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Rae JWB, Gray WR, Wills RCJ, Eisenman I, Fitzhugh B, Fotheringham M, Littley EFM, Rafter PA, Rees-Owen R, Ridgwell A, Taylor B, Burke A. Overturning circulation, nutrient limitation, and warming in the Glacial North Pacific. Sci Adv 2020; 6:6/50/eabd1654. [PMID: 33298448 PMCID: PMC7725469 DOI: 10.1126/sciadv.abd1654] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/21/2020] [Indexed: 06/12/2023]
Abstract
Although the Pacific Ocean is a major reservoir of heat and CO2, and thus an important component of the global climate system, its circulation under different climatic conditions is poorly understood. Here, we present evidence that during the Last Glacial Maximum (LGM), the North Pacific was better ventilated at intermediate depths and had surface waters with lower nutrients, higher salinity, and warmer temperatures compared to today. Modeling shows that this pattern is well explained by enhanced Pacific meridional overturning circulation (PMOC), which brings warm, salty, and nutrient-poor subtropical waters to high latitudes. Enhanced PMOC at the LGM would have lowered atmospheric CO2-in part through synergy with the Southern Ocean-and supported an equable regional climate, which may have aided human habitability in Beringia, and migration from Asia to North America.
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Affiliation(s)
- J W B Rae
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK.
| | - W R Gray
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Université Paris-Saclay, Gif-sur-Yvette, France
| | - R C J Wills
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
| | - I Eisenman
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - B Fitzhugh
- Department of Anthropology, University of Washington, Seattle, WA 98195, USA
| | - M Fotheringham
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - E F M Littley
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - P A Rafter
- Department of Earth System Science, University of California, Irvine, Irvine, CA 92697, USA
| | - R Rees-Owen
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - A Ridgwell
- Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - B Taylor
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - A Burke
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
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