Credit retirement
The permanent removal of a carbon credit from circulation for a stated use.
Example
A registry record can show that a unit is no longer available for transfer.
The catch
Retirement confirms a registry action, not every aspect of project quality.
In more depth
Credit retirement, explained.
Credit retirement is the moment a credit is used up, so a claim should rest on retired units, never on credits merely bought or held. Until retirement, a unit can be resold and claimed by someone else. A sound retirement record in the carbon registry names the beneficiary and the purpose, a detail that prevents confusion when a seller retires credits on behalf of many customers.
Check the dates as well. A credit retired this year may carry an old credit vintage, meaning the reduction happened long before the emissions it is meant to balance. Vocabulary varies between systems. Compliance schemes speak of surrendering a carbon allowance, and some registries use cancellation for other purposes, such as covering reversals from a buffer pool.