Environmental Attribute will be severed from the physical product, and the evidence of severing and of the product entering the supply chain that will be provided at each issuance request;
• The Project's GHG accounting boundary, as defined by the underlying product certification;
• the Emission Reduction Value, and the method by which it is derived from the certified Carbon Intensity and the Baseline.
• where the emission impact relies on the storage of carbon:
  • the storage site and operator, the storage permit and any applicable long-term stewardship regime, and the MRV Protocol reference;
  • a monitoring plan meeting the requirements of Section 2.5.7.2, including the clear assignment of responsibilities of parties involved in monitoring and reporting to Isometric, how monitoring data will be obtained where the Project Proponent does not operate the storage site, and how monitoring will be maintained on transfer of the site to another operator or to a long-term stewardship regime;
  • whether The Project's underlying activity carries a material physical or local impact for the purposes of Section 3.8, and where it does, a description of stakeholder, community, or other interested party Consultations and mechanisms for ongoing communication, and outcomes of any such discussions;

Isometric will not publicly disclose sensitive business information inherent to data included in the PDD or otherwise provided by the Project Proponent. Information will be labeled as sensitive by the Project Proponent, and Isometric will communicate to the Project Proponent whether any information deemed sensitive is necessary to be shared in order to accurately reflect Removal and/or Reduction GHG calculations, or EACs issuances. Sensitive business information may include, but is not limited to:

• locations,
• names,
• proprietary processes,
• non-public acquisitions/partnership plans, etc.

This cannot prevent the disclosure of baselines and other underlying assumptions critical for robust quantification of Removals, Reductions or Environmental Attributes.

• G-GYAF-0Projects must apply Conservative Uncertainty factors and make Conservative assumptions when using Models or Proxy measurements.
• G-4K64-0Projects must disclose and justify all assumptions and estimations.
• G-R81S-0Projects must assess and clearly outline Uncertainty arising from Models and Proxy measurements.
• G-BWXE-0Projects must show that Proxies are well-correlated with the variable of interest.
• G-ZHS3-0Projects must provide Proxy data, empirical fits, correlation data, and sources to Isometric, to be verified during verification.
• G-K6MR-0Projects must use Models from a Reputable Source and/or demonstrate their reliability through peer review, testing, or correlation with empirical data.
• G-6VGD-0Projects must outline the source of Models, any modifications, input parameters, data used, and validation results.

Projects are only eligible to claim Certificates for activities that are exclusively registered with the Isometric Registry. Projects are only eligible to receive Certificates on the Isometric Registry using an Isometric Certified Protocol.

Prior to Project registration on the Isometric Registry, projects must undergo a 10 day public comment period. Isometric will review all comments received during that period, and share these with the Project Proponent and The Project’s appointed VVB.

If any material comments are received during the initial 10-day period, or a stakeholder requests additional time to provide input, Isometric will extend the public comment period to a total of 30 days.

In response to comments received, Isometric or the appointed VVB may issue clarification requests or corrective action requests to the Project Proponent during the validation process. Any such corrective action requests must be addressed by the Project Proponent during the validation process. Isometric will publish a summary of comments received once Project validation is complete.

At time of Project application and Validation, Projects must use the latest available version of a Certified Protocol, unless a grace period has been explicitly specified by Isometric, whereby a former version of a Protocol may continue to be used for a defined time period. Where Validation occurs after Project application, the Protocol version required is that which was latest at the time of application.

Projects must conform to all relevant laws and regulations in the jurisdiction in which they operate.

Projects must meet the Additionality requirements set out in Section 3.5 Additionality.

Projects must use appropriate Emission Factors as set out in relevant Protocols. Protocols and Modules set guidelines for the types of emissions factors and sources of emission factors that are acceptable.

The Project Proponent is responsible for notifying Isometric of any changes to operations that could change the eligibility of their process. Following notification, The Project's eligibility must be assessed at The Project's next verification.

Projects are eligible to begin submitting GHG Statements to Isometric following Project Validation. Once Removals or Reductions are Verified, they may be used to issue Certificates. A single project can issue Removal Certificates, Reduction Certificates, EACs or a combination of these. See Section 6 for more information on Crediting.

The initial Crediting Period Start Date for a Project designates the beginning of operational removal, reduction or EAC-generating activity for The Project. The requested Crediting Period Start Date must be no earlier than 5 years before the initial submission of The Project to the Registry. GHG Statements or EAC issuance requests may be submitted for activity which took place on or following the Crediting Period Start Date.

In addition, for EACs, the period between production of the underlying product and the EAC issuance request must not exceed the limit set by the relevant Protocol.

Projects are eligible to Issue Certificates for the duration of the Crediting Period specified in The Project's PDD. If a Project Proponent wishes to renew the Crediting Period of a Project, an updated PDD must be provided and The Project must be re-Validated. There is no limit on the number of times a project can be renewed providing it is still in compliance with the relevant Certified Protocol. In general, the maximum Crediting Period is 10 years, unless otherwise specified by the relevant Certified Protocol. The only Certified Protocols which currently allow for a longer period are the Biogenic Carbon Capture and Storage Protocol and Direct Air Capture Protocol, which each have a 15 year Crediting Period, and Biosphere Protocols in which the Crediting Period is defined per project.

Unless otherwise specified in the applicable Protocol or Module, if a validated Project has not undergone a verification for more than 12 months since the previous verification, an updated PDD must be provided and The Project must be re-Validated.

Isometric does not Issue Ex-ante Certificates.

Additionality is assessed against four pillars: Financial, Common Practice, Environmental and Regulatory. The assessment differs by Certificate type.

For Reductions and Removals, the Project Proponent must be able to demonstrate four pillars of Additionality (Financial, Common Practice, Environmental and Regulatory), in order to show that the claimed environmental impact would not have otherwise occurred in the Baseline Scenario.

A Reduction or Removal Project can be considered Additional when all of the following criteria are met.

As per the requirements in Additionality, Projects must demonstrate that activities similar to the activities of the proposed Project are not Common Practice, by following the framework outlined here.

Projects must successfully demonstrate Common Practice Additionality via one of the following approaches. The approach chosen must be described in The Project PDD:

2. Or, Projects may complete a full Common Practice Analysis, as described below.

Technology Readiness Levels (TRLs) of Pathways as defined by IPCC ⁴, and otherwise as estimated by Isometric. TRL of Biochar Projects may vary based on the maturity of the specific capture technology employed (e.g. biomass-boiler retrofits may indicate a higher TRL). TRL of Oceans & Rivers taken as range estimated by IPCC⁴ (1-2) and RMI⁵ (4-7) to reflect the fact that Oceans & Rivers pathway has a wide range of TRLs depending on the individual technology in question.TRL of Landfill Methane Flaring and Utilization taken as estimated by a report commissioned by the UK’s Climate Change Committee (CCC)⁶

Projects must describe the applicable geographic area under consideration for the analysis. The default area is the country of Project operation, however The Project may propose a more specific region with justification, as outlined below.

If a Project proposes a more specific applicable geographic area, The Project must justify the essential distinctions between the applicable geographic area and the rest of the country of Project operation that give rise to different implementation conditions pertinent to The Project activity. Relevant factors may include:

• Differences in laws, regulations or policies;
• Geological or climatic differences;
• Economic or socioeconomic conditions;
• Market conditions or access to resources;
• Availability and accessibility of infrastructure;
• Labor force and expertise.

Project Proponents must select one of the following two methods for undertaking a Common Practice analysis, within the applicable geographic area:

• (i) For Projects deploying distributed technologies, such as enhanced rock weathering, or reforestation, proceed to “Method for assessing Common Practice for distributed technologies”.
• (ii) For Projects operating discrete facilities, or plants, proceed to “Method for assessing Common Practice for discrete facilities”.

• The Project must define market penetration, or Common Practice, in terms of recent uptake or existing stock/diffusion of technologies, services or practices in relation to a realistic market size.
• Identify the relevant population of subjects, such as a similar class of adopters or landowners, within the selected applicable geographic area.
• Where similar activities to the proposed Project activity are identified, compare The Project activity to these other activities. Identify and explain any essential distinctions between the proposed Project and similar activities. Essential distinctions may be related to, for example:
  • Differences in laws, regulations or policies;
  • Geological or climatic differences;
  • Economic or socioeconomic conditions;
  • Market conditions or access to resources;
  • Availability and accessibility of infrastructure;
  • Labor force and expertise;
  • Significant changes in circumstances, which affect the implementation of The Project activity, in comparison to similar activities.
• Calculate the cumulative market penetration rate (as a percentage) of The Project activity within the population who have not received Carbon Finance revenue (e.g., where activities are neither part of a registered Isometric Project, nor registered under other GHG programs), in the sample of adopters.
• If the market penetration rate is below 20%, the activity is considered to demonstrate Common Practice additionality.

• Assess the extent to which similar activities to the proposed Project activity have been implemented previously or are currently underway in the applicable geographic area. Similar activities are those with comparable technologies or practices, scales, and regulatory environments.
• Exclude activities which are under validation or registered under the Isometric Standard; activities under other GHG programs may optionally be excluded. Record $N_{all}$ as the total remaining number of similar projects or activities.
• Where similar activities to the proposed Project activity are identified, compare The Project activity to these other activities. Identify and explain any essential distinctions between the proposed Project and similar activities. Essential distinctions may be related to, for example:
  • Differences in laws, regulations or policies;
  • Geological or climatic differences;
  • Economic or socioeconomic conditions;
  • Market conditions or access to resources;
  • Availability and accessibility of infrastructure;
  • Labor force and expertise;
  • Significant changes in circumstances, which affect the implementation of The Project activity, in comparison to similar activities.
• Identify the following parameters, and assess Common Practice additionality, as follows:
  • $N_{all}$, defined as the total number of similar projects in the applicable geographic area.
  • $N_{diff}$, defined as those projects which have essential distinctions from the proposed Project.
  • Calculate the “Common Practice factor” $F = 1 – (N_{diff} / N_{all})$, which represents the share of similar projects without essential distinction in the applicable geographic area.
  • The proposed Project activity is considered to demonstrate Common Practice additionality where:
    • $N_{all}$ is less than or equal to 3;
    • Or, $F$ is below or equal to 20%.

As per the above requirements in Additionality, the requirements of this section are only relevant where Removals or Reductions are not the main purpose and the only source of revenue of a Project.

The Project Proponent must determine the IRR for The Project without Carbon Finance revenues. For new Projects, The Project must ultimately demonstrate:

• a zero or negative IRR; or
• an IRR of less than the cost of capital (required rate of return) or return on equity for The Project.

A Project may justify a higher IRR as additional if the Project Proponent can demonstrate that The Project requires such an IRR to enable financing for higher risk Projects, which may require higher interest rate loans, high interest rate venture or equity investment, or similar.

The Project must demonstrate that the economic performance of the mitigation activity increases decisively through carbon credit revenues, and that carbon credit revenues can raise the economic performance at or above the required financial benchmark (IRR).

At a minimum, the IRR analysis must include variation of the factors above by ±20% or by a more appropriate value based on historical data or literature.

For pre-existing Projects:

• Projects must also provide an estimate of the quantity of Removals and/or Reductions that would occur in the absence of Carbon Finance.
• Removals and/or Reductions only in excess of this quantity may be considered Financially Additional.

