The field of marine Carbon Dioxide Removal (mCDR) has gone through a remarkable transformation over the past two decades, shifting from a collection of research-focused experiments and inquiries into a small, nascent industry. The sector’s promise to deliver affordable, scalable, and durable carbon dioxide removal (CDR) solutions has driven this growth and is observed through the increase in mCDR startups: from only three founded before 2017 to more than 45 today. ^{The startup count, excludes service providers and includes only organizations focusing on tech and project developers. It is based on Third Derivative’s desktop research and data from The State of CDR (2024) – Chapter 3: Demonstration and Upscaling; The University of Oxford; https://portal.stateofcdr.org/chapter/3 . 1}

As with all CDR pathways, mCDR’s continued growth relies on an accurate evaluation of carbon removal. Building trust in the industry and generating revenue from corresponding carbon credit sales requires robust measurement and modeling of CDR outcomes; hence, the critical role of developing practical and trustworthy monitoring, reporting, and verification (MRV) systems for mCDR. In a nutshell, MRV involves the integration of direct measurements and sophisticated modeling techniques to accurately quantify carbon removal and storage.

Due to the importance of MRV and the relative newness of the mCDR field, current and prospective industry players seek to better understand the key organizational steps needed to develop robust MRV capabilities to support their business objectives. In the absence of an established MRV playbook, there is a need and opportunity to align stakeholders around common perspectives and expectations for the steps, timelines, and resources needed to strategically develop and deploy an MRV system.

Equally important is the need for organizations to proactively and clearly communicate their MRV development strategy. Given the diversity of stakeholders seeking to understand and engage with a startup’s plan for MRV, a clearly communicated, transparent, long-term MRV strategy can help mCDR companies both achieve their removal goals and secure funding for their operations and projects.

As [C]Worthy and RMI’s Third Derivative have heard in conversations with many mCDR stakeholders, each group of stakeholders needs clear planning and communication about MRV. Here are some examples of questions stakeholders are asking:

• Early-stage mCDR startups:
• What are the key phases, tasks, and resources required for a robust MRV strategy?
• What tasks and issues should be considered and planned for that are interconnected with the MRV process?
• Are there impartial resources that can be used to explain the MRV strategy to internal teammates (e.g., startup leaders who do not work on MRV) or external partners (e.g., prospective investors or offtakers)?
• Prospective mCDR investors:
• What personnel skills, resources, and time are required to properly implement a rigorous MRV plan?
• What type of MRV support will an mCDR startup need?
• What are the appropriate MRV milestones for each project size or company stage?
• Prospective industry project partners (e.g., desalination plants or shellfish farms serving as project sites for mCDR):
• How might I be involved in the MRV process?
• Will the MRV process affect our operations, permitting, and community relationships?
• Prospective coastal community groups or planners:
• Are local environmental impacts being effectively monitored?

With these questions in mind, [C]Worthy and Third Derivative have developed a tool to support planning for and communication about MRV development plans. Through desktop research and interviews with mCDR researchers, startup founders, policy experts, and investors, we created a roadmap to illuminate the broad stages of MRV activity that most mCDR suppliers will move through.

Spanning mCDR approaches and deployment methods, the roadmap outlines the nine major steps that an mCDR startup will take on its MRV journey, roughly when each step should be taken, and the level of effort or resources required for each step over time.

It is important to note that many additional essential activities intertwine with the MRV functions for an mCDR deployment. For example, CDR technology and engineering systems design, community engagement, project permits, and environmental monitoring all connect closely with MRV. Planning and resourcing for each of these activities and understanding how they dovetail with the MRV process are paramount to a project’s or company’s success. That being said, this roadmap focuses exclusively on MRV activities related to CDR. ^{Each of the topics listed above is equally important, requiring its own substantive dedicated resources and processes. Furthermore, other experts are already working on guidance for these distinct and interconnected processes. To minimize duplicative effort and leave space for appropriate rigor in addressing these related topics, we have included references to related considerations and a resource list on these topics in the Conclusion section. 2}

The roadmap presented in this report is meant to be flexible to the needs and processes of individual stakeholders, acting as a starting point for planning and communication rather than as a prescriptive documentation of exact timing and level of effort for each step. This report includes:

• A brief introduction to the mCDR sector and its MRV;
• An overview of the roadmap structure;
• Details on each of the steps in the MRV journey;
• Considerations and additional resources to complement the roadmap.

