Résumé
The international consensus on the urgent necessity to act to protect a vulnerable environment and endangered biodiversity raises key challenges, including the need to improve and accelerate estimating carbon stocks and changes in coastal ecosystems on a global scale. Remote sensing methods, combined with ground truthing and modelling, are essential for addressing this challenge cost-effectively.The ESA Coastal Blue Carbon project is an unprecedented effort to review, assess, and attempt to provide key elements for the sustainable management of Blue Carbon Ecosystems (BCEs) through diverse case studies. Over two years, a multidisciplinary consortium is investigating the mangrove, seagrass, and tidal salt marsh BCEs in France, Canada, Spain and French Guiana. The project aims to develop innovative tools and methods based on Earth Observation (EO) to estimate and monitor changes in carbon stocks, and brings together a community of end-users, to ensure the tools meet the operational needs, including:Conservation stakeholders aiming to enhance the impact of their actions. Decision-makers looking to integrate blue carbon into national carbon accounting and set ambitious mitigation targets. The financial sector seeking reliable blue carbon investment opportunities. Our rationale is to capitalise on existing data and multi-scale resolution imagery to assess the potential for global replicability of the space-based methodologies from highly representative pilot regions of the main BCEs across three different continents. The project consists of two phases: the first focuses on developing and consolidating requirements to create new methods on test areas, while the second emphasizes upscaling demonstration, and impact assessment. We aim at producing maps of carbon storage estimates for three different years from 2015 to 2025, with a spatial resolution no coarser than 10m while ensuring active participation from Early Adopters.The project has been submitted to be endorsed under the Global Ocean – Blue Carbon Programme of UNESCO Ocean Decade.