A number of counties in California are largely agricultural, with a few small communities. Most of that agricultural land is intensively farmed, much of it irrigated. This situation presents the opportunity to sequester large amounts of carbon relative to the total greenhouse gas emissions from all county activities. In other words, the county can approach a level of net-zero emissions with a surplus available to share with other jurisdictions, particularly with those in within a county.

Since many of these counties are already planning to use this sequestration strategy to meet its own emission reduction goals, these reductions will be real, additional, and verifiable, meeting the gold standard for use as credits by other jurisdictions. The county has a strong incentive to ensure that these reductions are of sufficient quality to meet its own targets, which should make these attractive to other jurisdictions, unlike other credits offered in the marketplace.

A county would establish a Carbon Mitigation Bank using a similar framework to habitat conservation mitigation banks.^[1] The county would establish the parameters that achieve the requisite carbon sequestration and then collect in-lieu fees to cover the costs of the bank’s expenses. By expanding the number of jurisdictions contributing and receiving coverage, overall carbon emissions can be reduced more cost-effectively.

Sequestration from working lands can be achieved at a lower cost than most alternatives. For this reason, a county can use its surplus to finance much of its share of the sequestration program by offering it to cities in the county at a margin above the implementation cost sufficient to cover the county’s share of the costs as well. For example, it may cost $50 per CO₂e ton sequestered, and the County may use only half of the potential sequestration to meet its own target. The County could then offer its surplus credits to the other jurisdictions at $100 per ton, which is likely less than the cost of additional reductions elsewhere, to cover the full program costs.

M.Cubed proposed this financing mechanism for both Yolo and Sonoma in their climate action plans. Both counties could potentially sequesters hundreds of thousands of tons annually, implying this could be a major revenue source for meeting broader targets.