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Carbon Ratings

Sylvera Carbon Credit Ratings: Frameworks & Processes White Paper

April 12, 2022
Sylvera carbon credit ratings framework

Buyers and traders of carbon credits have very little insight into their quality. This has been holding back voluntary carbon markets (VCMs) from reaching their full potential of helping to avert the climate crisis. The Sylvera carbon credit rating system was designed to change this. Sylvera ratings give a fair reflection of carbon credit quality, regardless of the type of carbon project issuing the credit. This makes it possible for buyers and traders to compare carbon credit quality from the same or different project types. Insight into the quality of carbon credits enables buyers and traders to act with greater confidence, driving funds toward high-quality projects and away from lower-quality projects, helping to scale VCMs and mitigate climate change. 

In this overview of our rating system processes we’ll answer:

  • What is a Sylvera carbon credit rating? 
  • How do we create a Sylvera carbon credit rating?
  • What makes our ratings unique and reliable?
Download the comprehensive white paper here, or read an intro below.

What is a Sylvera carbon credit rating?

What Moody’s ratings are to bond credits, Sylvera ratings are to carbon credits. 

A Sylvera carbon credit rating assesses the likelihood that the credits issued by a carbon project have delivered on their claims of avoiding (meaning reducing) or removing of one metric ton of carbon dioxide (tCO2), or other greenhouse gasses (GHGs), measured in CO2 equivalent (tC02e).

A Sylvera rating is a combination of three core scoring pillars: carbon, additionality and permanence. Over-crediting risk is assessed in additionality. Our ratings are updated quarterly and when significant events occur. This Sylvera rating is reflected on a scale from AAA to D. AAA represents the highest likelihood that the project has delivered on its claim to avoid or remove GHGs and is highly additional with low permanence risks. D represents the lowest likelihood the project has met its claimed performance, is not additional, has high permanence risks or both. 

While we assess the biodiversity and community co-benefits of projects, and make this information available through our co-benefits score, this score is not included in the Sylvera rating. As such, the Sylvera rating is a direct reflection on the project’s ability to avoid or remove GHGs. The project’s co-benefits can be thought of as additional benefits derived from the project which may yield a premium in price. For example, a project with an A Sylvera rating and high co-benefits score may be more valuable to buyers and fetch a higher price than another A-rated project that delivers no co-benefits.

Watch our video for an introduction to how Sylvera rates carbon projects, explained by our Head of Nature-Based Solutions Frameworks, Jess Roberts:

How and when should you use Sylvera carbon credit ratings?

Sylvera ratings can be used to inform trading and investment decisions for your carbon credit portfolio.

If you’re a corporate sustainability leader, you’ll be looking to buy the best carbon credits to meet corporate climate commitments like covering your unabatable emissions outside of your supply chain. Sylvera’s carbon credit ratings can help you identify high-quality carbon credits with low reputational risk to your organization. Because we regularly update them, our ratings also allow you to continually manage and optimize your carbon credit portfolio and actively mitigate any reputational risks that may arise in the future. 

If you’re a carbon trader, you can similarly use Sylvera’s carbon credit ratings to identify and purchase credits that are currently undervalued and may see an increase in value in the future, while also identifying high-quality credits to sell to clients. Our periodic updates allow for portfolio management and optimization, as well as ongoing risk management.

Alongside each individual rating, we include the underlying analysis we used to arrive at the rating, as well as extensive commentary about the carbon project and credits analyzed. Our ratings are best used in conjunction with this in-depth information we provide.

Key benefits of using our carbon credit ratings

  • Confidence: We help you pick the best carbon credits, which means you don’t waste money on bad investments or put your reputation at risk. 
  • Choice: We aim to give you a view of the whole market you can trust. We don’t sell credits and never will. We aren’t paid by developers to rate projects either. You determine the most cost-effective way to buy — whether it’s direct to project developer, via broker or exchange.
  • Efficiency: We save you time and money spent on due diligence, enabling you to move quickly with a lean team.

Why did Sylvera create a new system for rating carbon credits?

VCMs can be powerful tools for mitigating climate change. They have the potential to direct investment into high-impact, high integrity projects funded by carbon credits, whether the project is avoiding or reducing GHGs by protecting or restoring forests, installing renewable energy plants or deploying new technologies that remove GHGs from the atmosphere. 

