CARBON CREDIT RATINGS: HOW THEY WORK AND WHAT COMPANIES SHOULD KNOW

WHAT IS A CARBON CREDIT RATING?

A carbon credit rating is an independent assessment of the likelihood that a carbon credit delivers the climate benefit it claims.

Rating agencies evaluate project-specific risks that could affect the quantity, durability and credibility of an emission reduction or carbon removal. These may include weaknesses in additionality, baseline setting, carbon accounting, permanence, project implementation and monitoring.

Rather than producing only a pass-or-fail result, rating agencies translate complex technical analysis into a graded score. This can help buyers compare carbon projects across different project types, countries, methodologies and crediting periods.

A carbon credit rating should be understood as an informed assessment of risk, not as a guarantee that every credit will deliver exactly one tonne of verified climate benefit. 

WHY ARE CARBON CREDIT RATINGS IMPORTANT?

The voluntary carbon market includes thousands of projects operating under different standards, methodologies and local conditions.

Although carbon standards establish rules for project development, monitoring and verification, certification alone does not show how one certified project compares with another. Two projects registered under the same standard or methodology may still have substantially different risks.

Carbon credit ratings provide buyers, investors and intermediaries with an additional, independent perspective on those risks.

They can help companies:

  • compare projects using a consistent analytical framework
  • identify potential integrity risks before purchasing credits
  • narrow a large project universe into a manageable shortlist
  • understand the strengths and weaknesses behind a headline score
  • establish minimum procurement criteria
  • monitor changes in project risk over time
  • support internal decision-making and documentation

Ratings are particularly useful as a screening and comparison tool. However, their value depends on understanding what the rating measures, which information was available and how the agency reached its conclusion.

WHAT DO CARBON CREDIT RATINGS ASSESS?

Most carbon credit rating methodologies seek to determine how likely a project is to deliver the emission reduction or carbon removal it claims.

The precise assessment framework varies by agency, project type and rating product. Nevertheless, several recurring areas form the basis of most assessments.

1. ADDITIONALITY

Additionality examines whether the climate benefit would have occurred without the project and the financing provided through carbon credits.

A rating agency may assess:

  • financial additionality
  • regulatory requirements
  • investment barriers
  • alternative land-use or investment scenarios
  • common practice in the relevant market or region
  • the importance of carbon revenues to project viability

If the activity was already legally required, commercially attractive or likely to happen without carbon finance, the project may present a higher additionality risk.

2. BASELINE CREDIBILITY

The baseline represents what would most likely have happened without the carbon project.

Rating agencies examine whether the baseline is realistic, evidence-based and sufficiently conservative. An inflated baseline can make a project appear to avoid more emissions than it actually does.

For example, a forest conservation project may receive too many credits if its baseline assumes a level of future deforestation that is not supported by historical data, comparable areas or credible land-use modelling.

3. CARBON ACCOUNTING AND QUANTIFICATION

Carbon accounting assesses whether the project’s emission reductions or removals have been quantified accurately and conservatively.

Relevant factors may include:

  • data quality
  • model selection
  • sampling design
  • biomass estimates
  • carbon pools
  • emissions sources
  • uncertainty deductions
  • leakage assumptions
  • monitoring frequency
  • the treatment of missing or incomplete data

The objective is to determine whether the number of credits issued is supported by the underlying climate outcome.

4. PERMANENCE AND REVERSAL RISK

For projects that store carbon or protect existing carbon stocks, rating agencies assess the likelihood that the climate benefit will persist.

Risks may include:

  • wildfire
  • drought
  • storms and flooding
  • pests and disease
  • illegal logging
  • land conversion
  • changes in land tenure
  • political instability
  • insufficient long-term financing
  • weak community support
  • inadequate monitoring or buffer arrangements

The relevance of these factors varies considerably between forestry, soil-carbon, blue-carbon, biochar, geological storage and other project types.

5. LEAKAGE

Leakage occurs when a project reduces emissions in one location but causes emissions to increase elsewhere.

For example, preventing deforestation within one project area may simply shift agricultural expansion or timber extraction to a neighbouring region.

Rating agencies assess whether possible leakage has been identified, quantified and appropriately deducted from the project’s credited climate benefit.