• The IRR determination must be completed in accordance with generally-accepted accounting practices. 
• The assumptions, data and conclusions of the analysis must be consistent with information presented to the company’s decision-making management and investors/lenders. 
• The key assumptions underpinning the analysis – in particular the benchmark (cost of capital, required rate of return, or return on equity) and the baseline revenue and cost projections – must be substantiated with verifiable supporting evidence and be reasonable as at the time of the investment decision. Where an appropriate benchmark or other supporting evidence is not available, the Project Proponent must instead explain why and provide the most appropriate available basis for the assumption.
• Cash flows and the benchmark must be expressed on a consistent basis: both in real terms or both in nominal terms, and both pre-tax or both post-tax. Where the analysis is conducted in nominal terms and the benchmark is available only in real terms (or vice versa), the Project Proponent must convert one to the other and state the inflation assumption used. Inflation must be applied consistently across all revenue and cost lines.
• The IRR and its benchmark must be determined on a matching basis. Where a project (unlevered) IRR is used, it must exclude financing cash flows and reflect returns to all capital providers, and must be compared against the cost of capital or required rate of return (e.g. weighted average cost of capital). Where an equity IRR is used, it must reflect only the equity-funded portion of the investment and returns to equity holders, and must be compared against the return on equity. The two bases must not be combined within a single calculation, and the Project Proponent must select and apply one basis consistently throughout the analysis.

Project Proponents must demonstrate Regulatory Additionality, meaning that The Project is not required by existing laws, regulations, policies, or other binding obligations. If the activity is required by such legal requirements, The Project is not considered Additional.

Legal requirements that must be considered include, but are not limited to:

• any national, state, municipality or other local law or regulation; and
• any policy, such as a procurement practice that requires the specific Project activity.

Buyer-side frameworks for EACs apply differing Additionality bars. As such, the way in which each pillar is demonstrated and reported, and whether active demonstration is required or may be presumed is set by the relevant Protocol.

The principles for assessing each of the four pillars of Additionality for EACs are as follows:

• Financial: the Environmental Attribute reflects production that would not have occurred at the same scale without the revenue enabled by EAC issuance. Where the low-carbon production method is inherently more costly than the conventional alternative, the relevant Protocol may determine that Financial Additionality is presumed and does not require case-by-case demonstration.
• Common Practice: the low-carbon production method is not yet common practice in the relevant sector and geography.
• Environmental: the Environmental Attribute delivers a net reduction in emissions against the Baseline.
• Regulatory: the Environmental Attribute is not required by a regulatory, policy or other legal requirement, or exceeds the minimum regulatory requirement.

Where an Additionality assessment is required by the relevant Protocol, the results of this Additionality assessment will be recorded as an EAC attribute under Section 5.1 and published on the Registry, so that a Beneficiary can assess it against the requirements of its own framework or claim.

Leakage may be a result of activity shifting, market transformation or shifts in ecosystem processes and can relate to both upstream and downstream activities.

For Environmental Attributes, an assessment of Leakage is required only where the relevant Certified Protocol requires it.

Projects must report a list of all parameters that are used in the Removal or Reduction calculations.

Uncertainty information will vary depending on the data, but may include the type of distribution and parameters needed to describe uncertainty and/or shape of the data when plotted. Appendix A provides additional guidelines for assessing different types of uncertainties.

The Uncertainty information may be obtained from instrument calibrations, measurement variability, published literature, Proxies, expert judgment, and/or other Reputable Sources.

A. Conservative estimate of input parameters B. Variance propagation C. Monte Carlo Simulations

Option A is suitable for Projects where it is difficult to obtain detailed information on input parameter distributions. Using conservative estimates of input parameters will lead to a Conservative Removal or Reduction estimate.

Option B can be used when parameters follow normal distributions and errors are linear (i.e., errors increase linearly as parameter values increase) and independent (i.e., changing one variable has no effect on another variable).

Option C provides a more comprehensive representation of Uncertainties and may result in more Certificates Issued. This approach is suitable for Projects where sufficient information is available for all input variables so that Monte Carlo Simulations can be conducted.

As Removal and Reduction quantifications become better-constrained and more data is gathered, Protocols may progress from using Option A to Option B to Option C.

For Option A, a uniform distribution is assumed for all parameters, unless it can be demonstrated otherwise. Isometric recommends that the value used in the Removal or Reduction calculation be either ≤16^th or ≥84^th percentile, depending on which one yields a more Conservative estimate of Removal or Reduction. There may be instances where a parameter might only have a few reported values, and it does not make sense to assume a continuous distribution. In these cases, it would be more appropriate to use the minimum or maximum value as the Conservative estimate. See Appendix A for some examples.

For Option B, the variance must be defined for all input parameters. Variance propagation should be conducted following uncertainty propagation rules⁸, where the outcome is the variance in the Removal or Reduction. Isometric recommends that the Conservative Removal or Reduction estimate be at least 1 standard deviation (square-root of the variance) below the mean, equivalent to ≤16^th percentile.

For Option C, the input distributions must be specified for all input parameters. The final distribution for the Removal or Reduction is determined by randomly sampling from input distributions many times (e.g., n = 1,000).⁹ The Conservative estimate of Removal or Reduction will be ≤16^th percentile for consistency between Option B and C in the case of normal distributions.

Parameter Uncertainties that are based on expert judgment and which contribute the most significantly to the final Removal or Reduction calculation (based on a Sensitivity Analysis) will be subject to expert review by Isometric and/or selected Science Network experts.

For EACs, the Uncertainty in the Carbon Intensity of the underlying product is inherited from the certification scheme under which the product is certified.

The relevant Protocol sets the requirements for inherited Uncertainty, including the rules that apply when the underlying certification does not specify treatment of Uncertainty.

This section sets the requirements for engaging the people and communities affected by a Project. It applies to all Projects generating Removals or Reductions, and to any EACs Project whose underlying activity carries a material physical or local impact, including new land use, physical construction, risk of physical or economic displacement, or proximity to Indigenous Peoples and Local Communities (IPLCs).

For EACs, the relevant Protocol sets out how the condition is assessed and evidenced for the value chain it covers, including what satisfies it where the underlying activity is covered by an equivalent external scheme.

• Systematically documented and made public or accessible upon reasonable request.

Project Proponents must inform Isometric inform Isometric about any new grievances that are raised no later than 14 days after receipt by the Project Proponent.

Remediation of any unintentional harm, caused directly or indirectly by a project, must be carried out by a Project Proponent. Failure to adequately remediate any harm caused may result in cessation of Certificate issuance.

The consideration of environmental and social impacts must be ongoing throughout a Project's lifespan and assessments updated when necessary, and must include provisions for Project closure and post-closure.

It is the responsibility of The Project to ensure that any EIA or SIA undertaken meets all local, regional and national and international regulations and laws.

Assessments undertaken to evaluate the potential for environmental harm by a Project may be undertaken with varying formats, names and costs, depending on the location of a Project. These assessments are commonly named environmental impact assessments (EIA) and are often required under specific environmental laws or regulations. Within some countries, such as the U.S., multiple levels or types of EIA may exist. Within the U.S. EIAs exist as Environmental Impact Statements (EIS) and Environmental Assessments (EA), with requirements for each type of assessment varying on a federal and state by state basis. It is the responsibility of the Project Proponent to identify specific requirements for EIAs within the location and type of a Project. Within this Standard all such assessments are referred to as Environmental Impact Assessments (EIA).

These assessments and mitigation strategies must consider the potential negative environmental risks from a Project’s implementation. This must include, but is not limited to, the following, as outlined in the ICVCM Core Carbon Principles¹⁰:

These assessments and mitigation strategies must consider the potential negative social risks from a Project’s implementation. This must include, but is not limited to, the following, as outlined in the ICVCM Core Carbon Principles¹⁰:

The SDGs are a set of 17 global and interconnected goals established by the United Nations in 2015 to address a wide range of social, economic and environmental issues.

Such an explanation must be included in The Project Design Document. If applicable, a qualitative assessment must be included for any positive impacts identified in relation to SDGs other than SDG13. Project Proponents must provide information on any standardized assessment tools and methods used as part of this explanation.

Removals and Reductions Projects credited under the Isometric Standard must use project-level consequential analysis to determine net removals or reductions associated with project activities. Projects must be assessed against a baseline scenario of The Project not taking place. Attributional analysis is acceptable as a proxy for project emissions accounting.

Projects may submit Removals and Reductions in the same GHG Statement but they must be reported separately:

• The Project's removals, associated counterfactual and emissions allocated to removals must be presented together in net metric tonnes of CO₂e.
• The Project's reductions, associated counterfactual and emissions allocated to reductions must be presented together in net metric tonnes of CO₂e. Gross reductions and associated counterfactuals must be subdivided into avoided fossil CO₂ and avoided non-CO₂ greenhouse gasses.

For EACs, Projects must determine the carbon intensity (CI) of the underlying product using a methodology independently verified under a recognized Product Certification Scheme, as detailed in the relevant Certified Protocol. For further information on underlying product certification, refer to Section 3.13.

All evidence and data related to the underlying quantification of Removals, Reductions, or Environmental Attributes will be available to the public through Isometric's platform for any Verified Certificate. This includes:

• Project Design Document
• Measurements taken
• Emission factors used
• Scientific literature used

The Project Proponent may request for confidential information to be restricted, whereby it will only be available to authorized Buyers, Isometric and designated VVBs (during Validation or Verification). This includes emissions factors from licensed databases. However, all other numerical data produced or used as part of the quantification of CO₂e removed or reduced, or the Environmental Attribute represented by an EAC, may not be restricted in this way.

This section does not apply to Reductions or Removals.

For EACs, Projects must ensure the underlying material or activity holds current certification, either under a relevant Isometric Protocol or under a recognized external Product Certification Scheme accepted by that Protocol (for example, certification by a relevant body as a low-carbon material, sustainable fuel, or renewable electricity source).

Where a recognized external Product Certification Scheme is relied upon, Projects must:

• provide the product certification to Isometric and to the appointed VVB
• demonstrate that the product certification was verified independently of the Project Proponent
• identify the verifying body together with the accreditation it holds for the scheme applied.

In such cases, Isometric does not reproduce or re-verify the certification. At Validation, the appointed VVB confirms that it meets the requirements of this section and of the relevant Protocol.

The body verifying the certification on behalf of the Project Proponent and the VVB conducting Project Validation and Surveillance Audits on behalf of Isometric may be the same body, or separate bodies, provided the qualification requirements applicable to each function are met.

The Product Certification Scheme and product certificate reference are recorded as EAC attributes under Section 5.1.

This section defines the requirements for Validation and Verification of Projects on the Isometric Registry. Accredited VVBs Validate Projects, Verify Removals and Reductions, and perform Surveillance Audits for EACs, in line with this Isometric Standard and a Certified Protocol.

All VVBs are approved by Isometric independently and impartially based on alignment with Conflict of Interest policies, rotation of VVB policies, oversight on quality, and the following requirements:

• VVBs must be able to demonstrate accreditation from:
  • an International Accreditation Forum¹⁷ member against ISO 14065 or other relevant ISO standard, including but not limited to ISO 14034, ISO 17020, ISO 17029; or
  • a relevant governmental or intergovernmental regulatory body.
• Alternatively, on a case-by-case basis, if VVBs are able to demonstrate to Isometric that they satisfy all required Verification needs and competencies required for the relevant Protocol and follow the guidelines of ISO 19011 or other relevant standards, they may be approved.
• For EACs, the VVB conducting Project Validation and Surveillance Audits (as set out in Section 4.2) must maintain team expertise in the EAC pathway certified under the relevant Protocol.

