Additionality

Additionality is one of the central concepts behind the practice of offsetting.  Additional emissions reductions are those which occur only because of the altered set of incentives created by GHG markets -- if something can be considered business as usual it is not additional. In other words, countries and/or firms must make an active contribution to emission reduction in order to earn or sell credits instead of relying on pre-existing projects planned for other reasons. The Kyoto Protocol requires that emission reductions from Clean Development Mechanism and Joint Implementation projects must be additional to those emissions cuts that would occur anyway under the baseline scenario.  Carbon offsets in voluntary markets are considered additional if they represent a project that would not have existed if it had not specifically been an offset project.  Financial additionality is a CDM requirement stating that projects within the CDM framework must not be funded by existing Official Development Assistance commitments; additional funding must be specifically committed to achieving greenhouse gas reductions.

Environmental additionality requires that emission reductions represent a physical reduction or avoidance of emissions over what would have occurred under a business as usual scenario.