6. MONITORING AND PROJECT IMPLEMENTATION

A credible methodology does not automatically guarantee successful implementation.

Ratings may therefore examine whether the project:

  • has adequate operational capacity
  • follows its stated monitoring plan
  • collects reliable field data
  • reports results transparently
  • responds to identified risks
  • has sufficient financing
  • works effectively with local stakeholders
  • can deliver its activities over the required period

This helps distinguish risks in the methodology from risks in the implementation of a specific project.

7. GOVERNANCE, LEGAL AND SOCIAL RISKS

Some agencies also assess project governance, legal compliance, land rights, benefit-sharing and environmental or social safeguards.

These factors may affect the durability and credibility of the project. Unclear land tenure, weak governance or conflict with local communities can undermine project implementation and increase the probability that the anticipated climate benefits will not be delivered.

However, agencies do not all incorporate these factors into their headline ratings in the same way.

DO CARBON CREDIT RATINGS INCLUDE BIODIVERSITY AND SOCIAL BENEFITS?

The treatment of biodiversity, community benefits and other co-benefits differs between rating agencies.

Some agencies assess co-benefits separately from the main carbon-integrity rating. Sylvera, for example, evaluates biodiversity and community outcomes through a separate co-benefits score that is not included in its headline rating. Calyx Global separately evaluates greenhouse-gas integrity, Sustainable Development Goal impacts and environmental and social risks. MSCI, by contrast, includes co-benefits as one of several criteria within its broader Carbon Project Ratings framework.

This distinction matters because carbon integrity and wider project impact are related but not identical.

A project may deliver substantial biodiversity or community benefits while presenting weaknesses in its baseline, additionality or permanence. Conversely, a project may have strong carbon accounting but limited wider environmental or social benefits.

Companies seeking both robust carbon integrity and strong co-benefits should therefore review each dimension explicitly rather than relying on a single headline score.

WHO PROVIDES CARBON CREDIT RATINGS?

Widely used commercial providers include:

  • BeZero Carbon
  • Sylvera
  • Calyx Global
  • MSCI Carbon Markets

This list is not necessarily exhaustive, and the market continues to develop.

Each provider applies its own methodology, analytical framework, data sources and scoring scale. Their assessment scopes may also differ. Depending on the agency and product, a rating may apply to a project, methodology, crediting period, vintage or proposed project that has not yet issued credits.

BeZero describes its ratings as project-level, risk-based assessments and currently uses an eight-point scale from AAA to D. MSCI uses a composite project rating from AAA to CCC, while Calyx Global uses a different scale for its greenhouse-gas integrity assessments. Rating scales should therefore not be treated as directly equivalent.

WHY CAN THE SAME PROJECT RECEIVE DIFFERENT RATINGS?

Carbon credit ratings are analytical opinions about risk and uncertainty. They are not purely mechanical measurements.

Two agencies may assess the same project differently because they:

  • use different methodologies
  • apply different scoring scales
  • weight risk factors differently
  • make different assumptions
  • use different data sources
  • assess different vintages or crediting periods
  • update their ratings at different times
  • interpret incomplete evidence differently
  • place different emphasis on project-level and methodology-level risks
  • treat co-benefits, safeguards and delivery risks differently

One agency may view the evidence supporting a project’s baseline as sufficiently conservative, while another may consider the same evidence uncertain. Neither conclusion necessarily proves that one agency is objectively correct and the other is wrong.

The disagreement may instead reveal where uncertainty is concentrated.

Comparing the underlying assessments can therefore be more informative than comparing only the headline scores. Independent research has also documented meaningful differences between agencies’ approaches to additionality, non-permanence, leakage, safeguards and co-benefits.

HOW SHOULD COMPANIES USE CARBON CREDIT RATINGS?

Carbon credit ratings are most useful as one structured input into a broader procurement and due-diligence process.

They should not replace a company’s own decision-making framework.

USE RATINGS AS AN INITIAL SCREEN

Ratings can help companies reduce a large project universe to a more manageable shortlist.

A buyer may establish minimum rating requirements, exclude projects with specific risk characteristics or prioritise projects that perform consistently across several assessment criteria.