Every Project is subject to external assurance by both Isometric and an independent VVB. All Projects undergo an initial Validation carried out by a VVB. Thereafter, Removals and Reductions are Verified by a VVB, while EAC issuance requests are reviewed by Isometric and subject to periodic VVB Surveillance Audit, as set out in the sections below.

All Projects must undergo an initial Project Validation, carried out by an independent VVB, to assess conformity with the Isometric Standard, and with the applied Certified Protocol. Once a Project has been Validated, The Project is subsequently able to submit GHG Statements or EACs issuance requests to Isometric. Additional requirements are listed below.

• Project Validation may occur at the same time as the first Verification, or before the first Verification.
• If a Project Proponent wishes to renew the Crediting Period of a Project, an updated PDD must be provided and The Project must be re-Validated.
• Unless otherwise specified in the relevant Certified Protocol, a site visit is required during the first Validation or Verification of a Project. For subsequent Verifications, the VVB must identify whether a site visit is needed, based on an independent risk assessment.

For Removals and Reductions, each GHG Statement is Verified by the VVB in line with ISO 14064-3 before the corresponding Removals or Reductions are eligible for issuance. The level of assurance for Verifications must be reasonable.

Unless otherwise specified in the applicable Protocol or Module, Removals or Reductions may be Verified annually, or more frequently, according to the requirements of the relevant Certified Protocol, or at the Project Proponent's request.

Each EAC issuance request is subject to an Issuance Review carried out by Isometric before the corresponding EACs are eligible for issuance. An Issuance Review does not require a VVB. At Issuance Review, Isometric will confirm that:

• The Project is Validated and complies with the re-Validation frequency set in the relevant Certified Protocol;
• the issuance request falls within the Validated scope of The Project;
• the underlying product holds current certification, and the Carbon Intensity and any Emission Reduction Value carried by the EACs are consistent with it;
• the quantity and specified characteristics of the EACs are based on independently verified data, and do not exceed independently verified production for the period;
• the underlying physical product has entered the supply chain, and the Environmental Attribute has been severed from it;
• the period between production of the underlying product and the issuance request is within the limit set in the relevant Certified Protocol; and
• the Certificate Attributes required under Section 5.1 and the relevant Certified Protocol are complete.

Isometric may accept the issuance request, request clarification from the Project Proponent, or reject it. The acceptable forms of evidence are set out in the relevant Protocol.

Isometric will record the outcome of each Issuance Review, and will make each issuance request, its supporting evidence and the record of Issuance Review available to the VVB at Surveillance Audit and at re-Validation.

Where an Environmental Attribute relies on certification of the underlying product, that certification is separately verified under the applicable certification scheme and is not re-verified by Isometric or the VVB.

Projects issuing EACs are additionally subject to a Surveillance Audit carried out by a VVB. Each Surveillance Audit occurs on an annual basis, unless otherwise specified in the relevant Certified Protocol. 

At each Surveillance Audit and at re-Validation, the VVB must review a representative sample of the issuance requests made since the previous audit and confirm their conformity with the Validated scope of The Project and the relevant Certified Protocol. The level of assurance for Surveillance Audits must be reasonable. Non-conformities identified through sampling are addressed in accordance with Section 5.9.

Prior to Validation, Verification of a Removal or Reduction, or a Surveillance Audit, the VVB must prepare a Validation/Verification/Surveillance Audit plan that details the activities and schedules. The plan may be revised as necessary during the process. The plan must be communicated with the Project Proponent and must include, at minimum:

• the scope and objectives;
• identification of the Validation/Verification/Surveillance Audit team and their roles;
• client/responsible party contact;
• schedule of activities;
• level of assurance;
• Verification our Audit criteria;
• Materiality; and
• schedule for site visits.

For Verification of Reductions and Removals, the Verifier must produce a report that documents the activities, results, findings, and conclusion of the Verification. The Verification report must contain, at a minimum¹⁸:

• a statement that the Project Proponent is responsible for the fair presentation of the PDD in accordance with the criteria;
• a statement that the Verifier is responsible for expressing an opinion on the PDD based on the Verification;
• a description of the Verification evidence-gathering procedures used to assess the PDD;
• the Verification opinion, which will state the net Removal and/or net Reduction during the covered period to a reasonable Level of Assurance;
• the date of the report;
• the Verifier’s location;
• the Verifier’s signature;
• a summary of the GHG Statement;
• reference to the Verification criteria; and
• Verification scope.

For Surveillance Audits for EACs, the report must contain, at a minimum: 

• a description of the sample of issuance requests reviewed and the basis of its selection;
• a description of the evidence-gathering procedures used; 
• the opinion on the conformity of the sampled issuance requests with the Validated scope of The Project and the relevant Certified Protocol; 
• the date of the report; 
• the VVB's location; 
• the VVB's signature; 
• reference to the Surveillance Audit criteria; and
• the Surveillance Audit scope.

Following this process, Isometric will review the project documents used for Validation, Verification, or Surveillance Audit, and either accept them, request corrections or clarifications for the Project Proponent or VVB to address, or reject them. Once Isometric has reviewed and approved the initial Validation Report for a Project, The Project will be listed as Validated on the Registry, with the date of Isometric’s approval listed as the “Approval Date” (also known as a “registration date”) of The Project.

For Verifications, once Isometric has accepted a Verification Report, the corresponding Removals and Reductions will be deemed Verified, and eligible for issuance of Certificates.

For Validations, Verifications of Reductions and Removals, and Surveillance Audits, the results of the Validation, Verification, or Surveillance Audit process, including the Validation/Verification/Surveillance Audit Report and Opinion, will be made available for each Project.

For Removals and Reductions, the threshold for Materiality, considering the totality of all omissions, errors and mis-statements, is 5% of net Removal or Reduction for all Projects. To accept a Verification Opinion, Isometric requires that discrepancies between the Removal or Reduction Claimed by the Project Proponent and that estimated by the VVB for a given statement be less than the Materiality threshold.

For EACs, the Materiality threshold is set by the relevant Protocol, and may be based on the product certification standard under which the underlying product is certified.

Qualitative Materiality issues may also be identified and documented, such as[^ISO-GUM]:

• control issues that erode the verifier’s confidence in the reported data;
• poorly managed documented information;
• difficulty in locating requested information;
• noncompliance with regulations indirectly related to GHG emissions, removals or storage.

Any organization which has been involved in the development of a particular Project may not act as a VVB for Validation and/or Verification purposes for that Project.

To minimize the risk of conflicts of interest occurring between the Project Proponent and the VVB, Isometric will select and engage VVBs for Project Validation and Verification, and VVBs must complete a conflict of interest disclosure.

Isometric requires that Projects must work with a single VVB for no longer than five consecutive years. A given VVB may conduct Verification for a Project during no more than five out of seven consecutive years.

In addition to the qualification requirements, Isometric may oversee VVB activity during the Validation, Surveillance Audit, and/or Verification process, and may suspend approval of a previously approved VVB. Oversight can include review of VVB documentation, including Verification and sampling plans, reports, opinions and conflict of interest disclosures, as well as review of Project Proponent documentation.

Isometric will report significant and/or repeated VVB performance concerns to the relevant accreditation body.

Isometric issues three Certificate Types:

• Carbon Dioxide Removal Certificates, representing one net metric tonne of verified CO₂e removal, and
• Emission Reduction Certificates, representing one net metric tonne of verified CO₂e reduction of specified greenhouse gasses generated by an existing emitter.
• Environmental Attribute Certificates (EACs), representing the verified environmental attributes of one Functional Unit of a certified product, fuel, or service.

Certificates may be Issued, Transferred and Retired on the Isometric Registry according to the rules and requirements set out in this section.

Isometric is the sole Certificate issuing body on the Isometric Registry.

Certificates have only one owner at any time. A full ownership history is tracked and is publicly visible for each Certificate. Each Certificate is Issued Ex-post: Removal and Reduction certificates against a net Verified Removal or Reduction,  and EACs against the verified environmental attributes of a Functional Unit of a certified product, fuel, or service. This ensures that each Certificate is accounted for only once, and that any Certificate can be traced back to an individual Removal, Reduction, or Environmental Attribute.

Each Certificate has a publicly available history of ownership that indicates when the Certificate was first Issued, who it was first Issued to, if and when it was subsequently Delivered or Transferred, if and when it was Retired and by whom, on behalf of whom.

When first Issued, a Certificate's status is Active. Upon Retirement of a Certificate, its status becomes Retired. Similarly, upon Cancellation of a Certificate (for example, in compensation for erroneous overissuance, or in compensation for a Reversal as outlined in Reversals and Buffer Pools), its status becomes Cancelled.

An EAC may also reach the end of life through Expiry, upon which its status becomes Expired, as outlined in 5.4.3 Expiry. Removal and Reduction Certificates do not expire.

Certificate metadata include:

• Unique Serial Number;
• Certificate Type (Removal, Reduction or Environmental Attribute);
• Durability;
• Protocol version the Certificate was issued against;
• Issuance Date;
• Issuing Project;
• Issuing Project Proponent;
• Country of Removal, Reduction or EAC-generating activity;
• Ownership history, including the current Owner (the Owner who is retiring the Certificate) and all previous Owners and Transfer Dates;
• Retirement Date;
• Retirement Beneficiaries;
• Certificate Status; and
• Vintage.

EACs additionally carry the following attributes as a minimum, with pathway-specific attributes defined in the relevant Protocol:

• Product pathway (e.g. Cement or Steel);
• Functional Unit;
• Product type (e.g. “CEM I”);
• Carbon Intensity, expressed per Functional Unit;
• Emission Reduction Value;
• Baseline value and Baseline type;
• Product certification scheme and certificate reference;
• Production period;
• Site or facility and location;
• Market designation (voluntary or compliance);
• Additionality labelling (as defined in the relevant Protocol);
• Geographic scope;
• Expiry Date.

Certificates are Issued representing a specific Removal, Reduction or Environmental Attribute. This process is undertaken once the net Removal or Reduction has been Verified against the respective Protocol, or Isometric has reviewed an issuance request for an EAC. Certificates are always Issued to the Project Proponent. The Project Proponent is then able to Deliver Certificates to Buyer Certificate Accounts on the Registry, and can do so at a time and in an order of their own discretion.

Deliveries can be made by Project Proponents to the Certificate Accounts of other Account Holders (e.g., Buyer Certificate Accounts), resulting in transfer of ownership of one or more newly Issued Certificates. Further Transfers can be made by Certificate Account Holders' Certificate Accounts, resulting in transfer of ownership of one or more Certificates. For each Certificate, the initial Delivery and all Transfers are logged on the Certificate and made publicly available in the Certificate's history.

Project Proponent Deliveries are subject to the following rules:

• Project Proponents can only Deliver Certificates that have been Issued;
• Project Proponents can only Deliver Certificates that they own; and
• Project Proponents can only Deliver Certificates to to organizations that have an active Isometric Registry Certificate Account.

Account Holder Transfers are subject to the following rules:

• Account Holders can only Transfer Certificates that they own, and no Certificate Account may hold a negative balance; and
• Account Holders can only Transfer Certificates to another organization that has a Certificate Account on the Isometric Registry.

For Environmental Attributes, there may be multiple actors in the product value chain, between whom EACs may be transferred. The relevant actor types, and any restrictions on the direction of transfer, on the parties to a Transfer, or on the number of Transfers, will be set out in the relevant Protocol.

