Additionality
Additionality is the extent to which an intervention causes an outcome beyond what would reasonably have occurred without it. Applying Additionality requires a stated emissions scope, inventory boundary, baseline, energy system, and assessment horizon. Those choices determine how Additionality can be compared or acted upon.
In simple terms
In practical use, Additionality is the extent to which an intervention causes an outcome beyond what would reasonably have occurred without it. For Additionality, the label organizes a condition or relationship but does not by itself demonstrate performance or compliance within a declared emissions scope, inventory boundary, baseline, energy system, and assessment horizon. Because the counterfactual cannot be observed directly, the conclusion depends on transparent evidence, assumptions, and a credible baseline. Additionality connects with Carbon offset and Climate change; each can affect its application without sharing its definition. The candidate link between Additionality and Grid emissions factor remains a separate expansion question supported here by UNFCCC Article 6.4 Supervisory Body.
Why it matters
Additionality matters because decisions about it determine which emissions enter an inventory, which transition option appears credible, and how progress is compared over time. A defensible use of Additionality therefore exposes its boundary, method, evidence, responsible actor, and uncertainty before a conclusion is accepted. That discipline keeps Carbon offset and Climate change from being treated as proof of Additionality when their criteria, scope, or results differ.
Example
An emissions and energy team evaluates Additionality for a defined decision and records the relevant emissions scope, inventory boundary, baseline, energy system, and assessment horizon. For Additionality, the team uses cited material from UNFCCC Article 6.4 Supervisory Body to frame the decision and distinguish the idea from adjacent concepts, documenting the period, data, assumptions, and comparison with Carbon offset. It treats Climate change and Grid emissions factor as separate questions rather than proxies for Additionality.
How it differs
Carbon offset
Additionality is a concept; Carbon offset has a different function. Evidence for Carbon offset does not establish Additionality unless both sets of applicable criteria are met.