Article 6.4 and permanence: the core problem for forests

The Article 6.4 permanence standard, and where it stands

The Article 6.4 Supervisory Body adopted its permanence standard (A6.4-STAN-METH-007, version 01.0) at COP30 in October 2025. The MEP014 meeting in early July 2026 produced version 02.0 of the draft standard (A6.4-MEP014-A02-APPX05). Public submissions will inform further development at a future MEP meeting before the standard goes to the Supervisory Body.

What the permanence standard covers

The standard’s scope covers all activities with reversal risk, including forests, CCS, enhanced weathering, and ocean storage. Standard fossil fuel emission reduction activities, including renewable energy, energy efficiency, fuel switching are explicitly carved out as not subject to reversal risk requirements, since the fuels in question do not interact with the atmosphere in their natural deposits or during storage.

Defining “negligible risk of reversal”

For nature-based activities, the critical unresolved question is the definition of ‘negligible risk of reversal’; the threshold at which projects can exit post-crediting monitoring obligations. Version 02.0 defines negligible risk as ‘a loss of no more than a maximum percentage to be specified in methodologies on the basis of guidance to be developed in the reversal risk assessment tool.’

The draft Article 6.4 reversal risk assessment tool (A6.4-MEP014-A07)

The recently released draft of the risk assessment tool now states:

MEP notes that the Reversals Standard directs mechanism methodologies to define a negligible risk of reversal, expressed as a maximum percentage and based on guidance provided in the draft methodological tool. However, the MEP also notes that such guidance may not be relevant to activities that reduce non-renewable biomass consumption.

Presumably, this would also apply to projects that increase biomass, given the increasing risk to these activities from climate change itself (e.g., fire).

The MEP is scheduled to continue considering the draft tool at its sixteenth meeting, MEP016 (7 to 11 September 2026).

The 100-year steady-state requirement (paragraph 50)

The standard requires that for a project to exit post-crediting monitoring, stored GHGs must have ‘reached and will remain in a steady state or, where relevant, are stabilized for at least 100 years from the year of demonstration of negligible risk of reversal’ (paragraph 50).

The tool continues:

A determination that an Article 6.4 activity has a negligible risk of reversal is primarily relevant where an Article 6.4 activity seeks to terminate post-crediting monitoring obligations, consistent with paragraph 28(a) of version 01.0 of the Removals Standard and section 4.2.2 of version 01.0 of the Information Note. Under paragraphs 13 and 15 of version 01.0 of the Reversals Standard, mechanism methodologies addressing nonrenewable biomass consumption may request alternatives to post-crediting monitoring. If a mechanism methodology proposed an exemption from this requirement and the Supervisory Body approved that exemption, there would be no practical need for an activity participant to demonstrate that the corresponding Article 6.4 activity has a negligible risk of reversal.

For forest activities, achieving and demonstrating the required stability for 100 years is virtually impossible, and therefore, as stated in the tool the negligible risk avenue is unlikely to apply. There is still no clarity over what “alternatives to post-crediting monitoring” would be acceptable.

The asymmetry with geological storage

For geological storage, this is a tractable requirement: CO₂ injected into a saline aquifer mineralises over time, and the steady-state condition can be demonstrated through geochemical modelling and site monitoring data. The standard’s footnote confirms that for sub-surface CO₂ storage the criteria may pertain to the behaviour of the stored CO₂ in the reservoir. A living forest cannot make an equivalent claim. Forest carbon stocks are inherently dynamic and subject to succession, disturbance, climate-driven mortality, and fire risk that increases as the climate changes. No forest activity can credibly demonstrate that its carbon will remain in a steady state for 100 years. The monitoring obligation is not indefinite on its face; the exit pathway appears to exist, but for forests, it is not a viable option.

Paragraph 62: the unresolved remediation architecture

What remains unresolved and critical for forests is the remediation architecture. Paragraph 62 of the Removals Standard covers alternative measures for addressing reversals, including insurance and trust mechanisms; the options for implementing it are still in development. Without clear alternatives or centralised mechanisms for post-crediting monitoring, projects will be stuck with unreasonable expectations and need to plan for 100-year monitoring requirements.

Project-level risk, portfolio-level remediation

The preferable architecture would assess risk at project level but allow remediation and post-credit monitoring to be managed at portfolio level, which is the logic of the ICVCM’s Permanence Trust concept, rather than requiring every individual project to independently satisfy every requirement. Without realistic options, forest carbon projects will not be able to move ahead, or will be significantly burdened by ongoing monitoring up to 100 years, as they will never be able to reach and remain in a “steady state” for a 100 years.