It is essential for any carbon neutral program to be robust and to offset all remaining emissions of the defined subject to zero. This requires that any carbon credits used must have credibly demonstrated additionality during their development process.
The carbon accounting standards which are eligible under The CarbonNeutral Protocol require each project to undergo tests for additionality, which is then checked by an independent third- party auditor during the validation process.
Without well-defined baseline scenarios and additionality tests, any claims of net emissions reductions would lack environmental integrity (i.e. they would not be reductions in the first place). Any statement by an organization based upon these claimed “reductions” could be misleading or false.
Therefore, it is important that the additionality of a project is robustly tested and audited. The carbon accounting standards referenced in this guidance define best practice in assessing and determining the additionality of emission reduction projects.
When testing for additionality on a proposed project, the first step is to determine the baseline scenario – i.e. the hypothetical description of what would have most likely occurred in the absence of any intervention to mitigate the impact of GHG emissions. The baseline for a project activity is the projected GHG emissions that are calculated to occur in the absence of the proposed project activity. Once a suitable baseline has been determined it must be validated. Validation requires a third-party audit by a qualified auditor to ensure the baseline meets the requirements of the given carbon accounting standard and methodology.
When the project activity is in progress, GHG emissions from within the project area can be monitored and verified. Any reduction of emissions as compared to the baseline of the project are therefore additional and can be verified and issued as carbon credits (CERs, VCUs, GS VERs, CRTs, ERTs) in accordance with the rules of the applicable carbon accounting standard.
For a more detailed, technical discussion of the methods for calculating additionality or how best to define additionality, see the following resources:
cdm.unfccc.int/Reference/Guidclarif/glos_CDM.pdf
The UNFCCC Clean Development Mechanism Glossary
https://verra.org/wp-content/uploads/2018/03/VCS-Guidance- Standardized-Methods-v3.3_0.pdf
See section 4.6 of the Verra guidance document: “Guidance for Standardized Methods” (8 October 2013, v3.3) for methods for determining additionality within a CarbonNeutral Protocol eligible carbon accounting standard
Search “additionality” for articles on the challenges of defining and measuring additionality
https://www.offsetguide.org/high-quality-offsets/additionality/ high-quality-offsets-additionality-how-carbon-offset-programs- address-additionality/
Further information on methodologies for determining additionality