PCS CN 004 Stability vs Permanence_v1.0
Document identification
Document code: PCS-CN-004
Title: Stability vs Permanence
Applies to: PCS durability-related approaches (including biochar and other long-duration storage contexts as applicable)
Purpose: Clarifies conceptual distinction and consistent application of “stability” and “permanence” in PCS documentation and assessments
Version history and change log
Table DC-1. Revision history
v1.0
TBD
Draft
Release for public consultation
PCS
TBD
Governance note on versioning and archiving
Only the latest approved version of this Clarification Note shall be used. Superseded versions shall be archived and retained for traceability and audit purposes, consistent with PCS governance rules.
Chapter 1 - Purpose and Context
This Clarification Note defines the regulatory boundary between biochar stability and permanence under the Planetary Carbon Standard. It establishes how each concept is applied, and clarifies their respective roles in carbon removal crediting and post-crediting obligations.
Biochar stability and permanence serve distinct functions within PCS-MT-002. Stability is applied at the time of quantification to classify durable carbon, while permanence governs the continued retention of credited carbon over time. These concepts must not be conflated.
This clarification provides the authoritative interpretation of that separation. It does not introduce new eligibility criteria, modify quantification equations, or alter permanence obligations. It clarifies the correct application of existing requirements under PCS-MT-002 and PCS-TA-010.
Chapter 2 - Definition of Stability
Stability under the Planetary Carbon Standard refers to the intrinsic resistance of biochar carbon to biological and chemical degradation, as determined by its material properties at the time of production.
Stability is assessed through measurable indicators that reflect the degree of carbon transformation achieved during thermochemical conversion. These indicators are applied conservatively to classify the fraction of biochar carbon that may be considered durable for the purpose of carbon removal accounting.
Stability is applied at the time of quantification. It does not represent a prediction of future carbon behavior, nor does it constitute a guarantee that carbon will remain stored indefinitely.
Stability classification serves only to determine eligibility and creditable fractions at issuance. It has no bearing on post-crediting management obligations or on the treatment of future losses.
Chapter 3 - Definition of Permanence
Permanence under the Planetary Carbon Standard refers to the continued retention of credited carbon over time, following credit issuance. It is a governance and risk-management concept that addresses the possibility of future loss, disturbance, or reversal of stored carbon.
Permanence is not a material property of biochar. It is determined by how biochar is stored or applied, how custody and control are maintained, and how risks of disturbance are managed throughout the permanence obligation period.
Permanence obligations apply after credit issuance and remain in force regardless of the stability classification applied at quantification. A high stability classification does not eliminate, reduce, or replace permanence obligations.
Any loss of credited biochar carbon during the permanence period constitutes a reversal and must be treated in accordance with PCS reversal and corrective action provisions, irrespective of the original stability fraction applied.
Chapter 4 - Boundary Between Stability and Permanence
Stability and permanence operate at different stages of the carbon removal lifecycle and address different risks. Stability is applied at the point of quantification to conservatively classify the fraction of biochar carbon eligible for crediting. Permanence applies after credit issuance and governs the continued retention of that credited carbon.
Stability does not reduce, replace, or substitute permanence obligations. The application of a stability fraction reflects a conservative eligibility determination and does not constitute assurance against future loss.
Permanence obligations apply to all credited biochar carbon regardless of stability classification. Reversals must be addressed even where the biochar exhibits high intrinsic stability.
Stability must not be used to justify reduced monitoring, relaxed management controls, shortened obligation periods, or exemption from reversal treatment.
Chapter 5 - Treatment of Reversals
A reversal occurs when credited biochar carbon is lost, disturbed, or otherwise returned to the atmosphere during the permanence obligation period. Reversal determination is based on the occurrence of loss, not on the intrinsic stability classification of the biochar.
Stability classification applied at quantification does not affect whether a reversal has occurred, nor does it alter the requirement to address such reversals. All credited biochar carbon is subject to reversal provisions irrespective of the stability fraction applied at issuance.
Where a reversal occurs, the quantity of carbon affected must be identified and addressed in accordance with PCS reversal and corrective action procedures. This applies equally to intentional and unintentional losses, subject to applicable governance provisions.
Claims that high stability materially reduces or negates reversal obligations are not permitted. Stability does not provide exemption from reversal treatment or post-crediting responsibilities.
Chapter 6 - Implications for Quantification and Tool Use
Stability is applied within quantification to determine the fraction of biochar carbon eligible for crediting at issuance. This application is final for the monitoring period and is not recalculated based on future conditions or events.
The PCS biochar quantification tool applies stability conservatively through evidence-based inputs and automated safeguards. The tool’s application of stability fractions does not alter permanence obligations and does not imply reduced monitoring or risk management requirements.
Tool outputs must reflect capped and conservatively interpreted stability fractions. Manual adjustments intended to reflect future expectations, reduced reversal likelihood, or perceived durability beyond measured evidence are not permitted.
Quantification outcomes produced by the tool must be interpreted as issuance-period determinations only. Post-crediting events affecting permanence are addressed through reversal provisions and do not retroactively modify the stability fraction applied at issuance.
Chapter 7 - Final Provisions
This Clarification Note provides the authoritative interpretation of the relationship between stability and permanence under the Planetary Carbon Standard. It confirms that stability is applied solely for conservative classification at the time of quantification, while permanence governs post-crediting obligations and reversal treatment.
Nothing in this Clarification Note modifies eligibility criteria, quantification equations, or governance requirements established under applicable PCS methodologies and tools. It clarifies their correct interpretation and application.
This Clarification Note enters into force on the date of publication and applies to all relevant projects and verification activities from that date onward, subject to PCS transitional provisions.