However, VCMs and associated projects have been the subject of several public scandals. They’ve acquired a reputation for having an unreliable or negative impact on local environments and communities, and the climate, resulting in them being accused of greenwashing.

This is because of: 

  1. a lack of international and local regulations 
  2. carbon credit certification and registration organizations that verify carbon projects to issue credits, not, as yet, fully checking certain claims that carbon project developers make in their project reports, creating a leaky system where inaccurate project claims aren’t caught in time and low-quality projects remain on the market 
  3. a lack of independent data providers looking into the historic and current performance of carbon projects
  4. a proliferation of diverse carbon credit project types, resulting in complex methodologies, including cases where several methodologies are in place for a single project type on a single verification organization’s registry
  5. a requirement for deep technical expertise to assess how well carbon projects are executed and the validity of their claims.

As an answer to this problem, we built a team of independent, highly specialized technical experts, to develop a new system for evaluating and rating the ability of carbon credit projects to avoid or reduce GHG emissions or remove carbon, or other GHGs. Our unique system also accounts for the impacts of carbon projects on local ecosystems and communities. 

We’re serving as a source of truth for carbon markets, helping direct capital into the best carbon projects, and creating a world where ecosystems are properly valued and protecting our future is incentivized.

Our scoring pillars

As stated previously, a Sylvera rating is based on three core pillars: carbon, additionality and permanence. These pillars give a clear indication of which carbon credits are most likely to avoid or remove GHGs when comparing the carbon credits across project types. Pillar scores are combined into a Sylvera rating that provides a holistic view of carbon credit quality. One strong pillar score cannot compensate for another weak pillar and lead to an inflated Sylvera rating. We do not simply average the pillar scores to obtain the overall Sylvera rating. For example, we consider additionality as a limiting factor, so though a project may have a perfect carbon score, the Sylvera score will not be high if the project is unlikely to be additional.

Carbon score

Our carbon score verifies whether a project is accurately reporting on its activities which directly translates to its overall avoidance (meaning reduction) or removal of CO2, and other GHGs, measured in CO2, equivalent (CO2e). We verify these activities, which include the planting of trees and the protection against deforestation, by comparing data provided by the project developers with our own measurements using satellite imagery and machine learning (ML). This includes any increases in GHG emissions that have occurred outside the project boundary as a result of the project’s activities, known as leakage. This carbon score is shown as a percentage. If our analysis finds that a project’s activities have exceeded its claims, it’ll have a carbon score above 100%. If we find that the project activities are less than what has been claimed, meaning that the project has not met its GHG emissions reduction or removals claims, it’ll get a carbon score below 100%. Carbon score should not be considered in isolation and must take additionality, particularly strength of baseline and over-crediting risk, and permanence into account.

Additionality score

Our additionality score is split into two sub-components: 1. the additionality of the project’s activities and 2. over-crediting risk

1. Additionality of the project’s activities

Additionality of activities assesses the likelihood that a carbon project’s activities that are designed to avoid or remove GHGs would or wouldn’t have been implemented in the absence of revenue generated through the sale of carbon credits. Additionality of activities is assessed based on the project’s financial additionality, political and regulatory additionality, and a common practice analysis.

2. Over-crediting risk

We also assess the risk of over-crediting: whether the number of carbon credits a project has issued is justified. For avoided emissions projects, over-crediting risk is assessed by evaluating the reasonableness of the project’s claimed baseline. Project baselines represent the emissions that would have occurred in the business-as-usual (BAU) or counterfactual scenario, the one that would have taken place without the implementation of the project. The quantity of carbon credits a project proponent is able to sell in a given crediting period is calculated by taking the baseline and then subtracting actual emissions from the project area and any leakage emissions. Therefore, it is imperative that a project establishes a reasonable baseline scenario, otherwise the project is subject to over-crediting risk. For example, if a project claims that in the counterfactual scenario 1,000 tCO2e would have been emitted but our analysis shows that historical trends indicate that only 100 tCO2e would have likely been emitted, then the amount of avoided emissions claimed by the project is drastically overstated due to an inflated baseline. For nature-based carbon removal projects, such as afforestation projects, over-crediting risk is assessed by evaluating whether the emissions removal claims are unjustified through the omission of key biological and mechanical factors. Other factors that can lead to over-crediting in nature-based solutions are also considered, such as improper accounting of leakage and the use of unreasonable or out-dated carbon stock assumptions.

