What is a additionality?

Additionality is defined in 6/CMP.1, Annex, paragraph 18 as follows:

A small-scale afforestation or reforestation project activity under the CDM is additional if the actual net greenhouse gas removals by sinks are increased above the sum of the changes in carbon stocks in the carbon pools within the project boundary that would have occurred in the absence of the registered small-scale afforestation or reforestation project activity under the CDM (6/CMP.1, Annex, paragraph 18).

In other words, additionality is the requirement that the greenhouse gas removals after the implementation of the SSC A/R project activity are greater than those that would have occurred in the baseline scenario (the most plausible alternative scenario to the implementation of the SSC A/R project activity).  This baseline scenario may be the business-as-usual case (that is, the continuation of current sequestration levels in the absence of the CDM project activity), or it may be some other scenario which involves a gradual increase of sequestration.

Additionality is a principal condition for the eligibility of any project under the CDM. The Kyoto Protocol provides that:

Emission reductions resulting from each project activity shall be certified by operational entities to be designated by the Conference of the Parties serving as the meeting of the Parties to this Protocol, on the basis of: ...

2. Real, measurable and long-term benefits related to the mitigation of climate change; and
3. Reductions in emissions that are additional to any that would occur in the absence of the certified project activity (Kyoto Protocol, Article 12(5)).

Additionality is a requirement for validation, and will be confirmed by the designated operational entity (DOE) as part of the validation report:

The DOE selected by project participants to validate a proposed small-scale afforestation or reforestation project activity under the CDM, being under a contractual arrangement with them, shall review the project design document and any supporting documentation to confirm that the following requirements have been met:

4. The proposed small-scale afforestation and reforestation project activity under the CDM is additional if the actual net greenhouse gas removals by sinks are increased above the sum of the changes in carbon stocks in the carbon pools within the project boundary that would have occurred in the absence of the registered small-scale afforestation or
   reforestation project activity under the CDM, in accordance with paragraphs 18-19 below (6/CMP.1, Annex, paragraph 15(d)).

Paragraphs 18 and 19 set out the requirements relating to baselines and additionality.

DOEs must also assess project participants' prior consideration of the CDM. If projects start on or after 2 August and have not been published for global stakeholder consultation, the DOEs must ensure project participants have informed the host party DNA or the UNFCCC secretariat of their intention to seek CDM status.

For a new project activity with a start date on or after 2 August 2008 and for which PDD has not been published for global stakeholder consultation or a new methodology proposed to the Executive Board before the project activity start date, the DOE shall ensure by means of confirmation from the DNA or UNFCCC secretariat that PPs had informed the Host Party DNA and/or the UNFCCC secretariat in writing of the commencement of the project activity and of their intention to seek CDM status. If such a notification has not been provided by the project participants the DOE shall determine that the CDM was not seriously considered in the decision to implement the project activity (EB 44, Annex 3, paragraph 99).

If the projects start date before 2 August 2008, DOE's must assess the project participant's prior consideration of the CDM using document reviews.

For an existing project activity with a start date before 2 August 2008, for which the start date is prior to the date of publication of the PDD for global stakeholder consultation, the DOE shall assess the project participant's prior consideration of the CDM through document reviews and shall satisfy following requirements:

1. Evidence that must indicate that awareness of the CDM prior to the project activity start date, and that the benefits of the CDM were a decisive factor in the decision to proceed with the project.
2. Evidence to support this would include, inter alia, minutes and/or notes related to the consideration of the decision by the Board of Directors, or equivalent, of the project participant, to undertake the project as a proposed CDM project activity.
3. Reliable evidence from project participants that must indicate that continuing and real actions were taken to secure CDM status for the project in parallel with its implementation. Evidence to support this should include, inter alia, contracts with consultants for CDM/PDD/methodology services, Emission Reduction Purchase Agreements or other documentation related to the sale of the potential CERs (including correspondence with multilateral financial institutions or carbon funds), evidence of agreements or negotiations with a DOE for validation services, submission of a new methodology to the CDM Executive Board, publication in newspaper, interviews with DNA, earlier correspondence on the project with the DNA or the UNFCCC secretariat (EB 44, Annex 3, paragraph 100).