Addressing the big issues

The Article 6.4 Supervisory Body asked for more detail on how carbon removal fits into the bigger picture. This is our response.

We would like to thank the Supervisory Body for taking the time to build up a balanced evidence base to understand the climate benefits, co-benefits and liabilities of a broad range of carbon removal approaches. Your efforts to create an Information Note that will serve as a strong foundation for guidance on carbon removals is of crucial importance: the rules around Article 6.4 will set the floor for activities under Article 6.2 and shape how the voluntary carbon market and policy-makers define carbon removals.

Separately from this submission, our organisation – Rethinking Removals – has coordinated with organisations across the global carbon removals ecosystem to provide the Supervisory Body with detailed line-by-line information and evidence on their specific technologies and approaches to monitoring, reporting and addressing risks. You will have received these individually from the various organisations and groups.

In this submission, we would like to touch on a few common, overarching and very important issues, which we have discussed at length with the above organisations, with policy makers, voluntary rule-setters and climate NGOs, and with members of the Rethinking Removals Doers Club, a group of over 20 organisations, working to implement or enable first-of-a-kind, commercial-scale carbon removal projects in countries from Kenya to the US and Sweden. The conclusions here are a summary of these multiple conversations, dialogues and engagements. We hope they are helpful as you make your deliberations.

1)    Carbon reductions and removals need to go hand in hand – and they can!

There is a very real – and very reasonable – fear that leaning on carbon removals for any part of our climate plans risks letting people off the hook and reducing our essential focus on reductions. The IPCC tells us that we need to reduce emissions much faster than we are currently doing, and there is plenty of fear about anything that might take away from that.

However, it’s now too late to look at this as an either/or option. The IPCC also tells us that we need to build the capacity to remove emissions much faster than we are doing at the moment, and there is rising fear that we are not doing this quickly enough and will not have nearly enough capacity when we need it.

What we need is to put the two together, accelerating both reductions and removals at pace, so they are not fighting each other but work together to achieve our climate goals. There are several ways to do this, and the most promising is a push to create separate targets so that countries, organisations and individuals can be judged against their progress on both reductions and removals. What’s clear is that we no longer have the choice of one or the other. We have to develop both, in parallel, as fast as we can. As Kumi Naidoo, former executive director of Greenpeace, recently put it: “We don’t have time to choose between stopping emissions and removing CO2 from the air. We need to do both to survive.”

2)    Carbon removals are a significant economic opportunity for the Global South.

The amount of carbon removals now needed is daunting, especially as we are starting from such a low level. The IPCC estimates we must remove up to 100 million tonnes CO2e per year by 2030 – and between 5 and 16 billion tonnes of CO2e per year by 2050, to have a chance at meeting global climate targets.

To have any chance of achieving that, all carbon removal approaches need to be scaled up urgently and rapidly – and this particularly applies to the more novel, nascent and expensive approaches, in order to get them quickly down the cost curve.

The best places to do this are arguably those with low emissions that don’t have a trade-off between reductions and removals and can focus their renewable energy resources on developing high-durability, high-cost removals quickly and cheaply. In other words, many countries in the Global South. This has important potential advantages when it comes to sustainable development, because energy-hungry carbon removals plants have the potential not only to kick-start green industrial economic development in the Global South but also to unlock investment in renewable energy at scale.

To date developing untapped renewable resources is difficult precisely because many countries, especially in Africa, do not have large industrial off-takers to act as anchor tenants. Developing carbon removals approaches with high renewable energy needs, paid for by the Global North, can break this cycle by providing the demand that can and make it economically feasible to develop renewable energy at scale. This has high potential to open up much greater access to renewable electricity in many countries in the Global South.

That’s one big reason that the Article 6.4 framework is especially important for countries in the Global South – some of which have already decided that the economic opportunity of developing carbon removals will be an important part of their sustainable development pathways. For example, the Kenyan government recently hosted a national workshop focused on establishing a hub for direct air capture in central Kenya.