A Certificate reaches the end of its life through Retirement, Expiry or Cancellation. Each is irreversible, and a Certificate that has reached the end of its life may not be Transferred or Retired. Retirement and Cancellation apply to all Certificate Types, while Expiry applies only to EACs.

Retirement is the mechanism by which a Certificate's ownership state is finalized.

This ensures that once the net tonne of CO₂e, or the Environmental Attribute represented by the retired Certificate is used towards an accounting activity, it can never be used again by the owner, the Beneficiary of the retirement, or any other actor.

The Beneficiary of a Retirement is the organization on behalf of whom the Certificate was retired. Each Beneficiary must be named on the Retirement Statement and publicly identified. Beneficiaries can be the current holder of a Certificate at the time of retirement, or an organization that is specified by the Statement Account holder during the Retirement procedure. The Account holder can retire Certificates by following the Retirement process through their Certificate Account on the Registry.

The owner of an unretired Certificate may publicly market its ownership of that Certificate, as well as the potential for the Certificate to be retired by any current or future owners, but only the Beneficiary of a Retirement Statement may claim the environmental benefits associated with that Certificate.

Retirement is subject to the following rules:

• a Certificate Account holder can only retire Certificates they own, which are in their Certificate Account;
• a Certificate can only be Retired once; and
• any number of Certificates can be retired at any given time, provided that number of Certificates does not exceed the number of Certificates held by the Certificate Account.

For the purposes of the retirement of a CRCF certified unit, Certificate account holders must state the purpose for which Certificates are being retired or cancelled as part of the retirement process and this information must be contained in the Retirement Statement giving effect to Article 16(1)(e) of Commission Implementing Regulation (EU) 2025/2358.

For an EAC, more than one organization may be named as a Beneficiary of a single Retirement, provided each claim is distinct and non-overlapping. The number of Beneficiaries permitted, and the basis on which their claims must be distinguished, are set out in the relevant Certified Protocol.

Retirement for Conversion occurs where an EAC is Retired to enable the Issuance of a new EAC in the same value chain, typically where the underlying product has been converted into the next product in that chain.

The input EAC must be Retired before the output EAC is Issued. The linkage between the Retired input EAC and the newly Issued output EAC, together with any conversion factors, will be documented on the Isometric Registry. The available conversion routes, and the conversion factors that apply, are set out in the relevant Protocol.

Retirement for Conversion ensures that the same environmental impact is not claimed at more than one point along a value chain.

Removal and Reduction Certificates do not expire.

EACs have an expiration date, specified upon issuance, to ensure temporal alignment between when the physical product was produced and when the claims are made. 

Requirements for the maximum period of time between issuance and expiration are set in the relevant Certified Protocol. The default expiry period is 24 months, unless otherwise specified by the Protocol. Upon Expiry, an EAC can no longer be Transferred or Retired.

Cancellation is the permanent invalidation of a Certificate by Isometric. A Canceled Certificate may not be Delivered, Transferred or Retired.

Isometric may Cancel a Certificate in compensation for erroneous overissuance, for a Reversal, (as set out in Section 5.6 Reversals) or following a Non-Conformity (as set out in Section 5.9 Non-Conformities and Sanctions).

Retirement Statements serve as proof of the Retirement of one or more Certificates to make a claim, and are produced only on completion of a Retirement. Every Retirement Statement relates to one or more Retired Certificates. If more than one Certificate is Retired at a time, the Statements will list all Retired Certificates. Retirement Statements show the relationship between retired Certificates and the Removal, Reduction, or Environmental Attribute they derive from.

This section outlines how Reversals are handled on the Isometric Registry.

All Reversals will be reviewed by the Isometric Science Team.

Note that changes to calculations as a result of updates to Protocols are not considered Reversals, and will generally not affect previously issued Certificates. However, Isometric will monitor for significant impacts due to Protocol updates to ensure overall quality and to address system level impacts (e.g. considerable evolution of scientific consensus).

For Reductions and Removals, when a Reversal is identified, Certificates will be Canceled from the Project Proponent's Buffer Pool to compensate for the Reversal, according to the requirements in Section 5.6.2.

For Environmental Attributes, no Buffer Pool is maintained. A Reversal is instead compensated through Cancellation of the affected EACs, or from The Project's future issuances. Cases where Project Proponents cease operations will be addressed on an individual basis. The relevant Certified Protocol sets out how a quantity of CO₂ released in a Reversal is converted into a quantity of EACs, reflecting the relationship between the stored carbon and the Functional Unit for that pathway.

In the event that a Project Proponent is temporarily unable to comply with monitoring requirements as outlined in the relevant Protocol, the treatment of possible Reversals will be assessed on a case by case basis by Isometric, in consultation with The Project VVB.

Furthermore, Reversals are classed as either Avoidable or Unavoidable, according to the following requirements:

• Where a Project Proponent ceases ongoing monitoring, this will be deemed an Avoidable Reversal.
• Where a Reversal occurs over which the Project Proponent has influence or control, including for example in relation to poor project management or operational negligence, this will be deemed an Avoidable Reversal.
• Where a Reversal occurs over which the Project Proponent has no control, including natural disasters, encroachment by outside actors, or occurrence of other demonstrably unforeseeable factors reasonably considered to be outside of the Project Proponent’s control, this will be deemed an Unavoidable Reversal.

The classification of a Reversal as either Avoidable or Unavoidable will be made by Isometric, in consultation with The Project VVB, according to the above requirements. For Reductions and Removals, this classification has implications in relation to the Project Proponent’s Buffer Pool, as outlined in Buffer Pools.

For Reductions and/or Removals, Isometric will maintain a Buffer Pool of Certificates in accounts specific to each Project Proponent, from which Certificates will be Canceled in the case of a Reversal. The number of Certificates to be Canceled must equal the size of the Reversal.

In the case of Biosphere Protocols, a Buffer Pool of Certificates specific to each Protocol will be maintained, and further requirements applicable to such Buffer Pools are set out in the applicable Protocols.

Isometric reserves the right to amend its Buffer Pool approach given notice and consultation with Project Proponents in line with this Standard's Updates to Protocols policy.

By default, all Reductions and/or Removals Projects must make buffer pool contributions, except for Projects which meet either one of the following criteria:

1. Projects deemed to have a “No observable risk” Risk of Reversal, as indicated in 2.5.9 Risk of Reversal;
2. Projects operating within a recognized regulatory scheme that requires compensation for reversals, as outlined in 5.6.4 Recognition of Equivalent Regulatory Schemes.
3. Projects participating in Isometric’s insurance pilot, as outlined in 5.6.5 Recognition of Insurance for Reversal Risk Mitigation.

For Projects contributing to a buffer pool, whenever Certificates are Issued following a Verified Removal or Reduction, a percentage of these Certificates will be Issued to the Project Proponent's Buffer Pool account, according to the Buffer Pool Size below.

Certificates in a Buffer Pool cannot be Transferred, or used to make Deliveries during the Crediting Period or after the Crediting Period has ended, as they are held to accommodate for as long as there is a risk of Reversal from a Project. Exceptions may occur when Uncertainty decreases and thus Buffer Pool size is amended for a Project Proponent, in which case extra Buffer Pool Certificates may be used to make Deliveries.

In the case that there are insufficient Certificates in a Project Proponent's Buffer Pool to compensate for any triggered Reversals, all further Certificates Issued from Removals and/or Reductions conducted by the Project Proponent (whether from the same Project, or other Projects run by the same Project Proponent) will be assigned to their Buffer Pool and Canceled, until all such Reversals have been fully compensated. Cases where Project Proponents cease operations will be addressed on an individual basis.

The Buffer Pool Size is determined by the Risk of Reversal of a given approach, as outlined below. The Risk of Reversal is defined in the relevant Certified Protocol. Projects with a higher Risk of Reversal have a correspondingly larger Buffer Pool. Note that the Buffer Pool is applied in addition to the Conservative approach taken in the quantification of net CO₂e Removal or Reduction, whereby uncertainty is factored into the Credited Removal or Reduction. The following Buffer Pool sizes may be subject to change in future Standard versions based on empirical data.

Where an Avoidable Reversal has occurred, a Project Proponent must reimburse their Buffer Pool account by transferring a number of Certificates equal to the size of the Reversal to the Buffer Account. While there are any outstanding Avoidable Reversals to be remedied in this way, all further Certificates Issued from Removals and/or Reductions conducted by the Project Proponent (whether from the same Project, or other Projects run by the same Project Proponent) will be assigned to their Buffer Pool, until all such Reversals have been fully remedied.

Where an Unavoidable Reversal has occurred, the Project Proponent is not required to reimburse their Buffer Pool account.

Where a Project's Risk of Reversal assessment is revised downward, or where Isometric reduces the buffer pool contribution rate associated with a given risk category, the Project Proponent may be entitled to request a refund of the difference between Certificates previously contributed to the buffer pool and the amount that would have been required under the revised assessment or rate, so long as no Reversals have been triggered by The Project.

Any such refund shall be contingent upon confirmation of the revised risk of reversal assessment by The Project’s VVB at The Project's next verification. Upon successful verification confirming the lower risk assessment, and confirmation of a refund request by Isometric, the applicable number of Certificates will be transferred to the Project Proponent’s account.

For the avoidance of doubt, where a change in Risk of Reversal assessment results from a material change in storage technology or a change to The Project's selected Storage Module(s) applicable only to new issuances—such that previous issuances would continue to be assessed at the original Risk of Reversal level—refunds under this section shall not apply to those previous issuances.

Where a Project Proponent can demonstrate that a Project is operating within a regulatory scheme that requires compensation for reversals, The Project may forgo Buffer Pool contributions. Recognition of an equivalent regulatory scheme means that reversals from the qualifying storage reservoir occurring under that scheme are considered compensated through the scheme’s own mechanisms, and the Project Proponent is not required to compensate for these reversals through the Buffer Pool or other procedures defined in this Standard. The Project Proponent remains responsible for monitoring and reporting reversals in accordance with the Reversals requirements of this Standard.

The requirements for regulatory schemes to be considered as equivalent are:

• A binding cap-and-trade scheme with zero free allowances for storage operators, such that any reversal is sufficiently compensated by an equivalent reduction in GHGs under the scheme.
• A legally mandated requirement for the storage operator to be able to cover the full financial liability of the maximum possible storage inventory.

The following regulatory schemes are recognized as providing qualifying coverage:

• EU CCS Directive (Directive 2009/31/EC): Projects storing CO₂ in geological formations within the European Economic Area (EEA), where the storage operator maintains financial security in accordance with Article 19.

Suppliers seeking recognition under other regulatory schemes should contact Isometric with details of the applicable requirements. Recognition will be granted where Isometric determines the scheme provides substantially similar or improved protection compared to the buffer pool mechanism.

Isometric is piloting the recognition of insurance as an alternative mechanism for mitigating reversal risk. The relevant Protocol will specify whether a Project is eligible to participate in the pilot. Where a Project is eligible, the Project Proponent may elect to participate, and will then follow the requirements of Isometric's Insurance Framework, including obtaining qualifying insurance coverage from an insurer approved by Isometric, instead of the Buffer Pool requirements set out in 5.6.2 Buffer Pools. Enrollment in the pilot does not preclude the possibility of concurrent, reduced buffer pool contributions. The Project Proponent remains responsible for monitoring and reporting Reversals in accordance with the Reversals requirements of this Standard.

Further requirements for the pilot, including the approval of insurers and the treatment of Reversals under insurance, will be set out in Isometric's Insurance Framework and the relevant Protocols.

Project Proponents interested in participating in the pilot should contact Isometric.

