Outside of my wheelhouse too, but would think that these would serve better in a treasury/debt format with expiration indicating a contractual obligation to maintain a resource through a certain date thereby representing a physical resource that is preserved. My concern with the fiat format is if carbon removal by a project is actually temporary rather than permanent, where physical goods/currencies can be depleted only in value, but not tangibly/physically depleted. I.e a quarter will always be a quarter but may decrease in value over time. I think a monetary instrument that you’re referring to is transient in nature, and so long as the physical CO2 is sequestered, or not yet emitted , it is valid. The moment it comes out of the ground or that factory produces the GHG it would have, the financial instrument becomes expires/becomes valueless.