Moreover, there are other ways in which sustainable development and carbon dioxide removal – in its many forms – can intersect and reinforce each other powerfully. In addition to the climate impact, several African governments aim to use carbon removals to tap additional revenue streams, create jobs, support small-holder farmers, open access to renewable energy, build out infrastructure and improve waste management in mining and agriculture. The framework set by Article 6.4 will play a key role in enabling or blocking these projects.

3)    Carbon removals go beyond ‘nature vs engineered’ to span a very wide spectrum of approaches that involve the application of both natural resources and human ingenuity.

Though it is hugely tempting to put carbon removals into two neat, tidy categories – ‘nature-based’ and ‘engineered’ – this no longer represents anything close to the full range of carbon removal approaches. Already we have biochar, bioenergy with carbon capture and storage and enhanced rock weathering , all of which combine nature-based benefits with enhanced CO2 storage through engineering processes. And this is a fast-moving industry, with many new technologies and approaches in development.

A year ago, no one was thinking about the potential of enhanced rock weathering in Africa to mitigate soil nutrient depletion, support small-holder farmers and recycle mine waste; 18 months ago, no-one had imagined that direct air capture and storage solutions developed in Iceland could make sense in Kenya, creating anchor demand to drive development of grid infrastructure and much wider access to energy. As the science and technology develop, the same evolution could be true for ocean alkalinity enhancement projects, new approaches to increasing the durability of soil carbon removal or new hybrid approaches that seek to combine the strengths of different kinds of carbon removals.

For these opportunities to be realised, we need dynamic ways to categorise carbon removals, focusing attention on specific approaches (or ranges of approaches) in specific places and models. Sticking to the outdated categorical binary of ‘engineered’ and ‘nature-based’ would render many of the above developments impossible to realise. As the sector continues to expand and diversify, virtually every carbon removal approach is now a hybrid of nature and engineering.

4)    Rules and frameworks need to be applicable across the entire spectrum of solutions.

We welcome the Supervisory Body’s renewed focus on the specific mandate set by CMA3 to elaborate on rules, modalities and procedures for MRV, addressing reversals, avoidance of leakage and avoidance of other negative environmental and social impacts. If this industry is to provide the scale needed to have its essential climate benefit, while also supporting sustainable development, it needs a neutral and science-based framework that provides rules on permanence, leakage and liabilities. Above all the industry needs rules that determine which projects are credible, effective and sustainable – which is a challenging task in its own right. As we hope the above comments demonstrate, we believe this will be vastly more effective than defining which specific removal approaches are in scope and which not.

Again, thank you for all your hard work in this space. We know that the task of creating robust rules for Article 6 and the rest of the Paris agreement is challenging and often thankless. Your efforts and careful attention are very much appreciated.

Rethinking Removals Doers Club

Members of the Doers Club and participants in discussions on this response include: 1PointFive, American Carbon Registry, C-Capsule, Carbon Engineering, Carbonfuture, Carbonplace, Cella, Charm Industrial, Climate Action Platform – Africa,, CUR8, Drax, JPMorganChase, Kita, NextGen Facility, Northern Lights, Planetary, Puro, Rubicon, Salesforce, Shopify, South Pole, Sylvera, Stockholm Exergi and UNDO Carbon. 


Our Article 6.4 response

When an UNFCCC info note argued that durable carbon removals are not suitable for implementation in the Global South and not part of climate mitigation, the Doers Club had to respond.

Dear Supervisory Body:

Thank you for the opportunity to respond to your important work to incorporate carbon removals in the implementation of Article 6.4. In particular, we want to share our thoughts on the Information Note entitled “Removal activities under the Article 6.4 mechanism” (A6.4-SB005-AA-A09 version 0.40), which is intended to inform discussions at your next meeting.

We represent the Carbon Removals Doers Club, a group of over 20 organizations, working to implement or enable first-of-a-kind, commercial-scale carbon removal projects with durable storage. We embrace a range of different approaches, including direct air capture and storage (DACS), bioenergy with carbon capture and storage (BECCS), enhanced rock weathering, bio-oil and biochar. Together our projects will durably remove around 70 MT of CO2 from the atmosphere by 2030 – still far from the scale IPCC scientists say is required by 2030 to support a 1.5°C or even a 2°C ambition.