Isometric has rules and procedures in place to mitigate the risk of occurrence of Double Counting, which can occur in different ways, including double issuance, double use and double claiming.

Double issuance (occurring when more than one unique unit is Issued for the same Removal or Reduction activity, or Environmental Attribute) is not permissible, and Isometric has checks in place to mitigate the possibility of double issuance. Any Removal or Reduction activity, or Environmental Attribute, listed on the Isometric registry must not be listed on another program, and may not be used to make a separate Removal, Reduction or Environmental Attribute claim elsewhere. If The Project is associated with production of a commodity which is claiming an environmental attribute, the removals, or reductions may not be counted towards this environmental attribute.

In addition, it is not permissible to issue Certificates resulting from activities generating Removals, Reductions or Environmental Attributes, where Certificates related to the same environmental impacts of the activity are traded in any other carbon crediting or EAC program.

Furthermore, it is not permitted to register Removal, Reduction or EAC activities for Projects with overlapping GHG accounting boundaries, except in the following circumstances:

• Projects whose physical Removal activities incorporate carbon sequestration which would individually be eligible under separate Isometric Protocols, and which may be registered as individual Projects under this Standard using separate Protocols; or
• Projects which incorporate Removal, Reduction or EAC activities that would individually be eligible under separate Isometric Protocols, and which may be registered as individual Projects under this Standard using separate Protocols.

In both of the above circumstances, the GHG accounting boundary of The Project must not overlap with activities registered with any other carbon crediting program. Secondly, the GHG accounting boundary must be clearly described between such Projects to ensure that all carbon fluxes are fully accounted for precisely once, thereby avoiding the possibility of double issuance.

Double use (occurring when an Issued Certificate is further transferred, used or retired after already having been retired) is mitigated through a transparent, public record of all Certificates and Retirements, ensuring all Retirements used as claims towards mitigation targets can be uniquely identified, and can be traced back to the specific Removal, Reduction or Environmental Attribute the Certificate was Issued against. Once a Certificate has been Retired, it cannot be used further, and a unique, public Retirement Statement is produced.

Double claiming (occurring when an Issued Certificate is claimed twice towards achieving mitigation targets or goals) is not permitted on the Isometric Registry. For any Certificate, no separate Removal, Reduction, or Environmental Attribute claims may be made for the underlying impact from which the Certificate was Issued. Isometric will monitor for instances of Double claiming, and Certificate Account users engaging in double claiming may have their Certificate Account suspended.

Because a Book and Claim system decouples the Environmental Attribute from the physical product, EACs are subject to the following additional safeguards, with detailed requirements set out in the relevant Protocols:

• One EAC per attribute. Only one EAC may be Issued for a quantity of physical product carrying a given Environmental Attribute. Where a quantity of product carries more than one distinct Environmental Attribute, a separate EAC may be Issued for each, provided the attributes do not overlap and each is quantified within its own boundary, as set out in the relevant Protocol.
• EAC Co-Claiming. Where more than one organization is named as a Beneficiary of a single Retirement under Section 5.4.1.1 EAC Co-claiming, each claim must be distinct and non-overlapping on the basis set out in the relevant Protocol.
• Double disclosure. The environmental attribute represented by an EAC must not be claimed by any means other than Retirement of that EAC, including through a producer's own GHG inventory, product environmental declaration, or compliance reporting. At Issuance, The Project must attest that the attribute has not been and will not be claimed by any means other than EAC Retirement.
• Residual mix. Where required by the relevant Protocol, a residual mix, the production within the Book and Claim system whose environmental attributes are not represented by an EAC, is calculated so that attributes that have been sold are not implicitly counted by others, and so that voluntary and compliance claims are kept separate.

The Isometric Registry operates alongside other registries that may issue Certificates against the same or similar underlying activities and certification schemes. Without coordination, this creates a risk of cross-registry double counting.

Isometric will assess adoption or alignment with inter-registry coordination frameworks that meet the following minimum integrity expectations:

• Operated or governed by a body independent of any participating registry, with a published conflict-of-interest policy
• Defined membership and assurance requirements for participating registries
• Data-sharing architecture that protects commercially sensitive supplier data while enabling detection of double issuance
• Clear rules for dispute resolution where suspected double issuance is identified

Isometric will cooperate with other registries on a case-by-case basis to prevent the same underlying attribute from being issued, transferred or retired in more than one registry. Cooperation may include information-sharing on issued and retired Certificates, mutual verification of certification chains, and joint response to suspected cases of double counting. Pathway Protocols may specify additional inter-registry coordination requirements where sector-specific frameworks exist.

As part of the Validation process, Isometric’s Registry Operations Team and the appointed VVB will conduct desk based checks to understand whether the Project Proponent is currently participating or has participated in another carbon certification scheme. If participation is identified and was not disclosed, Isometric will take remedial action as appropriate in line with the rules of the Isometric Standard and The Project will be excluded from registration under the CRCF and issuance of CRCF certified units.

Project Proponents wishing to issue Certificates that would be eligible as emissions units for the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) must comply with Isometric’s CORSIA Eligibility Policy.

To mitigate the risk of double claiming of any CORSIA-eligible emissions units, Project Proponents must agree with Isometric suitable mechanisms to compensate for double claims of their CORSIA-eligible emissions units by airline operators for CORSIA and Host Countries working towards fulfillment of Nationally Determined Contributions (NDCs).

Project Proponents of CORSIA-eligible emissions must also comply with the information and reporting requirements in Isometric’s CORSIA Eligibility Policy, including monitoring relevant Host Country reporting and submitting accurate, timely information on corresponding adjustments to Isometric.

Project Proponents must report their sustainable development contributions or co-benefits in their Project Design Document, including indicators specified by Isometric and those that are publicly specified by a host country, for Certificates to be identified as CORSIA-eligible emissions units.

For Projects wishing to issue CORSIA-eligible emission units, a CORSIA Reversal Buffer Pool of Certificates will be maintained with contributions determined by the Risk of Reversal defined in the relevant certified Protocol. More detail can be found in Isometric’s CORSIA Eligibility Policy.

Isometric commits to being the final guarantor of CORSIA-eligible emissions units, if other safeguards to reimburse CORSIA-eligible emissions units, such as a project's buffer pool contributions, other mechanisms outlined in Buffer Pools or insurance policies, are insufficient to fully compensate for any reversal of issued CORSIA-eligible emission units. Further detail is provided in the CORSIA Eligibility Policy.

During a Validation, Verification or Surveillance Audit conducted by a VVB, or during an EAC Issuance Review by Isometric, if any non-conformities with Protocol or Standard requirements are identified, they will be classified according to three categories: Minor Non-Conformity, Major Non-Conformity, and Critical Non-Conformity.

The categorization of the non-conformity will determine the severity of the associated sanction Isometric will apply to the Project Proponent.

• Minor Non-Conformity: a violation of the Isometric Standard or Protocol that has a limited impact, constitutes an isolated or temporary lapse, and would not result in a fundamental systemic failure if not corrected.
• Major Non-Conformity: a violation of the Isometric rules or procedures that has been repeated by the Project Proponent, revealing systematic problems either in combination with further non-conformities or on its own merit. This includes, but is not limited to:
  • systematic problems with GHG data reported, such as incorrect documentation identified in more than 10% of the claims included in the representative sample;
  • failure to provide relevant information to the VVB, such as the information needed for the purposes of an audit;
  • omission of a Project Proponent declaring its participation in other carbon removal or GHG reduction certification schemes during the certification process;
• Critical Non-Conformity: violations that jeopardize the integrity of the Isometric Standard, including fraud, irreversible non-conformity, falsification of GHG data, or deliberate misstatement of activity. For instance, fabrication of data or submission of fraudulent GHG statements.

For the purposes of the issuance of a CRCF certificate of compliance, a failure to meet the requirements of relevant Modules and Protocols approved under the CRCF, as well as the quality criteria set out in Articles 4 to 7 of Regulation (EU) 2024/3012¹⁹, will also be categorized as a Critical Non-Conformity.

Based on the classification of the non-conformities in Non-Conformities, Isometric will apply the following sanctions, which are in accordance with the CRCF implementing regulation. The applicable sanction applied will depend on whether the Certificates or CRCF Certificate of Compliance have been issued.

In the case of a Minor Non-Conformity, the Project Proponent must remediate the issue during the current Validation or Verification, unless the VVB determines that it may be recorded as a Forward Action Request. Any such Forward Action Request must be addressed at the next verification, or by a date specified by the Verifier, and in any event within 12 months at the latest.

A Forward Action Request is an official audit finding or recommendation used during the validation or verification. It highlights a minor issue or future implementation task that does not block current approval, but must be checked and resolved during a later audit. If the Forward Action Request or minor conformity is not resolved within 12 months at the latest the issue will be immediately re-classified as a Major Non-Conformity.

In the case of a Major Non-Conformity, if a Project has not been validated or a CRCF Certificate of Compliance has not been issued, The Project will not be validated and no CRCF Certificate of Compliance will be issued until the non-conformity has been resolved. Where a CRCF Certificate of Compliance has already been issued or The Project has been validated, its Certificate of Compliance and further Certificate issuance to The Project will be suspended. The Project Proponent must implement remedial measures within 90 days of the major non-conformity being identified. If this remedial action does not occur within 90 days, The Project’s CRCF Certificate of Compliance will be canceled and The Project will be delisted from the registry.

In the case of Critical Non-Conformity identified during a Verification or monitoring audit, or through Isometric's internal monitoring or complaints process, no further Certificates will be issued. Any Certificates previously issued that are attributable to the Non-Conformity will be deemed as having undergone a Reversal, and the procedure in Reversals and Buffer Pools will apply. Any CRCF certified units will be subject to immediate cancellation and the remediation procedures described in Remediation for Fraud will apply. Where the affected Certificates are not backed by a Buffer Pool, the impairment is instead remedied through cancellation of the affected CreditsCertificates and compensation from future issuances. Any CRCF certified units will be subject to immediate cancellation and the remediation procedures described in Remediation for Fraud will apply.

In the case of a CRCF certificate of compliance, the certificate will be canceled and there will be no further issuance of CRCF certified units. In the case of Projects seeking eligibility under the CRCF, where Validation has been refused or the CRCF Certificate of Compliance has been cancelled following a Critical Non-Conformity, the Project Proponent (or its legal predecessor) may not re-apply for CRCF certification under the Isometric Standard until a period of at least 12 months has passed from the date of refusal or cancellation, in line with Article 7(3) of Commission Implementing Regulation (EU) 2025/2358. Re-application before the end of the fixed period will be rejected. Any re-application must demonstrate that the issues which led to the Critical Non-Conformity have been thoroughly addressed. Isometric may extend the fixed period beyond 12 months where the characteristics of the activity warrant a longer bar, in line with Article 7(3).

Failure to comply with the requirements contained in certification methodologies referred to in Article 8 of Regulation (EU) 2024/3012 will be automatically classified as a Critical Non-Conformity, as required by Article 6(3)(a).

Any further Certificate issuance to The Project will be suspended. In the case of Projects which are not seeking eligibility under CRCF, the Project Proponent may re-apply to issue Certificates if they demonstrate that the issues which lead to the Critical Non-Conformity have been thoroughly addressed.

Project Proponents wishing to issue Certificates under the EU’s Carbon Removal and Carbon Farming certification scheme are subject to additional procedures and requirements to ensure they comply with the applicable legislation.

