Citadel Academy Division
GHG Verification & Validation
ISO 14064-3:2019 Training Handbook
Training Code: CA-GHG-003  |  Reference: BS EN ISO 14064-3:2019  |  Published: 2019
Citadel Engineering Company
Citadel Academy Division
Training Code
CA-GHG-003
Standard
ISO 14064-3:2019
Page
1 of 75
CA-GHG-003 | About Us | Page 2 of 75
About Citadel Engineering Company
Our Mission
Citadel Engineering Company is a leading industrial engineering and technical services firm delivering world-class solutions across energy, environment, and infrastructure sectors.
Core Competencies
Technical Consulting
Engineering assessments, audits, and compliance advisory
Inspection & Verification
GHG, structural, and process verification services
Training & Certification
Delivered through Citadel Academy Division
CA-GHG-003 | About Citadel Academy | Page 3 of 75
About Citadel Academy Division
Accredited Training
Internationally aligned programs mapped to ISO, ASME, API, and BSI standards for engineering professionals.
Certification Programs
Recognized certificates in GHG management, verification, validation, and environmental compliance.
Industry Reach
Serving oil & gas, manufacturing, utilities, forestry, and transportation sectors worldwide.
Expert Instructors
Delivered by certified verifiers, validators, and environmental engineers with field experience.
CA-GHG-003 | Training Objectives | Page 4 of 75
Training Objectives
Upon completion of this program, participants will be able to:
1
Understand the ISO 14060 Family
Explain the role of ISO 14064-3:2019 within the broader GHG standards ecosystem.
2
Apply Verification Principles
Plan, execute, and complete GHG verification engagements at reasonable and limited assurance levels.
3
Conduct Validation Engagements
Assess assumptions, limitations, and methods supporting future GHG statements.
4
Issue Opinions
Draft unmodified, modified, and adverse opinions in accordance with the standard.
5
Apply AUP & Mixed Engagements
Understand agreed-upon procedures and mixed engagement frameworks.
CA-GHG-003 | Training Modules | Page 5 of 75
Training Modules Overview
Module 1: Introduction & Background
Climate change context, ISO 14060 family, scope of ISO 14064-3
Module 2: Key Terms & Definitions
GHG terminology, entities, inventory, statements, verification/validation concepts
Module 3: Principles & Pre-Engagement
Impartiality, evidence-based approach, engagement types, materiality
Module 4: Verification Process
Planning, risk assessment, evidence gathering, site visits, completion, opinion
Module 5: Validation Process
Strategic analysis, estimate testing, GHG activity characteristics, opinion
Module 6: AUP, Mixed Engagements & Reporting
Agreed-upon procedures, mixed engagements, independent review, opinion issuance
CA-GHG-003 | Module 1: Introduction | Page 6 of 75
Module 1: Introduction & Background
Climate change arising from anthropogenic activity is one of the greatest challenges facing the world, with implications for human and natural systems, resource availability, economic activity, and human wellbeing.
The Challenge
GHG concentrations in the atmosphere must be mitigated through quantification, monitoring, reporting, and verification.
The Response
International, regional, national, and local initiatives by public and private sectors to reduce GHG emissions.
The Standard
ISO 14064-3:2019 provides the specification and guidance for verification and validation of GHG statements.
CA-GHG-003 | Module 1: ISO 14060 Family | Page 7 of 75
The ISO 14060 Family of Standards
Figure 1 — Relationship among the ISO 14060 family of GHG standards. ISO 14064-1 governs organization-level inventories; ISO 14064-2 governs project-level emission reductions; ISO 14067 governs carbon footprint of products. All feed GHG statements that are subject to ISO 14064-3 verification/validation, supported by ISO 14065 (body requirements) and ISO 14066 (team competence).
CA-GHG-003 | Module 1: Standard Overview | Page 8 of 75
What ISO 14064-3:2019 Covers
Scope
Specifies principles and requirements and provides guidance for verifying and validating GHG statements applicable to organization, project, and product GHG statements.
Key Changes from 2006 Edition
  • Verification and validation now discussed in sequence, not in parallel
  • New dedicated validation section (Clause 7)
  • New Annex A: Limited level of assurance
  • New Annex C: Agreed-upon procedures (AUP)
  • New Annex D: Mixed engagement guidance
Who Uses This Standard?
First-, second- and third-party verifiers/validators
GHG project developers and commissioners
Internal auditors of GHG data
GHG programme administrators
Investor, finance, and insurance communities
Regulators and accreditation bodies
CA-GHG-003 | Module 2: Key Terms | Page 9 of 75
Module 2: Key Terms — Greenhouse Gases
Greenhouse Gas (GHG)
Gaseous constituent of the atmosphere that absorbs and emits radiation at specific infrared wavelengths. Includes CO₂, CH₄, N₂O, HFCs, PFCs, and SF₆.
Global Warming Potential (GWP)
Index measuring radiative forcing of a GHG relative to CO₂ over a chosen time horizon. Referenced from the latest IPCC Assessment Report.
Carbon Footprint of Product (CFP)
Sum of GHG emissions and removals in a product system, expressed as CO₂ equivalents, based on life cycle assessment using the single impact category of climate change.
GHG Emission or Removal Factor
Coefficient relating GHG activity data with GHG emissions or removals.
CA-GHG-003 | Module 2: Entities | Page 10 of 75
Key Entities in GHG Verification & Validation
Understanding the roles of each entity is critical to designing and executing a compliant engagement. The responsible party prepares the GHG statement; the verifier/validator provides independent assurance; the intended user relies on the opinion for decisions.
CA-GHG-003 | Module 2: GHG Inventory Terms | Page 11 of 75
GHG Inventory Terminology
GHG Source
Process that releases a GHG into the atmosphere (e.g., combustion).
GHG Emission
Release of a GHG into the atmosphere.
