A6.4 mechanism
Short form for the mechanism established by Article 6, paragraph 4, of the Paris Agreement.
Definitions & Vocabulary
UNFCCC/ETF and Article 6 vocabulary — short, consistent terms so Parties and partners use the same language across BTR text and annexed tables.
LoA → Adjustment → Validator → Annual Information → BTR · evidence-ledWhat this page covers
- Core Article 6 vocabulary and ETF/BTR reporting
- Programme terms like allocation and escrow events
- Buyer, trader, developer, insurer concepts used on this site
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A
A6.4ERs
Article 6, paragraph 4, emission reductions issued under the A6.4 mechanism.
Accreditation
Process by which the Supervisory Body recognizes an operational entity as a DOE for A6.4.
Acquiring Party
Participating Party that acquires ITMOs for use (e.g., towards its NDC or for other international mitigation purposes).
Additionality
Condition that the mitigation would not have occurred in the absence of incentives from the mechanism and beyond legal requirements.
Adjustment (corresponding)
Accounting adjustment applied by Participating Parties to avoid double counting when ITMOs or A6.4ERs are authorized for use and transferred internationally.
Authorization (LoA)
Formal decision by a Participating Party (typically via a Letter of Authorization, LoA) specifying whether mitigation outcomes (ITMOs or A6.4ERs) are authorized for use towards its NDC and/or for other international mitigation purposes.
Authorization scope
Statement within an authorization specifying whether units are authorized for use towards the authorizing Party’s NDC, for other international mitigation purposes, or both.
Annual Information (Article 6)
Information submitted annually by Participating Parties on cooperative approaches under Article 6.2, including authorization, creation/issuance, first transfer, acquisition, use, and corresponding adjustments; feeds the Article 6 Technical Expert Review.
B
Baseline
Reference emissions or removals level against which mitigation outcomes are quantified under methodologies.
BTR
Biennial Transparency Report submitted under the Enhanced Transparency Framework (Article 13).
C
CMA
Conference of the Parties serving as the meeting of the Parties to the Paris Agreement.
COP
Conference of the Parties to the UNFCCC.
Corresponding adjustment
Accounting adjustment applied by Participating Parties to avoid double counting when ITMOs/A6.4ERs are used.
CORSIA
Carbon Offsetting and Reduction Scheme for International Aviation adopted by ICAO.
CRT
Common Reporting Tables for national GHG inventory reporting in BTRs.
CTF
Common Tabular Formats for tracking NDC progress and reporting support.
Cooperative approach
Approach under Article 6.2 whereby Parties cooperate in the transfer and use of ITMOs consistent with guidance adopted by the CMA.
Regular information (Article 6.2)
Material submitted by a Participating Party as an annex to its BTR that contains the CTF tables and narrative required for Article 6.2 participation.
Cancellation
Act of rendering a mitigation outcome unusable for further transfer or use (e.g., for results-based climate finance or non-NDC uses), recorded in the relevant registry.
D
DNA
Designated National Authority responsible for Article 6 authorizations in a Host Party.
DOE
Designated Operational Entity accredited to validate and verify A6.4 projects and programmes of activities.
E
ETF
Enhanced Transparency Framework under Article 13 of the Paris Agreement.
EUEC
Emissions Unit Eligibility Criteria under CORSIA specifying program-level integrity requirements.
F
FMCP
Facilitative, Multilateral Consideration of Progress under the ETF.
First transfer
The first international transfer of an ITMO from the registry/account of the authorizing/Host Party; triggers accounting (e.g., for corresponding adjustments) consistent with Article 6.2 guidance.
G
GST
Global Stocktake under Article 14 that assesses collective progress every five years.
GWP
Global Warming Potentials used to convert gases to CO2-equivalent.
H
Host Party
Party authorizing use of A6.4ERs and participating in cooperative approaches.
I
IPCC
Intergovernmental Panel on Climate Change, provider of inventory guidelines.
ITMO
Internationally Transferred Mitigation Outcome used towards an NDC under Article 6.2.
K
Key category analysis
Identification of source and sink categories that have a significant influence on a country’s inventory level, trend or uncertainty.
L
Leakage
Changes in emissions/removals outside the activity boundary attributable to the activity (positive or negative).
LULUCF
Land Use, Land-Use Change and Forestry sector in national inventories.
M
Materiality
Thresholds used by DOEs during verification to determine whether an error or omission could influence results.
Monitoring plan
Plan describing parameters, methods and QA/QC to monitor an activity’s outcomes for verification/issuance.
MPGs
Modalities, Procedures and Guidelines for the ETF (decision 18/CMA.1).
N
NDC
Nationally Determined Contribution under Article 4 of the Paris Agreement.
NDC Common Tabular Formats
Machine-readable tables Parties submit under the ETF that present indicators and accounting information to track progress toward the NDC.
National Inventory Document
Textual document accompanying the inventory CRTs that explains methods, data sources, QA/QC, key categories and recalculations.
NIR
National Inventory Report of anthropogenic emissions by sources and removals by sinks of greenhouse gases.
Non-permanence
Risk that achieved removals or reductions are reversed (especially for removals activities) and how it is addressed.
P
Pre-BTR confirmation
Programme term used by BTR Prime to denote an evidence memo that host and acquiring Party Annual Information entries match for the relevant year(s). This practical confidence step supports market processes ahead of BTR publication and does not replace UNFCCC reviews (Article 6 TER or ETF Technical Expert Review).
Participating Party
A Party participating in a cooperative approach under Article 6.2 (Host or Acquiring Party).
Paris Agreement
International treaty under the UNFCCC adopted in 2015 that aims to limit global warming and strengthen climate resilience.
PoA
Programme of Activities under Article 6.4 (bundle of component projects).
Q
QA/QC
Quality Assurance / Quality Control procedures applied to inventory preparation and reporting.
R
Recalculation
Update of previously submitted estimates to reflect methodological improvements or new data, applied consistently across the time series.
Registry (Article 6)
System that records authorization, creation/issuance, first transfer, acquisition, use and cancellation of mitigation outcomes for cooperative approaches and/or the A6.4 mechanism.
S
Standardized baseline
Baseline established for a sector/region to facilitate consistent quantification under methodologies.
Structured summary
ETF reporting element that compiles indicators and accounting information in CTFs to track progress towards the NDC.
T
TER
Article 6 Technical Expert Review of information on cooperative approaches (including initial, annual and regular information), conducted by an Article 6 technical expert review team (TERT).
TERT
Article 6 Technical Expert Review Team that conducts the TER.
Technical Expert Review (ETF)
Technical Expert Review of a Party’s BTR under the Enhanced Transparency Framework (Article 13), distinct from the Article 6 TER.
U
UNFCCC
United Nations Framework Convention on Climate Change.
Use (Article 6)
Application of an authorized ITMO/A6.4ER to an end use (e.g., towards an NDC or other international mitigation purposes) as recorded in the registry and reflected in accounting.
Uncertainty analysis
Quantitative assessment of the uncertainty associated with emission and removal estimates, consistent with IPCC guidance.
Inventory Management System
Domestic system of institutional, legal and procedural arrangements for preparing, archiving and improving the national GHG inventory.
V
Validation
Independent assessment by a DOE that a proposed project or PoA meets applicable A6.4 rules.
Verification
Independent assessment by a DOE of the monitored emission reductions or removals prior to issuance.