Earth Observation for Coastal Ecosystem Accounting: A Match made in Heaven for Natural Climate Solutions

Kurzfassung

Blue carbon ecosystems like seagrasses, mangroves, and tidal flats provide globally significant yet vastly underestimated and impacted ecosystem services to humans, economies, sustainability, biodiversity and ecosystems, the so-called natural climate solutions (NCS). Accelerating climate change, biodiversity loss, eutrophication, coastal development, and uneven levels of protection are all placing significant stress on the extent, condition, services and financial benefits of these coastal ecosystems, worldwide. Contemporary approaches are urgently needed to reverse and halt this accelerating reduction of our global natural capital to avoid crossing tipping points and cascading impacts across the interconnected environmental and artificial ecosystem. Ecosystem Accounting (EA) presents a new holistic, comprehensive approach to streamline physical, monetary, and thematic evaluation for natural ecosystems, integrating their immense value and services into national and international policy making, funding, and data-driven action. The conceptualization and adaptation of the System of environmental-Economic Accounting (SEEA) EA by the United Nations Statistical Commission signals a new era of holistic, integrated statistical, technological, ecological, and financial solutions for the conservation, restoration and protection of ecosystems like seagrasses and mangroves. Although a very promising systems approach, EA approaches and applications for coastal ecosystems are still very much in their infancy, if not non-existent. In parallel, unprecedented advances in Earth Observation during the last decade—cloud computing, artificial intelligence (AI), big satellite data from the Sentinel. Landsat, and PlanetScope satellite sensors—are offering a vast, transparent and homogeneous knowledge base for our Earth’s natural capital. Integrating global field and citizen observations in synergistic Earth System Science and Earth Observations approaches comprise very promising big data paradigms that can transform data and evidence to sustainable insights and solutions. Amalgamating those big data paradigms in ecosystem accounting frameworks can lay the foundations of the next generation of large-scale decision support systems for natural ecosystems. These support systems will transform physical ecosystem accounts reliant on ecological knowledge into economic units, measurable targets, and thematic accounts organized around environmental policies. This realization will in turn supercharge targeted financing, policies, and actions across the entire terrestrial, coastal and marine realm. Here we present a novel coastal ecosystem accounting prototype, built end-to-end within the cloud platform of the Google Earth Engine after six years of research and development in coastal aquatic Earth Observation. Our prototype harnesses the powerful parallel processing of the Earth Engine cloud, the full public archive of the European Union Copernicus Sentinel-2 satellites, globally aggregated reference datasets, and AI-guided big data analytics to map the ecosystem extent, condition, and services of seagrass ecosystems. More specifically, our modular apparatus synthesizes analysis-ready data cubes using terabytes of 10 m satellite images, whose pixels are then transformed into a multitude of seagrass-related thematic (e.g., subtidal areal extent, turbidity, carbon stocks and sequestration, and biodiversity) and continuous accounts (e.g., extent probability, bathymetry, water quality). We showcase recent national seagrass EA applications, including their accuracies and uncertainties, across largely-uncharted underwater biomes, the Western Indian Ocean, the entire Mediterranean, and the Caribbean, spreading across more than 30 countries and 300,000 sq km. We targeted these coastal biomes due to their vast blue carbon and coastal biodiversity stocks, notable lack of spatially explicit information, and uneven uptake in global funding mechanisms and policy agendas. Our introduced EA prototype and its coastal applications concern only baseline mapping of biophysical stocks of a single ecosystem. In the next phase of research and development, we aim to integrate fit-for-purpose ecological modelling, economic evaluation techniques, and remotely sensed change detection into our Earth System Science-Ecosystem Accounting prototype. We envisage that this amalgamation of legacy and modern mapping, modelling, and observations will enable policy makers and governments to see the forest for the trees concerning the world’s blue carbon ecosystems. This will ultimately safeguard balanced blue carbon conservation and restoration financing, accounting, decision making, and resilience within and beyond the 21st century.