Simulating deglacial radiocarbon anomalies with pH‐neutral geologic carbon

R. A. Green; P. A. Rafter; C. Sun; W. R. Gray; J. W. B. Rae; M. Pelly; C. Xu; K. Thirumalai; J. R. Southon; F. Pavia; M. P. Hain

doi:10.1029/2025pa005217

Simulating deglacial radiocarbon anomalies with pH‐neutral geologic carbon

R. A. Green^*
, P. A. Rafter
, C. Sun
, W. R. Gray
, J. W. B. Rae
, M. Pelly
, C. Xu
, K. Thirumalai
, J. R. Southon
, F. Pavia
, M. P. Hain

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

There is currently no explanation or carbon cycle model scenario for severe radiocarbon (¹⁴C) depletion reconstructed in the intermediate depth eastern tropical North Pacific Ocean (ETNP) at the end of the last ice age. Here, we develop new constraints on hypothesized geologic carbon release based on the boron isotope pH proxy and regional refinement of a global carbon cycle model. We find that pH‐neutral release of ∼800 Pg C over 5,000 years can produce the radiocarbon anomalies in the ETNP while inducing neither a large pH anomaly nor CaCO₃ dissolution (as observed) and causing minimal atmospheric CO₂ rise. Mass‐balance considerations dictate that the anomalous carbon was concentrated near the geologic source in the ETNP without significantly affecting radiocarbon‐based reconstructions of global ocean circulation change.

Original language	English
Article number	e2025PA005217
Number of pages	13
Journal	Paleoceanography and Paleoclimatology
Volume	41
Issue number	5
Early online date	6 May 2026
DOIs	https://doi.org/10.1029/2025pa005217
Publication status	Published - 6 May 2026

Keywords

Deglaciation
Radiocarbon anomalies
Neutralized geologic carbon addition
Eastern tropical North Pacific
Carbon cycle modeling
Boron isotopes

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10.1029/2025pa005217

Green_2026_P&P_Simulating-deglacial-radiocarbon-anomalies_AAM_CCBY
Copyright © 2026 the Authors. This work has been made available online in accordance with the University of St Andrews Open Access policy. This accepted manuscript is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The final published version of this work is available at https://doi.org/10.1029/2025PA005217
Accepted author manuscript, 1.12 MBLicence: CC BY

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INTRIGUED: Investigating the role of the: INTRIGUED: Investigating The Role of the North Pacific in Glacial and Deglacial CO2 and Climate
Rae, J. (PI) & Burke, A. (CoI)
Natural Environment Research Council
1/06/16 → 31/01/20
Project: Standard

Cite this

@article{1c3dce7533714fdb9e74ab0126136b7e,

title = "Simulating deglacial radiocarbon anomalies with pH‐neutral geologic carbon",

abstract = "There is currently no explanation or carbon cycle model scenario for severe radiocarbon (14C) depletion reconstructed in the intermediate depth eastern tropical North Pacific Ocean (ETNP) at the end of the last ice age. Here, we develop new constraints on hypothesized geologic carbon release based on the boron isotope pH proxy and regional refinement of a global carbon cycle model. We find that pH‐neutral release of ∼800 Pg C over 5,000 years can produce the radiocarbon anomalies in the ETNP while inducing neither a large pH anomaly nor CaCO3 dissolution (as observed) and causing minimal atmospheric CO2 rise. Mass‐balance considerations dictate that the anomalous carbon was concentrated near the geologic source in the ETNP without significantly affecting radiocarbon‐based reconstructions of global ocean circulation change.",

keywords = "Deglaciation, Radiocarbon anomalies, Neutralized geologic carbon addition, Eastern tropical North Pacific, Carbon cycle modeling, Boron isotopes",

author = "Green, \{R. A.\} and Rafter, \{P. A.\} and C. Sun and Gray, \{W. R.\} and Rae, \{J. W. B.\} and M. Pelly and C. Xu and K. Thirumalai and Southon, \{J. R.\} and F. Pavia and Hain, \{M. P.\}",

note = "Funding: National Science Foundation. Grant Numbers: OCE-2032343, OCE-1636005, AGS-2303599, OCE-2503657; NERC. Grant Number: NE/N011716/1",

year = "2026",

month = may,

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doi = "10.1029/2025pa005217",

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volume = "41",

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TY - JOUR

T1 - Simulating deglacial radiocarbon anomalies with pH‐neutral geologic carbon

AU - Green, R. A.

AU - Rafter, P. A.

AU - Sun, C.

AU - Gray, W. R.

AU - Rae, J. W. B.

AU - Pelly, M.

AU - Xu, C.

AU - Thirumalai, K.

AU - Southon, J. R.

AU - Pavia, F.

AU - Hain, M. P.

N1 - Funding: National Science Foundation. Grant Numbers: OCE-2032343, OCE-1636005, AGS-2303599, OCE-2503657; NERC. Grant Number: NE/N011716/1

PY - 2026/5/6

Y1 - 2026/5/6

N2 - There is currently no explanation or carbon cycle model scenario for severe radiocarbon (14C) depletion reconstructed in the intermediate depth eastern tropical North Pacific Ocean (ETNP) at the end of the last ice age. Here, we develop new constraints on hypothesized geologic carbon release based on the boron isotope pH proxy and regional refinement of a global carbon cycle model. We find that pH‐neutral release of ∼800 Pg C over 5,000 years can produce the radiocarbon anomalies in the ETNP while inducing neither a large pH anomaly nor CaCO3 dissolution (as observed) and causing minimal atmospheric CO2 rise. Mass‐balance considerations dictate that the anomalous carbon was concentrated near the geologic source in the ETNP without significantly affecting radiocarbon‐based reconstructions of global ocean circulation change.

AB - There is currently no explanation or carbon cycle model scenario for severe radiocarbon (14C) depletion reconstructed in the intermediate depth eastern tropical North Pacific Ocean (ETNP) at the end of the last ice age. Here, we develop new constraints on hypothesized geologic carbon release based on the boron isotope pH proxy and regional refinement of a global carbon cycle model. We find that pH‐neutral release of ∼800 Pg C over 5,000 years can produce the radiocarbon anomalies in the ETNP while inducing neither a large pH anomaly nor CaCO3 dissolution (as observed) and causing minimal atmospheric CO2 rise. Mass‐balance considerations dictate that the anomalous carbon was concentrated near the geologic source in the ETNP without significantly affecting radiocarbon‐based reconstructions of global ocean circulation change.

KW - Deglaciation

KW - Radiocarbon anomalies

KW - Neutralized geologic carbon addition

KW - Eastern tropical North Pacific

KW - Carbon cycle modeling

KW - Boron isotopes

U2 - 10.1029/2025pa005217

DO - 10.1029/2025pa005217

M3 - Article

SN - 2572-4517

VL - 41

JO - Paleoceanography and Paleoclimatology

JF - Paleoceanography and Paleoclimatology

IS - 5

M1 - e2025PA005217

ER -

Simulating deglacial radiocarbon anomalies with pH‐neutral geologic carbon

Abstract

Keywords

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INTRIGUED: Investigating the role of the: INTRIGUED: Investigating The Role of the North Pacific in Glacial and Deglacial CO2 and Climate

Cite this