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Analysis and Evaluation of the CORSIA Offsetting Mechanism for use in International Aviation

Background and Objective

In October 2016, the International Civil Aviation Organisation (ICAO) agreed the introduction of a global market-based instrument, the Carbon Offset and Reduction Scheme for International Aviation (CORSIA). CORSIA is designed as a major component of the ICAO package of measures to reduce the climate impact of international aviation and contribute to climate-neutral growth in the aviation sector based on 2020 emission levels. CORSIA’s detailed rules are currently the subject of policy-level negotiations led by the ICAO in which potential linkages with the market-based instruments contained in the Paris Agreement are to be taken into account. Funded by the German Environment Agency (UBA), the project on the “Analysis and assessment of the design of an offsetting system for international aviation” aims to inform the negotiations on CORSIA’s design.   


As part of the UBA-funded project, researchers from Öko-Institut, the Stockholm Environment Institute and the NewClimate Institute assessed and evaluated various issues considered critical in implementing CORSIA and achieving climate-neutral growth. The research topics were published in discussion papers.

One discussion paper analysed the Emission Unit Eligibility Criteria (EUC) adopted in March 2019. The EUCs set out the requirements that carbon-offsetting programmes must meet to be eligible to supply carbon offset credits for use under the CORSIA scheme. The authors conclude that, for the most part, the current EUCs deliver the design components needed in assessing the environmental integrity of carbon offsetting programmes. However, the review of the EUCs showed that they could benefit from a more detailed description of the key programme requirements and procedures.  

A second discussion paper estimates under different scenarios the potential carbon offset credit supply to the CORSIA scheme. The authors find that existing activities conducted under the four programmes could supply some 18 billion offset credits for emission reductions achieved between 2013 and 2035. This equates to more than six times the total expected demand under CORSIA during that same period. Other unused offset credits are also available in addition to this future supply. The authors thus conclude that the ICAO must introduce eligibility restrictions if CORSIA is to result in additional emission reductions. 

In a third discussion paper, the authors analyse the provisions that could be adopted and implemented under the Paris Agreement to avoid double counting between CORSIA and nationally determined contributions (NDCs). The authors find that some of the approaches considered under Article 6 for use in accounting for emission reductions either cannot be used under CORSIA or are not necessarily robust. The discussion paper sets out various options and approaches to improve the accounting rules which should be taken into account in the negotiations on Article 6. 

Results and Outlook

In November 2019, a final project report was published summarising the key research results contained in the three discussion papers. The results of the project were presented to international experts at several events. 

Analysis and Evaluation of the CORSIA Offsetting Mechanism for use in International Aviation

Role of BMU: Research funding

Lifecycle: 2017 - 2019

Implementation: Öko-Institut e.V.

Other Organisations Involved: Stockholm Environment Institute, NewClimate Institute

Contact: Lambert Schneider,

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