Avoiding double counting between CORSIA and NDC's

This discussion paper assesses how robust accounting could be implemented under the Paris Agreement in order to avoid double counting between nationally determined contributions (NDCs) and the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) implemented under the International Civil Aviation Organization (ICAO). The paper focuses on how host countries of carbon-offset projects can account for the use of offset credits under CORSIA by reporting 'adjustments' in the 'structured summaries' of their biennial transparency reports prepared under Article 13 of the Paris Agreement.

The paper finds that several accounting approaches considered in the international negotiations on Article 6 of the Paris Agreement for international transfers of mitigation outcomes between countries cannot not be implemented in the specific context of CORSIA where the offset credits are used by airline operators or may not robustly avoid double counting.