Permanence

Full explainer

Permanence is the requirement that a carbon project's emissions reductions or removals remain in place over a specified time horizon — typically 100 years for forestry and nature-based projects, reflecting CO₂'s atmospheric residence time. A forest that sequesters carbon and is then cleared 30 years later has 'reversed' its claimed reductions, undermining the original credit.

Registries manage permanence risk through several mechanisms: buffer pools (a percentage of each project's credits set aside to cover future reversals across the registry), monitoring requirements throughout the crediting period, and post-crediting verification cycles. ICVCM CCP-eligibility requires robust permanence management. KarbonLens's reversal-risk sub-score (35 % of the integrity composite) operationalises the permanence concept by tracking satellite-detected forest loss inside project polygons over the prior 90 days.

Related terms

• Additionality
• ICVCM
• MRV