additionality
noun [ U ]
uk/əˌdɪʃəˈnæləti/ us ECONOMICS, FINANCE UK
the situation in which a government or organization is able to get money for a project from another government or organization, especially the European Union, only if it pays for most of the project itself:
The principle of 'additionality', decrees that money should go only to projects that would not have gone ahead with normal public sector funding.
ENVIRONMENT
the reduction in the amount of carbon dioxide gas released into the environment that happens only as a result of trading carbon credits:
The buzzword in the industry is "additionality" - the idea that offset purchases lead to additional greenhouse gas reductions.