Marine CDR encompasses activities that enhance the natural capacity of aquatic environments (lakes, rivers, and oceans) to remove carbon dioxide (CO₂) from the atmosphere for long-term storage. These approaches span biological, geochemical, and synthetic pathways to CDR, including activities such as ecosystem restoration, biomass sinking, ocean alkalinity enhancement via electrochemical or mineral approaches, and direct removal of CO₂ from water via electrochemistry. Many mCDR approaches have environmental co-benefits, such as coastal restoration or ocean de-acidification. For more information about mCDR approaches, refer to the Ocean Visions mCDR Roadmaps or RMI’s publication library.ⁱ

For full quantification of carbon removal from the atmosphere, most mCDR applications require a combination of in situ measurements as well as the use of hydrodynamic and biogeochemical models. These mechanistic models (typically developed by academic scientists and available for open evaluation) play an important role in the quantification of carbon removal because they account for aspects of the carbon removal processes that occur over timescales of many years, with spatial footprints that extend across ocean basins. ^{For example, see the Ocean Alkalinity Enhancement (OAE) and Direct Ocean Removal (DOR) Atlas; CarbonPlan, “OAE Efficiency – CarbonPlan,” 2025, https://carbonplan.org/research/oae-efficiency 3} Also, since aquatic environments like the ocean are highly dynamic and heterogeneous, it is a common scientific practice to augment field observations with physics-based modeling information to obtain a clearer picture of any project’s outcome.

Across mCDR approaches, direct measurements provide useful information within or very near the operational bounds of a project site. In the water near the mCDR project site, direct measurements may include automated sensors and repeat manual sampling of seawater chemistry (e.g., pH, dissolved organic carbon, total alkalinity) and biologically relevant seawater characteristics (e.g., nutrients, oxygen). Additionally, sensors can be placed in this “near-field” environment to verify that the full CDR project engineering is working as intended and meeting design and regulatory requirements. As a rule of thumb, perturbations to the chemistry or biology become extremely dilute within several hundreds of meters of the project site, and, beyond that point, modeling systems track and quantify the small changes in chemistry that lead to carbon uptake.

At times, we have encountered stakeholder skepticism regarding the importance and validity of using models as an input to the MRV process. But, an integrated approach that uses both modeling and direct measurement is common in many industries and applications with high accuracy and safety requirements for certification ^{Examples of industries that use both modeling and direct measurement as part of an integrated approach include the aerospace, defense, and medical industries in the Additive Manufacturing Certification for critical components under ASTM F42/ISO TC 261; International Organization for Standardization (ISO), ISO/TC 261 on Additive Manufacturing (2018), https://committee.iso.org/home/tc261; the automotive industry in its Automotive Safety Certification (SAE J1739); AMREPInspect, 'Quality Control in Automotive Industry: Standards & Techniques,' 2025, https://amrepinspect.com/blog/quality-control-in-automotive-industry; and, in aviation, Federal Aviation Administration (FAA) regulations specifying design, performance, and safety standards for airplanes under 14 CFR Part 23, which allow the use of approved simulation models to demonstrate compliance; Federal Aviation Administration, Methodology for Dynamic Seat Certification by Analysis for Use in Parts 23, 25, 27, and 29 Airplanes and Rotorcraft, https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1033628. 4} , and, as in many fields and CDR pathways, is the scientific best practice for quantification.

Planning for this two-pronged approach at the early stages of a startup’s development helps with resource planning and communication about MRV strategies; it also helps future-proof the processes and technologies initially considered by the project developer.

Given the importance of MRV for mCDR projects, the roadmap was designed as a guiding tool to inspire practical consideration and strategic communication about an organizational-level MRV strategy. While it is primarily written from the perspective of an mCDR project developer (i.e., an mCDR startup), it can guide a wide range of audiences through the planning or assessment of an MRV strategy. It can also facilitate communicating MRV plans for individual or multistage projects to key stakeholders, including internal teams, investors, project partners, and the local community members.

This section explores how different stakeholders may use this roadmap in addition to outlining primary features of the roadmap and critical considerations for each of its steps.

Potential roadmap users and use cases:

mCDR project developers can use the roadmap to guide the development and articulation of their MRV strategy. Since early-stage project developers often focus on solving immediate technical and financial challenges, they can use the roadmap to consider future MRV development steps that may require longer-term planning or resourcing. Even when a developer has a long-term MRV plan, this framework can serve as a reference for discussions about the timing and resource requirements for each step.

