Permanence
The duration for which a claimed climate benefit remains in place, including the risk of reversal.
Example
Stored forest carbon can be released by fire or land-use change.
The catch
Durability expectations differ between intervention types.
In more depth
Permanence, explained.
Permanence is the question of whether a climate benefit can be undone, and the answer depends on the kind of benefit. Destroying methane that would otherwise have escaped cannot be reversed, because the gas no longer exists. Carbon held in trees, soils or wood products stays at risk for as long as it is stored. Geological storage, where CO₂ is injected into suitable rock, carries far lower reversal risk when the site is well chosen and monitored.
Crediting programmes manage reversal risk in layers. Most set aside a share of credits in a buffer pool that is cancelled to cover losses, and others add long periods of oversight and legal protection for the land. The ICVCM's Core Carbon Principles include permanence as an integrity requirement. Approved credits must show how reversals will be monitored and compensated.
A contract term is a different thing from permanence. A carbon credit from a forest project with a defined crediting period says nothing about the trees once it ends. When comparing claims, match the durability of the storage to the durability of the emission it is meant to balance. Part of a fossil CO₂ emission keeps warming the planet for centuries, so pairing it with storage that may last decades leaves a gap.
In the journal