SAGE will establish a fully operational Green Deal Data Space (GDDS) aimed at increasing the accessibility, integration, and use of green and environmental data across the EU: This will then support the key pillars of the European Green Deal—Zero Pollution, Climate Adaptation, Biodiversity, and the Circular Economy Action Plan. Building directly on the GDDS GREAT project community and results, and aligned with the Digital Europe Programme's strategic focus on AI, cybersecurity, advanced computing, and data infrastructure, SAGE will leverage outcomes from the European Strategy for Data and research facilitated by Horizon Europe. SAGE's outcomes include seamlessly integrating fragmented environmental data through federation, enriching data with consistent quality, validation, and interoperable metadata, and strengthening capabilities for data transformation, processing, analysis, forecasting, target setting, and performance monitoring. SAGE aspires to foster informed decision-making and policy formulation based on robust data and evidence. The beneficiaries will be businesses seeking compliance with EGD regulations, government bodies seeking to optimize environmental impacts, citizens and citizen scientists engaged in environmental stewardship, and researchers aiming to deepen our understanding of the environment. Co-funded by Digital Europe and project partners, it builds on GREAT’s groundwork, using federated datasets, AI-driven analytics, and FAIR-compliant tools to empower businesses, governments, researchers, and citizens. By 2028, SAGE will deploy 10 real-world pilots and establish a sustainable company to scale the GDDS, ensuring data-driven decisions for Europe’s green transition.