GHG Sink
Process that removes a GHG from the atmosphere (e.g., forests).
GHG Removal
Withdrawal of a GHG from the atmosphere by GHG sinks.
GHG Reservoir
Component that accumulates, stores, and releases GHGs (e.g., carbon stock in forests).
GHG Storage
Process for retaining captured GHGs so they do not reach the atmosphere.
GHG Inventory
List of GHG sources, sinks, and reservoirs with quantified emissions and removals for a defined period.
Base Year
Specific historical period for comparing GHG emissions or removals over time.
CA-GHG-003 | Module 2: Statement Terms | Page 12 of 75
GHG Statement & Project Terminology
GHG Statement
Factual and objective declaration providing the subject matter for verification or validation. Must be clearly identifiable and capable of consistent evaluation against criteria.
GHG Project
Activity or activities that alter GHG baseline conditions, causing emission reductions or removal enhancements.
GHG Baseline
Quantitative reference of GHG emissions/removals that would have occurred in the absence of a GHG project.
Baseline Scenario
Hypothetical reference case representing conditions most likely to occur without the proposed GHG project.
GHG Emission Reduction
Quantified decrease in GHG emissions between a baseline scenario and the GHG project.
GHG Removal Enhancement
Quantified increase in GHG removals between a baseline scenario and the GHG project.
CA-GHG-003 | Module 2: Verification Terms | Page 13 of 75
Verification & Validation Core Definitions
CA-GHG-003 | Module 3: Principles | Page 14 of 75
Module 3: Principles of Verification & Validation
Impartiality
Design and execute the engagement objectively, without introducing bias.
Evidence-Based Approach
Employ a rational method for reaching reliable, reproducible conclusions based on sufficient evidence.
Fair Presentation
Truthfully and fairly present activities, findings, conclusions, and opinions. Report significant obstacles.
Documentation
Document the engagement to establish the basis for conclusions and conformity with criteria.
Conservativeness
When assessing comparable alternatives, use a cautiously moderate selection.
CA-GHG-003 | Module 3: Engagement Types | Page 15 of 75
Choosing the Right Engagement Type
Figure 2 — Decision process for engagement type. If an opinion is needed and the GHG statement is historical → Verification. If an opinion is needed and the GHG statement is prospective → Validation. If no opinion is needed → Agreed-Upon Procedures (AUP).
CA-GHG-003 | Module 3: Pre-Engagement | Page 16 of 75
Pre-Engagement Activities (Clause 5.1)
Before commencing any engagement, the verifier/validator must confirm and agree with the client on all key parameters:
1
Type
Verification, validation, or AUP
2
Objectives
Accuracy of GHG statement; conformity with criteria
3
Criteria
Standards or GHG programme requirements
4
Scope
Boundaries, facilities, GHG SSRs, time period
5
Materiality
Quantitative and qualitative thresholds

Key Rule: The level of assurance must be specified prior to the start of verification and cannot be changed during the engagement. A new engagement must be started if a change is required.
CA-GHG-003 | Module 3: Materiality | Page 17 of 75
Understanding Materiality
Quantitative Materiality
Refers to error in value in the GHG statement. Examples:
  • Misstatements in reported emissions
  • Incomplete inventories
  • Misclassified GHG emissions
  • Misapplication of calculations
Qualitative Materiality
Refers to intangible issues affecting the GHG statement. Examples:
  • Control issues eroding confidence in reported data
  • Poorly managed documented information
  • Difficulty locating requested information
  • Noncompliance with regulations indirectly related to GHG emissions

Note: Performance materiality is set lower than the intended user's threshold to catch aggregated misstatements that might be material.
CA-GHG-003 | Module 3: Evidence Techniques | Page 18 of 75
Evidence-Gathering Activities & Techniques (Clause 5.3)
Verifiers and validators shall use one or more of these techniques to gather sufficient and appropriate evidence. The selection depends on the risk assessment and the nature of the GHG statement being assessed.
CA-GHG-003 | Module 4: Verification | Page 19 of 75
Module 4: The Verification Process
The verification process follows a structured sequence from pre-engagement through to opinion issuance. Documentation (Clause 5.4.4) runs parallel to every stage, ensuring a complete audit trail.
CA-GHG-003 | Module 4: Verification Process Flow | Page 20 of 75
Verification Process — Full Flow (Figure 3)
Figure 3 — Verification process. Each stage — from pre-engagement agreement through team selection, planning, execution, completion, independent review, to opinion issuance — is supported by continuous verification documentation (Clause 5.4.4).
CA-GHG-003 | Module 4: Strategic Analysis | Page 21 of 75
Verification Planning: Strategic Analysis (Clause 6.1.1)
The verifier shall perform a strategic analysis to understand the activities and complexity of the organization, project, or product, and to determine the nature and extent of verification activities.
General Considerations (a–t)
  • Relevant sector information and nature of operations
  • Criteria requirements including regulatory/GHG programme requirements
  • Intended user's materiality threshold (qualitative and quantitative)
  • Scope, boundaries, and time boundary for data
  • GHG SSRs and their contribution to the overall statement
  • Changes from prior reporting periods
  • Quantification and reporting methods; data management systems
  • Results of previous verifications and sensitivity/uncertainty analyses
Additional Requirements
For Projects
Project plan, validation report results, monitoring plan and methodology, monitoring report.
For Products (CFP)
Life cycle interpretation results, functional/declared unit, unit process characteristics, life-cycle stages, cut-offs.
CA-GHG-003 | Module 4: Risk Assessment | Page 22 of 75
Verification Planning: Risk Assessment (Clause 6.1.2)
Inherent Risk
Risk of material misstatement due to the nature of the GHG activity, independent of controls.
Control Risk
Risk that the responsible party's controls fail to prevent or detect material misstatements.
Detection Risk
Risk that the verifier's evidence-gathering activities fail to detect existing material misstatements.
