Carbon sequestration ought to be permanent on climate-relevant timescales

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S1462901125002394

Authors: Stephanie H. Arcusa, Klaus S. Lackner

01 October 2025

https://doi.org/10.1016/j.envsci.2025.104223

Highlights

•Markets for carbon removal credits are expanding despite the lack of agreed definitions of permanent

•The natural carbon cycle will take tens of thousands of years to reabsorb the carbon released by fossil carbon consumption.

•There is a distinction between the scientific concept of durability and the policy choice of permanence.

•The choice of how long is long enough will affect future generations and the ability to sustain net-zero conditions.

Abstract

Markets for durable carbon removal credits are expanding despite conflicting rules and standards. A major unresolved issue surrounds the permanence of sequestration and what it means. We draw from the principles of ‘intergenerational equity’ and the ‘polluter-pays’ to argue that sequestration ought to be permanent on climate-relevant timescales which geoscience has determined to be in excess of 10000 years. This is far longer than the typical durability of carbon credits. In this perspective, we examine the implications of having to guarantee the permanence of carbon removal either by permanent sequestration or by a sequence of temporary storage. We will review the science underlying the definition of climate-relevant permanence. We will ask why we should care, who gets to reap the benefits from not guaranteeing permanence, who will suffer the consequences, who pays for permanence, and who gets to decide.

Source: ScienceDirect