How can one carbon pool token, like CHAR, represent one tonne of carbon?

When they're tokenized, carbon credits are represented as TCO2 tokens. When a TCO2 token is deposited in a carbon pool, it is locked, and a corresponding carbon pool token, like CHAR, is created.

Every carbon pool token in circulation is backed by a TCO2 token. This can be verified by looking at a third party website like a block scanner and inspecting the contents of the pool, or by auditing the contents using a function like fetchPoolContents.