For emissions and removals, risks are assessed for: occurrence, completeness, accuracy, cut-off, and classification. For storage: existence, rights and obligations, completeness, accuracy, and allocation.

Key Principle: The higher the risk of misstatement, the more persuasive evidence the verifier must obtain. Risk assessment outputs directly drive the verification and evidence-gathering plans.
CA-GHG-003 | Module 4: Evidence Gathering | Page 23 of 75
Evidence-Gathering Activities (Clause 6.1.3)
Data Trail (6.1.3.2)
The verifier must design activities to determine the existence of data trails for material emissions, removals, and/or storage — tracing GHG information back to primary data sources.
GHG Information System & Controls (6.1.3.3)
Assess design and effectiveness of the GHG information system, including data collection, processing, consolidation, reporting, instrument calibration, and prior verification results.
Specific Techniques
Analytical Testing
Identify fluctuations inconsistent with expectations; investigate differences with additional evidence.
Control Testing
Test operating effectiveness of controls; assess deviations and their impact on reliance.
Estimate Testing
Evaluate methodology, assumptions, and data quality; develop independent estimate or range.
Sampling
Consider purpose and population characteristics when designing the sample.
CA-GHG-003 | Module 4: Site Visits | Page 24 of 75
Site Visits (Clause 6.1.4)
Site visits are planned and performed to gather information needed to reduce verification risk and aid evidence-gathering design.
When a Site Visit is Mandatory
Initial verification; change of ownership of a material site; unexplained material changes in emissions; addition of material GHG SSRs; significant changes in data management or scope.
What to Assess During Site Visits
Operations relevant to GHG SSRs; data management and control systems; physical infrastructure; equipment and calibration; processes and material flows; scope and boundaries; personnel activities; sampling methodologies; quality control procedures.
Waiving a Site Visit
A verifier may determine a site visit is not necessary based on risk assessment results. The rationale must be justified and documented.
CA-GHG-003 | Module 4: Verification Plans | Page 25 of 75
Verification Plan & Evidence-Gathering Plan (Clauses 6.1.5–6.1.7)
Verification Plan Must Include:
  • Scope and objectives
  • Verification team identification and roles
  • Client/responsible party contact
  • Schedule of verification activities
  • Level of assurance
  • Verification criteria
  • Materiality thresholds
  • Schedule for site visits

The verification plan is communicated to the responsible party. The evidence-gathering plan is not communicated to the client or responsible party.
Plan Amendments — Approved by Team Leader When:
  • Change in scope or timing of verification activities
  • Change in evidence-gathering procedures
  • Change in locations or sources of information
  • Identification of new risks or concerns during verification
Approval
Both the verification plan and evidence-gathering plan must be approved by the team leader before execution begins.
CA-GHG-003 | Module 4: Completion | Page 26 of 75
Verification Completion & Evaluation (Clause 6.3)
Evaluate Changes in Risks & Materiality
Assess any changes that occurred over the course of the verification; confirm analytical procedures remain representative.
Evaluate Sufficiency & Appropriateness of Evidence
Determine if collected evidence is sufficient to reach a conclusion; develop additional activities if not.
Evaluate & Document Material Misstatements
Identify and document all material misstatements found during the verification.
Evaluate Conformity with Criteria
Assess any nonconformity; for projects, evaluate implementation, operation, monitoring plan, and prior validations.
Evaluate Changes from Prior Periods
Determine whether incomparable changes from prior periods have been appropriately disclosed.
CA-GHG-003 | Module 4: Opinions | Page 27 of 75
Verification Opinions (Clause 6.3.2)
The type of opinion issued depends on the sufficiency of evidence, the application of criteria, and the effectiveness of controls. A modified opinion must be confined to specific elements and not representative of a substantial portion of the GHG statement.
CA-GHG-003 | Module 4: Verification Report | Page 28 of 75
Verification Report Contents (Clause 6.3.3)
Mandatory Report Elements
  • Appropriate title and addressee
  • Statement of responsible party's responsibility
  • Statement of verifier's responsibility
  • Description of evidence-gathering procedures used
  • The verification opinion
  • Date of the report
  • Verifier's location and signature
  • Summary of the GHG statement
  • Reference to verification criteria
  • Verification scope
Documented Information (Clause 5.4.4)
The verifier must maintain records of:
  • Engagement terms
  • Verification and evidence-gathering plans
  • Who performed activities and when
  • Collected evidence
  • Requests for clarification, misstatements, nonconformities
  • Communication with responsible party on material misstatements
  • Conclusions and opinions
  • Independent reviewer name, date, and comments
CA-GHG-003 | Module 5: Validation | Page 29 of 75
Module 5: The Validation Process
Validation differs from verification because its subject is prospective data and information — generally based on past performance but applied to future activities. The purpose is to provide assurance on the assumptions, limitations, and methods used to develop a GHG statement about future outcomes.
Verification
Historical data — "Is the past statement materially correct?"
Validation
Future estimates — "Are the assumptions and methods reasonable?"
CA-GHG-003 | Module 5: Validation Process Flow | Page 30 of 75
Validation Process — Full Flow (Figure 4)
Figure 4 — Validation process. The validation process mirrors the verification process structure but applies to prospective GHG statements. Key additions include estimate testing, assessment of GHG-related activity characteristics, and evaluation of proper disclosure during execution.
CA-GHG-003 | Module 5: Validation Planning | Page 31 of 75
Validation Planning: Strategic Analysis & Estimate Testing (Clauses 7.1.1–7.1.3)
Strategic Analysis (7.1.1)
The validator must have sufficient understanding of the GHG-related activity to:
  • Identify types of potential material misstatements and their likelihood
  • Select evidence-gathering procedures providing a basis for assessment
Considerations include sector information, nature of operations, criteria requirements, materiality thresholds, proper disclosure, scope and boundaries, SSRs, quantification methods, data management, and uncertainty/sensitivity analyses.