However, minimum thresholds must be defined for each agency’s methodology and scale. A rating such as BBB does not necessarily represent precisely the same risk level across different providers.

REVIEW THE ANALYSIS BEHIND THE SCORE

A headline rating does not explain why a project received that score.

Companies should examine:

  • which factors strengthened the assessment
  • which factors reduced it
  • whether any information was unavailable
  • how uncertainties were treated
  • whether the rating applies to the relevant vintage
  • whether any material risks remain unresolved
  • which factors could trigger a future downgrade

A project with a moderate rating driven by one clearly understood risk may be more suitable than a project with a higher rating but limited transparency.

COMPARE MULTIPLE SOURCES WHERE AVAILABLE

Where more than one rating is available, comparison can reveal areas of agreement and disagreement.

Convergence between independent providers may increase confidence, although it should not be treated as proof that all risks have been resolved.

Divergence can be equally useful. It may indicate that the project depends on uncertain assumptions or that agencies interpret the available evidence differently.

CHECK THE DATE, SCOPE AND VINTAGE

A carbon project can change over time.

New monitoring reports, satellite data, verification findings, methodology revisions, political developments or reversal events may alter its risk profile.

Companies should therefore check:

  • when the rating was issued or updated
  • which crediting period it covers
  • whether it applies to the project or a specific vintage
  • whether new information has been published since the assessment
  • whether the project is under review or rating watch

Calyx Global, for example, explicitly provides vintage-level assessments to reflect changes in project conditions over time.

COMBINE RATINGS WITH PROJECT DUE DILIGENCE

A robust review should also consider:

  • the project design document
  • validation and verification reports
  • monitoring data
  • satellite and geospatial evidence
  • financial additionality
  • project governance
  • land and carbon rights
  • benefit-sharing arrangements
  • environmental and social safeguards
  • the project developer’s track record
  • the buyer’s intended climate claim

Ratings can direct attention towards the most material risks, but the underlying documentation remains essential.

MONITOR RATINGS AFTER PURCHASE

Due diligence should not end when credits are purchased or retired.

Companies should monitor relevant projects for:

  • rating changes
  • updated monitoring reports
  • reversals
  • disputes
  • methodology changes
  • regulatory developments
  • new satellite findings
  • changes in project ownership or governance

This is particularly important for long-term procurement agreements and portfolios containing nature-based credits.

CARBON CREDIT RATINGS VS. CARBON STANDARDS 

Carbon standards and carbon credit ratings serve different purposes.

A carbon-crediting standard or program, such as Verra’s Verified Carbon Standard or Gold Standard, establishes requirements for project eligibility, methodologies, validation, monitoring, verification and credit issuance. Projects must demonstrate conformity with the relevant program rules before credits can be issued.

A carbon credit rating is a comparative, graded assessment of the risks associated with a specific project, credit or vintage. It is produced independently of the carbon-crediting program.

In simplified terms:

  • a standard asks whether a project meets the applicable program and methodology requirements
  • a rating asks how likely the credit is to deliver its claimed outcome and how its risks compare with those of other credits

A certified credit can therefore still present meaningful project-level risks. Certification and ratings should be considered complementary rather than interchangeable.

HOW DO CARBON CREDIT RATINGS DIFFER FROM THE CCP LABEL?

The Core Carbon Principles were developed by the Integrity Council for the Voluntary Carbon Market as a global benchmark for high-integrity carbon credits.

The ICVCM assesses carbon-crediting programs and categories of credits against its Assessment Framework. Eligible credits from approved programs and categories may receive the CCP label. This is different from an independent, graded risk assessment of every individual project.

A project-level rating may therefore still identify risks that are not resolved by program or methodology-level CCP eligibility.

The two tools answer different questions:

  • the CCP label indicates that the relevant program and credit category meet the ICVCM’s applicable integrity criteria
  • a rating provides a more granular opinion on the risks of a particular project, credit or vintage

Neither should automatically replace buyer-level due diligence.

LIMITATIONS OF CARBON CREDIT RATINGS

Ratings improve transparency, but they also have limitations.

