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OpenAir’s Response to the UNFCCC Supervisory Body’s Information Note on Removal activities under the Article 6.4 mechanism

OpenAir's submitted response to the UNFCCC Supervisory Board's commentary on carbon removals under the Article 6.4 mechanism (A6.4-SB005-AA-A09), May 24, 2023

May 24, 2023

Supervisory Body

United Nations Framework Convention on Climate Change (UNFCCC)

By Email: Supervisory-Body@unfccc.int 

RE:  Input to SB005 2022 Annotated Agenda and Related Annexes

Dear Supervisory Body: 

Thank you for your continuing efforts to ensure that the UNFCCC incorporates high-quality carbon dioxide removal (CDR) into a future Article 6.4 mechanism. OpenAir is an all-volunteer, member-led, and global organization dedicated to the responsible and equitable advancement of carbon removal. We  very much appreciate your invitation to provide input in advance of the Fifth Meeting of the Supervisory Body on 31 May, 2023. 

Specifically, we would like to share some thoughts in response to the Information Note entitled “Removal activities under the Article 6.4 mechanism” (A6.4-SB005-AA-A09 version 0.40):

1. The Note does not consistently reflect the clear scientific consensus that CDR will be needed at gigatonne scale by mid-century for us to have any chance of limiting warming to 1.5 or even 2°C. The recent IPCC AR6 Synthesis Report goes so far as to assert that this gigatonne-scale CDR is “unavoidable.” We would request that this scientific consensus be consistently reflected in the Article 6.4 deliberations and resulting mechanism.

2. We are extremely concerned by the assertion in Table 3.2 of the Note that “engineered” CDR “activities do not contribute to sustainable development, are not suitable for implementation in the developing countries [sic] and do not contribute to the reducing the global mitigation costs, and therefore do not serve any of the objectives of the Article 6.4 mechanism.” These assertions are demonstrably false on every level, contradictory to global scientific consensus including the IPCC, and should be removed from the draft. Speaking specifically to the sustainable development assertion, we would be happy to connect with Supervisory Body with the *many* companies and organizations doing amazing work to equitably and responsibly deploy CDR in the Global South.

3. We are additionally concerned by the assertion in Table 3.2 of the Note that “engineered” CDR methods are “technologically and economically unproven.” CDR is a new commercial sector, and the range of potential pathways are at varying stages of discovery, development, and deployment. However the sector is advancing quickly, and there are  a number of approaches ready for eligibility under Article 6.4 now, with more expected to reach that stage of maturity in coming years. Given this dynamism, we recommend that the Supervisory Body rethink this language, and consider a method-neutral, criteria based framework for eligibility of CDR under a future 6.4 mechanism. See #4 below for more detail on this point.

4. It is important to highlight that CDR encompasses a range of pathways, from land-based soil and forest carbon sinks; biomass-based carbon removal and storage (BiCRS); to marine carbon dioxide removal (mCDR); to mineralization-based approaches; to direct air capture (DAC) – as  well as emergent and potentially as yet undiscovered methods. The Note currently focuses heavily on “land-based” solutions – which are necessary but insufficient to meet our climate goals – and enumerates only four of the many potential CDR pathways as “engineering based activities,” a label we do not recommend given that virtually every CDR approach is a hybrid of nature and engineering. We would suggest, instead of labeling and enumerating individual CDR pathways, that the Supervisory Body define the criteria that a given CDR project must demonstrate to be eligible under the Article 6.4 mechanism – and let science, innovation, and the market compete to deliver the solutions offering the greatest climate impact and other co-benefits. We further recommend that the Supervisory Body follow the IPCC’s lead to define CDR as” anthropogenic activities removing carbon dioxide (CO2) from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products” (IPCC AR6 WGIII Report p1,796) – and not create a new definition. The Carbon Business Council recently published an Issue Brief on defining CDR for policy that could be a helpful resource in this regard.

5.Finally we are concerned by the emphasis in the Note on tonne-year accounting, a concept that has little to no current acceptance in the CDR sector, and that is problematic in its application in terms of devaluing the high-quality long-duration CDR approaches necessary to counterbalance residual fossil carbon emissions, and durably remove carbon dioxide from the atmosphere. We urge the Supervisory Body to consider the voluminous feedback you have received to date on this issue, and further point you to important research from Carbonplan and Carbon Direct on tonne-year accounting.

We would be pleased to discuss these issues further with the Supervisory Body, and greatly appreciate your continuing work to achieve a safe, just and equitable climate future, as well as the opportunity to submit this input for your consideration. 


Toby Bryce – Policy and Market Development, OpenAir

Chris Neidl – Co-Founder, OpenAir


Toby Bryce Toby Bryce is based in Brooklyn, NY and works on CDR policy and market development for OpenAir. Toby Bryce is based in Brooklyn, NY and works on CDR policy and market development for OpenAir. He is active in the CDR ecosystem more generally as an advisor to companies and organization on commercialization, market development, and policy. Follow Toby on Twitter: twitter.com/wtbryce