Estimate Testing (7.1.3)
The validator shall evaluate whether assumptions comply with criteria and whether future value estimates are appropriate by assessing:
  • Appropriateness of the estimate methodology
  • Applicability of assumptions in the estimate
  • Quality of data used in the estimate

The validator must develop his/her own estimate or range to evaluate the responsible party's estimate.
CA-GHG-003 | Module 5: Activity Characteristics | Page 32 of 75
Assessment of GHG-Related Activity Characteristics (Clause 7.1.4)
Each characteristic must be assessed through targeted evidence-gathering activities. The validator must confirm calculations, assess conservativeness, and evaluate whether proper disclosure has occurred.
CA-GHG-003 | Module 5: Key Characteristics | Page 33 of 75
Key Validation Characteristics — Deep Dive
Baseline Scenario Selection (7.1.4.5)
Assess whether the baseline is the most appropriate, plausible, and complete hypothetical scenario. Must be credible, documented, repeatable, and recognized by the intended user. Consider conservativeness, uncertainty, common practice, and operating environment.
Secondary Effects / Leakage (7.1.4.7)
For activities asserting emission reductions or removal enhancements, assess whether material economic effects during the GHG statement period will change emissions outside the activity boundary. Assess completeness and accuracy of adjustments.
Uncertainty & Sensitivity (7.1.4.13–7.1.4.14)
Identify uncertainties greater than expected; assess their effect on the GHG statement; determine appropriate course of action. Identify assumptions with high potential for change and assess whether changes are material.
CA-GHG-003 | Module 5: Validation Execution | Page 34 of 75
Validation Execution & Completion (Clauses 7.2–7.3)
Execution (7.2)
  • Conduct validation per the validation plan
  • Conduct evidence-gathering per the evidence-gathering plan
  • Evaluate the GHG statement against validation criteria
  • Assess uncorrected misstatements individually and in aggregate
  • Assess conformity with criteria and re-assess recognition
  • Evaluate proper disclosure: accuracy, completeness, fairness, and alignment with intended users' needs
Validation Report Must Include (7.3.3):
  • Title, addressee, responsible party statement
  • Validator's responsibility statement
  • Description of evidence-gathering procedures
  • Validation opinion
  • Date, location, and signature
  • Description of validated baseline or reference
  • Projected emission reductions or removal enhancements
  • Validation scope
CA-GHG-003 | Module 6: AUP | Page 35 of 75
Module 6: Agreed-Upon Procedures (AUP) — Annex C
Figure C.1 — AUP Process. AUP is used when intended users do not require assurance on the GHG statement but require a qualified verifier to test specific aspects using verification techniques. No opinion is expressed — the intended user(s) assess results and draw their own conclusions. The report contains the AUP and results, including errors and exceptions identified.
CA-GHG-003 | Module 6: AUP Details | Page 36 of 75
AUP — Roles, Application & Appropriate Procedures
Intended User Responsibilities
  • Responsible for the subject matter
  • Takes responsibility for sufficiency of AUP for their purposes
  • Assumes risk of misunderstanding or misusing findings
Appropriate AUP Include:
  • Sampling after agreeing on relevant parameters
  • Inspection of specified documents
  • Confirmation of specific information with third parties
  • Comparison of documents against specified attributes
  • Performance of mathematical computations
Inappropriate AUP Include:
  • Simply reading work performed by others with no supporting material
  • Evaluating competency or objectivity of another party
  • Obtaining a general understanding of a subject
  • Interpreting documents outside the verifier's expertise

Key Rule: AUP shall NOT be used for verification or validation of GHG statements developed in accordance with ISO 14064-1, ISO 14064-2, or ISO 14067. AUP is a separate engagement type.
CA-GHG-003 | Module 6: Mixed Engagement | Page 37 of 75
Mixed Engagements (Annex D)
A mixed engagement combines verification and validation activities performed at the same time and on the same GHG statement. It is not applicable for GHG projects.
When Verification Applies
Emissions, removals, and/or storage are historical and sufficient evidence can be obtained.
When Validation Applies
Emissions, removals, and/or storage will occur in the future and sufficient evidence of likelihood can be obtained.
When AUP Applies
Intended users require results of verification evidence-gathering activities but do not require the verifier's opinion.

A mixed engagement must clearly report to intended users the boundaries, methodology, and results from each type of engagement. Areas not addressed must be identified.
CA-GHG-003 | Module 6: Independent Review | Page 38 of 75
Independent Review (Clause 8)
An independent review must be completed before the opinion is issued. The independent reviewer must be competent and different from the persons who conducted the verification/validation.
Appropriateness of team competencies
Whether verification/validation was designed appropriately
Whether all activities were completed
Significant decisions made during the engagement
Sufficiency and appropriateness of evidence collected
Whether evidence supports the proposed opinion
Conformity with ISO 14064-3, including risk assessment, data trails, and GHG activity characteristics
CA-GHG-003 | Module 6: Opinion Issuance | Page 39 of 75
Issuance of Opinion (Clause 9)
Types of Opinions (9.2)
  • Unmodified
  • Modified
  • Adverse
Opinion Name Variants (Table 1)
Different GHG programmes use different terminology for the same opinion types. For example, "Unmodified" may be called "Unqualified," "Positive," or "Satisfactory" depending on the programme.
Contents of Opinion (9.3)
  • Identification of the GHG-related activity
  • Identification of the GHG statement (date and period)
  • Identification of the responsible party
  • Identification of criteria used
  • Declaration of conformity with ISO 14064-3
  • Verifier's conclusion including level of assurance
  • Validator's conclusion
  • Date of the opinion

For modified opinions, the reason for modification must appear before the conclusion. For forecasts, the opinion must explain that actual results may differ from the forecast.
