A CO2 offset, also named CO2 credit, is a unit of measure representing the reduction or removal of one metric ton of carbon dioxide (or its equivalent in other greenhouse gases) from the atmosphere through a project or activity.
A project, certified with any of the CO2 certification standards, can issue 1 credit for each 1.000 kg of CO2 emission offset (for a reforestation project) or CO2 emission avoidance (for a conservation project). In most standards, these credits are not divided into smaller portions (no half or quarter credits with less than 1.000 kg).
Below we provide you a glossary of frequent terms that you may encounter in our documents. Feel free to check their definitions as you read through them.
- Additionality
Additionality is a crucial concept in carbon offsetting, ensuring that the emissions reductions achieved by a project are above and beyond what would have occurred in the absence of the project. In other words, the project must provide a net positive impact on reducing greenhouse gas emissions. Read more in question How do you ensure that the CO2 offsets you sell are additional and not just shifting emissions? - Baseline
Estimated amount of greenhouse gas emissions that would occur in a specific area without the implementation of the offset project. The baseline serves as a reference point against which the project's carbon reduction or sequestration achievements can be measured, ensuring that the CO2 offsets generated are additional and result in real, quantifiable, and verifiable emission reductions. - Co-benefits
Additional positive environmental, social, and economic outcomes that arise from the project beyond the primary goal of reducing or sequestering greenhouse gas emissions. Co-benefits can include improvements in biodiversity, ecosystem services, local community livelihoods, and sustainable development. - Reforestation project (CO2 emission offset/ removal): A project that actually plants new trees. These new trees absorb CO2 from the atmosphere when they are growing. The wood of the tree growth is converted into CO2 credits.
- Conservation project (CO2 emission avoidance): A project that actually protects existing trees from being deforested or burned. This tree loss would lead to more CO2 emissions. Not any forest falls under this category of CO2 conservation, as the project has to prove that the forest is threatened and without the project’s protection the trees would be lost.
- Certification Process:
- Step 2 = Project Verification: The project has to go through a standardized verification process proving the amount of CO2 emissions offsetted or avoided during a certain period of time (minimum 1 year). After this verification the project is authorized to issue the corresponding CO2 credits and sell them on the voluntary market
- Vintage: The vintage refers to the year when the project verifies its CO2 emission offsets / avoidance. The CO2 emissions are calculated from the last year of vintage (= CO2 verification) of the project. The minimum vintage period is one year but it can last up to 10 years.
- Ex-post verification (reforestation and conservation projects): The project has to prove the actual tree growth of all planted trees (CO2 offset) or prove the actual conservation of trees (CO2 avoidance) between 2 vintage years. Thus, this verification verifies the actual results of the project after a period of time and it can only issue credits according to the results obtained during that period.
- Ex-ante verification (only reforestation projects): The project plants a certain number of trees (normally with a yearly vintage) and estimates the CO2 offset of these trees during a lifespan of 10-20 years. The estimated CO2 (following the calculation methodology of the standard) is then verified and the CO2 credits can be issued accordingly. The project has then to monitor these planted trees and to prove periodically that the trees grow according to their initial estimations. If the actual tree growth and CO2 offset decreases below a fixed buffer quantity the project is requested to take action in order to reach the “promised” offset rates during the agreed tree lifespan.
- CO2 standard’s registry: Each CO2 certification standard operates its own registry with credit accounts for all projects. All verified CO2 credits are transferred to the project’s registry account after each verification (with a unique number for each credit). The project can then sell these CO2 credits (retire them in the name of the buyer (if the buyer does not have a registry account), or transfer them to the buyer’s registry account (TN has a reseller account on the VCS, PlanVivo and Goldstandard registries, so we can buy credits from the projects and resell them to our clients (retirement of the CO2 credits from our TN account in the name of the client). All retirements of credits are publicly accessible on the standard’s registry (so the clients can actually prove that their credits have been correctly retired in their name)
- Project Owner: Landowner of the land that belongs to the project (where the trees are planted or protected)
- Project Proponent / Developer: Entity that represents the project (can be the landowner or another third party entity) and follows one of the official certification methodologies imposed by each CO2 standard to validate the project and verify the CO2 emission offset / avoidance. The project proponent, following the standard’s methodology, prepares all the documentation required for the project validation and verification.
- Project Validator: Independent and official auditors (authorized by each certification standard) which prove that all the documentation and data prepared by the project proponent represents the project’s status correctly and complies with chosen methodology (review of project documents and CO2 calculations, project onside visits, interviews with project staff, etc.)
- Twinning is a unique concept developed by Tree-Nation that only concerns projects using the VCS (Verified Carbon Standard). Since VCS projects focus on preserving mature forests and do not include new tree planting, Twinning adds value by supplementing each VCS offset with the planting of a new tree. For every VCS-certified CO₂ offset purchased, Tree-Nation plants additional trees that will sequester a similar amount of CO₂ over its lifetime. However, only the VCS-certified offset is officially counted in your CO₂ claims (and CO2 counters in your forest); the additional tree provides extra environmental and social benefits without altering the certified CO₂ total. This approach ensures that VCS-certified offsets support both verified carbon reduction/avoidance and reforestation, allowing you to offer the new trees as gifts to clients while amplifying the environmental impact of your purchase. Find Twinning projects here.