Projects seeking Validation under the Isometric Standard must indicate whether they wish to be approved to issue CRCF certified units. If so, Projects must use an appropriate Isometric Protocol and must comply with the procedures and requirements described in this Section.

Certification bodies and Project Proponents participating in the scheme are required by Isometric to cooperate with the Commission and the national competent authorities of the Member States, including granting access to the premises of Project Proponents where requested, and making available all information needed to fulfil their tasks under Articles 10, 12 and 13 of the CRCF Regulation.

If a Member State has reasonable doubts about the ability of a specific certification body to carry out its audit work and shares this with Isometric, Isometric shall immediately investigate and inform the Member States and the Commission of the outcome and any corrective actions.

In addition to the Validation and Verification Body Qualification Requirements set out in Validation and Verification Body Qualification Requirements, Isometric will apply the following additional requirements when appointing a VVB as a Certification Body under the CRCF:

The VVB must have the relevant legal status to perform certification activities through one of the following qualifying criteria, in line with Article 13(1)–(3) of Commission Implementing Regulation (EU) 2025/2358:

• accreditation by a National Accreditation Body in accordance with Regulation (EC) No 765/2008, against EN ISO/IEC 17065 and also EN ISO/IEC 17029 and EN ISO 14065; or
• recognition by a national competent authority referred to in Article 10(1) of Regulation (EU) 2024/3012.

The VVB must also meet the following requirements:

• auditors must have the knowledge, experience, skills and capacity necessary for effectively conducting the audit, including a minimum of 2 years' experience in Life-Cycle Assessment, or proven relevant level of capacity;
• auditors must have specific experience in auditing GHG emission calculations in accordance with the relevant Protocols and Modules;
• auditors must, depending on the specific types of activity audited, have additional experience as relevant in the fields of agriculture, agronomy, ecology, forestry, natural science, silviculture, engineering, building materials and embodied carbon, energy management or a related field;

For the avoidance of doubt, individual auditors must meet the conflict of interest requirements set out in Isometric’s VVB policy and must be independent of the activity being audited.

Verification reports issued must include all information listed in Annex III of the Commission Implementing Regulation.

Isometric will run training courses for VVBs. This will include an exam which tests an auditor's (verifier's) overall technical expertise in the area. Auditors must participate in the training courses before performing audits for Isometric. Isometric will also provide guidance to VVBs on other relevant aspects of CRCF certification, including updates on the regulatory framework or findings from Isometric's internal monitoring process.

For Projects seeking eligibility under CRCF, Isometric will exclude a Project from this Standard in the following circumstances:

• the Project Proponent (or its legal predecessor) failed to disclose the relevant information required under Prevention of Scheme Hopping.
• the Project Proponent (or its legal predecessor) failed a Verification under another scheme, unless said audit occurred more than 3 years prior to the current application or the previous certification scheme has ceased operations.
• the Project Proponent (or its legal predecessor) withdrew from another scheme prior to the first Verification, unless the Project Proponent can demonstrate the withdrawal was unavoidable and not caused by a Critical or Major Non-Conformity.

Isometric will ensure an efficient and timely exchange of information as it relates to the prevention of scheme hopping with other certification schemes. Where required, Isometric will ensure an efficient and timely exchange of audit information between Isometric and other authorised certification schemes to support the effective preparation and conduct of the audit.

Isometric has a CRCF complaints policy in place. This compliance policy allows for complaints and whistleblowing to Isometric with respect to VVBs and Project Proponents.

Isometric ensures the protection of natural or legal persons who report infringements or lodge complaints in good faith in accordance with the Whistleblower Protection Directive (EU) 2019/1937 of the European Parliament and of the Council.

Isometric will maintain a register of all complaints made which relate to Projects issued under the CRCF. Upon request from a Member State or the Commission, Isometric will share all documents related to the complaint and its handling.

As standard, Isometric will pursue the approach to remediation described in Isometric’s CRCF complaints policy. Where necessary, Isometric will apply the relevant remediation measures and sanctions for non-conformity by Project Proponents as set out in Non-Conformities and Sanctions of this Standard. Where necessary, Isometric will take corrective measures on its governance structure or on its internal monitoring process.

If Member States have reasonable doubts about the ability of a specific certification body to carry out its audit work, they may share that information with the other Member States, the Commission and the certification scheme. Isometric will immediately investigate and inform the Member States and the Commission of the outcome and any corrective actions.

Certification Bodies and participating Operators seeking to issue CRCF certified units are subject to supervision by the national competent authorities of the Member States under Article 10 of Regulation (EU) 2024/3012 and by the Commission under Article 13 of the same legislation.

Certification Bodies and Operators must cooperate with the Commission and with the national competent authorities of the Member States in the exercise of those functions, including by:

• granting access to the premises of Operators where requested; and
• making available all information those authorities require to fulfil their tasks under Article 10(1) of Regulation (EU) 2024/3012.

Certification Bodies must additionally:

• provide the information Member States require in order to supervise the operation of Certification Bodies pursuant to Article 10 of Regulation (EU) 2024/3012;
• provide the information Isometric requires in order to comply with Article 13 of Regulation (EU) 2024/3012; and
• verify the accuracy of information entered into the Isometric Registry and the Union Registry.

Where a Member State has established a procedure for Certification Bodies to register for supervision, Certification Bodies must register in each Member State in which they conduct audits under the CRCF, irrespective of where the Certification Body's head office is located. Certification Bodies must notify Isometric of the outcome of any supervision, and of any finding, suspension or withdrawal affecting their recognition, within five business days.

Isometric will cooperate with the national competent authorities supervising its appointed Certification Bodies, including with any Member State appointed as lead audit supervisor where a Certification Body conducts audits in more than one Member State, and will make available the Registry records, Certification Body documentation and Operator documentation needed for that supervision. 

Certification Bodies which do not wish to comply with the terms of this section, and the associated requirements of Article 15(1-5) of the Implementing Regulation*,* will not be permitted to conduct audits under the CRCF legislation.

In cases where CRCF certificates have been issued on the basis of fraudulent information, the associated Certificate Account of the Project Proponent will be suspended and any necessary compensation will be provided through cancellation of certified units.

The Project Proponent must procure an equivalent number of CRCF units and immediately cancel them within 90 days of notification. If the Project Proponent fails to do this, as a last resort Isometric will procure a corresponding number of CRCF certificates and cancel them.

Isometric will implement a system of internal monitoring to verify compliance of Project Proponents with the rules and procedures applied by this Standard and to ensure the quality of the work carried out by the auditors of the Certification Bodies.

Internal monitoring will be carried out at least once a year or at least at the same frequency of the audits to reflect the certification scope, as well as the level of risk of the activities carried out by the Project Proponents.

As part of the internal monitoring, Isometric will require Certification Bodies to provide all reports of the Validation (certification audit), Verification (re-certification audit), or monitoring audit. The internal monitoring will cover a random and risk-based sample of those audit reports by each Certification Body.

Isometric will also run annual training programmes for all Certification Bodies. This will cover any updates to the certification process, regulatory and scientific developments in Carbon Removal, all regulatory developments in relation to the CRCF and any relevant findings from Isometric’s internal monitoring process.

This section details requirements from Annex I of Regulation (EU) 2024/3012.

A CRCF activity plan is equivalent to an Isometric Project Design Document (PDD). PDD requirements are detailed in the Documentation section of the Isometric Standard. The following additional requirements apply to all Isometric CRCF PDDs:

• All entities in the carbon removal value chain involved in delivery of the activity must be identified as Project participants.
• For Removals, the PDD must demonstrate that estimates of $CR_{baseline} - CR_{total} - GHG_{associated} > 0$, where:
  • $CR_{baseline}$ is the amount of carbon removals under the baseline;
  • $CR_{total}$ is the total amount of carbon removals of the activity;
  • $GHG_{associated}$ is the increase in direct and indirect greenhouse gas emissions over the entire lifecycle of the activity which are attributable to its implementation, including indirect land use change, calculated, where applicable, in accordance with the Protocols set forth in the 2006 IPCC Guidelines for National Greenhouse Gas Inventories and any further refinement to these 2006 IPCC Guidelines.
• PDD must include a description of the Materiality tests applied by the PP in accordance with the Materiality section of the Isometric GHG Accounting Module or the relevant Isometric CRCF Protocol.

A CRCF monitoring plan is equivalent to the Monitoring Plan section of each Isometric Project Design Document (PDD), in conjunction with The Project’s preliminary GHG Statement submitted during Validation.

All Isometric CRCF PDDs and GHG Statements must include:

• a description of the procedure for managing the competences of personnel responsible for monitoring and reporting where applicable, the default values used for calculation factors indicating the source of the factor, or the relevant source, from which the default factor will be retrieved periodically;
• where applicable, a list of laboratories engaged in carrying out relevant analytical procedures; where measurements are taken, a description of the measurement method including descriptions of all written procedures relevant for the measurement;
• application of the Quality Assurance requirements in Quality Assurance.

Project Proponents must keep records of all relevant data and information for at least 10 years after the end of the Monitoring Period.

A CRCF monitoring report is equivalent to the GHG Statement submitted during Verification of Certificates.

A GHG Statement contains all parameters measured and calculated for the quantification of removals and emissions of GHGs associated with The Project. The contents of a GHG Statement are defined by the relevant Isometric CRCF Protocol.

All Isometric CRCF Projects must convert emissions of non-CO₂ GHGs to CO₂e using the 100-year Global Warming Potentials set out in Annex I to the Delegated Regulation (EU) 2020/1044.

Project Proponents must:

• ensure that all relevant measuring equipment is calibrated, adjusted and checked at regular intervals, including prior to use, and checked against measurement standards traceable to international measurement standards where available, and proportionate to the risks identified.
• where components of the measuring systems cannot be calibrated, identify these in the Monitoring Plan and propose alternative control activities.
• when the equipment is found not to comply with required performance, the Project Proponent must promptly take necessary corrective action.

All measurements shall be conducted with calibrated measurement equipment according to industry standards including, where applicable:

• EN 14181 Stationary source emissions — Quality assurance of automated measuring systems;
• EN 15259 Air quality — Measurement of stationary source emissions — Requirements for measurement sections and sites and for the measurement objective, plan and report;
• ISO 16911-2 Stationary source emissions — Manual and automatic determination of velocity and volume flow rate in ducts.

Laboratories conducting analysis on behalf of The Project must be ISO 17025 accredited unless the Project Proponent can demonstrate this is not technically feasible or would incur unreasonable costs. The Project Proponent must demonstrate any non-accredited laboratory meets the requirements of ISO 17025 through ISO 9001 accreditation, other certified Quality Management System, or otherwise submit a PDD Appendix containing the following evidence for the laboratory:

• management of the personnel's competence for the specific tasks assigned;
• suitability of accommodation and environmental conditions;
• selection of analytical methods and relevant standards;
• where applicable, management of sampling and sample preparation, including control of sample integrity; where applicable, development and validation of new analytical methods or application of methods not covered by international or national standards;
• uncertainty estimation;
• management of equipment, including procedures for calibration, adjustment, maintenance and repair of equipment, and record keeping thereof;
• management and control of data, documents and software;
• management of calibration items and reference materials; quality assurance for calibration and test results, including regular participation in proficiency testing schemes, applying analytical methods to certified reference materials, or inter-comparison with an accredited laboratory;
• management of outsourced processes;
• management of assignments, customer complaints, and ensuring timely corrective action.