CA-GHG-003 | Module 6: Post-Opinion | Page 40 of 75
Facts Discovered After Verification/Validation (Clause 10)
Obligation
The verifier/validator must obtain sufficient evidence and identify relevant information up to the date of the opinion.
If New Facts Are Discovered After the Opinion Date
Take appropriate action, including communicating the matter as soon as practicable to the responsible party, the client, and the GHG programme.
Wider Communication
The verifier/validator may also communicate to other interested parties that reliance on the original opinion may now be compromised given the discovered facts or new information.
CA-GHG-003 | Levels of Assurance | Page 41 of 75
Levels of Assurance — Annex A
Figure A.1 — Levels of assurance. Limited assurance has higher verification risk, less extensive evidence-gathering, and uses a negative form of opinion ("nothing has come to our attention..."). Reasonable assurance reduces verification risk to an acceptably low level and uses a positive form of opinion. Neither provides absolute assurance.
CA-GHG-003 | Limited Assurance | Page 42 of 75
Limited Level of Assurance — Key Differences (Annex A)

Rule: A verifier shall not change levels of assurance once an engagement has begun. Insufficiency of evidence cannot be addressed by changing the level of assurance.
CA-GHG-003 | Conservativeness | Page 43 of 75
Interpreting Conservativeness (Annex B.9)
Conservativeness is a principle used to choose between options that are similar in completeness and accuracy. The principles of completeness and accuracy always apply first — conservativeness may then apply.
Organizational Inventory Meeting a Target
Overstatement of the inventory would be conservative — it is harder to meet the target.
Establishing a Base Year
Overstatement of the inventory would be conservative — a higher base year makes future reductions easier to demonstrate.
Project Claiming Emission Reductions for Monetary Value
Understatement of the baseline and overstatement of project emissions would be conservative — it reduces the claimed credits.

This principle applies equally to both verification and validation engagements.
Practical Examples
Practical Examples
The following real-world scenarios demonstrate the application of ISO 14064-3:2019 in practice. Each example includes a scenario description, step-by-step process, and expected outcome.
CA-GHG-003 | Practical Example 1 | Page 45 of 75
Practical Example 1: Verification of an Organization's GHG Inventory
Scenario
A large manufacturing company (ABC Manufacturing Ltd.) has prepared its annual GHG inventory for the period 1 January–31 December 2023, covering stationary combustion, mobile combustion, and process emissions. The company's GHG programme requires a reasonable level of assurance verification. A third-party verification body (Citadel Engineering) is engaged.
Step-by-Step Process
1. Pre-Engagement: Agree on type (verification), level (reasonable), objectives, criteria (ISO 14064-1 + national GHG programme), scope (all three emission categories, 2023 period), and materiality threshold (5% quantitative). 2. Strategic Analysis: Review sector benchmarks, prior verification results, data management system documentation, and quantification methods. 3. Risk Assessment: Identify high inherent risk in process emissions (complex calculations); moderate control risk in mobile combustion (decentralized data collection). 4. Evidence Gathering: Site visit to main facility; sampling of fuel invoices; recalculation of stationary combustion emissions; analytical testing comparing energy intensity ratios to prior years. 5. Completion: One material misstatement identified in process emissions (incorrect emission factor applied). Responsible party corrects the GHG statement. Verifier re-evaluates. 6. Opinion: Unmodified opinion issued after correction.
Expected Outcome
The GHG inventory is verified as materially correct and conforming to criteria. An unmodified opinion is issued, providing the GHG programme and intended users with high confidence in the reported emissions data. The corrected emission factor is documented for future reference.
CA-GHG-003 | Practical Example 2 | Page 46 of 75
Practical Example 2: Validation of a GHG Project (Forestry Carbon Sequestration)
Scenario
A forestry company proposes a GHG project to enhance carbon sequestration through reforestation of 5,000 hectares over 20 years. The project claims projected removal enhancements of 250,000 tCO₂e over the project period. A validation engagement is required before the project can be registered with a voluntary GHG programme.
Step-by-Step Process
1. Pre-Engagement: Agree on validation type, objectives (assess reasonableness of assumptions and methods), criteria (voluntary GHG programme methodology), scope (reforestation activities, 20-year period), and materiality. 2. Strategic Analysis: Review project plan, baseline scenario documentation, monitoring methodology, and sector-specific sequestration data. 3. Estimate Testing: Assess growth rate assumptions, species-specific carbon accumulation factors, and permanence assumptions. Develop independent estimate range. 4. Activity Characteristics Assessment: Evaluate recognition (additionality confirmed), ownership (land title verified), GHG boundaries (leakage from displaced land use assessed), baseline scenario (most plausible alternative land use confirmed), functional equivalence, and uncertainty. 5. Proper Disclosure: Assess whether the GHG statement accurately discloses assumptions, limitations, and uncertainty ranges. 6. Opinion: Modified opinion issued — the validator concludes the assumptions are reasonable but notes that growth rate assumptions are at the optimistic end of the credible range, which is disclosed in the opinion.
Expected Outcome
A modified validation opinion is issued, informing the intended user that the assumptions provide a reasonable basis for the forecast, with a qualification noting the optimistic growth rate assumptions. Actual results may differ materially from the forecast. The project proceeds to registration with the qualification noted.
CA-GHG-003 | Questions & Exercises | Page 47 of 75
Questions & Exercises
Basic Questions
3–5 foundational knowledge questions
Intermediate Questions
3–5 applied knowledge questions
Scenario-Based Question
1 complex real-world scenario
CA-GHG-003 | Basic Questions | Page 48 of 75
Basic Questions (Knowledge Level)
1
Question 1
What is the difference between verification and validation as defined in ISO 14064-3:2019?
2
Question 2
Name three types of GHGs listed in ISO 14064-3:2019 and their chemical symbols.
3
Question 3
What are the five core principles of verification and validation outlined in Clause 4 of ISO 14064-3:2019?
