Methodology · Version 3.2 · March 2026
Ten independent factors. Satellite-verified data. A transparent, versioned scoring framework applied consistently across 3,200+ projects, 180+ methodology types, and every major voluntary and compliance registry.
Section 01
A seven-tier scale from AAA (highest quality, lowest risk) to D (material misrepresentation or permanent reversal). Every rating reflects a composite of the 10-factor assessment, applied consistently across all methodology types and registries. Scores are expressed as 0–100 composites with a tier boundary at each level.
Within tiers AA through B, SYNE Carbon applies plus (+) and minus (−) modifiers indicating relative position within the tier range. A project rated AA+ sits near the top of the AA band (87–89) while AA− sits near the lower boundary (80–82). AAA and D carry no modifier.
Section 02
Each factor is scored independently on a 0–100 scale, then weighted and combined into the composite rating. Factor weights reflect their relative importance to carbon credit integrity and are reviewed annually by the SYNE Carbon Methodology Committee.
The most critical dimension of carbon credit integrity. Additionality tests whether the claimed emissions reductions would have occurred without the carbon project — i.e., whether the project is additional to what would have happened under a credible business-as-usual scenario.
SYNE Carbon assesses additionality using satellite-verified baseline construction, counterfactual scenario modelling, financial and barrier analysis, and common practice tests. Projects are penalised for weak baseline periods, inappropriate reference regions, and financially viable business-as-usual alternatives.
Carbon stored or avoided today must remain stored or avoided. Permanence scoring quantifies the probability of reversal across three risk dimensions — physical (fire, drought, pest), legal (land tenure, policy changes), and political (government stability, regulatory continuity).
For nature-based projects, buffer pool adequacy is assessed against SYNE's independent risk estimate. Projects where the registry-held buffer is insufficient to cover estimated reversal risk are penalised accordingly. Continuous satellite monitoring feeds live permanence score updates.
Measurement, Reporting, and Verification quality is assessed across five sub-dimensions: measurement methodology rigor, reporting completeness and frequency, verification body independence, verification cycle compliance, and data chain-of-custody integrity from project to registry to market.
Projects using continuous automated monitoring or satellite-based MRV are rewarded with higher scores. Projects relying on infrequent field sampling with long verification cycles and weak VVB independence are penalised. For Teravent technology removals, sensor-level data logging records are reviewed directly.
The reference scenario against which emissions reductions are measured determines the total credit volume. Baseline integrity assesses whether the reference level is conservative, appropriately defined, and consistent with observable land-use trajectories in the reference region.
SYNE Carbon independently constructs satellite-derived reference scenarios using Landsat (1990–present), ESA CCI Land Cover annual maps, and Global Forest Watch deforestation data — then compares these against registry-approved baselines to identify over-inflation in baseline scenarios.
Beyond carbon, high-quality projects generate verified co-benefits — biodiversity protection, community livelihood improvement, water security, and gender equity. This factor assesses the strength and verifiability of co-benefit claims across the 17 UN SDG targets.
Co-benefits are scored on evidence quality (self-reported vs third-party certified vs satellite-verified), claim scope (number of SDGs with material contribution), and claims integrity (whether stated co-benefits are consistent with independent evidence). Gold Standard CCB and VCS Jurisdictional REDD+ co-benefit data are directly ingested.
Leakage occurs when carbon-emitting activities are displaced outside the project boundary rather than genuinely reduced. SYNE Carbon assesses three leakage types: market leakage (displaced economic activity), activity leakage (displaced land use), and ecological leakage (transboundary ecosystem effects).
Satellite monitoring of a 50km buffer zone around project boundaries detects activity leakage. Market leakage is modelled using commodity price and deforestation frontier data. Projects with high leakage scores that are not adequately discounted in credit issuance volumes are penalised.
Carbon projects operating in jurisdictions with unstable governance, weak rule of law, or active political risk to carbon market participation face elevated probability of project suspension, land confiscation, or regulatory invalidation. Political risk is assessed at both national and sub-national levels.
SYNE Carbon integrates World Bank Governance Indicators, Freedom House political risk scores, World Risk Index data, and Carbon Market Policy Uncertainty indices to construct a project-level political risk score. Scores are updated semi-annually or upon trigger events (elections, policy announcements, conflict escalation).
Project integrity assesses the governance, transparency, and track record of the project developer and verification body. This includes developer history across all rated projects, verification body conflict-of-interest review, project documentation completeness, registry compliance history, and any regulatory or legal actions.