Some of our Club members have submitted detailed responses for review. We are writing collectively to highlight several assumptions in the Information Note on carbon removals that we believe would prevent durable carbon removals from playing a role in the mechanism and block the opportunity for developing countries to leverage growth in carbon removal services for their own sustainable development.

  1. Table 3.2 of the Note asserts that “engineered” CDR “activities 1) do not contribute to sustainable development, 2) are not suitable for implementation in “developing countries”, and 3) do not contribute to the reduction of global mitigation costs, and therefore do not serve any of the objectives of the Article 6.4 mechanism.” We believe strongly that these assertions are arbitrary and without basis in evidence, and do not reflect real world developments in the carbon removal sector.

A more rigorous engagement with these developments would support the opposite conclusion: that technology-based carbon removal pathways offer strong potential economic and sustainability benefits in the Global South. In particular, the Global South’s abundance of untapped renewable energy potential is key: removal solutions with a high need for renewable energy, can provide anchor industrial demand that will enable investment in renewable energy, thus improving energy access. This abundance, paired with low existing emissions, means limited moral hazard for the deployment of new renewable energy capacity, as there is little high emission industrial infrastructure to displace.

We urge the Supervisory Body to take the time to directly engage with any of the dozens of CDR practitioners and companies currently actively planning or considering projects or activities in the Global South. The Doers Club would be pleased to help facilitate that engagement.

  • Table 3.2 of the Note asserts that “engineered” carbon removal methods are “technologically and economically unproven.” CDR is a young industry, to be sure, but also a dynamic and rapidly evolving field that encompasses a great range of pathways and technologies, and one that continues to marshal considerable resources and investment to support extensive research and development, and accelerated rates of commercialization. This year has seen several high-volume commercial deals and offtake agreements between new durable carbon removal developers and established corporate buyers. The Doers Club would be happy to facilitate discussions with Supervisory Body members and alternates to help fill the information gap in this fast-changing area.
  1. The Note’s skepticism about uncertainties related to technology-based CDR today must be balanced with the reality that it will be necessary at gigatonne scale in order for 1.5C or 2C temperature change targets to be met, per the IPCC AR 6 Synthesis Report. In light of this imperative, the appropriate position on CDR, we believe, should be one focused on accelerating testing and validation of high potential pathways to mitigate uncertainties; not one that delays such necessary progress in the interest of caution.

In addition to our reservations regarding the substance of the note, the Doers Club would like to highlight our concerns related to the process behind it. Firstly, while we welcome the opportunity to contribute, the week-long “call for input” is unlikely to be a sufficient timeframe for all stakeholders to make submissions. The Body would benefit from the broadest and most inclusive consultation possible to inform its work, so we suggest extending this timeframe for future calls. Secondly, the synthesis of information in the latest of the iteration of the note does not clearly reflect the balance of stakeholder input – comments which are made by single stakeholders appear to receive the same weight of consideration as those which have been made by many stakeholders. The Doers Club would welcome a more clearly broken-down synthesis of stakeholder feedback for the Body to use, including insight into the number and diversity of stakeholders behind the highlighted responses. Finally, the Doers Club highlights the format limitations of calls for input and written responses. We see strong benefit in giving our members the opportunity to present directly to the Body and Secretariat. We stand by to either facilitate or participate in such an occasion.

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.

Best regards,

The Carbon Removals Doers Club

NOTE: The Article 6.4 Supervisory Body received 104 responses, many of them collective, like ours – and virtually all of them in favour of a broad approach to carbon removals. The chair Olga Gassan-zade said during the meeting: “I don’t want to create an impression that we haven’t been struck by the strength of the response. And that it that hasn’t made a difference. It did. It was very helpful….We have heard you. The approach that we are taking is to be general and then become more specific.”


Bioenergy with carbon capture and storage

Based on a Doers Club deep dive discussion, led by Angela Hepworth, Commercial Director at Drax, and Johan Börje, BECCS lead at Stockholm Exergi.