4
Question 4
What is the difference between reasonable assurance and limited assurance in the context of GHG verification?
5
Question 5
List four items that must be agreed upon during pre-engagement activities (Clause 5.1) before a verification or validation can begin.
CA-GHG-003 | Basic Answers | Page 49 of 75
Basic Questions — Model Answers
Q1 Answer
Verification evaluates historical GHG data to determine if the statement is materially correct and conforms to criteria. Validation evaluates the reasonableness of assumptions, limitations, and methods supporting a statement about future activities.
Q2 Answer
Carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆).
Q3 Answer
Impartiality, Evidence-based approach, Fair presentation, Documentation, Conservativeness.
Q4 Answer
Reasonable assurance provides a high but not absolute level of confidence (positive opinion form); limited assurance provides a reduced level of confidence (negative opinion form) with less extensive evidence-gathering.
Q5 Answer
Type of engagement, level of assurance, objectives, criteria, scope, and materiality threshold.
CA-GHG-003 | Intermediate Questions | Page 50 of 75
Intermediate Questions (Application Level)
1
Question 1
A verifier identifies a material misstatement in a GHG statement during execution. The responsible party refuses to correct it within a reasonable period. What actions must the verifier take according to Clause 5.4.1?
2
Question 2
Explain the concept of "performance materiality" and how it differs from the intended user's quantitative materiality threshold. Why is it set lower?
3
Question 3
Under what circumstances is a site visit mandatory during a verification engagement? Name at least four conditions from Clause 6.1.4.2.
4
Question 4
What are the three types of risks that must be identified and assessed in a risk assessment (Clause 6.1.2.2)? How do they relate to each other?
5
Question 5
Describe the key differences between an AUP engagement and a verification engagement. When would an AUP be appropriate?
CA-GHG-003 | Intermediate Answers | Page 51 of 75
Intermediate Questions — Model Answers
Q1 Answer
If the responsible party does not respond appropriately, the verifier informs the client. If the client also does not respond appropriately, the verifier must either issue a modified or adverse opinion, or withdraw from the engagement.
Q2 Answer
Performance materiality is set lower than the intended user's threshold to identify individual misstatements that, when aggregated, might be material. It provides a buffer to catch smaller errors before they accumulate to a material level.
Q3 Answer
Initial verification; subsequent verification without knowledge of prior activities; change of ownership of a material site; misstatements indicating need for site visit; unexplained material changes in emissions; addition of material GHG SSRs; material changes in scope; significant changes in data management.
Q4 Answer
Inherent risk (nature of the GHG activity), control risk (failure of responsible party's controls), and detection risk (failure of verifier's evidence-gathering). Together they determine overall verification risk. Higher inherent or control risk requires lower detection risk (more extensive evidence-gathering).
Q5 Answer
AUP reports on results of specific verification activities without providing an opinion. The intended user(s) assess results and draw their own conclusions. AUP is appropriate when intended users do not require assurance but need a qualified verifier to test specific aspects of a GHG statement.
CA-GHG-003 | Scenario Question | Page 52 of 75
Scenario-Based Question

Scenario: You are a lead verifier at Citadel Engineering engaged to perform a reasonable assurance verification of XYZ Energy's GHG inventory for 2023. During execution, your team discovers the following: (1) XYZ Energy used an outdated emission factor for natural gas combustion that overstates emissions by 8% — above your 5% materiality threshold. (2) XYZ Energy cannot provide calibration records for three key flow meters used to measure fuel consumption at their largest facility. (3) Your independent reviewer raises a concern that the evidence-gathering plan did not adequately address risks at a newly acquired subsidiary that contributes 12% of total reported emissions.
Questions:
  1. What type of opinion would you issue if XYZ Energy corrects the emission factor but cannot provide the calibration records? Justify your answer.
  1. How should you respond to the independent reviewer's concern about the subsidiary? What actions are required?
  1. Draft the key elements of the verification opinion you would issue, including the type of opinion and the reason for any modification.
CA-GHG-003 | Scenario Answer | Page 53 of 75
Scenario-Based Question — Model Answer
Answer 1: Opinion Type
A modified opinion would be appropriate. The emission factor misstatement is corrected (removing the material misstatement), but the inability to provide calibration records represents a scope limitation affecting the verifier's ability to confirm the accuracy of fuel consumption data. The modification is confined to specific elements (flow meter data at one facility) and must be described before the conclusion in the opinion.
Answer 2: Independent Reviewer Concern
The verification team must address the concern by modifying the evidence-gathering plan (approved by the team leader) to include additional evidence-gathering activities at the newly acquired subsidiary. This may require a site visit to the subsidiary. The independent reviewer's concern and the team's response must be documented. The independent review results must be documented before the opinion is issued.
Answer 3: Key Opinion Elements
Type: Modified opinion. Reason: "Except for the possible effects of the matter described in the following paragraph, in our opinion the GHG inventory presents fairly, in all material respects..." Modification paragraph: "We were unable to obtain calibration records for three flow meters at [Facility Name], which measure fuel consumption representing approximately [X]% of total reported emissions. We were therefore unable to confirm the accuracy of the fuel consumption data for this facility."
CA-GHG-003 | Safety & Compliance | Page 54 of 75
Safety & Compliance in GHG Verification
GHG verification and validation activities must be conducted in compliance with applicable health, safety, and environmental regulations, particularly during site visits to industrial facilities.
Personal Protective Equipment
Verifiers must comply with site-specific PPE requirements during facility visits (hard hats, safety boots, high-visibility vests, respiratory protection where required).
Regulatory Compliance
Noncompliance with regulations indirectly related to GHG emissions is a qualitative materiality consideration under ISO 14064-3:2019 (Clause 5.1.7).
Data Confidentiality
Verifiers must maintain confidentiality of all client data and information obtained during the engagement, consistent with engagement terms.
