Carbon Rating System

Learn how the carbon rating system works

Projects are rated based on 4 key emissions impact criteria (Additionality, Permanence, Quantification / Measurability and Leakage), along with the methodology review status by Integrity Council for the Voluntary Carbon Market (ICVCM) Core Carbon Principles (CCPs)

Each criteria is rated out of 5, with 5 being the highest rating. An overall project rating is provided (which is an average of each individual criteria ratings).

Key project documentation is reviewed to determine the assessment. This includes Project Design Documents (PDDs), verification and monitoring reports. The ratings are predominantly produced through using Artificial Intelligence (AI) based algorithms. Each project is reviewed based on its own individual merits, and a justification for each rating is provided.

Search the Carbon Offset Project Ratings


In the context of carbon offsetting, additionality refers to the principle that a carbon offset project must result in carbon emissions reductions or removals that are additional to what would have occurred without the project. This means that the emissions reductions must be beyond what is required by law, beyond what is financially viable without the offset revenue, and beyond what would happen under a business-as-usual scenario.

For a carbon offset project to be considered additional, it must meet certain criteria:

1. Regulatory Surplus: The project’s emissions reductions must exceed any reductions required by existing laws, regulations, or policies.
2. Financial Additionality: The project would not have been financially viable without the income from selling carbon credits. This often involves demonstrating that the project faces financial, technological, or other barriers that would prevent it from being implemented without the additional funds provided by carbon credits.
3. Common Practice: The project’s activities must not be common practice within the industry or region. This ensures that the project is not simply reflecting standard practices that would happen regardless of the carbon offset market.
4. Baseline Scenario: There must be a clear and credible baseline scenario, showing what the emissions would have been in the absence of the project. The emissions reductions are then calculated as the difference between the baseline scenario and the actual emissions with the project in place.

The concept of additionality is crucial for ensuring the environmental integrity of carbon offsets, as it ensures that each carbon credit represents a real, measurable, and verifiable reduction in greenhouse gas emissions. Without additionality, there is a risk that the carbon offset market could fund projects that do not actually contribute to reducing overall emissions, thus undermining the goal of mitigating climate change.


In the context of carbon offsetting, permanence refers to the durability and longevity of the carbon emissions reductions or removals achieved by a carbon offset project. It addresses the risk that the carbon sequestered or emissions reduced by a project might be reversed in the future. Ensuring permanence means that the carbon benefits claimed by the offset must persist over a long period, typically decades to centuries.

Key considerations for permanence in carbon offsetting include:

1. Duration: The length of time for which the carbon reductions or removals remain effective. Permanent reductions mean that the carbon is kept out of the atmosphere indefinitely, not just temporarily.

2. Reversal Risk: The potential for carbon benefits to be negated due to natural events (like wildfires, disease, or drought) or human activities (like deforestation, land-use change, or poor project management). Effective carbon offset projects must have mechanisms in place to minimize and manage these risks.

3. Monitoring and Verification: Ongoing monitoring and verification are essential to ensure that the carbon reductions or removals remain intact over time. Regular checks help detect any reversals and implement corrective actions if necessary.

4. Insurance and Buffer Pools: Many carbon offset programs use buffer pools or insurance mechanisms to account for potential reversals. A portion of the credits from all projects is set aside in a buffer pool to cover any losses due to unforeseen reversals, ensuring the overall integrity of the carbon offset program.

5. Project Longevity: Projects need to have a long-term management plan and commitments to maintain the carbon benefits. This may involve legal agreements, land use planning, and financial arrangements to support the project's sustainability over time.

Permanence is a critical aspect of carbon offsetting because it ensures that the carbon credits represent a lasting contribution to climate change mitigation. Without permanence, the effectiveness of carbon offsets in reducing atmospheric greenhouse gas concentrations could be significantly undermined.



In the context of carbon offsetting, measurability refers to the ability to accurately quantify the greenhouse gas (GHG) emissions reductions or removals achieved by a carbon offset project. It ensures that the carbon benefits claimed by the project can be reliably measured, verified, and reported.

