An interdisciplinary study on Scottish saltmarsh blue carbon : data uncertainty and values in policy design

Abstract

The potential of saltmarshes to store carbon has recently been gaining increasing interest in the Scottish policy arena, particularly in the face of the recently declared climate emergency. Yet, while there are first estimates of saltmarshes’ overall carbon storage capacity, there is still significant uncertainty concerning the average soil depth of Scottish saltmarshes, and thus their total organic carbon stock. Moreover, other aspects, such as the value of the carbon storage ecosystem service and how it could be incorporated into Scottish policy, are under-researched. This thesis therefore takes a holistic and interdisciplinary approach connecting natural science, economics, and social science to investigate the potential of Scottish saltmarshes for climate change mitigation. A scenario approach is used to analyse the potential organic carbon stocks according to different average saltmarsh depths to reduce the uncertainty regarding the total Scottish saltmarsh stocks. A choice experiment was then conducted to investigate the Scottish public’s preferences and willingness to pay for the improvement of saltmarsh ecosystem services, particularly the carbon storage service. Furthermore, the experiment tests the significance of the influence of information provision on individuals’ preferences and willingness to pay. Lastly, this thesis presents an in-depth study on blue carbon policy integration based on expert-interviews to close the link between science and policy. This work suggests that even though climate change is a pressing issue, Scottish saltmarsh climate change mitigation contributions are comparatively minor and that other saltmarsh ecosystem services must not be disregarded to facilitate a prioritisation of the carbon storage service. In terms of policy integration, this means that it may be beneficial to integrate saltmarshes and their carbon storage service into the Scottish Marine Spatial Planning framework rather than climate change mitigation policy specifically.