Summary/Abstract
This paper aims to: i) elucidate major issues around additionality, leakage, and permanence in the design of policy for sequestration of soil carbon, in the context of transaction costs and uncertainty; ii) identify potential perverse outcomes and inefficiencies in some of the policy approaches that have been proposed; and iii) consider the policy implications. The study builds on the existing literature, extending it by focusing on issues that have not previously been emphasized, or in some cases, not previously recognized. These issues include that practices may be additional temporarily and yet not worth supporting in the short term; that practices can ultimately leak more emissions than they sequester and yet still be financially attractive to landholders; and that the use of a 100- year rule (or similar) as a proxy for permanence can lead to atmospheric carbon levels being higher than they would have been in the absence of a sequestration policy.