  • The BECCS process includes four elements:
  • Sustainably-sourced biomass. Mostly wood residues and by-products from the timber industry, such as sawmill residues and forest thinnings.
  • Biomass is used in power stations to produce electricity and heat. (BECCS integration also possible at biomass-to-fuel plants, but capture efficiency is lower than for power/heat.)
  • Power plants are retrofitted or constructed with carbon capture and storage (CCS) technology, capturing 95% of flue gas
  • CO2 is transported to geological storage sites via pipeline or ship
  • Three preconditions for BECCS scaleup: access to geological storage, access to sustaionable forest biomass for energy production and strong political support, including initial government aid.
  • The Drax and Stockholm Exergi deployment approaches are very similar, but Drax focuses on power generation, whereas Stockholm Exergi’s facility is tied to the existing district heating sector in Sweden and other Nordics, which comprises both heat and power (CHP) production.
  • Multiple waste-to-energy plants (with 50% biogenic waste) can serve as a platform for BECCS and are scheduled to go online in 2026-27 timeframe. Sweden is also looking at pulp and paper plants
Permanent geological storage that can be accurately measured and monitoredPublic perception and civil society resistance challenges around biomass
Materially cheaper than other high-durability removal pathwaysUnderdeveloped carbon transport and storage infrastructure
No to low additional energy needs – energy for capture sourced from renewable biomass generator, with potential for re-use of waste process heatEarly projects require both government support and VCM revenue
Co-benefits: produces power/heat, can use waste wood products linked to forest fires, supports sustainable forest industryRequires very strong focus on sustainable biomass sourcing
High long-term gigatonne scale potential 
Political support in key early markets 
Favourable LCA – robust processes in place to quantify supply chain emissions 
Technically well understood solution  that leverages existing sectors and infrastructure 


  • No industrial scale facilities in operation based on forest biomass, but BECCS recently saw an impressive number of advance market sales confirmed recently, with delivery in the next couple of years.
  • Drax: Initial market focus: US and UK biomass power plants (global target: 14 million tonnes on line by 2030); longer-term focus on Canada, EU and Asia, plus smaller plants that can be online by 2026. Has a 2m tonne deal with Respira and other smaller deals.
  • Stockholm Exergi: No plans to expand beyond Europe. Most development will occur in Sweden and other Nordics, but open to sharing technology for development in other geographies. Funding from EU, Swedish reverse auction and VCM buyers. District heat customers are interested in buying a dual product: heat and negative emissions. Total potential based on existing plants around 2 million tonnes a year.
  • Cost per tonne: around $300 recently announced for small amount, but lower for scale purchases. Cost-curve reduction expected. Estimating for 2025-2035 period: $200 – $400/tonne; after that, lower.
  • The critical need is to reduce transaction costs on the supply and demand side through ‘super standardization’ and secure efficient transport solutions.
  • Rules needed to allow for co-funding between voluntary and compliance markets. Both are required to scale a gigatonne industry in a timeline that is unprecedented in history. High demand from voluntary corporate buyers relieves competitive pressure for limited public money. Double-claiming between public and private sectors – which enables co-funding –

does not lead to double-counting in the climate inventory if accounting systems are kept separate.


  • Accounting methods and third-party evaluation protocols for capture units are still under development. In the absence of agreed upon common standards, we emphasize key principles that must be met under any future methodology.
  • Commodity traders and other financial market makers are putting pressure on reaching common standards, but still significant divergence.
  • Standardization is “absolutely fundamental” and will capture upsteam factors related to biomass sourcing, scrutinising along several dimensions:
    • Alternate end uses of feedstock used for BECCS are considered
    • Impact on forest carbon stocks in sourcing regions assessed.
  • Both Drax and Stockholm Exergi only source residuals, and don’t compete for wood that would go to long-lived products that could represent temporary carbon sinks.
BECCS will make the forest industry more sustainable.” BECCS adds a third dimension to the forestry mix (in addition to forestry product suppliers and power producers). CDR buyers with stringent additionality, MRV and sustainability standards and requirements, are major players demanding a high degree of transparency. Power consumers are less visible, lack clear influence channels, and command less leverage in imposing demand for sustainability and transparency on the forestry industry.

