Guyana’s flagship jurisdictional REDD+ programme, approved to supply the CORSIA aviation offsetting market, has had its 2023 vintage over-credited by 40% after a clerical error passed through successive rounds of audits undetected, according to Carbon Pulse. For airlines sourcing CORSIA-eligible units and for investors treating sovereign forest carbon as a compliance-grade asset, the discovery matters twice over: it hits one of the highest-profile jurisdictional programmes in the market, and it was a ratings agency, not the verification chain, that brought it to light.
A 40% Error on a Single Vintage
The over-crediting affects one vintage of the programme and stems from a clerical error that eluded successive rounds of audits, according to Carbon Pulse. Project stakeholders are now working to claw back millions in issuance volume.
The programme’s status raises the stakes. Because it is approved to supply CORSIA, its credits serve buyers with a regulatory obligation rather than a discretionary climate claim. An integrity failure in that segment travels further than one in the purely voluntary market, because purchasing decisions are anchored to eligibility rules that assume the underlying quantification is sound.
The ratings agency behind the finding is identifiable from the programme architecture’s own response. In its public statement, the ART Secretariat said it was aware of and working to correct the error in the calculation of Guyana’s 2023 credits prior to notification by BeZero, according to the ART Secretariat statement.
ART Moves to Freeze, Correct and Cancel
ART, the Architecture for REDD+ Transactions, laid out its remediation sequence in the statement dated October 13, 2026. The secretariat is working with the Government of Guyana and the Validation and Verification Body in line with ART’s published process for addressing an error found after verification, per the statement.
While that process runs, the Government of Guyana has transferred what ART describes as a conservative volume of 2023 TREES Credits that have not been transacted to an ART Registry Administrator account. Once the corrected volume of 2023 credits is verified, ART will remedy any over-issuance by canceling 2023 TREES Credits in line with the ART Registry Terms of Use, and the remaining credits will be transferred back to the Government of Guyana, according to the statement.
The design is containment first, correction second. Freezing untransacted units prevents the excess from spreading further through the market while the recalculation is verified, and cancellation restores the issuance total to the corrected figure.
Why a Clerical Error Cuts Deep at Jurisdictional Scale
Jurisdictional REDD+ exists to solve the integrity problems of small, fragmented forest projects: leakage between project boundaries, inconsistent baselines and uneven verification capacity. A clerical error large enough to inflate a vintage by 40%, surviving multiple audit rounds, strikes at precisely the assurance the jurisdictional model is meant to provide.
ART had already moved to tighten its oversight architecture before this case became public. In August, it launched its revised TREES Validation and Verification Standard, TVVS Version 3, which codifies new and more detailed competency and procedural requirements for VVBs and outlines additional oversight elements conducted by the ART Secretariat, according to the statement. ART says those changes resulted from its experience with the initial validations and verifications under TREES and from stakeholder feedback. The Guyana correction will now be read as a live test of whether that strengthened framework works as intended.
What Buyers and Investors Should Do Now
The immediate screen is vintage-level. Any portfolio, procurement pipeline or CORSIA compliance plan touching Guyana TREES Credits from 2023 needs to establish whether the units were transacted or remain in the frozen administrator account, and what volume the corrected verification will confirm.
Beyond this programme, the episode changes the evidentiary weight of two documents. A verification statement no longer closes the quantification question on its own, since the error passed successive audit rounds. And an independent ratings assessment has demonstrated it can catch what the formal chain missed, which strengthens the case for treating ratings as a procurement input rather than a marketing extra.
What to Watch
Three markers will define the fallout. First, the verified corrected volume for the 2023 vintage, which will convert the 40% estimate into a final cancellation figure. Second, confirmation on the ART registry that the over-issued credits have been canceled and the remainder returned to the Government of Guyana. Third, whether the VVB involved faces consequences under the competency requirements of TVVS Version 3, and whether ART or the ratings agencies extend scrutiny to the programme’s other vintages.
