Scientific review: approaches to carbon additionality
Evaluating common carbon additionality tests and their suitability for inclusion in the Woodland Carbon Code
Carbon additionality is used to calculate the extent to which a project or activity results in net greenhouse gas emissions savings or sequestration above and beyond those that would have occurred even if the project had not taken place. Forest Research carried out a thorough review of the principles and methodologies for additionality assessments, providing the Forestry Commission with an evidence base for its Woodland Carbon Code.
Key findings and recommendations
Additionality is multi-faceted – at least 23 forms of additionality
Differences in tests relate to rigour-cost trade-offs rather than differences between ex-post and ex-ante crediting
Significant effects from “hidden” mechanisms seldom covered explicitly by additionality tests (e.g. gaming additionality)
Determining additionality is imprecise and is likely to remain controversial even where comparatively stringent tests are applied