Application checks

1.  Companies applying with carbon offset products for certification must be registered with a national authority.

2. A detailed description of the proposed emissions datasets and methodologies to be used for all calculations must be provided at the point of application.

3. Carbon credits used to balance QAS Certified offsets must meet the strict eligibility criteria of the Procedures, anchored to the ICVCM’s Core Carbon Principles and CORSIA assessment.

4. Excluded methodology families must not be used — including most grid-connected renewable energy, survey-based cookstoves, and land-use projects crediting against avoided-deforestation baselines.

5. Industrial gas credits (HFC-23, nitric acid, adipic acid) may be used only under the modern, conservative methodology versions the Procedures permit.

6. Projects with non-permanent storage (forestry, soil carbon) must contribute to a programme-level buffer pool insuring against reversals.

7. The QAS, its Directors and any related bodies never provide paid consultancy to applicants: certification cannot be bought, only earned.

8. Every audit is conducted by an accredited Independent Auditor; once audit begins the QAS steps back, and applicants’ commercial data is seen by the auditor alone.

9. ‘Avoidance credits must already have delivered their emission reductions when issued — never ex-ante. Removal credits may be contracted for future delivery only under a binding contract, with a replacement remedy and clear disclosure at the point of sale.

Emissions calculations

10.  QAS-Certified carbon offsets must be calculated from a particular activity over a defined period of time.

11.  Real world data sets should be used in preference to modelled data where available, for example measured route-specific airline fuel consumption data.

12.  Modelled calculation methodologies must use an accepted methodology where available, including the WRI Greenhouse Gas Protocol, national methodologies such as DESNZ and the EPA, and those produced by respected independent organisations such ISO, IEA, IPCC and the EU.

13.  Emissions calculations must be based on the most recent datasets available at the time of application or renewal for QAS certification.

14.  Where a methodology describes more than one method of calculating emissions, the offset provider should use the most accurate figures available for each defined activity.

15.  Summary methodology information should be made available to consumers and must be accurate and concise.

16.  Different emissions factors should not be used for renewable energy tariffs where grid-average figures already account for the renewable fuel mix.

17.  Scope 2 offset volumes default to location-based grid factors; market-based reductions require high-integrity sourcing such as PPAs or on-site generation.

18.  A minimum radiative-forcing multiplier of 1.7 must be applied to all flight emissions.

19.  Providers must disclose the basis on which flight emissions are calculated, including the distance basis and any uplift factors applied.

20.  Modelled calculation using average flight distance or actual Great Circle flight distances must uplift by 8% to take into account indirect routing and delays.

21.  Modelled calculation using car test cycle emission factors must uplift by 23% to convert to ‘real-world’ emission factor values.

22.  Plug-in hybrids must be calculated from actual fuel consumed, or with a 300% uplift on manufacturer figures.

Transparency checks

23.  All references made to a QAS Certified offset must either refer prominently to the activity and period of time against which it is made, or link to a page where that information is displayed.

24. At least two out of three of the following must be provided to consumers at or before the point of sale: total price, price per tCO2e and total tCO2e. It should also be clear to the consumer if the sales taxes are included or excluded where they exist in the country of purchase.

25.  Summary calculation methodology information should be made available at or before the point of purchase.

26.  All non QAS-certified offsets must be clearly separated from QAS-certified offsets to avoid any potential confusion by consumers.

27.  Marketing and advertising must be clear and truthful, complying with the CMA Green Claims Code, EU Directive 2024/825 and the FTC Green Guides. Stakeholders must not be misled.

28.  Use of the QAS Quality Mark must adhere to the Quality Mark Licence Agreement, for the duration of certification only.

29.  Every online use of the Quality Mark must link to the QAS certified register, so anyone can check a claim in one click.

30.  Providers back every claim they make — and any claim wording they supply to clients — with a substantiation file open to the Independent Auditor.

31. In the EU and UK, certified offsets are communicated as climate contributions — and the QAS also certifies standalone Climate Contributions of a client-chosen quantity. Unqualified ‘carbon neutral’ product claims must not be made.

32. Offsets used against organisational emissions must state exactly which emission scopes they cover.

33.  QAS Certification must never be used to substantiate future net-zero targets unless independently supported by published, verifiable transition plans.

Renewal checks

34.  Organisations wishing to renew QAS-Certified carbon offsets must confirm any changes to the information provided at application in writing.

35.  A Statement of Account must be provided showing total sales of QAS Certified and non QAS Certified carbon offsets, plus the credit retirement information to balance both accounts over the prior period of QAS-Certification. Both accounts must net to zero.

36. The Statement of Account must be signed off by a qualified accountant or auditor.

37.  All QAS Certified offsets sold during the certification period must be balanced by credits retired on the designated public registry within six months of the period’s end, with direct evidence verified by the Independent Auditor.

38.  Credits retired in advance of sale must be exclusively reserved against QAS Certified offsets and never counted against any other sale, claim or obligation.

39.  Certification decisions may be appealed to persons who took no part in the assessment, and anyone may raise a complaint, which the QAS must investigate and answer.

40.  All QAS Certified offsets must undergo renewal audit 12 months later; the status of every offset — including any that lapses unverified — is published on the QAS website.

QAS Certification Procedures

Download the QAS Certification Procedures Carbon Offsets v2.8 (pdf)

This is the full & definitive set of rules for the QAS Carbon Offset Standard.

Back to top