Every credit a registry issues ends in one of two places: retired against someone’s claim, or still sitting in an account. The second pile is the market’s inventory, and it is the number that decides whether a new project can sell. According to the Berkeley Carbon Trading Project’s Voluntary Registry Offsets Database (release 2026-06), which covers Verra, Gold Standard, ACR, the Climate Action Reserve, ART and Isometric:
2.65 billion credits have been issued across 11,468 projects. 1.56 billion have been retired. 1.09 billion are still out there.
Not all inventory is the same. REDD+ has the largest unretired pile, 163 million credits, but 65% of what it issued has been retired. Cookstoves have retired only 47% of 230 million issued. Jurisdictional REDD+, almost all of it Guyana’s ART credits, has retired about a fifth. HFC and gas-leak projects sit at similar levels. Those are the types where a new project competes with old stock.
| Type | Issued, M | Unretired, M | Retired share |
|---|---|---|---|
| REDD+ | 463 | 163 | 65% |
| Wind | 355 | 133 | 63% |
| Cookstoves | 230 | 121 | 47% |
| Hydropower | 235 | 101 | 57% |
| Improved Forest Management | 286 | 89 | 69% |
| Solar - Centralized | 128 | 53 | 59% |
| Jurisdictional REDD+ | 60 | 47 | 22% |
| Landfill Methane | 131 | 46 | 65% |
| HFC Replacement in Foam Production | 46 | 37 | 20% |
| Leak Detection & Repair in Gas Systems | 45 | 34 | 24% |
| Afforestation/Reforestation | 79 | 27 | 66% |
| HFC Refrigerant Reclamation | 30 | 21 | 31% |
The ten largest piles
| Project | Type | Issued, M | Unretired, M |
|---|---|---|---|
| GuyanaART · Guyana | Jurisdictional REDD+ | 58.4 | 45.8 |
| Cordillera Azul National Park REDD ProjectVCS · Peru | REDD+ | 36.6 | 20.8 |
| The Mai Ndombe REDD+ ProjectVCS · DRC | REDD+ | 42.5 | 19.2 |
| Southern Cardamom REDD+ ProjectVCS · Cambodia | REDD+ | 27.6 | 19.0 |
| Hydroelectric Project in Kinnaur District in Himachal PradeshVCS · India | Hydropower | 30.8 | 17.2 |
| GS10884 - KOKO Kenya - Ethanol Cookstoves Program - CPA-0002GOLD · Kenya | Cookstoves | 14.9 | 14.8 |
| Phlogiston Phase ICAR · United States | N2O Destruction in Adipic Acid Production | 23.3 | 13.5 |
| Reducing Gas Leakages within the Titas Gas Distribution Network in BangladeshVCS · Bangladesh | Leak Detection & Repair in Gas Systems | 12.4 | 11.8 |
| Foz do Chapecó ProjectVCS · Brazil | Hydropower | 13.7 | 11.3 |
| REDD project in Brazil nut concessions in Madre de Dios, PeruVCS · Peru | REDD+ | 19.1 | 10.6 |
Why a developer cares. If you are building a project of a type with a deep unretired pile, your offtaker can buy the old stock instead. That is the case for building to the integrity screens (CCP, CORSIA eligibility, Article 6 authorisation) that old stock cannot meet. The inventory is a price ceiling for everyone who does not.
Berkeley’s database is a research dataset compiled from registry records; it is updated a few times a year. We use it for issuance and retirement because the registries we read daily do not all publish volumes in a form we can track. We will move these figures to our own daily count as we add it.
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