Valuing Blue Carbon Ecosystem Services: Hedonic Evidence from Atlantic Salt Marshes

This paper estimates the implicit value of salt marsh ecosystem services along the French Atlantic coast using a hedonic pricing framework applied to over one million residential transactions across 16 departments (2012–2021). We estimate separate Box-Cox hedonic models for each department, systematically rejecting the log-linear specification and documenting substantial cross-departmental heterogeneity in marsh capitalization effects. Salt marsh proximity exerts a predominantly negative effect on property prices in most departments, with sign reversals in coastal configurations where marshes form part of a broader amenity bundle. The PPRi flood risk indicator is positively capitalized in most departments, consistent with a regulatory salience effect rather than risk compensation. These results suggest that housing markets capitalize regulatory constraints and amenity bundles rather than ecosystem service value per se, with direct implications for coastal conservation policy and benefit-transfer exercises