These include:

  • dependence on the availability and quality of project data
  • methodological differences between agencies
  • uncertainty in forward-looking assumptions
  • different rating scopes and dates
  • limited comparability between scoring systems
  • the possibility of rating changes
  • incomplete project documentation
  • differences in how safeguards and co-benefits are treated
  • the risk of overreliance on a single headline score

A high rating does not eliminate all project risk. A lower rating also does not necessarily mean that a project has no value.

The relevant question is whether the identified risks are understood, acceptable and compatible with the buyer’s objectives.

FREQUENTLY ASKED QUESTIONS ABOUT CARBON CREDIT RATINGS

Can companies rely only on carbon credit ratings?

No.

Ratings provide a valuable independent view, but they do not replace project documentation, validation and verification, buyer-level due diligence or strategic assessment.

They are also not infallible. Agencies may reach different conclusions, and ratings may change when new information becomes available.

The strongest approach combines ratings with:

  • project documentation
  • independent technical analysis
  • geospatial evidence
  • financial and legal review
  • safeguard assessment
  • evaluation of the project developer
  • alignment with the company’s procurement and climate strategy

Are carbon credit ratings independent from carbon standards?

Yes. Commercial rating agencies generally operate independently from the standards that register projects and issue credits.

Their role is not to certify the project again. Instead, they analyse the risk that a certified or proposed credit may not deliver its claimed climate benefit.

Companies should still review potential conflicts of interest, governance arrangements and the transparency of each agency’s methodology. 

How do ratings assess permanence in nature-based projects?

Rating agencies may combine historical evidence, project documentation, geospatial analysis and forward-looking risk assessment.

Factors can include:

  • land and carbon rights
  • wildfire exposure
  • drought
  • pests and disease
  • storms and flooding
  • sea-level rise
  • illegal logging
  • land-use pressure
  • community support
  • long-term financing
  • monitoring arrangements
  • buffer-pool contributions
  • procedures for compensating reversals

Satellite and remote-sensing data can help agencies compare reported project outcomes with observable changes on the ground.

Do ratings consider biodiversity benefits?

Often, but not always in the same way.

Some agencies report biodiversity, community or Sustainable Development Goal outcomes separately from their central carbon-integrity rating. Others incorporate co-benefits into a wider composite assessment.

Buyers should check the methodology rather than assume that a high headline rating automatically represents strong biodiversity or social impact.

Can a project have strong co-benefits but still receive a weaker carbon rating?

Yes.

A project may deliver meaningful biodiversity protection, employment or community benefits while presenting weaknesses in its carbon baseline, additionality, quantification or permanence.

Because co-benefits and carbon integrity measure different outcomes, strong performance in one area does not automatically compensate for weak performance in the other.

Companies seeking both should assess both dimensions independently. 

Why do ratings differ between rating agencies?

Ratings differ because agencies use different methodologies, data, assumptions, weightings, scopes and assessment dates.

They may also interpret uncertainty differently or assess different vintages of the same project.

Different ratings should therefore be treated as differing professional opinions about risk, not automatically as evidence that one agency has made an error.

Can a carbon credit rating change over time?

Yes.

A rating may change when new information becomes available, including:

  • monitoring data
  • verification reports
  • satellite imagery
  • reversal events
  • methodology updates
  • changes in project governance
  • legal disputes
  • changes in land-use pressure
  • new scientific evidence

Companies should use the latest applicable rating and continue monitoring material projects after purchase. 

Does a high rating guarantee a high-quality carbon credit?

No rating can provide an absolute guarantee.

A high rating indicates that the agency considers the project comparatively likely to deliver its claimed climate outcome based on its methodology and the evidence available at the time.

Buyers should still assess the project’s strategic fit, documentation, safeguards, governance and any risks not fully captured by the headline score.

What should buyers check before using a rating?

Buyers should verify:

  • which agency issued the rating
  • the agency’s rating scale
  • the definition of each rating level
  • the assessment methodology
  • the date of the rating
  • the relevant project and vintage
  • the evidence used
  • unresolved uncertainties
  • whether the rating is under review
  • whether co-benefits are included or scored separately
  • whether another agency has assessed the same project

At FORLIANCE, carbon credit ratings are used as one input within a broader project-selection and due-diligence process. We assess the underlying project evidence, integrity risks, safeguards, implementation partner and strategic suitability rather than relying on a single score. 

Contact us, we’re happy to assist you.

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