Scientific document describing potential for satellite remote sensing to estimate blue carbon at regional scales within European coastal systems

Grant Agreement: 101082021Project Acronym: MARCO-BOLOProject Title: MARine COastal BiOdiversity Long-term ObservationsDeliverable Number: D5.3Work Package Number: WP5Deliverable Title: Scientific document describing potential for satellite remote sensing to estimate blue carbon at regional scales within European coastal systemsDue Date: 31.05.2025Submission Date: 17.10.2025Ares ref: Ref. Ares(2025)8980017 dated 21/10/2025 MARCO-BOLO Task 5.3 “Spatial mapping of blue carbon benefits” evaluates how satellite remote sensing can advance the mapping of blue carbon stocks across Europe, with a particular focus on seagrass meadows due to their importance for the European region. This work responds to the urgent need for robust, scalable approaches to quantify and monitor carbon stocks in European coastal habitats, supporting emerging policy and reporting requirements. Our approach integrated five core activities: Synthesising the scientific literature on remote sensing applications for seagrass carbon mapping. Collaborating with MPA-EUROPE to compile and publish the EURO-CARBON database, the most comprehensive collection of organic carbon measurements for coastal habitats in Europe. Pairing large-scale environmental datasets from NASA and Copernicus with in situ sediment carbon measurements, enabling spatially explicit modelling. Engaging stakeholders through co-design sessions to ensure scientific outputs align with policy and management needs. Developing and testing predictive models for seagrass carbon stocks using environmental variables. Our models demonstrated high explanatory power (R² > 0.8), identifying bottom temperature, sea surface wave height, phosphate concentration, near-surface pH, and remote sensing reflectance at 443 nm as key predictors. Notably, using organic carbon density as the response variable improved model performance and policy relevance. We conclude that satellite remote sensing and global oceanographic data products already provide substantial opportunities for evaluating and monitoring blue carbon services in seagrass beds. Anticipated advances — including new satellite missions and enhanced computational capabilities — will further increase these opportunities. Currently, no countries in Europe have included seagrass beds in their emission inventories and climate plans, despite the prevalence of seagrasses along many coastlines. From 2026, reporting of wetlands under LULUCF may become mandatory for EU member states, but whether this will apply to seagrass beds depends on if member states consider them as “managed” marine ecosystems. Either way, policy needs for reporting carbon stocks are growing, and we show that remote sensing and global oceanographic data products can contribute substantially to mapping blue carbon benefits in Europe.