Same tonne, multiple claims — product “carbon footprint reduction,” voluntary credit, and compliance instrument simultaneously.
Value-chain ambiguity — grower, pyrolyzer, farmer, and credit buyer without clear ownership contracts. Isometric and CSI emphasize single credit owner + registry tracking.
Methodology overlap — soil-carbon farming methodologies and biochar CDR both claiming the same C.
Practice stacking — NRCS soil carbon amendment in US ag cost-share payments coexist with voluntary CDR credits only if contracts prevent double claiming the same tonne.
Practical safeguards
Contractually assign who owns the climate claim before application
Retire unique registry tonnes; do not also market unretired “carbon-negative” product claims for the same mass
Disclose stacking of NRCS / other ag payments with credit issuance
Maintain chain-of-custody records (often ≥5 years)—see MRV Stack