Voluntary Carbon Market Reset: Integrity, Tiers, and the Removal Pivot

The 2024 to 2026 integrity reset #

The voluntary carbon market entered 2024 carrying the reputational damage of two years of media investigations into REDD+ over crediting, deforestation baselines, and avoided emissions claims that did not survive third party scrutiny. Issuance fell from 192 megatonnes of CO2 equivalent in 2022 to roughly 95 megatonnes in 2024 according to Ecosystem Marketplace and Trove Research tracking, with retirement volumes lagging issuance for the first time in the modern market's history. Corporate buyers paused programs, board level climate committees demanded integrity attestations, and several Fortune 500 companies retracted prior offset claims.

Three institutions reshaped the market in response. The Integrity Council for the Voluntary Carbon Market, an independent governance body chaired by Annette Nazareth, published its first Core Carbon Principles assessments between June and December 2024. The Voluntary Carbon Markets Integrity Initiative released Claims Code of Practice 2.0 in late 2024 with tiered silver, gold, and platinum claim labels. The Science Based Targets initiative published Beyond Value Chain Mitigation guidance in July 2024, clarifying that companies may finance mitigation outside their value chain as a credible complement to, not a substitute for, scope 1 through 3 abatement. The combined effect was bifurcation rather than collapse, with CCP eligible categories rising from a 2023 floor of 4 to 6 dollars to a 2025 range of 8 to 25 dollars, while non CCP legacy stock traded at 1 to 3 dollars and in many cases sat unsold.

ICVCM Core Carbon Principles: what passed and what failed #

The ICVCM assessment process tests methodologies, not individual projects, against ten Core Carbon Principles covering additionality, permanence, robust quantification, no double counting, and sustainable development. A methodology either earns the CCP label, is rejected, or is sent back for revision. The first wave of decisions, concentrated in mid to late 2024, set the precedent that has shaped issuance and pricing into 2026.

The headline result was the rejection of the first batch of REDD+ project level methodologies. Verra's VM0007, VM0009, and VM0015, which together accounted for the bulk of historical REDD+ issuance, did not pass CCP review. The reasons cited were baseline construction that overstated avoided deforestation, leakage accounting that did not survive landscape level testing, and permanence buffers that fell below the durability threshold the ICVCM applies to nature based avoidance. Jurisdictional REDD+ under the ART TREES standard, which sets baselines at the country or state level rather than at the project boundary, fared better and remains under active CCP review.

Afforestation, Reforestation and Revegetation was partially approved. Verra's VM0047 ARR methodology earned the CCP label in late 2024, while older ARR methodologies were narrowed or retired. Article 5 ozone depleting substance destruction received the CCP label as did select landfill gas capture categories. Cookstove methodologies were sent back for revision after independent academic work documented over crediting in default emission factors. The practical implication is a binary supply curve: CCP eligible credits represent a smaller share of historical issuance than the market assumed in 2023, and the gap between issuance volume and CCP eligible volume drives the price tier structure shown below.

VCMI Claims Code 2.0 and the SBTi BVCM split #

VCMI Claims Code 2.0 introduced a tiered claims architecture that buyers earn by combining ongoing decarbonization performance with the use of high integrity carbon credits. The silver tier requires retirement of CCP eligible credits equal to 20 to 60 percent of remaining scope 1 and 2 emissions for the claim year, alongside a public near term Science Based Targets initiative aligned target. Gold lifts the threshold to 60 to 100 percent. Platinum requires 100 percent or more of remaining scope 1 to 3 emissions, with all credits drawn from CCP eligible categories and at least a defined minimum from durable removals.

The SBTi July 2024 Beyond Value Chain Mitigation guidance is the structural complement to VCMI. SBTi reaffirmed that offsets cannot be counted against a company's scope 1, 2, or 3 reduction targets, but it explicitly endorsed BVCM as a credible parallel channel for funding mitigation outside the value chain. The guidance encourages companies on track with their SBTi targets to invest at least the social cost of carbon multiplied by their unabated residual emissions into BVCM activity each year. The combined effect for buyers is that two questions now precede any purchase: is the company on track with its SBTi target, and is the credit CCP eligible. Treasury and sustainability teams that previously bought on price now buy on label.

Verra v4 and standards consolidation #

Verra, which administers the Verified Carbon Standard and remains the largest registry by historical issuance, rolled out version 4 of the VCS Program through 2024 and 2025. The headline changes were tighter additionality testing, dynamic baselines for forestry that update with observed deforestation pressure rather than relying on ten year historical averages, mandatory leakage assessment at the landscape rather than project boundary, and a buffer pool revision that lifted average withholdings on nature based projects. Verra also accelerated retirement of legacy methodologies and required projects above defined thresholds to transition or wind down.

Gold Standard, the second largest registry, ran a parallel update emphasizing community co benefits, gendered impact reporting, and stricter cookstove default factors. The American Carbon Registry and Climate Action Reserve aligned more selectively with CCP criteria. The result is methodological convergence at the top of the market and a long tail of orphaned legacy credits that no buyer with an integrity policy will retire. Issuance shares shifted measurably toward methodologies with clear CCP pathways, and registries without CCP labels in their pipeline lost market share through 2025. The competitive dynamic increasingly resembles an oligopoly disciplined by an external integrity benchmark rather than a fragmented market of competing standards.

