The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales.
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| Title: | The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales. |
|---|---|
| Authors: | Grosselindemann, Hendrik1,2 (AUTHOR) hgrosselindemann@gmail.com, Burger, Friedrich A.1,2 (AUTHOR), Frölicher, Thomas L.1,2 (AUTHOR) |
| Source: | Biogeosciences. 2026, Vol. 23 Issue 10, p3299-3321. 23p. |
| Subject Terms: | *Ocean acidification, *Climate change mitigation, *Carbon cycle, *Greenhouse gases, *Carbon dioxide reduction, *Atmospheric models, Paris Agreement (2016) |
| Abstract: | Carbon dioxide removal (CDR) strategies such as ocean alkalinity enhancement (OAE) are likely required in addition to rapid emissions reductions to limit global warming to well below 2 °C. However, the long-term efficiency of OAE and its potential to mitigate climate change and ocean acidification remain uncertain. Here, we investigate efficiencies, climate and ocean acidification responses of idealized OAE using a fully coupled, emission-driven Earth system model across three global warming stabilization scenarios (1.5, 2, and 3 °C) spanning 1861–2500. OAE is implemented as a continuous global surface alkalinity addition of 0.14 Pmolyr-1 following the CDRMIP protocol from 2026 onward. Our results show that OAE reduces atmospheric CO2 by 73–130 ppm by 2500, with larger reductions under higher warming scenarios and during the first 100 to 200 years of alkalinity addition. In contrast, global surface air temperature decreases nearly linearly by 0.14–0.17 °C per century across all scenarios, indicating that the cooling rate due to OAE is largely insensitive to the emission pathway and background warming level. The interpretation of OAE efficiency depends strongly on the chosen metric. The global gross ocean carbon capture efficiency of about 0.79 remains close to the theoretical maximum, reflecting the negative emissions through OAE, whereas the net ocean capture and atmospheric CO2 reduction efficiencies are substantially lower and decline over time due to carbon cycle feedbacks in response to lowered atmospheric CO2. OAE mitigates ocean acidification, at the surface as well as in the interior ocean, with most centennial-scale mitigation arising from atmospheric CO2 drawdown, an effect shared with other CDR approaches. Direct chemical effects of added alkalinity contribute transiently and diminish over time as the ocean–atmosphere system equilibrates. Overall, our results underscore that rapid emission reductions remain the most effective strategy for achieving the Paris Agreement goals and mitigating ocean acidification. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Header | DbId: enr DbLabel: Energy & Power Source An: 194401792 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Grosselindemann%2C+Hendrik%22">Grosselindemann, Hendrik</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> hgrosselindemann@gmail.com</i><br /><searchLink fieldCode="AR" term="%22Burger%2C+Friedrich+A%2E%22">Burger, Friedrich A.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Frölicher%2C+Thomas+L%2E%22">Frölicher, Thomas L.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Biogeosciences%22">Biogeosciences</searchLink>. 2026, Vol. 23 Issue 10, p3299-3321. 23p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Ocean+acidification%22">Ocean acidification</searchLink><br />*<searchLink fieldCode="DE" term="%22Climate+change+mitigation%22">Climate change mitigation</searchLink><br />*<searchLink fieldCode="DE" term="%22Carbon+cycle%22">Carbon cycle</searchLink><br />*<searchLink fieldCode="DE" term="%22Greenhouse+gases%22">Greenhouse gases</searchLink><br />*<searchLink fieldCode="DE" term="%22Carbon+dioxide+reduction%22">Carbon dioxide reduction</searchLink><br />*<searchLink fieldCode="DE" term="%22Atmospheric+models%22">Atmospheric models</searchLink><br /><searchLink fieldCode="DE" term="%22Paris+Agreement+%282016%29%22">Paris Agreement (2016)</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Carbon dioxide removal (CDR) strategies such as ocean alkalinity enhancement (OAE) are likely required in addition to rapid emissions reductions to limit global warming to well below 2 °C. However, the long-term efficiency of OAE and its potential to mitigate climate change and ocean acidification remain uncertain. Here, we investigate efficiencies, climate and ocean acidification responses of idealized OAE using a fully coupled, emission-driven Earth system model across three global warming stabilization scenarios (1.5, 2, and 3 °C) spanning 1861–2500. OAE is implemented as a continuous global surface alkalinity addition of 0.14 Pmolyr-1 following the CDRMIP protocol from 2026 onward. Our results show that OAE reduces atmospheric CO2 by 73–130 ppm by 2500, with larger reductions under higher warming scenarios and during the first 100 to 200 years of alkalinity addition. In contrast, global surface air temperature decreases nearly linearly by 0.14–0.17 °C per century across all scenarios, indicating that the cooling rate due to OAE is largely insensitive to the emission pathway and background warming level. The interpretation of OAE efficiency depends strongly on the chosen metric. The global gross ocean carbon capture efficiency of about 0.79 remains close to the theoretical maximum, reflecting the negative emissions through OAE, whereas the net ocean capture and atmospheric CO2 reduction efficiencies are substantially lower and decline over time due to carbon cycle feedbacks in response to lowered atmospheric CO2. OAE mitigates ocean acidification, at the surface as well as in the interior ocean, with most centennial-scale mitigation arising from atmospheric CO2 drawdown, an effect shared with other CDR approaches. Direct chemical effects of added alkalinity contribute transiently and diminish over time as the ocean–atmosphere system equilibrates. Overall, our results underscore that rapid emission reductions remain the most effective strategy for achieving the Paris Agreement goals and mitigating ocean acidification. [ABSTRACT FROM AUTHOR] |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.5194/bg-23-3299-2026 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 23 StartPage: 3299 Subjects: – SubjectFull: Ocean acidification Type: general – SubjectFull: Climate change mitigation Type: general – SubjectFull: Carbon cycle Type: general – SubjectFull: Greenhouse gases Type: general – SubjectFull: Carbon dioxide reduction Type: general – SubjectFull: Atmospheric models Type: general – SubjectFull: Paris Agreement (2016) Type: general Titles: – TitleFull: The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Grosselindemann, Hendrik – PersonEntity: Name: NameFull: Burger, Friedrich A. – PersonEntity: Name: NameFull: Frölicher, Thomas L. IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 05 Text: 2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 17264170 Numbering: – Type: volume Value: 23 – Type: issue Value: 10 Titles: – TitleFull: Biogeosciences Type: main |
| ResultId | 1 |