SYNE Carbon maintains a Developer Integrity Registry tracking every project developer across all rated projects — identifying patterns of baseline manipulation, verification shopping, or serial under-delivery. Projects from developers with integrity flags are assessed at elevated scrutiny with score adjustments applied.
Distinct from co-benefit quality (Factor 5), SDG Alignment assesses the breadth of sustainable development outcomes across the 17 SDGs — particularly whether the project makes a material, independent contribution to goals beyond climate (SDG 13), such as biodiversity (SDG 15), clean water (SDG 6), and poverty reduction (SDG 1).
SDG alignment is scored by mapping verified project activities against 169 SDG targets and 232 global indicators, using both self-reported evidence and third-party certified data from Gold Standard SDG Impact Tool, CCBA Standards, and direct satellite measurement where applicable.
Whether a credit meets the eligibility criteria for CORSIA Phase 1 and Phase 2 compliance use determines a significant part of its addressable market and premium pricing. This factor assesses conformance with ICAO's CORSIA Eligible Emissions Unit (CEEU) criteria and Article 6 corresponding adjustment status.
SYNE Carbon tracks CORSIA Technical Advisory Body approvals, corresponding adjustment commitments by host country, vintage eligibility windows, and double-counting risk under Article 6.2 and 6.4 mechanisms — updated in real time as ICAO and UNFCCC publish eligibility changes.
Section 03
SYNE Carbon's ratings engine draws on more than 20 independent data sources across satellite imagery, earth science databases, political risk analytics, and registry data feeds. No single data source dominates any factor — redundancy and cross-validation are built into every assessment.
Core optical imagery for NDVI, EVI, canopy cover, and land-use change detection. Primary sensor for vegetation health monitoring and deforestation detection across all forest carbon projects.
All-weather forest monitoring through cloud cover. Primary source for above-ground biomass estimation and tropical project monitoring where optical imagery is persistently obscured.
Daily active fire monitoring across all project areas. Near-real-time detection of fire events that trigger permanence risk alerts and emergency rating reviews for affected projects.
Historical baseline engine. Land-use change data back to 1972 underpins all additionality and baseline construction analysis — the longest continuous earth observation record available for any carbon project.
L-Band SAR penetrates dense forest canopy to estimate above-ground biomass in high-biomass tropical forests where C-Band SAR saturates. Critical for REDD+ projects in the Amazon, Congo Basin, and Southeast Asian forests.
Near-real-time deforestation alerts. GFW's Hansen dataset and GLAD alert system provide the deforestation monitoring layer for early warning on reversal risk across all forest carbon projects covered by SYNE.
Global soil organic carbon stock estimates and sequestration rate baselines. Used in SYNE's Soil Intelligence module for agricultural and land restoration project assessment and permanence scoring.
Rule of law, government effectiveness, political stability, and regulatory quality scores feeding the Political Risk factor (Factor 7) for all projects in developing-market jurisdictions.
Direct API integrations with all major voluntary and compliance registries, providing real-time issuance, retirement, and transfer event tracking. Registry data feeds are the authoritative source for credit volume, vintage, and project status.
Section 04
Every SYNE Carbon rating follows an eight-stage process — from initial data collection through ongoing surveillance. The process is fully documented, version-controlled, and subject to annual methodology review. All ratings are produced without any commercial relationship with rated project developers.
Project documentation, registry records, verification reports, and all publicly available project design documents are collected and structured. Registry API integration ensures automated updates on issuance, retirement, and status changes.
Project boundary polygons are submitted to the Earth Intelligence pipeline. Sentinel-2, Sentinel-1 SAR, Landsat, and MODIS data are processed via Google Earth Engine for vegetation metrics, land-use change history, and fire monitoring status.
SYNE Carbon constructs an independent satellite-derived reference scenario using historical land-use change data. This independent baseline is compared against the registry-approved baseline to identify potential over-inflation.
Each of the 10 factors is scored 0–100 by dedicated analytical modules. Factor scores are produced by a combination of quantitative models (satellite-derived) and qualitative assessments (documentation review). Each score is fully explainable and citable.
The 10 weighted factor scores are combined into a composite score (0–100). The composite score maps to a rating tier (D through AAA) with plus/minus modifiers applied within AA–B tiers. Score flooring rules are applied where a single factor below a critical threshold caps the composite.
All initial ratings undergo a two-stage internal review: a quantitative consistency check (automated) and a qualitative review by a senior analyst. Ratings that fall near tier boundaries or involve novel methodology types undergo extended committee review.
Ratings are published to the SYNE Carbon database and delivered via REST API. Each rating includes the composite score, all 10 factor scores, key findings, data provenance citations, methodology version number, and the next scheduled review date.