Funders, such as donors, equity investors, and debt providers, can better assess how their funding may finance the specific steps or components of a company’s MRV activities. This tool can help funders and project developers align expectations as they discuss the realistic effort levels required to achieve specific steps and the associated milestones and deliverables.

Industrial project partners can identify the timing and steps that may connect to their existing infrastructure, monitoring processes, and regulatory or societal obligations. Using this tool can initiate proactive and precise coordination, streamlining project deployment.

Lastly, for audiences including regulators and the public, the roadmap can invite productive engagement with project developers and the MRV planning process. It offers transparency into an MRV plan's rigor and timelines, as well as a common language for a constructive dialogue.

Unpacking the underlying components of the roadmap reveals additional context for these audiences.

As outlined in Exhibit 2 below, we identified nine key steps a startup may take on its MRV journey. We note that some resource-intensive processes crucial for responsible project deployment are outside the scope of this MRV roadmap, such as CDR engineering process design, environmental baseline monitoring, local community engagement, and collaboration with permitting agencies. These can take significant time and resources (e.g., obtaining pilot permits can take more than two years and cost over $1 million) and are interconnected with the MRV roadmap. Recommended resources for these topics can be found in the Conclusion section. A short description of the nine steps in Exhibit 2 and their effort levels over time are as follows:

1. Develop and document an MRV strategy: Before a project developer begins work on any specific project, the company's leadership team should outline an organization-level plan for resourcing the MRV function. It should incorporate the context and goals of the company’s mCDR innovation, its technology readiness level (TRL), and the local circumstances of any planned project site. The timeline and urgency for bringing in external support for this step should consider the in-house expertise of the leadership team. For example, a highly technical or scientifically experienced leadership team could delay hiring an external MRV lead as they lean into their internal expertise. The strategy can be further refined once an MRV/quantification lead is identified or hired and then revisited periodically as the project developer learns from deployments and shifting business conditions.
2. Designate an MRV/quantification lead: Once the high-level requirements for MRV are outlined in a strategy, a qualified quantification lead should be hired externally or identified from the existing team. The qualifications for this role should match the technical, scientific, and project management expertise required for managing the entire MRV process, keeping in mind that the responsibilities of an MRV lead will intersect with engineering, scientific, project management, and stakeholder engagement functions of the project and organization.
3. Identify, acquire, and begin testing the technology stack needed for modeling and measurement: A process for identifying, building, licensing, or contracting the MRV technology stack should start before the first field pilot and will require moderately significant resources until a demonstration-scale project has been deployed. Note that time and resources should be allocated for testing each piece of the stack as well as overall integration. Because the MRV technology stack will potentially serve multiple projects over a long period of time, mCDR companies should consider the maturity and reusability of any capital-intensive acquisitions. When companies expect capital-intensive monitoring or modeling technology to become obsolete within a few years, they may want to consider contracting for equipment or services.
4. Adopt or develop an MRV protocol to cover the technology and method of deployment: mCDR project developers who intend to sell carbon removal credits will most likely need to align their MRV practices and outcomes with the standards, methodologies, and protocols required by a carbon removal registry. CDR.fyi has a helpful explainer of these different terms. ⁱⁱ Working with a registry will help a project developer identify if an existing protocol can be used or adapted for their approach. If not, more significant resources will be required to draft and validate a new protocol through a combination of in-house effort and third-party support and could take more than six months. Unless the mCDR approach changes meaningfully over time, the initial protocol should be sufficient for future deployments. Developers should be aware that only a small number of registries exist that currently certify mCDR projects. The MRV lead should expect to interface closely with the registry to complete the crediting process.
5. Draft the executable project-specific MRV plan: For each project deployment, project developers will need to build a project-specific MRV plan based on the requirements outlined in their MRV protocol from step 4. The plan should be tailored to the specific deployment and can serve as the guide for daily activities. This plan is expected to dovetail with engineering design, community engagement, and regulatory compliance plans and requires active coordination across all major logistical functions of project deployment. While a new plan will need to be developed for each project deployment — requiring significant effort for each new project — lessons from previous deployments and the industry evolvement should moderately decrease the level of effort required for later deployments.
6. Identify a data management system for collection, storage, and dissemination of in situ sampling and modeling data: The team should identify a robust, fit-for-purpose data management system that enables it to collect, track, and report all project data. A rigorous process for selecting or building an initial data management system that is flexible across project locations and scales may prevent the need to switch data management systems for future, larger deployments.
7. Designate a monitoring and modeling team (in-house or contracted, at local and regional scales for each project): The project developer may need local monitoring and local/regional/global modeling teams (in-house or contracted) for each project. These teams will execute the project-specific MRV plan, sampling, and modeling to track the outcomes of the project deployment. Depending on project locations, some of these teams may be shared across deployments (e.g., shared modeling team or shared local monitoring team if projects are deployed in the same location), or new teams may need to be hired for each deployment (e.g., if an external partner has access to a pre-configured model for a new project location).
8. Collect, analyze, and report project data: It’s time to execute! The project developer should monitor project logistics and data to ensure that the teams are following the MRV plan and protocol correctly to meet all regulatory requirements, honor all commitments to stakeholders, and mitigate any unforeseen outcomes. This can be a personnel-intensive stage, requiring tight logistical coordination across nearly every team on a project. It is important to keep in mind that any in-water deployment will involve high levels of natural variability and operational uncertainty, requiring proactive management to anticipate and address potential mishaps. As with step 5 (developing the MRV plan), each project will require a surge in effort level, though intensity will decrease as the team learns from past deployments.
9. Share lessons with the CDR industry: Throughout this process, but particularly during and after the setup of each deployment, the project developer should share findings with the local community, interested academics, and the broader industry. While it may be counterintuitive for separate for-profit mCDR companies to share learnings, doing so can have a long-term net-positive impact on both the organization and the environment by supporting the responsible advancement of the entire industry.

