The capacity to store carbon over time without releasing it back to the atmosphere (Smith et al., 2024). The durability of a carbon store is governed by the expected longevity and risk of reversal back into the atmosphere. Evidence suggests that less durable forms of carbon removal are significantly less effective in addressing residual emissions, and could lead to greater global temperature increases in the long term compared with more permanent forms. With respect to a quantitative definition expressed in terms of years, durability has proven difficult to define, and there is a lack of consensus among policymakers.