14 Jun 2023
 | 14 Jun 2023
Status: a revised version of this preprint is currently under review for the journal SP.

Monitoring, Reporting, and Verification for Ocean Alkalinity Enhancement

David T. Ho, Laurent Bopp, Jaime B. Palter, Matthew C. Long, Philip Boyd, Griet Neukermans, and Lennart Bach

Abstract. Monitoring, Reporting, and Verification (MRV) refers to the multistep process of monitoring the amount of greenhouse gas removed by a Carbon Dioxide Removal (CDR) activity and reporting the results of the monitoring to a third party. The third party then verifies the reporting so the results. While MRV is usually conducted in pursuit of certification in a voluntary or regulated CDR market, this chapter focuses on key recommendations for MRV relevant to ocean alkalinity enhancement (OAE) research. Early-stage MRV for OAE research may become the foundation on which markets are built. Therefore, we argue that such research carries a special obligation toward comprehensiveness, reproducibility, and transparency. Observational approaches during field trials should aim to quantify the delivery of alkalinity to seawater and monitor for secondary precipitation, biotic calcification, and other ecosystem changes that can feed back on sources or sinks of greenhouse gases where alkalinity is measurably elevated. Observations of resultant shifts in ocean pCO2 and pH can help determine the efficacy of OAE and are amenable to autonomous monitoring. However, because the ocean is turbulent and energetic and CO2 equilibration between the ocean and atmosphere can take several months or longer, added alkalinity will be diluted to perturbation levels undetectable above background variability on timescales relevant for MRV. Therefore, comprehensive quantification of carbon removal via OAE will be impossible through observational methods alone and numerical simulations will be required. The development of fit-for-purpose models, carefully validated against observational data, will be a critical part of MRV research.

David T. Ho et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on sp-2023-2', Steve Rackley, 18 Jun 2023
    • AC1: 'Reply on CC1', David Ho, 28 Sep 2023
  • RC1: 'Comment on sp-2023-2', Christopher R. Pearce, 10 Jul 2023
    • AC2: 'Reply on RC1', David Ho, 28 Sep 2023
  • RC2: 'Comment on sp-2023-2', Anonymous Referee #2, 11 Jul 2023
    • AC3: 'Reply on RC2', David Ho, 28 Sep 2023
  • RC3: 'Comment on sp-2023-2', Anonymous Referee #3, 12 Jul 2023
    • AC4: 'Reply on RC3', David Ho, 28 Sep 2023
  • RC4: 'Comment on sp-2023-2', Justin Ries, 16 Aug 2023
    • AC5: 'Reply on RC4', David Ho, 28 Sep 2023

David T. Ho et al.

David T. Ho et al.


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Latest update: 29 Sep 2023
Short summary
This is the MRV chapter of the OAE Best Practice Guide.