Key aspects of measurability in carbon offsetting include:

1. Quantification Methods: The use of standardized and scientifically robust methods to calculate the amount of GHG emissions reduced or removed by the project. These methods should be transparent, reproducible, and based on established protocols.

2. Baseline Establishment: Defining a clear and credible baseline scenario that represents the emissions level in the absence of the project. This baseline is essential for comparing actual emissions with and without the project, thereby determining the net carbon benefits.

3. Monitoring: Continuous and systematic tracking of relevant data to measure the project's emissions reductions or removals over time. This may involve monitoring various parameters such as energy use, fuel consumption, forest growth, or soil carbon levels.

4. Verification: Independent third-party verification of the project's measurements and calculations to ensure accuracy and credibility. Verifiers assess whether the project's reported emissions reductions or removals are real, additional, and correctly quantified.

5. Reporting: Regular and transparent reporting of the project's carbon benefits, including detailed documentation of the methodologies, data, and assumptions used in the measurements. This helps maintain transparency and trust in the carbon offset market.

6. Accuracy and Precision: Ensuring that the measurements are accurate (close to the true value) and precise (consistent and repeatable). High-quality data collection and analysis techniques are necessary to minimize uncertainties and improve the reliability of the measured emissions reductions or removals.

Measurability is crucial for the integrity and effectiveness of carbon offsetting. It ensures that the carbon credits issued represent real and verifiable reductions in greenhouse gas emissions, providing confidence to buyers and stakeholders that their investments are making a genuine impact on climate change mitigation.


In the context of carbon offsetting, leakage refers to the unintended increase in greenhouse gas (GHG) emissions outside the boundaries of a carbon offset project as a result of the project's activities. Leakage can undermine the overall effectiveness of the project by offsetting some or all of the emissions reductions achieved within the project area.

Key aspects of leakage in carbon offsetting include:

1. Types of Leakage:
- Activity Shifting Leakage: This occurs when activities that produce emissions are simply moved from the project area to another location. For example, if a reforestation project prevents logging in one area, but the logging activity shifts to a nearby forest, the emissions reduction may be negated.
- Market Leakage: This happens when the project's activities affect market prices, leading to increased emissions elsewhere. For example, a reduction in timber supply due to a forest conservation project could raise timber prices, encouraging logging in other areas.

2. Leakage Assessment: Identifying and estimating potential leakage is crucial for understanding the true impact of a carbon offset project. This involves analyzing the project's influence on emissions sources and sinks beyond its immediate boundaries.

3. Leakage Mitigation: Implementing strategies to minimize or prevent leakage is essential. This can include supporting sustainable practices in surrounding areas, enhancing enforcement of environmental regulations, or creating incentives for low-emission activities.

4. Monitoring and Reporting: Ongoing monitoring of potential leakage effects is necessary to ensure that any leakage is detected and accounted for. Transparent reporting of leakage assessments and mitigation measures helps maintain the credibility of the carbon offset project.

5. Adjustment of Credits: To account for leakage, some carbon offset standards require a portion of the project's carbon credits to be set aside or discounted. This ensures that the net emissions reductions claimed are conservative and reflect any leakage.

Leakage is a critical consideration in carbon offsetting because it can significantly affect the actual climate benefits of a project. By properly assessing, mitigating, and accounting for leakage, project developers and stakeholders can ensure that carbon offset projects deliver genuine and lasting reductions in greenhouse gas emissions.

ICVCM CCP Submission Status

The Integrity Council for the Voluntary Carbon Market (ICVCM) has introduced their Core Carbon Principles (CCPs), which sets a new standard for carbon offsetting. 

As part of the project assessment, we consider if the methodology used for that project has been submitted, assessed and approved under the CCP.

The ratings for this criteria are:
1 = methodology either not submitted for rating or has failed to pass ICVCM CCP
3 = methodology submitted but waiting to be reviewed by ICVCM CCP
5 = methodology has been assessed and approved under the ICVCM CCP