Verra's Kariba REDD+ Decision and Market Impact Analysis

September 30, 2025
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TL;DR

Sylvera notes Verra's completion of its carbon accounting review of the Kariba REDD+ project, which found that 15.2 million carbon credits—55% of total issuance—were issued in excess of actual deforestation reduction achieved. This conclusion aligns with Sylvera's independent 2021 analysis of the Kariba carbon offset project, which identified 75-90% overstatement in projected deforestation rates and approximately 33% overstatement in carbon stock estimates.

Kariba Carbon Credits: What This Means for the Carbon Market

Understanding the Active Credit Exposure

While the headline figure of 15.2 million excess credits is substantial, the practical market impact is more contained than it may appear:

  • Only 4.9 million credits (18% of total issued) remain active and unretired. Verra is engaging with holders of these credits to request voluntary cancellation.
  • The remaining 10.3 million credits have already been retired for offsetting claims and will maintain their status as valid retirements in Verra's registry.
  • An additional 10.1 million verified-but-unissued credits have been permanently removed, though these were unlikely to enter the market given the project's 2023 suspension and subsequent withdrawal.
  • In a response, South Pole has requested that Verra cancel the 2.5 million credits held by the company, however it is unclear whether these have already been retired or not.

Precedent-Setting Implications for Carbon Credit Quality

This Verra carbon credit cancellation decision raises critical questions about registry accountability and market-wide precedent:

  • Compensation Mechanisms: It remains unclear what practical "compensation" Verra will seek for the 10.3 million already-retired credits. Whether this will be financial restitution or nominal acknowledgment will significantly impact how registries handle future over-issuance cases.
  • VM0009 Portfolio Risk: Verra previously indicated it would seek corrections if VM0048 jurisdictional baselines prove lower than VM0009 project-level baselines. The Kariba decision may signal Verra's willingness to pursue retroactive adjustments across the VM0009 portfolio.
  • Broader Methodology Review: As all Avoided Unplanned Deforestation (AUD) methodologies transition to VM0048, this precedent could extend beyond VM0009 to other project-level baseline approaches, particularly where significant baseline discrepancies exist.

Carbon Market Evolution and REDD+ Project Quality

The carbon accounting methodology that generated these discrepancies—VM0009—has been discontinued, and the market has evolved significantly:

  • Modern REDD+ projects utilize jurisdictional baselines aligned with national forest monitoring data, reducing projection-based risks
  • Due diligence standards have intensified across the market, with buyers demanding higher levels of independent verification
  • The case demonstrates why independent ratings and ongoing monitoring are essential components of carbon market integrity

What This Means for Carbon Credit Buyers

Carbon credit buyers and Sylvera customers should evaluate:

  • Active Kariba Holdings: The ~4.9 million active credits face voluntary cancellation requests. Holders must weigh reputational considerations against the validity status Verra has maintained for these credits.
  • Retired Kariba Credits: Previously retired credits remain valid in the Verra registry. However, stakeholders may question their environmental integrity despite their maintained status.
  • Broader VM0009 Exposure: Organizations holding credits from other VM0009 projects should assess whether similar baseline discrepancies could emerge, particularly for projects with high projected deforestation rates relative to jurisdictional data.

Carbon Credit Risk Mitigation Strategies

  • Methodology Diversification in Carbon Offsetting: Prioritize REDD+ projects using jurisdictional baselines (VM0048) or newer methodologies with reduced baseline projection risk
  • Enhanced Carbon Credit Due Diligence: Leverage independent carbon credit ratings that compare project-level baselines against jurisdictional deforestation data and satellite observations
  • Proactive Carbon Project Monitoring: Implement ongoing carbon project monitoring rather than one-time due diligence, as baseline accuracy can only be assessed over time

Strategic Positioning in the Carbon Market

The Kariba REDD+ case validates the importance of independent carbon verification that goes beyond registry certification:

  • Sylvera's 2021 carbon credit analysis (subscription required) pre-identified the over-crediting issues that Verra's review has now confirmed
  • Comparative baseline analysis in REDD+ projects—assessing project projections against observed deforestation data—is essential for identifying high-risk carbon credits
  • Carbon stock verification using remote sensing provides additional validation of carbon credit quality. Transparent data source disclosure is crucial for comparative analysis. Verra has not disclosed the data sources for its analysis, which would facilitate such comparisons. Sylvera's approach involved a Synthetic Aperture Radar-based deforestation detection method and carbon stock estimates calibrated by Multi-Scale LiDAR field measurements. For further information, please refer to our research.

