MAR-CO2 is structured around six key objectives aimed at enabling robust, transparent, and socially acceptable Monitoring, Reporting and Verification (MRV) systems for marine Carbon Dioxide Removal (mCDR):

1. Improved understanding of societal and governance considerations, and the role of MRV in enabling sustainable, acceptable, and just mCDR deployment through stakeholder engagement, governance analysis, and policy development.
2. Development of a fit-for-purpose observational toolkit capable of monitoring carbon removals, biodiversity impacts, and marine carbonate system responses in a precise, cost-effective, and traceable manner.
3. Creation of an integrated modelling toolkit bridging regional and global scales to assess mCDR performance, uncertainty, environmental impacts, and future scenarios.
4. Co-design of a novel mCDR Digital Twin integrating observations, modelling, artificial intelligence, and stakeholder feedback to support verification, attribution, and scenario analysis across spatial and temporal scales.
5. Development of ecological assessment tools to evaluate biodiversity impacts, ecosystem responses, and environmental trade-offs, supporting solutions that benefit climate mitigation, biodiversity, and environmental justice.
6. Enabling science-based decision-making through stakeholder engagement, capacity building, co-design processes, and policy-relevant guidance to support responsible climate action and governance.

To achieve these goals, MAR-CO2 will develop MRV systems that are science-based, solution-oriented, and tested in real-world pilot interventions. Through close collaboration with stakeholders from industry, academia, policy, and civil society, the project will ensure that future mCDR assessment frameworks are scientifically robust, practical, socially just, and fit for governance and decision-making.

CMCC role
CMCC leads Work Package 8, which focuses on the development of the requirements and core components of a Digital Twin for Monitoring, Reporting and Verification (MRV) of marine Carbon Dioxide Removal (mCDR). The objective is to design a robust and interoperable digital framework capable of verifying and attributing additional carbon removals, while ensuring alignment with major European initiatives such as the European Digital Twin of the Ocean (EDITO) and Destination Earth.

Activities
MAR-CO2 develops and tests innovative Monitoring, Reporting and Verification (MRV) systems for marine Carbon Dioxide Removal (mCDR) across multiple spatial and temporal scales.

Activities are carried out at four pilot-scale mCDR sites representing different carbon removal pathways, including Ocean Alkalinity Enhancement (OAE), Direct Ocean Carbon Capture (DOCC), and macroalgae cultivation.

Field campaigns will deploy a wide range of monitoring technologies to measure carbonate chemistry, greenhouse gas fluxes, carbon stocks, biodiversity indicators, ecosystem functioning, and potential environmental impacts. Observations will be collected both within and outside intervention areas to assess carbon removal efficiency, ecological responses, and long-term carbon storage potential.

These observations will be integrated with state-of-the-art ocean and Earth system models to evaluate the detectability, attribution, and durability of carbon removals across local, regional, and global scales. Modelling activities will support scenario testing, uncertainty assessment, and the evaluation of environmental impacts under different deployment strategies.

A central activity of the project is the development of a first-of-its-kind Digital Twin for marine Carbon Dioxide Removal. By combining real-time observations, modelling tools, artificial intelligence, and automated data workflows, the Digital Twin will enable scenario analysis, verification of carbon removals, and decision support for future mCDR applications. The system will be designed to ensure interoperability with major European initiatives, including the European Digital Twin of the Ocean.

MAR-CO2 will also contribute to the development of new monitoring technologies and methodologies that can be integrated into existing international ocean observing networks, supporting future large-scale assessment of marine carbon removal activities.

Expected results
MAR-CO2 will deliver the scientific, technological, and governance foundations required to support the responsible deployment of marine Carbon Dioxide Removal (mCDR) in Europe and beyond. A key result of the project will be the development of robust Monitoring, Reporting and Verification (MRV) and ecological MRV (eMRV) systems capable of accurately quantifying carbon removals while assessing biodiversity and ecosystem impacts.

The project will generate new observational tools, monitoring technologies, and modelling capabilities to improve the detection, attribution, and verification of marine carbon removals across multiple spatial scales. These advancements will support standardized methodologies and best-practice frameworks for mCDR assessment, contributing to future regulatory and certification systems.

A major outcome will be the development of a Digital Twin framework for mCDR, integrating observations, modelling, and advanced digital technologies to support transparent carbon accounting and decision-making. The project will also strengthen existing observing systems and data infrastructures, improving the availability of high-quality data for monitoring marine carbon removal activities.

MAR-CO2 will provide evidence-based recommendations to support European and international policy processes, including monitoring requirements, carbon removal certification schemes, and governance frameworks for mCDR. The project will contribute to the development of transparent and socially robust regulatory approaches for future climate mitigation strategies.

Through stakeholder engagement, co-design activities, and capacity building, MAR-CO2 will strengthen collaboration between academia, industry, policymakers, and civil society, helping build expertise, improve public understanding of mCDR, and support the development of credible and environmentally responsible carbon removal solutions.

Partners

• National Oceanography Centre (NOC)
• Barcelona Supercomputing Center – Centro Nacional de Supercomputación (BSC)
• Stiftung Wissenschaft und Politik (SWP)
• Universiteit Utrecht
• Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR)
• Stiftelsen GRID-Arendal
• Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici (CMCC)
• University of Manchester
• Planetary Technologies Inc.
• SeaO₂ BV
• MacroCarbon SL
• Planeteers GmbH