Permanence
The duration for which carbon remains stored and prevented from returning to the atmosphere.
What is Permanence?
In the context of carbon removal and carbon credits, permanence refers to the length of time that sequestered or stored carbon remains out of the atmosphere. It's a critical factor in evaluating the quality and climate integrity of carbon removal projects, as temporary storage offers less climate benefit than long-term or permanent storage.
Why is Permanence important?
Permanence is crucial because CO₂ has a long atmospheric lifetime. If sequestered carbon is released back into the atmosphere too quickly, the climate benefit is negated. High permanence ensures that the emissions reductions or removals are genuinely contributing to long-term climate stability, making projects with longer permanence more valuable.
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Frequently asked questions
Factors include the storage method (e.g., geological storage generally offers higher permanence than some nature-based solutions), the risk of reversal events (e.g., wildfires, land-use changes), and the monitoring and management practices in place.
While 100 years is a common benchmark for permanence in many carbon crediting standards, true climate permanence ideally means storage for hundreds to thousands of years, aligning with the atmospheric lifetime of CO₂.
Permanence is often addressed through risk assessments, buffer pools (reserves of credits set aside to cover potential reversals), long-term monitoring, and legal agreements ensuring continued storage.