Article 6: PACM, ITMOs, and corresponding adjustments #

Parallel to the voluntary track, the Paris Agreement's Article 6 mechanisms moved from rulebook to operation. Article 6.4, the Paris Agreement Crediting Mechanism, established its Methodology Expert Panel and Supervisory Body and worked toward operational launch around COP29 in Baku in November 2024. PACM is the successor to the Clean Development Mechanism and will issue A6.4ERs, with methodology approvals through 2025 and 2026 setting the early supply curve.

Article 6.2 governs cooperative approaches between countries through internationally transferred mitigation outcomes. Switzerland and Ghana signed and implemented the first ITMO transactions, with rice cultivation and e mobility projects authorized for transfer. Singapore signed implementation agreements with Bhutan, Papua New Guinea, and Ghana. Sweden signed with Ghana. Each transaction requires the host country to apply a corresponding adjustment to its Nationally Determined Contribution accounting, ensuring that mitigation is not double counted between buyer and seller country ledgers. The corresponding adjustment mechanism is the structural difference between Article 6 and the voluntary market: a VCM credit retired by a corporate buyer does not, by default, change either country's NDC accounting, while an ITMO transferred under Article 6.2 does. This makes Article 6 credits more expensive to produce but more legally defensible for sovereign and certain corporate buyers, and authorized credits that carry corresponding adjustment now trade at meaningful premia to otherwise identical unauthorized credits.

Removals versus avoidance and the durability frontier #

The clearest demand signal of the reset is the shift from avoidance to removal. Avoidance credits, which represent emissions that did not occur because of the project, dominated historical issuance and underpinned the REDD+ stock now in question. Removal credits, which take CO2 out of the atmosphere and store it, command a premium that has widened through the reset. Within removals, durability has become the second order discriminator. Buyers increasingly classify removals by storage horizon: short cycle biological at decades, long cycle biological at one hundred to several hundred years, and engineered or geological at one thousand years and beyond.

Microsoft has been the most aggressive buyer at the durable end, contracting more than 26 million tonnes of durable carbon removal across direct air capture with geological storage, biochar, enhanced rock weathering, bio energy with carbon capture and storage, and durable nature based portfolios. Google scaled a biochar focused portfolio anchored in agricultural feedstocks. Stripe's Frontier consortium, an advance market commitment from Stripe, Alphabet, Shopify, Meta, McKinsey and other partners, committed more than one billion dollars through 2030 to early stage durable removal suppliers and continued to set the technology readiness frontier.

Climeworks brought its Mammoth direct air capture facility online in Iceland with a nameplate capacity of 36,000 tonnes of CO2 removal per year, the largest operating direct air capture and storage facility in the world, with capture stored in basaltic rock through Carbfix. Heirloom built out a portfolio of carbonate based direct air capture sites in California and Louisiana, with the latter integrating into shared geological storage infrastructure. Ocean alkalinity enhancement and enhanced rock weathering moved from desk study to small pilot deployment. The shared characteristic of these pathways is that durability is engineered or geophysical rather than biological, removing the permanence risk that haunts forestry.

What buyers and developers should do in 2026 and 2027 #

For corporate buyers, the operative discipline is sequence. Set or refresh a Science Based Targets initiative aligned target before any purchase. Decompose residual emissions, the share that cannot be abated within a credible plan window, and apply a social cost of carbon estimate to that residual to size a Beyond Value Chain Mitigation budget. Allocate that budget across CCP eligible avoidance, ARR, and a defined minimum allocation to durable removals scaled to the buyer's net zero year. Document corresponding adjustment status for any credit used in claims that touch sovereign accounting, including CBAM exposed jurisdictions in the European Union.

For developers, the strategic choice is which CCP eligible track to anchor. Jurisdictional REDD+ under ART TREES, ARR under VM0047, and durable removal pathways each have different capital intensity, lead time, and execution risk profiles. Project pipelines built around legacy REDD+ methodologies face stranded asset risk and should be reviewed for transition to ART TREES or wind down. Removal developers face a different problem: the supply curve is steepening as buyer demand consolidates around a small number of credible suppliers, and the binding constraints are geological storage permitting, low carbon power for direct air capture, and supply of biomass for biochar and bio energy. For policy and standard setters, the priorities are interoperability between Article 6.4 PACM and the voluntary market, transparency of corresponding adjustment status at the credit level, and integrity of monitoring, reporting, and verification across pathways that increasingly span continents. The next eighteen months will determine whether the reset stabilizes a smaller but credible market or whether further integrity events push corporate buyers out altogether.

Sources #

• Core Carbon Principles assessment decisions and category labels
• Claims Code of Practice 2.0
• Beyond Value Chain Mitigation guidance, July 2024
• Verified Carbon Standard Program version 4 rules
• Standards and methodologies update
• Article 6 implementation tracker, ITMO authorizations
• Carbon Market Outlook 2026
• Voluntary carbon market issuance and retirement tracker
• State of the Voluntary Carbon Markets 2025
• Mammoth plant operations and capacity disclosures