These Guidelines are intended to facilitate the avoidance of double counting of greenhouse gas (GHG) emission reductions under the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), adopted by the International Civil Aviation Organization (ICAO) in 2016. The Guidelines aim to help entities that manage carbon offset-crediting programs (hereafter referred to as “programs”), as well as project owners, governments, non-governmental organizations, and other stakeholders, identify how and under which conditions double counting can occur, and offer guidance and good practice examples for avoiding different forms of double counting. The Guidelines could also inform the wider implementation of carbon market approaches, including in the context of the Paris Agreement.


The Guidelines were developed by the Avoiding Double Counting (ADC) Working Group, through a multi-stakeholder consensus decision-making process. The members of the working group are listed below. The ADC Working Group defined consensus as no dissent. The entire content of the Guidelines reflects a consensus outcome of the ADC Working Group, with one important exception:


ADC Working Group members Carbon Market Watch, Environmental Defense Fund, and World Wildlife Fund stress that while paragraph 77d in the Annex to Decision 18/CMA.1 on "Modalities, procedures and guidelines for the transparency framework for action and support referred to in Article 13 of the Paris Agreement" and paragraph 17 of Decision 4/CMA.1 on "Further guidance in relation to the mitigation section of decision 1/CP.21” provide important foundational elements for avoiding double counting, application of these CMA Decisions:

a) does not necessarily represent best practice,

b) may not be sufficient to avoid all forms of double counting, and

c) could be undermined by future CMA decisions.

For example, if the CMA were, in the future, to decide that Parties need not make corresponding adjustments when authorizing the use, for purposes other than towards NDCs, of credits issued for emissions reductions and removals originating outside the scope of NDCs, such a decision, in the view of these Working Group members, would allow double counting of mitigation efforts with CORSIA, undermining CORSIA’s environmental integrity. In such a case, these Working Group members would object to the use of such double counted credits for CORSIA compliance even though the Guidelines could be interpreted to allow such use.


American Carbon Registry

Carbon Market Watch

Climate Action Reserve

Environmental Defense Fund

Gold Standard Foundation

International Emissions Trading Association


World Wildlife Fund