Looking Forward: Carbon Market Integrity and REDD+ Quality

Verra's decision to review the Kariba project and subsequently cancel credits represents a welcome development for the market. Nevertheless, the underlying data and methodologies employed in this review have been available to market participants for several years, as evinced by Sylvera's prior analysis. The issuance and retirement of credits within the market since that time diminish the efficacy of Verra's retroactive intervention. 

To cultivate transparency and confidence, it is imperative that feedback cycles between crediting registries and independent third-party auditors (comprising ratings agencies, academic institutions, and regulatory bodies) be accelerated. This acceleration would facilitate the timely and substantive implementation of corrective actions moving forward.

This development represents a significant step in market accountability, though the practical impacts are more nuanced than headline figures suggest. The case underscores the critical importance of:

  • Independent, science-based project assessment beyond registry certification
  • Jurisdictional baseline approaches that reduce projection-based risks
  • Ongoing monitoring systems that validate credit quality over project lifetimes
  • Transparent registry processes for addressing quality issues when they emerge

Sylvera continues to provide independent analysis that helps market participants navigate these complexities with confidence, using transparent methodologies that assess both carbon accounting integrity and safeguard implementation. Contact us for an independent rating or get a demo of our comprehensive carbon data platform.

What happened with Kariba carbon credits?

Verra completed a carbon accounting review of the Kariba REDD+ project in September 2024 and found that 15.2 million carbon credits (55% of total issuance) were issued in excess of actual deforestation reduction achieved. Of these excess credits, 10.3 million have already been retired and will maintain their valid status, while 4.9 million active credits face voluntary cancellation requests. Verra also permanently removed 10.1 million verified-but-unissued credits and cancelled 5 million buffer pool credits.

How many Kariba carbon credits are affected by Verra's cancellation?

Total breakdown of 41.96 million verified emission reductions:

  • 26.82 million issued as VCUs (Verified Carbon Units)
    • 15.22 million identified as excess credits (55%)
      • 10.32 million already retired (status maintained)
      • 4.9 million active credits (voluntary cancellation requested)
    • 11.6 million valid credits (45%)
  • 10.08 million permanently removed (verified but never issued)
  • 5.05 million cancelled from buffer pool

In summary, 15.2 million credits are considered excess, but only 4.9 million active credits face potential cancellation.

Why were Kariba carbon credits over-issued?

Kariba credits were over-issued because the project's baseline deforestation projections significantly exceeded actual deforestation observed in the reference area. The project used Verra's VM0009 methodology, which relied on project-level predictions rather than jurisdictional historical data. Sylvera's 2021 independent analysis found that projected deforestation was 75-90% overstated and carbon stock was approximately 33% overstated. Verra's 2024 review confirmed these baseline discrepancies, leading to the determination that 55% of issued credits were excessive.

Do I need to cancel my Kariba carbon credits?

If you hold active (unretired) Kariba credits: Verra is requesting voluntary cancellation of the 4.9 million active excess credits. You must evaluate reputational considerations versus the fact that Verra has maintained their validity status. Cancellation is currently voluntary, not mandatory.

If you previously retired Kariba credits: Your retired credits will maintain their valid status in the Verra registry. However, stakeholders may question their environmental integrity despite maintained registry status.

Recommendation: Assess your risk tolerance, stakeholder expectations, and portfolio composition. Consider consulting independent carbon credit rating providers for guidance.

What is the difference between VM0009 and VM0048 methodologies?

VM0009 (discontinued) used project-level baseline predictions where developers estimated future deforestation in a project-defined reference area. This prediction-based approach created high over-crediting risk.

VM0048 (current standard) uses jurisdictional baselines based on historical deforestation data from government forest monitoring and national/regional datasets. This data-based approach significantly reduces baseline projection risks and improves transparency.

Key differences:

  • Baseline source: Developer estimates vs. government data
  • Reference area: Project-defined vs. national/regional
  • Verification: Periodic adjustment vs. aligned to national inventories
  • Risk level: High vs. lower over-crediting potential

The transition from VM0009 to VM0048 represents a major advancement in REDD+ carbon credit quality standards.

著者について

ジェス・ロバーツSylvera 格付け 担当副社長。地理情報科学の修士号と地質学・物理地理学の学士号を取得し、地理空間データを専門としています。学業終了後、ギリシャの海洋保護NGOとエジンバラのEcometricaでGISプロジェクトに従事。Sylvera入社する前は、レジリエンス・コンステレーション社の地理空間アドバイザーとして、ビジネスの持続可能性に関する重要な問題を解決するデータ製品の設計に従事。

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