Assessing the economic feasibility of voluntary carbon markets in land use management scenarios for Scottish saltmarshes

Saltmarshes have been valued for their multiple ecosystem services, including agriculture, recreation, habitats for fish and birds, coastal protection and carbon sequestration and long-term storage. However, because of the many threats faced, including rising sea levels, limited sediment supplies and anthropogenic impacts, saltmarshes require careful restoration and protection management to continue providing these benefits. In this study, we examined the feasibility of land abandonment caused by reinstated tidal flow in Scottish saltmarshes, based on the differential gains in soil carbon stock between natural saltmarshes and those manged for agricultural uses, and suggested considerations for a voluntary carbon market plan. The study's results showed that the proportion of Scottish saltmarshes used for agricultural activities was not very large (2.56 %, equivalent to 179.73 ha). The average net benefit (i.e., after removing the opportunity cost of land) of the new land use is GBP £ 5368.71/ha after a 67-year post-abandonment management program, showing that this model is economically viable to implement a carbon market mechanism. A voluntary carbon market scheme may be easier to implement than a compliance scheme, although the price of carbon credits under the voluntary carbon market is not high to fully compensate for the opportunity costs of land in all the Scottish regions. In effect, the carbon price at the break-even point (e.g., that balances the opportunity cost of land) in the Scottish regions varied widely (range £ 1.06–59.83/tC), which means that for regions with higher opportunity costs there is a need to consider compensating farmers through a blended private-public mechanism. Despite these difficulties, implementing saltmarshes management models for carbon market initiatives can benefit society in a broader sense, not just mitigate climate change.