Exhibit 1: How to read the tool

Exhibit 2: MRV roadmap

Download

As mentioned above, this framework is intended to serve as a starting point to inform transparent conversations about each of these steps. Its best use lies not in strict adherence, but in the clearer communication that arises from brainstorming and debating how to apply and resource these steps.

The journey to robust and credible MRV for mCDR is multifaceted. As we've explored in this report, it involves a diverse array of stakeholders, from pioneering startups and discerning investors to crucial industry partners, engaged current and future regulators, and local communities. Furthermore, an effective carbon MRV strategy is deeply interconnected with other critical processes, such as engineering, permitting, comprehensive environmental monitoring, and meaningful community engagement.

This interdependence calls for clarity and strategic planning. The MRV roadmap presented here is designed to be a versatile tool, adaptable to the unique circumstances of various mCDR technologies, project scales, and stakeholder communication needs. We encourage you to view it not as a rigid prescription but as a flexible framework to guide MRV development, execution, and communication efforts, to ultimately help all navigate this evolving landscape with greater confidence.

The following resources offer insights into complementary and critical areas for mCDR development:

• Community engagement resources
• RMI’s Stakeholder Analysis and Mapping (S.A.M.) Tool: This free, web-based tool helps project developers identify and visualize stakeholder relationships and power dynamics. It simplifies the process of stakeholder analysis, enabling more effective engagement and communication strategies.ⁱⁱⁱ
• XPRIZE requirement for environmental justice in CDR projects: XPRIZE included a “Sustainability, Social License, and Environmental Justice” questionnaire as part of the Milestone Submission requirement for participating CDR startups.^iv
• Environmental monitoring resources
• Ocean Visions Environmental Impact Assessment Framework: This initiative aims to develop a comprehensive framework for assessing the environmental impacts of mCDR projects.^v
• Carbon to Sea Environmental Monitoring Guidelines: In collaboration with Plymouth Marine Laboratory, Carbon to Sea is developing consensus-driven guidelines for environmental impact monitoring in field research.^vi
• mCDR permitting resources
• Developments on international governance of mCDR: Romany Webb, deputy director at Sabin Center for Climate Change Law at Columbia University, outlines recent efforts to regulate mCDR, as well as a proposal for future regulation.^vii
• Model federal legislation for mCDR: The Sabin Center published model federal legislation for mCDR research in US waters.^viii

Ultimately, the path to scaling mCDR solutions relies on our collective ability to build trust through transparent and rigorous MRV. If you are interested in discussing how to apply this roadmap to your specific mCDR project or investment strategy, please contact us! We are committed to fostering the growth of this vital industry through clear guidance and collaborative engagement.

Contact the authors by emailing us at:

Third Derivative - [email protected]

[C]Worthy - [email protected]

The team expresses our heartfelt appreciation to the Jeremy and Hannelore Grantham Environmental Trust for its support and partnership in funding this work.

Endnotes