How Doers can help

  • Stimulating demand side – “getting advance buyers is among our most significant and immediate needs”. SBTi framework development is a key part of that. We need a more explicit and affirmative position from rule-setters regarding the importance of purchasing permanent removals today.
  • Advocating for common standards – working with CDR providers and standards-makers in concert to converge.
  • Dispelling misconceptions around sustainability commitments and systems related to biomass sourcing. Recent alarmism in media and civil society are delivering inaccurate and unbalanced accounts not rooted in realities on the ground. We need help balancing this with alternate messaging. 


Enhanced rock weathering

Based on a Technology Deep Dive presentation by Jim Mann, CEO of UNDO, in February 2023


  • Enhanced rock weathering (ERW) removes CO2 from the atmosphere by spreading large quantities of selected and finely ground rock material onto extensive land areas. 
  • ERW mimics and accelerates (50,000 x) the natural weathering processes of silicate rocks.
  • The carbon removal takes place over a 50-year “weathering curve”; with approximately 13% of removals taking place in the first year, and 90% over 20 years.
  • The rock is a waste by-product of mining and quarrying – it needs to be ground to dust.
  • Basalt generally has low heavy metal content and can be spread on agricultural land.
  • Other approaches use olivine that weathers more quickly but contains heavy metals.
  • Suitable locations depend on: rock mineralogy, weathering conditions and proximity of quarry/mine to suitable land.
  • The UNDO ERW value chain includes: quarry/mine owners, haulage companies, agricultural contractors and land-owners/farmers.


UNDO has the ambition to contract a GT of removals by 2030. Scale possible because:

  • rock waste is a vast resource – <10% of basalt mined annually needed to get to GT scale
  • uses existing mining, quarrying and agricultural processes and infrastructure
  • offers significant co-benefits (increased crop yield, jobs in rural areas, use of waste, ocean alkalinity)
Leverages existing infrastructureOpen system makes it hard to measure
High permanenceExtensive analysis of rock mineralogy needed
Huge scalability potentialRemoval takes place over multiple years
Cost reduction – potential to get to < $100/TAll OPEX costs are upfront – negative cash-flow
Very low energy requirementsValidation hard because science is new
Abundantly available rockLong education process for buyers
Clear co-benefits 
Use of by-product 
Can be developed in Global South 

Costs (UNDO)

  • Currently from $101/T to $160/T, excluding MRV
  • Current MRV costs are $70-80/T, but targeting single $/T costs once models validated
  • Targeting a selling price of <$150/T within the next few years
  • UNDO has undertaken a project to define a pathway to $100/T


Silicate rock powders increase crop yield (up to 40%) and help to mitigate soil nutrient depletion.2Zero Hunger
Projects can done with small-scale farmers and provide a cheap alternative to traditional fertilisers.8Decent work/economic growth
Can bring agronomic benefits for farmers, supporting regenerative practices, and recycles mine waste12Responsible consumption & production
Scalabale, affordable, permanent carbon removal13Climate action
Assists with ocean alkalinisation and improve the nitrogen cycle.14Life below water
Improves soil health and mitigates land degradation associated with BAU farming practices.15Life on land

Market maturity

  • A dozen companies globally working on ERW
  • UNDO is market leader having sold approximately 30,000 tonnes of (pre-methodology) removals.
  • The rest of the market has sold approximately 6-7KT of removals (Lithos, Eion, Greensand).
  • Buyers are “climate forward” companies (eg Stripe, Microsoft and XTX Markets) and resellers, including SuperCritical, Wren, Ceezer and Cur8.
  • UNDO is aiming to contract approximately 1MT of removals by the end of 2024 and spread enough rock to capture those 1MT by the end of 2025.


  • Standards are critical to identify high quality projects, offer assurance to buyers, identify bad actors.
  • Measurement is done through a modelling process, reflecting many different scenarios.  Model outputs need to be calibrated, or “trued up” with field data.
  • Life-cycle analysis (LCA) accounts for grinding, transport and spreading to get net removals.
  • Measuring carbonate storage in solid form is easier; measuring dissolved bicarbonates is more challenging – UNDO is working on measurement innovations.
  • Current MRV costs are high – associated with truing up the model; insurance can lower costs.
  • Identifying third-party verifiers with the right background is a challenge.