Project Proponents must include in their PDD a robust climate risk and vulnerability assessment with the following steps:

• screening of The Project to identify which physical climate risks from the list in Section II of Appendix A of Regulation 2021/2139 may affect the performance of The Project during its expected lifetime;
• where The Project is assessed to be at risk from one or more of the physical climate risks listed in the same Appendix, a climate risk and vulnerability assessment to assess the Materiality of the physical climate risks on The Project;
• an assessment of adaptation solutions that can reduce the identified physical climate risk.

The climate risk and vulnerability assessment is proportionate to the scale of The Project and its expected lifespan, such that:

• for Projects with an expected lifespan of less than 10 years, the assessment is performed, at least by using climate projections at the smallest appropriate scale;
• for all other Projects, the assessment is performed using the highest available resolution, state-of-the-art climate projections across the existing range of future scenarios consistent with the expected lifetime of the activity, including, at least, 10 to 30 year climate projections scenarios for major investments;
• the range of future scenarios are the IPCC representative concentration pathways RCP2.6, RCP4.5, RCP6.0 and RCP8.5.

The climate projections and assessment of impacts are based on best practice and available guidance and take into account the state-of-the-art science for vulnerability and risk analysis and related methodologies in line with the most recent IPCC reports, scientific peer-reviewed publications, and open source or paid models.

For existing Projects and new Projects using existing physical assets, the Project Proponent must prepare and execute a plan for adaptation solutions, over a period of time of up to five years, that reduce the most important identified physical climate risks that are material to that Project.

For new Projects and existing Projects using newly-built physical assets, the Project Proponent must integrate the adaptation solutions that reduce the most important identified physical climate risks that are material to that activity at the time of design and construction before the start of operations.

The adaptation solutions implemented must not adversely affect the adaptation efforts or the level of resilience to physical climate risks of other people, of nature, of cultural heritage, of assets and of other economic activities; and be consistent with local, sectoral, regional or national adaptation strategies and plans; and consider the use of nature-based solutions or rely on blue or green infrastructure to the extent possible.

In accordance with the requirements of Regulation (EU) 2024/3012, Isometric will make publicly available the following information related to its role as a Certification Scheme under the CRCF:

1. Contact information of Isometric, including postal address and email address.
2. The most recent version of Isometric’s governance rules and procedures, including the roles and responsibilities of all relevant bodies; details concerning the Board of Directors, Secretariat, and Technical Committee, or their equivalents; the registry of scheme participants; and comprehensive guidelines for the conduct of audits. Each rules and procedures document will include a date and version number and, where applicable, will summarise any changes made compared to the previous version of the document.
3. Each rules and procedures document will include a date and version number and, where applicable, will summarise any changes made compared to the previous version of the document.
4. The rules underlying the calculation of Isometric’s fees.
5. A link to the complaint submission and assessment procedures, including appeal procedures.
6. The actions taken by the certification scheme as a result of a complaint.
7. Operators with a withdrawn certificate, terminated certificate or expired certificate, for at least 36 months after the date of withdrawal, termination or expiry of the certificate.
8. Isometric will publish without delay any changes in the certification status of operators.
9. Certification bodies that are no longer entitled to conduct auditing under Isometric will be listed for at least 24 months on the scheme's website after the last audit with an indication to that effect.

Isometric will also publish an Annual Operation Report covering the preceding calendar year, which will contain the following material:

1. Information on market uptake, including the number and type of certified projects (categorised in accordance with the applicable CRCF methodology), and the amount, type and status of the certified CRCF units managed by Isometric;.
2. An overview of the activities carried out by Isometric in cooperation with the certification bodies in order to improve the overall certification process and the qualification and independence of auditors, including a list of technical workshops or other types of activities that facilitate the exchange of experience, knowledge and best practices as regards the implementation of the applicable certification methodologies adopted in accordance with Regulation (EU) 2024/3012.
3. An overview of the internal monitoring system and of its periodic review, including oversight of the work of certification bodies and their auditors. This overview will describe how the system effectively prevents fraudulent activities and this will record the number of cases of fraud or irregularities detected;
4. An overview of stakeholder engagement activities, including public consultations;
5. An overview of complaints received and, where relevant, any remedial measures or changes to the governance system necessary as part of the internal monitoring;
6. An overview of identified cases of non-conformity by operators or certification bodies, the number and description of cases where fraud has been identified, and an action plan setting out how each complaint or identified non-conformity is to be resolved; and
7. The criteria and process for the appointment of certification bodies.

This section applies only to activities certified by Isometric in its capacity as a certification scheme recognized under Article 13 of the CRCF Regulation. All other activities are governed by the Isometric Standard and the applicable Isometric Protocols in full.

Permanent carbon removal activities. For activities generating Permanent Carbon Removal Units as defined by the CRCF regulation, the applicable CRCF certification methodology is applied first and in full, and the Isometric Standard and the relevant Isometric CRCF Protocols and Modules apply in addition. In the event of any conflict between the Isometric Standard and the CRCF Legislation, the CRCF Legislation prevails in respect of the certification of compliance and the issuance of certified units under the CRCF. A conflict arises only where it is not possible to comply with both. Where the Isometric Standard, Protocols or Modules impose additional or stricter requirements that are compatible with the CRCF Legislation, Operators must comply with both.

Carbon farming activities. For activities generating Carbon Farming Sequestration Units or Soil Emission Reduction Units, the CRCF Legislation applies exclusively. Isometric does not impose additional or stricter quantification, baseline, additionality, durability, liability or sustainability requirements on such activities, and the requirements of the Isometric Standard and of Isometric's non-CRCF Protocols do not apply to them. For the avoidance of doubt, this clause does not displace:

1. requirements that the CRCF Legislation places on Isometric as a certification scheme, including the establishment and management of buffer pools, stress-testing and publication requirements, assessment of early-termination risk, guidance on risk-mitigation factors, and registry, reporting and data-sharing obligations all of which are covered in the relevant Carbon Farming methodologies, hosted on Isometric’s registry; and

2. Isometric's general scheme governance, including but not limited to conflict-of-interest, appeals and fee policies, which apply to all Operators.

Unit types and issuance. Carbon Farming Sequestration Units expire and are cancelled at the end of the applicable monitoring period unless long-term storage is proven through continued monitoring in accordance with the applicable certification methodology. Soil Emission Reduction Units are not subject to expiry.

Relationship to Isometric Credits. An Operator may not obtain both a Carbon Farming Sequestration Unit or Soil Emission Reduction Unit and an Isometric certificate in respect of the same tonne of net carbon removal or soil emission reduction. 

The Carbon Farming Protocols will be hosted in the Governance and Policies section of the Isometric Registry.

Isometric maintains a detailed glossary of equivalent CRCF and Isometric definitions, accessible here.

CRCF - stands for Carbon Removals and Carbon Farming and is an EU-wide voluntary framework for certifying carbon removals, carbon farming and carbon storage in products.

CRCF Certificate of Compliance - A conformity statement issued by a certification body certifying that a project complies with Regulation (EU) 2024/3012; equivalent to an Isometric Verification Report in conjunction with The Project Validation Report.

CRCF Certified Unit - a Credit issued in accordance with Regulation (EU) 2024/3012

Permanent Carbon Removal Unit - one tonne of CO₂e of certified permanent net carbon removal benefit generated by a permanent carbon removal activity under the CRCF, equivalent to durable carbon removal under the Isometric Standard

Carbon Farming Sequestration Unit - one tonne of CO₂e of certified temporary net carbon removal benefit generated by a carbon farming activity. Expires and is cancelled at the end of the Monitoring Period unless long-term storage is proven through continued monitoring

Soil Emission Reduction Unit - one tonne of CO₂e of certified net soil emission reduction benefit generated by a carbon farming activity

CRCF Activity - equivalent to an Isometric Project

CRCF Operator - equivalent to an Isometric Project Proponent

CRCF Certification Body - equivalent to a VVB

CRCF Certification Audit - equivalent to an Isometric Validation

CRCF Re-certification Audit - equivalent to an Isometric Verification

CRCF Activity Period - equivalent to an Isometric Crediting Period

CRCF Certification Period - equivalent to an Isometric Reporting Period

CRCF Activity Plan - equivalent to an Isometric Project Design Document (PDD)

CRCF Monitoring Plan - equivalent to the Monitoring Plan section of each Isometric Project Design Document (PDD)

CRCF Monitoring Report - equivalent to the GHG Statement submitted during Verification of Certificates

CRCF Monitoring Audit - an audit carried out by a certification body during the monitoring period to verify monitoring of stored carbon and any reversals

CRCF Withdrawn Certificate - a certificate that has been permanently canceled by the certification body or the certification scheme

CRCF Expired Certificate - a certificate that is no longer valid

CRCF Terminated Certificate - a certificate that has been voluntarily cancelled while it is still valid

CRCF Non-conformity - a failure by an operator or a certification body to comply with the rules and procedures established by the certification scheme, of which they are members or under which they operate

Calculation of Uncertainty should follow documented best practices, such as the requirements of the Joint Committee for Guides in Metrology (JCGM) JCGM100:2008 - Evaluation of measurement data — Guide to the expression of uncertainty in measurement (GUM)[^ISO-GUM]. Uncertainty can be assessed using two different methods:

• Type A Uncertainty, where Uncertainty is assessed by making repeated observations of the parameter of interest
• Type B Uncertainty, where Uncertainty is founded on a priori distributions, evaluated by scientific judgment based on all of the available information on the possible variability of the parameter of interest

Type B Uncertainties may frequently be encountered, since it is not always practical to make repeated measurements for every input parameter, and many input parameters are published values or estimated through other means.

Emission factors utilized should provide an Uncertainty value associated with the specific factor. Some databases from which emission factors are derived include and report the Uncertainty within the database²⁰. The factor used, its source, and the value of the Uncertainty reported and used, should be documented. For emission factors for which no Uncertainty information is provided, clearly document this and refer to Unknown Uncertainties.

See the GUM for details on calculation of parameter or measurement Uncertainty. For instance, measurement parameter Uncertainty estimates could be derived from manufacturers specifications or calibration records. If repeated measurements are taken, the type A uncertainty should be reported as the standard deviation. Uncertainties should be documented and reported for each measured parameter.

For laboratory analyses, Uncertainty may be reported based on laboratory quality assurance documentation, including laboratory calibration results and records which use a reference calibration standard that is traceable to a national standard.

For a reported value based on multiple laboratory analyses, for which the value is reported as a mean, the type A uncertainty is calculated based on the standard deviation of the value around the mean.

When published Uncertainty information is not available and calculation via direct measurement is not feasible, estimation of Uncertainty should follow documented best practices, such as guidance from the GUM for evaluating type B Uncertainty. The specific approaches taken should be clearly documented.

Specifically regarding emission factors, the default values for basic Uncertainty of Ecoinvent’s Overview and Methodology document may be used. Ecoinvent’s Protocol assumes a lognormal distribution for a value and then uses a Pedigree Matrix to assign uncertainties based on data quality.

Here are a couple of examples on how Option A (conservative estimate of input parameters) can be applied. These examples are for illustration purposes only:

Example 1: Uncertainty in Truck transportation carbon intensity

There are only a few carbon intensity factors published in a reputable emissions factor database for truck transportation. The factors range from 0.2 kg/km/t to 1.2 kg/km/t depending on different vehicle types, and the Project Proponent doesn’t know exactly what type of vehicle is used. In this case, a higher carbon intensity leads to less net CO₂e Removal or Reduction and there are only a few relevant emissions factors to choose from so a distribution is not assumed. The Project must take the conservative estimate to be the maximum value of 1.2 kg/km/t.

