What is a baseline?

The baseline (or 'baseline scenario') for a small-scale CDM project activity is defined in 4/CMP.1, Annex II, paragraph 27 as follows:

The baseline for a [small-scale] CDM project activity is the scenario that reasonably represents the anthropogenic emissions by sources of greenhouse gases that would occur in the absence of the proposed project activity (4/CMP.1, Annex II, paragraph 27).

In other words, a baseline for a CDM project activity is a hypothetical reference case, representing the volume of greenhouse gases  that would have been emitted if the project were not implemented.  Therefore, the baseline can be used to determine:

• whether a CDM project activity is additional; and
• the volume of additional greenhouse gas emission reductions achieved by a project activity.