Additionality

Projects registered as carbon reduction projects under the Clean Development Mechanism and Joint Implementation Mechanism must cause a drop in emissions further to those which would have occurred in the absence of these mechanisms

Source:

Climate Action Network International, "Climate Change Basics Glossary," Available Online at http://www.climatenetwork.org/climate-change-basics/climate-change-basics-glossary/?searchterm=glossary.  Retrieved October 27, 2008