2.4 Updates to Methodologies

2.4.1 Triggers for reviewing a methodology

2.4.1.1 Methodology Update Schedule

Methodologies and modules are reviewed periodically every 5 years. Alternatively, NCS may initiate a review at any time if a significant development in technology, legislation or scientific knowledge is perceived. Such a review must be completed within 6 months of receipt of the development.

If a review leads to a significant change in a methodology or module, it must go through the certification process for methodologies (2.1).

Changes are documented and processed according to the versioning of the methodologies (2.4.3). The changes are published together with the results of the public consultation (2.2). All versions of the methodologies and modules are archived and made publicly accessible.

NCS reserves the right to suspend and/or withdraw a methodology if there are credible, evidence-based concerns that the climate impact is overestimated or that additionality is not ensured. In such exceptional cases, NCS may take immediate action to suspend and/or withdraw a methodology. The methodology can then be reintroduced after the usual public consultation period in the event of a material change.

2.4.1.2 Changes in Reference Standards

All NCS-certified methodologies shall be independently validated against the latest version of ISO 14064-2. Currently, this is ISO 14064-2:2019.

Methodology developers shall ensure that any reference standards they may use in their methodology, such as the CDM Additionality Tool, are up to date.

This will be routinely ensured according to the 5-year update schedule.

2.4.2 Effects of an update on existing projects and issued certificates

Projects validated according to a previous version of a methodology and verified certificates remain unchanged until the project is revalidated, unless otherwise stated in the updated methodology with an explanation.

2.4.3 Methodology Versioning

The version numbers are updated according to the standard procedure of semantic versioning, whereby three positive integers A.B.C denote the version of the methodology.

• Major (integer A) - Is updated if the changes to the method have a significant impact on the issuing of certificates. A new major version must only be adopted by new projects seeking their first validation or by existing projects seeking their next crediting period extension. This version must follow the certification process for methodologies (2.1).

• Minor (Integer B) - Updated when the changes to the method have a significant impact on the issuance of certificates. All existing projects that have been validated with the corresponding major version must adopt this new minor version within a certain period of time. This version must follow the certification process for methodologies (2.1).

• Patch (Integer C) - Is updated if non-essential content has been changed in the method. For example, clarifications, corrected typos or references. This version does not need to follow the methodology certification process (2.1) and the public consultation requirements (2.2) do not need to be met. A full change log for each methodology, together with all previously published versions and their publication dates, is publicly available on the Nature Value website.