Understand the carbon market before you trust a claim in it.
An independent library for learning how carbon credits actually work, who verifies and grades them, and which organizations are quietly doing the work well, without ever selling you a credit ourselves.
Carbon markets are full of jargon, marketing and quiet asterisks
Voluntary and compliance carbon markets now move hundreds of millions of credits a year, yet most people, including many buyers, cannot explain the difference between a registry, a methodology and a rating agency. We built this coalition to close that gap with plain language, source linked education. We do not sell, broker or certify carbon credits, and we do not accept payment to feature an organization.
What is a carbon credit?
A carbon credit is a tradable certificate representing one metric tonne of CO2, or its equivalent in other greenhouse gases, that has been avoided, reduced or removed by a specific project. A buyer can retire it, permanently taking it out of circulation, to claim that tonne against their own emissions.
Voluntary Carbon Market
Companies, events and individuals buy credits by choice, usually to back a net zero pledge or offset an activity. Quality varies enormously because there is no single global regulator, which is why independent standards and rating agencies matter so much.
Compliance carbon market
Government mandated systems where regulated entities must surrender allowances or eligible offsets: the EU ETS, California's program (which recognizes credits from the American Carbon Registry and Climate Action Reserve) and the UK ETS. Rules and prices are set by regulation.
Additionality, permanence and leakage
Almost every controversy over junk carbon credits traces back to one of these three ideas.
Would this have happened anyway?
A credit should only represent reductions that would not have occurred without the carbon finance. If a forest was never going to be logged, protecting it is not additional. This is the most disputed and hardest to verify concept in the market.
Will the carbon stay stored?
A tree that stores carbon for 20 years and then burns has not delivered a permanent reduction. Geological storage and biochar can lock carbon away for centuries; some nature based projects carry real reversal risk, which is why buffer pools and insurance exist.
Did the problem just move?
If protecting one forest pushes loggers to the forest next door, the net impact is zero. Rigorous methodologies model and discount for leakage; weak ones ignore it.
Where carbon credits actually come from
Roughly ordered from lowest to highest typical durability.
Forestry and land use
Avoided deforestation (REDD+), new forest and improved forest management. The largest category, with high biodiversity benefits, and the most exposed to additionality and permanence criticism.
Soil carbon
No till farming, cover crops and managed grazing. Measurement is improving fast, but soil carbon can be re released if practices lapse.
Blue carbon
Mangroves, seagrass and wetlands store carbon several times faster per acre than most forests, and protect coasts and fisheries.
Biochar
Biomass heated without oxygen into a stable char that locks carbon away for 100+ years. Certified in detail by standards like Puro.earth.
Direct air capture and storage
Engineered capture injected into deep rock for centuries to millennia. Very durable and easy to measure, and the most expensive per tonne.
Renewable energy
Older avoided emissions credits from wind, solar and efficiency. Additionality is now widely questioned, and most major buyers have moved away.
Two very different promises, sold under the same word
Avoidance and reduction
Prevents a tonne that would otherwise have been emitted, like a clean cookstove or a wind farm displacing coal. It does not remove existing carbon.
Removal
Carbon actively pulled from the air and stored: forestry, biochar, soil carbon, direct air capture. Net zero standards such as SBTi increasingly require removals.
Why it matters
Ask which one you are buying before you make a neutral claim.
From project design to your retirement certificate
- 1Project design against a published methodology from a registry such as Verra or Gold Standard, with a baseline for what would have happened otherwise
- 2Validation by an accredited third party auditor before any credits are issued
- 3Monitoring and verification with satellite data, field measurement and periodic re audits
- 4Issuance of serialized credits into a public registry, one per verified tonne
- 5Independent rating by agencies like BeZero Carbon, Sylvera and Calyx Global
- 6Trade and retirement, permanently removing the credit so it can never be resold or claimed twice
Registries and standards bodies: where credits come from
Two jobs get confused constantly: issuing a credit, and grading how good it is. Here is a neutral map. We do not rank or endorse any of them.
| Registry | Focus | Notes |
|---|---|---|
| Verra (VCS) | Broadest coverage; largest voluntary registry | More than 4,000 projects in about 95 countries; an estimated 70 to 80% of all voluntary credits ever issued. |
| Gold Standard | Sustainable development co benefits | Founded in 2003 by WWF and other NGOs; requires co benefits aligned to the UN SDGs. |
| American Carbon Registry | U.S. compliance and voluntary | One of the oldest U.S. registries; eligible for California Cap and Trade. |
| Climate Action Reserve | U.S. compliance grade projects | Strong regulatory acceptance, especially in California. |
| Puro.earth | Engineered removal | Helsinki founded; issues CO2 Removal Certificates and runs the leading biochar methodology. |
Who grades credits after they are issued
| Agency | Approach | Notes |
|---|---|---|
| BeZero Carbon | Remote sensing plus analyst review | Rates 900+ projects on an AAA to D scale, published openly. |
| Sylvera | Automated data plus analyst review | Rates 680+ projects on delivery, additionality, permanence and co benefits. |
| Calyx Global | Programme, methodology and project level | Assessed 940+ projects across 27 types and 121 methodologies; adopted AAA to D in 2025. |
Buyer tip: the three agencies now share a letter scale, but their methods differ enough that the same project can land in different tiers. Cross reference at least two. Separately, the ICVCM assesses whole methodologies against its Core Carbon Principles: 59 methodologies assessed, 38 approved, and 100 million+ credits eligible for the CCP label. Verifiers such as Kiwa Inspecta, SGS, DNV and TÜV audit individual projects against standards like ISO 14064-2.
Carboreal is turning drained Finnish peat fields back into carbon sinks
Carboreal Oy plants diverse boreal forests on land unsuited for farming, with third party certified carbon accounting. Its Trammell S. Crow Forest in Rovaniemi, Lapland converts a former peat field into a forest expected to remove about 13,000 tonnes of CO2, protected in the Finnish land registry for at least 70 years. Disclosure: Carboreal is connected to this site through the Environmental Xperience at EarthX conference series, which hosts the Carboreal Carbon Stage.
Verified
ISO 14064-2 certification by Kiwa Inspecta.
Protected
Legally protected for a minimum of 70 years.
Documented
A well documented example of rigorous, verifiable carbon removal.
2nd Annual Carbon Conference
Hosted at the Environmental Xperience at EarthX 2027 on the Carboreal Carbon Stage at the Hilton Anatole. The conference returns for a second year of sessions on carbon markets, carbon capture, nature based solutions and carbon finance, building on a 2026 stage that drew climate scientists, ministers and market leaders from across the world.
Independent by design
What we are
An independent educational publisher, a neutral directory of registries and rating agencies, and a monthly spotlight on credible work.
What we are not
A carbon credit broker, seller or exchange; a certification or rating body; a paid placement platform.
How Org of the Month works
An editorial choice based on transparency, third party verification and public documentation. Any relationship is disclosed. Being featured is not an endorsement of every claim.
Questions, corrections or a nomination?
Carbon markets move fast. We welcome corrections to anything on this site.