Ethical Requirements
Verifiers and validators must comply with ethical requirements including impartiality, independence, and professional competence throughout the engagement.
CA-GHG-003 | Intentional Misstatement | Page 55 of 75
Intentional Misstatement & Noncompliance (Clause 5.4.3)
What Triggers This Clause?
If a matter comes to the verifier's/validator's attention that causes them to believe in the existence of:
  • Intentional misstatement by the responsible party
  • Noncompliance with laws and regulations
Required Actions
  • Communicate the matter to the appropriate parties as soon as practicable
  • Document the matter and the communication
  • Consider the impact on the verification/validation opinion
  • Consider whether to withdraw from the engagement

Important: The verifier/validator must act promptly. Delay in communicating intentional misstatement could compromise the integrity of the engagement and the verifier's/validator's professional standing.
CA-GHG-003 | Certification | Page 56 of 75
Certification & Evaluation
Assessment Method
Written examination covering basic, intermediate, and scenario-based questions. Minimum passing score: 70%.
Practical Assessment
Participants complete a simulated verification or validation engagement exercise, including risk assessment, evidence-gathering plan, and draft opinion.
Certificate Issued
Citadel Academy Certificate in GHG Verification & Validation (ISO 14064-3:2019) — valid for 3 years with CPD requirements.
Continuing Education
Annual refresher modules available through Citadel Academy to maintain certification and stay current with standard updates.
CA-GHG-003 | Evaluation Criteria | Page 57 of 75
Evaluation Criteria & Competency Framework
Based on ISO 14066 (Competence requirements for GHG validation teams and verification teams), participants are evaluated against the following competency areas:
CA-GHG-003 | Industry Applications | Page 58 of 75
Applications & Industry Use
ISO 14064-3:2019 is applied across a wide range of industries and regulatory contexts. Understanding these applications helps verifiers and validators tailor their approach to sector-specific risks and requirements.
CA-GHG-003 | Industry Sectors | Page 59 of 75
Key Industry Sectors & Applications
Oil & Gas
Verification of Scope 1 emissions from stationary and mobile combustion, flaring, venting, and fugitive emissions. Validation of emission reduction projects.
Manufacturing
Verification of process emissions, energy consumption, and product carbon footprints (ISO 14067). Supply chain GHG reporting.
Forestry & Land Use
Validation of carbon sequestration projects, REDD+ programmes, and afforestation/reforestation activities. Baseline scenario assessment.
Energy & Utilities
Verification of GHG inventories for power generators; validation of renewable energy projects and emission reduction claims for carbon markets.
CA-GHG-003 | Regulatory Applications | Page 60 of 75
Regulatory & Voluntary Programme Applications
Mandatory GHG Programmes
Emissions Trading Schemes (ETS)
EU ETS, UK ETS — annual verification of reported emissions required for compliance and allowance surrender.
National Reporting Obligations
Government-mandated GHG reporting programmes requiring third-party verification.
Credit for Early Action
Verification of emission reductions achieved before mandatory programme start dates.
Voluntary Programmes
Voluntary Carbon Markets
Verification and validation of carbon credits for buying and selling GHG allowances or offsets.
Sustainability Reporting
GRI, CDP, TCFD — voluntary GHG disclosure programmes requiring credible verification.
Corporate Net Zero Commitments
Verification of progress against science-based targets and net zero pledges.
CA-GHG-003 | ISO 14060 Family in Practice | Page 61 of 75
The ISO 14060 Family in Practice
CA-GHG-003 | AUP Examples | Page 62 of 75
AUP in Practice — Example Findings (Table C.2)
The following examples illustrate the difference between appropriate and inappropriate descriptions of AUP findings:

AUP findings must be factual and specific. Vague or general statements are not acceptable in AUP reports.
CA-GHG-003 | Mixed Engagement Example | Page 63 of 75
Mixed Engagement Opinion — Structure Example (Annex D)
The following illustrates the structure of a mixed engagement opinion combining verification, validation, and AUP for a product's GHG statement:
Verification Section
Covers onsite GHG emissions, removals, and storage; material and energy requirements; production data — all historical. Reasonable assurance. Positive form of opinion: "In our opinion, the onsite GHG inventory presents fairly, in all material respects..."
Validation Section
Covers forecast of downstream product use emissions (transportation, product use, disposal) — prospective. Limited assurance. Negative form: "Nothing comes to our attention which causes us to believe that these assumptions do not provide a reasonable basis for the forecast..."
AUP Section
Covers upstream GHG emissions where the verifier does not have access to the full data management system. Specific procedures agreed with intended user. No assurance expressed — factual findings only.
CA-GHG-003 | Why Citadel Academy | Page 64 of 75
Why Choose Citadel Academy?
15+
Years of Experience
Delivering technical training across the engineering and environmental sectors
500+
Certified Professionals
GHG verifiers, validators, and environmental engineers trained and certified
20+
Countries Served
International reach across energy, manufacturing, forestry, and utilities sectors
98%
Client Satisfaction
Consistently high ratings from corporate and government training clients
CA-GHG-003 | Citadel Academy Advantages | Page 65 of 75
Citadel Academy — Our Competitive Advantages
Expert-Led Instruction
All courses delivered by practicing verifiers, validators, and environmental engineers with direct field experience in ISO 14064-3 engagements.
Comprehensive Materials
Full training handbooks, case studies, practical exercises, and digital resources aligned to the latest edition of ISO 14064-3:2019.
Flexible Delivery
Available in-person, online, and hybrid formats. Customized corporate programs available for organizations requiring tailored content.
Recognized Certification
Citadel Academy certificates are recognized by GHG programme administrators, accreditation bodies, and industry employers worldwide.
CA-GHG-003 | Training Delivery Options | Page 66 of 75
Training Delivery Options
Contact Citadel Academy to discuss the most appropriate delivery format for your organization's needs. Volume discounts available for groups of 5 or more participants.
