This week, we deep dive into a paper recently published in Nature Communications. The study was led by Paul R. Halloran, affiliated with the Faculty of Environment, Science and Economy, of the University of Exeter, in Exeter (United Kingdom).
The article addresses the challenge of confidently verifying atmospheric CO₂ removal via abiotic marine carbon dioxide removal (mCDR) techniques, especially ocean alkalinity enhancement (OAE) and direct ocean carbon capture and storage (DOCCS). The authors present the findings of a stakeholder workshop, gathering parties spanning industry to government, and propose a foundational set of principles for monitoring, reporting, and verification (MRV) of these approaches, while acknowledging that today’s technologies and costs make full compliance difficult. They conclude that establishing clear, agreed MRV norms is essential to scale mCDR responsibly and avoid fragmented, incompatible systems, and discuss focal areas to drive down marine MRV costs.
This paper brings together both scientific and stakeholder perspectives on how to co-design MRV principles for abiotic marine carbon removal (i.e. non-biological techniques).
While many prior works focus on the technical modeling or geochemical aspects of ocean alkalinity enhancement or direct capture, this study explicitly centers the monitoring, reporting, and verification (MRV) challenge as a foundational barrier to commercialization and regulatory acceptance. By convening a workshop with industry, policy, verification bodies, and academia, the authors move beyond purely theoretical proposals to establish a shared framework that attempts to reconcile the differing needs (accuracy, cost, transparency, simplicity) of diverse actors.
In terms of results, the authors distill a set of “acceptable” MRV criteria: for instance, continuous monitoring of discharged water, near-field observation to validate dilution models, and periodic checks to confirm model reliability and uncertainty.
They contrast this with a lofty ideal of “perfect MRV” — full flux measurements and a perfect digital twin — which they argue is not only infeasible today but may also be unnecessarily costly and complex for stakeholders to accept. Their conclusions highlight that although these “acceptable” MRV protocols are technically feasible with current observational and modeling tools, in practice, the cost remains a significant barrier. The authors point to key levers for progress: development of autonomous sensors and platforms, more computationally efficient modeling, clearer regulatory mandates (i.e. an “ultimate regulator”), and coordinated field trials to reduce uncertainty. They also flag challenges of jurisdiction (e.g. water moving across Exclusive Economic Zones) and emphasize that MRV must combine credibility, accessibility, and transparency to be socially acceptable.
Here is a list of the main takeaways of this paper:
- A credible MRV framework is indispensable: without trusted verification, marine CDR cannot attract investment, regulatory support, or public confidence.
- The workshop found stakeholder alignment on minimum MRV principles (continuous measurement, modeling + near-field checks, uncertainty quantification) but recognized that a “perfect” standard is impractical today.
- The currently available observational & modeling tools suffice to build “acceptable” MRV, but the costs and uncertainties must come down to make mCDR viable.
- Progress hinges on innovation: more autonomous sensors, efficient models, better lab/field experiments, and harmonized regulatory mandates.
- Legal and governance complexities loom: waterborne CO₂ removal may cross jurisdictions, making clarity on who claims credit, responsibility, and oversight essential.
Read the full paper here: Seawater carbonate chemistry based carbon dioxide removal: towards commonly agreed principles for carbon monitoring, reporting, and verification