Carbon credit intelligence
Every carbon credit rating agency is ultimately answering the same underlying question — is this a real, additional, durable tonne? — through some version of the same four tests. This page takes each test in depth, then sets out how BeZero, Calyx Global and Sylvera each run it, based on what those agencies have published themselves.
Would the emission reduction or removal have happened anyway, without the revenue from selling the credit? A project that fails this test is over-credited from the day it is registered, regardless of how well it is run afterwards. In August 2024 the ICVCM ruled that eight renewable-energy methodologies could not carry the CCP label on exactly this ground — the projects were judged insufficiently additional because falling technology costs meant many would likely have proceeded without carbon finance. Those methodologies accounted for roughly 236 million unretired credits, about 32% of the voluntary market at the time.
Was the counterfactual — what would have happened without the project — realistic? An inflated baseline (for example, assuming a higher deforestation rate than actually applied, or crediting against an unrealistically high historical emissions rate) is the most common route to over-crediting. Verra separately excluded five of its older REDD+ methodologies from CCP assessment altogether; those methodologies produced roughly a quarter of all credits retired in 2023, and cannot carry the label under any future review of the same version.
Will the stored or avoided carbon stay out of the atmosphere? Forestry and soil-carbon projects carry reversal risk from fire, disease, drought and land-use change that geological and mineral storage largely avoid. Programmes typically manage this with buffer pools — a share of credits withheld and never issued, to cover future reversals across the portfolio rather than any one project.
Did the protected activity simply move elsewhere — logging displaced to the next valley rather than avoided, or emissions-intensive production relocated rather than reduced? Leakage is hardest to observe directly because it happens outside the project boundary, which is why agencies increasingly assess it through discount factors and regional monitoring rather than project-level data alone.
These four are the factors named by Carbon Market Watch’s comparison of the rating agencies and by the ICVCM Core Carbon Principles, which list additionality and permanence among the “emissions impact” principles a crediting programme and methodology must satisfy to carry the CCP label. Where these factors sit inside a UK sustainability disclosure is covered in carbon credits in sustainability reporting.
This is a factual summary of what each agency has published about its own approach, not an independent audit of any of them. None of the three publishes the exact formula that turns individual risk-factor scores into a final letter rating — each states that allocation follows scoring against its framework, without disclosing the weighting.
Publishes an analytical view of the likelihood that a project achieves a genuine tonne of carbon avoided or removed, expressed on the eight-point scale. BeZero states its risk-factor methodology is unchanged from its previous three-tier scale and directs users to its published methodology document for the full detail; deliberately forgoes trading, project development and MRV consulting to avoid conflicts of interest with the projects it rates.
Scores each project against a published GHG Integrity Framework covering four named factors: additionality; over-crediting, which it defines to include baseline accuracy, project-emissions accounting and leakage; permanence; and overlapping claims (guarding against the same reduction being counted twice). Runs a separate SDG co-benefits rating on its own +1 to +5 scale.
Builds a distinct assessment framework for each project type — REDD+, ARR, cookstoves and others are scored differently rather than against one generic template — and assesses carbon accounting, permanence and co-benefits within each.
Independent comparison has found the same project rated differently by different agencies. That is not evidence any one agency is wrong — it reflects genuinely different methodological choices (how each treats leakage, how each builds its baseline, how much weight each gives co-benefits) applied to the same underlying project. Screening a portfolio against more than one agency’s view, rather than relying on a single rating, is the practical response.
Carbon credit rating agencies are not currently regulated in the UK. The Financial Services and Markets Act 2000 (Regulated Activities) (ESG Ratings) Order 2025 — made 15 December 2025 — brings ESG ratings within FCA authorisation from 29 June 2028, but only where a rating is likely to influence a decision on an investment specified in the Regulated Activities Order. Voluntary carbon credits are not specified investments, and neither the Order nor the FCA’s consultation addresses carbon credit ratings expressly — this is a question of perimeter, not an exclusion written into the rules.
None of this changes what the rating itself is: an opinion on whether a tonne is real, not a regulated financial-services product. Buyers who want a fuller introduction to the agencies and their scales before returning to the four tests here can start with carbon credit ratings explained.
SRS Credit provides independent carbon credit risk analysis across rated and unrated projects.
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