CA-GHG-003 | Related Standards | Page 67 of 75
Related Standards & References
ISO Standards
  • ISO 14044:2006 — Life cycle assessment requirements and guidelines
  • ISO 14050 — Environmental management vocabulary
  • ISO 14064-1 — Organization-level GHG inventories
  • ISO 14064-2 — Project-level GHG emission reductions
  • ISO 14065 — Requirements for GHG validation/verification bodies
  • ISO 14066 — Competence requirements for GHG V&V teams
  • ISO 14067 — Carbon footprint of products
  • ISO/TR 14069 — Guidance for ISO 14064-1 application
  • ISO 19011 — Guidelines for auditing management systems
International Assurance Standards
  • ISAE 3000 — Assurance engagements other than audits or reviews of historical financial information
  • ISAE 3400 — Financial forecasts and projections
  • ISAE 3410 — Assurance engagements on greenhouse gas statements
  • ISRS 4400 — Engagements to perform agreed-upon procedures
IPCC References
  • IPCC Fifth Assessment Report: Climate Change 2013 "The Physical Science Basis"
  • Latest IPCC Assessment Report (for current GWP values)
CA-GHG-003 | Key Takeaways | Page 68 of 75
Key Takeaways — ISO 14064-3:2019
Verification vs. Validation
Verification = historical data; Validation = future estimates. Both require impartiality, evidence-based approach, fair presentation, documentation, and conservativeness.
Engagement Design
Pre-engagement agreement on type, level, objectives, criteria, scope, and materiality is foundational. The level of assurance cannot be changed once an engagement begins.
Risk-Based Approach
Risk assessment drives all evidence-gathering activities. Higher risk = more persuasive evidence required. Inherent, control, and detection risks must all be assessed.
Opinion Types
Unmodified, modified, adverse, or disclaim. The type depends on sufficiency of evidence, application of criteria, and effectiveness of controls.
AUP & Mixed Engagements
AUP reports findings without opinion. Mixed engagements combine verification, validation, and/or AUP with clearly delineated boundaries for each type.
Independent Review
Mandatory before opinion issuance. Reviewer must be competent and independent from the verification/validation team.
CA-GHG-003 | Summary Diagram | Page 69 of 75
ISO 14064-3:2019 — Complete Process Summary
This process applies to both verification and validation engagements, with documentation (Clause 5.4.4) running parallel to every stage. The specific activities within each stage differ between verification (Clause 6) and validation (Clause 7).
CA-GHG-003 | Glossary | Page 70 of 75
Glossary of Key Terms
CA-GHG-003 | BSI Publication Info | Page 71 of 75
Publication Information
British Standard Details
  • Title: BS EN ISO 14064-3:2019 — Greenhouse gases — Part 3: Specification with guidance for the verification and validation of greenhouse gas statements
  • ISBN: 978 0 580 94244 0
  • ICS: 13.020.40
  • Published: 31 May 2019
  • Supersedes: BS EN ISO 14064-3:2012 (withdrawn)
  • UK Committee: SES/1/7 — Greenhouse gas management and related activities
European Standard Details
  • Standard: EN ISO 14064-3 (May 2019)
  • Approved by CEN: 1 March 2019
  • Prepared by: ISO/TC 207 "Environmental management" in collaboration with CCMC
  • Official versions: English, French, German
  • Supersedes: EN ISO 14064-3:2012

Compliance with a British Standard cannot confer immunity from legal obligations.
CA-GHG-003 | BSI Contact | Page 72 of 75
BSI Standards — Useful Contacts & Resources
Customer Services
Tel: +44 345 086 9001 Email (orders): orders@bsigroup.com Email (enquiries): cservices@bsigroup.com
Knowledge Centre
Tel: +44 20 8996 7004 Email: knowledgecentre@bsigroup.com For technical queries and standard interpretations
Copyright & Licensing
Tel: +44 20 8996 7070 Email: copyright@bsigroup.com For permission to reproduce content from BSI publications
Online Resources
Standards shop: bsigroup.com/shop Subscriptions: bsigroup.com/subscriptions ISO Online browsing: iso.org/obp IEC Electropedia: electropedia.org
BSI Group Headquarters: 389 Chiswick High Road, London W4 4AL, UK
CA-GHG-003 | Next Steps | Page 73 of 75
Next Steps After This Training
Review the Standard
Obtain and study BS EN ISO 14064-3:2019 in full, with particular attention to Clauses 5–9 and Annexes A–D.
Complete the Assessment
Submit your written examination and practical engagement exercise to Citadel Academy for evaluation.
Seek Mentorship
Work alongside an experienced verifier or validator on a real engagement to build practical competence.
Obtain Certification
Upon successful assessment, receive your Citadel Academy Certificate in GHG Verification & Validation.
Maintain Competence
Engage in continuing professional development through Citadel Academy's annual refresher modules and industry updates.
CA-GHG-003 | Closing | Page 74 of 75
Thank You
Building Competence. Ensuring Integrity. Advancing Climate Action.
This training handbook has been prepared by Citadel Academy Division — Citadel Engineering Company in accordance with BS EN ISO 14064-3:2019. It is intended for training delivery and commercial presentation purposes.
Training Code
CA-GHG-003
Standard
BS EN ISO 14064-3:2019
Issued by
Citadel Academy Division
Page
74 of 75
CA-GHG-003 | Contact | Page 75 of 75
Contact Citadel Academy
Email Us
academy@citadelengineering.com For course enrollment, corporate training inquiries, and certification questions.
Call Us
Contact your regional Citadel Engineering office for training schedules, pricing, and customized program design.
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www.citadelengineering.com/academy Browse our full catalog of engineering and environmental training programs.
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Training Code: CA-GHG-003 | Reference: BS EN ISO 14064-3:2019 | © Citadel Engineering Company — Citadel Academy Division | Page 75 of 75