We don’t view additionality as binary, but rather as a continuum of likelihood as reflected in our score that ranges from 1 to 5. An additionality score of 5/5 indicates very high confidence that a project is additional and 1/5 indicates that we found a serious red flag questioning the project’s claims of additionality.

Permanence score

Our permanence score assesses whether the GHGs avoided or removed by a carbon project are likely to be maintained for an atmospherically significant period of time, usually about a century. 

We consider both natural risks and those related to people in our permanence assessment. We look at historic exposure to natural risks such as fires, droughts, floods, pests and hurricanes and evaluate trends and patterns. We also forecast natural risks with our in-house climate risk models and simulations. Risk factors related to people include land tenure rights, carbon credit issuance rights, free, prior and informed consent (FPIC) of indigenous populations, as well as, the project proponent’s access to capital and geopolitical risk factors. We view all these permanence risks as additive, meaning that we evaluate the likelihood and severity of a variety of risk factors individually, and then combine this into an overall risk score.

We score permanence out of 5, where a very high permanence (low risk) is indicated by 5/5 and a very low permanence (high risk) is indicated by 1/5.

Co-benefits score

In addition to our three core pillars, we also assess additional impacts of the project on the biodiversity and local community and show this as our co-benefits score. We exclude the co-benefits score from the Sylvera rating. This is because the primary function of a Sylvera rating is to assess the likelihood that the claimed GHGs have been avoided or removed. It also prevents a high co-benefits score from inflating the Sylvera rating for a project that is underperforming from the perspective of avoiding or removing GHGs. 

The scope, design and implementation of project activities that contribute to people-related United Nations Sustainable Development Goals (UN SDGs) are evaluated and the impacts of these are compared to progress towards these goals at local, regional and national levels. A similar assessment is undertaken to understand the threats to biodiversity in the project area, and the impact of protective schemes implemented by the project. Our co-benefits scores help customers identify carbon projects that have positive community and biodiversity impacts. We score co-benefits on a scale from 1 to 5, where 5/5 indicates exceptional progression on targeted SDGs, as well as extraordinary species richness and high-quality activities to reduce pressure on biodiversity, and 1/5 indicates very limited progression on targeted SDGs, very low species richness and a lack of activities to reduce pressure on biodiversity.

What makes Sylvera carbon credit ratings accurate and trustworthy?


We don’t and won’t ever sell carbon credits or receive payments from project developers to rate projects. Therefore, we have no incentive to provide ratings that are based on anything but our rigorous analysis. An external governance body, composed of independent individuals, also holds us to account. 


Our carbon credit ratings are based on an unrivaled depth of analysis. Other ratings are often based largely on a top-down analysis of project characteristics such as certification methodology. Top-down analysis is an insufficient indication of the quality of a project and we see significant variation of quality within certification methodologies. Therefore, while we conduct a top-down analysis too, we focus mostly on an in-depth bottom-up analysis.

Accuracy and objectivity

Our solutions combine the best of technological and human assessments. Purely technological solutions have uncertainties that need to be checked by humans for accuracy, while solely human assessments can be subjective, which is why we designed the frameworks and tests we use to arrive at our scores to be highly objective and based on numeric data where possible. 


The rationale that sits behind our ratings is provided in detailed commentary. Customers can dig into the scores that make up a Sylvera rating, the subscores that make up those scores, how these scores are weighted and what tests were used to arrive at them.

Continuous development and regular updates

We update our ratings quarterly to reflect the latest data on project performance and new project documentation. When significant events occur outside this quarterly cycle we update our ratings and notify our customers. Our team also continues to refine our processes as markets and our technologies develop.

World-leading research and development

We conduct world-class research to develop the most accurate estimations of forest carbon. Our research includes collaborations with the World Bank, NASA-JPL, UCL, UCLA and other leading institutions to gather measurements of forest carbon using state-of-the-art lidar technology. We are also active participants in several influential groups including Agriculture Innovation Mission for Climate (AIM4C), International Emissions Trading Association (IETA), World Economic Forum (WEF) UpLink, Space4Climate, SustainTech Accelerator and Tech Zero and, by extension, Race to Zero.

Download the complete white paper here.
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This article features expertise and contributions from many specialists in their respective fields employed across our organization.