Example 2: Uncertainty in ocean DIC retention

For enhanced weathering in agriculture, a downstream loss term in the Removal calculation that cannot be directly measured is the percentage of bicarbonate ions from weathering that is retained as dissolved inorganic carbon (DIC) upon reaching the ocean. A Project Proponent uses a regional ocean model to determine that the DIC retention fraction follows a normal distribution, with a mean of 0.90 and a standard deviation of 0.02. A lower DIC retention fraction results in less net CO₂e Removal, so the conservative estimate is taken to be 1 standard deviation below the mean (corresponding to the 16th percentile). The conservative estimate of the DIC retention index is thus 0.88.

This appendix provides the detailed stepwise process for reducing and documenting uncertainty. The stepwise process must be completed alongside GHG Statements submitted for verification. Projects must demonstrate how they plan to reduce and document uncertainty as part of validation.

Step 1 - Input parameters information

Protocols must report a list of all parameters that are used in the Removal or Reduction calculations. Where uncertainty data is available from external sources, such as for emission factors or relating to equipment calibration, or where uncertainty information is determined from project measurements, this must be reported.

Step 2 - Contribution analysis

Separately, a Contribution Analysis should be undertaken that demonstrates the impact of each GHG SSR on the final net Removal or Reduction. This analysis should calculate the contribution of each GHG SSR by expressing the emissions associated with that SSR during the Reporting Period as a percentage of the total net removals for the same period.

Step 3 - Sensitivity analysis

A sensitivity analysis must be conducted to evaluate the impact of uncertainty in each input parameter on the final net CO₂e removal or reduction. The method used must be clearly documented so results can be independently reproduced.

Where one input parameter contributes to multiple GHG SSRs, this must be treated as one input parameter.

The purpose of the sensitivity analysis is to determine how uncertainty in an individual input parameter affects the net CO₂e removal or reduction estimate. This is done by adjusting the parameter using an appropriate uncertainty factor and recalculating the net CO₂e removal or reduction while keeping all other parameters constant.

If the resulting change in net CO₂e removal or reduction is less than 1%, no further action is required. If the change is equal to, or exceeds 1%, the adjusted value must be used in the GHG Statement. An exception to this rule is allowable for input parameters where data has been adopted to calculate GHG emissions and, the Project Proponent can demonstrate that:

• The input parameter is based on accurate, verifiable primary data, or
• The value used is conservative.

Any such justification must be clearly documented and supported by evidence.

When dealing with uncertainty, Project Proponents must follow the hierarchy outlined below to determine uncertainty factors:

1. Some Protocols contain specific guidance on assessing uncertainty in parameters. Project Proponents must first consult the relevant Protocol for any explicit rules on uncertainty estimation.
2. If no specific rules are included on uncertainty estimation in the relevant Protocol, then Project Proponents must follow the general guidance outlined below to assess uncertainty.
3. For input parameters based on primary data from direct measurements, the uncertainty factor must be derived using appropriate statistical methods to directly calculate the standard deviation of the parameter. These methods provide a systematic approach to quantifying uncertainty in the final net CO₂e removal or reduction estimate.

For parameters not based on primary data, the uncertainty factor may be informed by:

• Third-party data, such as meter accuracy from manufacturers or uncertainty ranges published with emission factors (e.g., in databases like Ecoinvent);
• Context-specific considerations, such as variability in logistics, seasonal effects, or operational practices;
• A default value of ±20%, only when no better information is available and with justification for its use.

All uncertainty factors must be clearly referenced, and the basis for their selection must be documented. Acceptable sources include instrument calibration data, published literature, expert judgment, proxies, and other reputable references. Additional guidance on assessing different types of uncertainties is provided in Appendix A.

The Sensitivity analysis must be repeated when any of the following conditions are met:

• The previous assessment was conducted one year or more prior to the current verification;
• There has been a significant change in the Net Removal or Reduction estimate;
• There has been a change in activities associated with any of the relevant SSRs.

This questionnaire provides guidance on assessing Risk of Reversal, to be used by Protocols and Projects which need to make this assessment for use on the Isometric Registry.

This risk assessment identifies relevant material risk factors at the level of the Isometric Standard. The relevant risk factors from this Standard-level risk assessment are also specified at the Protocol level. Each relevant risk factor identified as part of a risk assessment must be included in the monitoring plan for a Project, and published as part of The Project Design Document.

The duration of required monitoring is determined in the relevant Protocol or Module. As above, the risk assessment informs the design of the monitoring plan requirements and consequently the extent, frequency and duration of monitoring.

Projects must re-assess their reversal risk using this questionnaire at the renewal of each crediting period, or sooner if:

• the relevant Protocol requires a more frequent assessment,
• monitoring identifies a reversal-related risk,
• The Project storage technology materially changes,
• an actual reversal event takes place.

If the relevant Protocol specifies that Reversals are not directly observable (i.e., the storage is an open system), The Project's Risk of Reversal is automatically "No observable risk." Such Projects do not need to complete this questionnaire, but must still maintain a monitoring plan in accordance with the requirements of the relevant Protocol. Where a Protocol does not specify this, Projects must complete the Risk of Reversal questionnaire.

Please see the Reversals and Buffer Pools for more details on how Risk of Reversal is used.

Note the Risk Score at any step cannot be negative.

Where Reversals are not directly observable (as specified in the relevant Protocol), a Project’s Risk of Reversal is automatically deemed “No observable risk”, and no buffer contributions are required.

For other Projects, Risk of Reversal is determined based on the score of the risk assessment questionnaire, as follows:

• 0: Very Low Risk Level (1% buffer)
• 1-2: Low Risk Level (5% buffer)
• 3-4: Medium Risk Level (7% buffer)
• 5+: High Risk Level (10-20% buffer)

Isometric's Uncertainty and Buffer Pool policies represent two mostly non-overlapping approaches for how Isometric plans to be conservative in how Certificates are quantified and to potentially insure against future events that may result in a Reversal. Specifically, in removal pathways that utilize large, open-system reservoirs (e.g., the ocean) where direct observation of a reversal is not feasible, Isometric's Uncertainty policy will generally result in a larger uncertainty discount²¹, and Isometric's Buffer Pool policy will generally result in a smaller Buffer Pool Size, or no Buffer Pool contribution. Conversely, in removal pathways that utilize closed-system reservoirs that are more straightforward to monitor, Isometric's Uncertainty policy will generally result in a smaller uncertainty discount, but the activity will be subject to a larger Buffer Pool Size. Below are two example scenarios that illustrate how and when these two policies are invoked.

Example 1: Ocean Alkalinity Enhancement

An OAE Project Proponent releases a known amount of alkalinity into the ocean. In accordance with the Protocol and PDD, the Project Proponent uses a model to estimate that the median CO₂ uptake after a certain amount of time is 100 tonnes. In accordance with Isometric's Uncertainty policy, the Project Proponent reports that the 16th percentile of CO₂ uptake outcomes is 15 tonnes below the median (resulting in a 15t uncertainty discount that is subtracted from the gross CO₂ removed). The Project Proponent does not need to complete a risk of reversal questionnaire, as Reversals are not directly observable for OAE, and as such The Project risk level is determined as “No observable risk” (resulting in no buffer pool contribution).

• Net CO₂e removed = 100t - 20t - 15t = 65t
  • Gross CO₂ removed: 100t
  • Counterfactual CO₂ removal and GHG emissions CO₂e: -20t
  • Uncertainty discount CO₂e: -15t
• Certificates issued to Project Proponent: 63.7 Certificates (65 - 1.3)
  • Total Certificates issued: 65 Certificates
  • Certificates deposited to Buffer Pool account: 65 Certificates 0% = 0 Certificates

Example 2: Bio-oil Production and Injection

A bio-oil production and injection Project Proponent produces 100 tonnes of bio-oil with a well-constrained GHG Assessment and counterfactuals (there is no uncertainty discount for the amount of CO₂e removed because conservative parameters were used in the calculation). This bio-oil is then injected into an underground reservoir that is equipped with a suite of chemical sensors that can measure CO₂ and methane. The corresponding PDD has provisions to continue monitoring for fugitive gases for 40 years after injection has concluded. The Project Proponent follows Isometric's guidance in answering the risk questionnaire and determines they have a Risk of Reversal that corresponds to Risk Level B (resulting in a 5% Buffer Pool Size).

• Net CO₂e removed = 100t - 20t - 0t = 80t
  • Gross CO₂ removed: 100t
  • Counterfactual CO₂ removal and GHG emissions CO₂e: -20t
• Certificates issued to Project Proponent: 76 Certificates (80 - 4)
  • Total Certificates Issued: 80 Certificates
  • Certificates deposited to Buffer Pool account: 80 Certificates 5% = 4 Certificates

1. https://www.epa.gov/ghgemissions/overview-greenhouse-gases ↩

2. https://www.ipcc.ch/assessment-report/ar6/ ↩

3. https://www.iso.org/standard/66454.html ↩

4. https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_Chapter12.pdf ↩ ↩²

5. https://rmi.org/insight/scaling-technological-greenhouse-gas-removal-a-global-roadmap-to-2050/ ↩

6. UK’s Climate Change Committee (CCC) commissioned report Assessment of Options to Reduce Emissions from Fossil Fuel Production and Fugitive Emissions ↩

7. https://unfccc.int/process/parties-non-party-stakeholders/parties-convention-and-observer-states ↩

8. http://www.geol.lsu.edu/jlorenzo/geophysics/uncertainties/Uncertaintiespart2.html#muldiv ↩

9. Johansen, A.M., Evers, L. and Whiteley, N., 2010. Monte Carlo methods. International Encyclopedia of Education, pp.296-303. ↩

10. Section 4: Assessment Framework - Core Carbon Principles 2023, The Integrity Council for the Voluntary Carbon Market ↩ ↩²

11. International Labour Organisation Convention 169 on Indigenous and Tribal Peoples ↩

12. United Nations Declaration on the Rights of Indigenous Peoples, 13 September 2007 ↩

13. A negative impact is any adverse effect from a particular action that leaves an individual or community worse off, (i.e. where given a choice between the status quo and their position after that action, the individual would strictly prefer the status quo). ↩

14. UN Guiding Principles on Business and Human Rights Reporting Framework with implementation guidance (2015); International Business Leaders Forum (IBLF) and International Finance Corporation (IFC) Guide to Human Rights Impact Assessment and Management (HRIAM), September 2011 ↩

15. FPIC must be obtained by following a suitable process. That process must identify the indigenous peoples concerned, document geographic and demographic mapping, involve a participatory communication approach which discloses project information transparently, reach consent, document any specific needs of indigenous peoples that must be included in The Project, and include a feedback and complaints mechanism. ↩

16. International Bill of Human Rights, United Nations ↩

17. https://iaf.nu/en/accreditation-bodies/ ↩

18. ISO 14064-3:2019, 6.3.3 ↩

19. Regulation (EU) 2024/3012 ↩

20. Databases such as Ecoinvent provide uncertainty factors, often based on a lognormal probability distribution, with a 95% confidence interval. The reported uncertainty accounts for systematic error, random error, and may also use a pedigree matrix to assign additional qualitative data quality impacts as an uncertainty value. These uncertainties are reported as a combined standard uncertainty. See details and examples for ecoinvent: https://support.ecoinvent.org/uncertainties ↩

21. "Uncertainty discount" is defined as the difference between the Conservative estimate of Removal, and the estimate of Removal in the absence of accounting for uncertainty ↩