Robert, it seems to me what you are talking about is "Risk." Risk is a product of Probability times Consequence. R=PxC. You've focused on Probability, will carbon stay sequestered? But I think that the Consequence factor can be transformed from an outcome factor to an input factor, i.e. cost to sequester, amount that can be sequestered, ability to scale, etc. For example, for Mineralization, if it costs a lot, or can't sequester large amounts, or isn't scalable, it might have a lower C score than say trees, which might be cheaper, sequester more carbon short term and might be more scalable. By assigning a C score based on a set of agreed on criteria, we'd then get a Risk value (Risk is not the right word now, maybe Weighted Sequestration Score) to help select different ways to sequester. That would allow us to select different incentives, policies etc for different methods rather than focusing on one or the other.

This approach might be similar to the Lazard levelized cost of energy which takes many factors to get a comparison on actual cost. It doesn't preclude one energy approach but gives them a weighting (in this case just cost) to help decision making and policy.

Hope this makes sense. Thanks for what you're doing.

Hobie