Articles | Volume 21, issue 1
Research article
 | Highlight paper
16 Jan 2024
Research article | Highlight paper |  | 16 Jan 2024

The additionality problem of ocean alkalinity enhancement

Lennart Thomas Bach


Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on bg-2023-122', Matthew Eisaman, 14 Aug 2023
    • AC1: 'Reply on RC1', Lennart Bach, 10 Nov 2023
    • AC2: 'Reply on RC1', Lennart Bach, 10 Nov 2023
  • RC2: 'Comment on bg-2023-122', Anonymous Referee #2, 28 Aug 2023
    • AC3: 'Reply on RC2', Lennart Bach, 10 Nov 2023
  • RC3: 'Comment on bg-2023-122', Anonymous Referee #3, 29 Aug 2023
    • AC4: 'Reply on RC3', Lennart Bach, 10 Nov 2023
  • RC4: 'Comment on bg-2023-122', Adam Subhas, 30 Aug 2023
    • AC5: 'Reply on RC4', Lennart Bach, 10 Nov 2023

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Publish subject to minor revisions (review by editor) (15 Nov 2023) by Jack Middelburg
AR by Lennart Bach on behalf of the Authors (17 Nov 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to technical corrections (21 Nov 2023) by Jack Middelburg
AR by Lennart Bach on behalf of the Authors (23 Nov 2023)  Author's response   Manuscript 
Reaching the Paris Agreement targets to limit global warming to 1.5 or 2°C implies not only reducing emissions, but also active carbon dioxide removal from the atmosphere. While land-based carbon dioxide removal or negative emission technologies have received most attention, ocean solutions are increasingly being considered. Ocean alkalinity enhancement (OAE), or alkalinization, is one promising ocean-based carbon dioxide technology. However, any new carbon dioxide removal technique needs thorough investigations for its effectiveness, longevity, benefits and lack of disbenefits, financial viability, social acceptance and governability. The paper by Bach is a nice illustration of the type of research that must be done if we are to consider large scale application of OAE. It focuses on the additionality problem of ocean alkalinity enhancement, specifically it investigates how the addition of alkalinity modifies the natural alkalinity cycle and in that way the efficiency of carbon dioxide sequestration.
Short summary
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Final-revised paper