Ratings are under continuous satellite surveillance. Trigger events — deforestation alerts, fire events, registry status changes, political risk changes, or new verification reports — initiate an automatic review. Non-triggered reviews occur on a rolling 16-day satellite cycle.
SYNE Carbon has no financial relationship with any rated project developer, registry, or carbon credit buyer. Ratings are produced solely on the basis of independent data analysis.
All satellite data sources are publicly available and independently reproducible. Every rating cites the specific data version, sensor, and processing pipeline used.
SYNE Carbon does not accept fees from project developers for faster or more favourable ratings. The ratings engine treats all projects equally regardless of market participant relationships.
SYNE Carbon analysts involved in ratings for a project or its developer must disclose any prior relationship and may be recused from the review at the discretion of the Methodology Committee.
Certain factor scores apply a floor to the composite rating — regardless of strong performance across other factors. If the Additionality score falls below 40, the composite is capped at B+. If MRV Quality falls below 35, the composite is capped at BBB. A Permanence score below 25 triggers an automatic D-watch review and may override the composite entirely.
Section 05
The SYNE Carbon ratings methodology is governed by a three-tier structure: the Methodology Committee (approval authority), the Scientific Advisory Board (independent review), and the Public Consultation process (external validation). All significant methodology changes are subject to a minimum 60-day public consultation before taking effect.
SYNE Carbon's internal Methodology Committee is responsible for approving all factor weights, scoring rubrics, data source selections, and tier boundary definitions. The Committee meets quarterly and includes representatives from the research, product, and compliance functions. All committee decisions are documented and published.
An external Scientific Advisory Board comprising carbon scientists, remote sensing experts, and climate policy specialists provides independent review of the methodology on an annual basis. The SAB's review covers factor relevance, data source adequacy, and weight appropriateness — published as a public SAB Report.
Significant changes to factor weights (≥2%), new methodology type coverage, or changes to tier boundaries are subject to a 60-day public consultation period. Draft methodology changes are published on syne.com/methodology/consultation — open to comment from any market participant, regulator, or researcher.
Every published rating references a methodology version number (current: v3.2). All historical ratings remain accessible under the methodology version in effect at the time of publication. Ratings and methodology documents are fully citable with persistent DOI-style identifiers for use in academic research and regulatory filings.
SYNE Carbon maintains a strict conflict of interest policy prohibiting analysts from rating projects where they hold a financial interest, have a prior commercial relationship, or have advised the project developer within the preceding 36 months. All conflicts are disclosed and managed by the Compliance function independently of the ratings team.
SYNE Carbon engages actively with ICAO's CORSIA Technical Advisory Body, the UNFCCC Article 6 Supervisory Body, the VCMI, the ICVCM, and national carbon market regulators. SYNE Carbon's methodology is designed to be consistent with evolving international integrity frameworks including the Core Carbon Principles (CCPs) and the Paris Agreement Article 6 rulebook.
Section 06
All methodology changes are documented, versioned, and published. Material changes (factor weight adjustments ≥2%, new factor introductions, tier boundary changes) require public consultation. Minor changes (data source updates, model recalibrations, new methodology type coverage) are published in the monthly update notes.
Updated Factor 10 (Regulatory Eligibility) to reflect ICAO CORSIA Phase 2 criteria effective January 2027. Added corresponding adjustment verification layer for Article 6 credit tracking. Updated vintage eligibility windows for all covered registries. No weight changes applied.
Upgraded vegetation monitoring pipeline to use fused Sentinel-2A/2B multi-pass compositing, reducing effective revisit time from 10 to 5 days. Updated permanence monitoring refresh rate for all active forest projects from 16-day to 5-day cycle. No factor weight changes.
SDG Alignment split from Co-Benefits (Factor 5) into a dedicated standalone factor (Factor 9). Co-Benefits weight reduced from 15% to 11%; new SDG Alignment factor assigned 7% weight. MRV Quality weight increased from 12% to 14% reflecting growing importance of continuous monitoring verification. Methodology underwent 60-day public consultation (July–September 2024) with 23 submissions received. Full consultation response published separately.
Added dedicated scoring rubrics for Enhanced Weathering, Ocean Alkalinity Enhancement (OAE), and Biochar projects on the Teravent registry. Extended the Teravent sensor-level data logging review to all DAC and BECCS projects. Updated Factor 3 (MRV Quality) rubric to reflect technology removal monitoring standards.
Access independent carbon ratings for 3,200+ projects via the SYNE Carbon platform or REST API. Every rating includes full factor-level scores, data provenance, and methodology version for complete auditability.