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An Z, Zhou W, Zhang Z, Zhang X, Liu Z, Sun Y, Clemens SC, Wu L, Zhao J, Shi Z, Ma X, Yan H, Li G, Cai Y, Yu J, Sun Y, Li S, Zhang Y, Stepanek C, Lohmann G, Dong G, Cheng H, Liu Y, Jin Z, Li T, Hao Y, Lei J, Cai W. Mid-Pleistocene climate transition triggered by Antarctic Ice Sheet growth. Science 2024; 385:560-565. [PMID: 39088600 DOI: 10.1126/science.abn4861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/06/2023] [Accepted: 06/28/2024] [Indexed: 08/03/2024]
Abstract
Despite extensive investigation, the nature and causes of the Mid-Pleistocene Transition remain enigmatic. In this work, we assess its linkage to asynchronous development of bipolar ice sheets by synthesizing Pleistocene mid- to high-latitude proxy records linked to hemispheric ice sheet evolution. Our results indicate substantial growth of the Antarctic Ice Sheets (AISs) at 2.0 to 1.25 million years ago, preceding the rapid expansion of Northern Hemisphere Ice Sheets after ~1.25 million years ago. Proxy-model comparisons suggest that AIS and associated Southern Ocean sea ice expansion can induce northern high-latitude cooling and enhanced moisture transport to the Northern Hemisphere, thus triggering the Mid-Pleistocene Transition. The dynamic processes involved are crucial for assessing modern global warming that is already inducing asynchronous bipolar melting of ice sheets.
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Affiliation(s)
- Zhisheng An
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing 100875, China
| | - Weijian Zhou
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing 100875, China
| | - Zeke Zhang
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing 210023, China
| | - Xu Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- British Antarctic Survey, Cambridge CB3 0ET, UK
| | - Zhonghui Liu
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Youbin Sun
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Steven C Clemens
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA
| | - Lixin Wu
- Laoshan Laboratory, Qingdao 266000, China
- Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies, Ocean University of China, Qingdao 266100, China
| | - Jiaju Zhao
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhengguo Shi
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xiaolin Ma
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hong Yan
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Gaojun Li
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing 210023, China
| | - Yanjun Cai
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jimin Yu
- Laoshan Laboratory, Qingdao 266000, China
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Yuchen Sun
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Siqi Li
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu'ao Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Christian Stepanek
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Gerrit Lohmann
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Guocheng Dong
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hai Cheng
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yu Liu
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Zhangdong Jin
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Tao Li
- Key Laboratory of Palaeobiology and Petroleum Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yifei Hao
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Jing Lei
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China
| | - Wenju Cai
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Laoshan Laboratory, Qingdao 266000, China
- Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies, Ocean University of China, Qingdao 266100, China
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2
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Ao H, Liebrand D, Dekkers MJ, Roberts AP, Jonell TN, Jin Z, Song Y, Liu Q, Sun Q, Li X, Huang C, Qiang X, Zhang P. Orbital- and millennial-scale Asian winter monsoon variability across the Pliocene-Pleistocene glacial intensification. Nat Commun 2024; 15:3364. [PMID: 38641605 PMCID: PMC11031568 DOI: 10.1038/s41467-024-47274-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/22/2024] [Indexed: 04/21/2024] Open
Abstract
Intensification of northern hemisphere glaciation (iNHG), ~2.7 million years ago (Ma), led to establishment of the Pleistocene to present-day bipolar icehouse state. Here we document evolution of orbital- and millennial-scale Asian winter monsoon (AWM) variability across the iNHG using a palaeomagnetically dated centennial-resolution grain size record between 3.6 and 1.9 Ma from a previously undescribed loess-palaeosol/red clay section on the central Chinese Loess Plateau. We find that the late Pliocene-early Pleistocene AWM was characterized by combined 41-kyr and ~100-kyr cycles, in response to ice volume and atmospheric CO2 forcing. Northern hemisphere ice sheet expansion, which was accompanied by an atmospheric CO2 concentration decline, substantially increased glacial AWM intensity and its orbitally oscillating amplitudes across the iNHG. Superposed on orbital variability, we find that millennial AWM intensity fluctuations persisted during both the warmer (higher-CO2) late Pliocene and colder (lower-CO2) early Pleistocene, in response to both external astronomical forcing and internal climate dynamics.
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Affiliation(s)
- Hong Ao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
- Laoshan Laboratory, Qingdao, China.
| | - Diederik Liebrand
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
| | - Mark J Dekkers
- Paleomagnetic Laboratory 'Fort Hoofddijk', Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | - Tara N Jonell
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
| | - Zhangdong Jin
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Laoshan Laboratory, Qingdao, China
| | - Yougui Song
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Qingsong Liu
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Qiang Sun
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, China
| | - Xinxia Li
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, China
| | - Chunju Huang
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, China
| | - Xiaoke Qiang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Peng Zhang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
- Laoshan Laboratory, Qingdao, China
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3
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Clark PU, Shakun JD, Rosenthal Y, Köhler P, Bartlein PJ. Global and regional temperature change over the past 4.5 million years. Science 2024; 383:884-890. [PMID: 38386742 DOI: 10.1126/science.adi1908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 01/16/2024] [Indexed: 02/24/2024]
Abstract
Much of our understanding of Cenozoic climate is based on the record of δ18O measured in benthic foraminifera. However, this measurement reflects a combined signal of global temperature and sea level, thus preventing a clear understanding of the interactions and feedbacks of the climate system in causing global temperature change. Our new reconstruction of temperature change over the past 4.5 million years includes two phases of long-term cooling, with the second phase of accelerated cooling during the Middle Pleistocene Transition (1.5 to 0.9 million years ago) being accompanied by a transition from dominant 41,000-year low-amplitude periodicity to dominant 100,000-year high-amplitude periodicity. Changes in the rates of long-term cooling and variability are consistent with changes in the carbon cycle driven initially by geologic processes, followed by additional changes in the Southern Ocean carbon cycle.
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Affiliation(s)
- Peter U Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
- School of Geography and Environmental Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - Jeremy D Shakun
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA 02467, USA
| | - Yair Rosenthal
- Department of Marine and Coastal Science, Rutgers The State University, New Brunswick, NJ 08901, USA
- Department of Earth and Planetary Sciences, Rutgers The State University, New Brunswick, NJ 08901, USA
| | - Peter Köhler
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, 27570 Bremerhaven, Germany
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4
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Subglacial precipitates record Antarctic ice sheet response to late Pleistocene millennial climate cycles. Nat Commun 2022; 13:5428. [PMID: 36109505 PMCID: PMC9477832 DOI: 10.1038/s41467-022-33009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
Ice cores and offshore sedimentary records demonstrate enhanced ice loss along Antarctic coastal margins during millennial-scale warm intervals within the last glacial termination. However, the distal location and short temporal coverage of these records leads to uncertainty in both the spatial footprint of ice loss, and whether millennial-scale ice response occurs outside of glacial terminations. Here we present a >100kyr archive of periodic transitions in subglacial precipitate mineralogy that are synchronous with Late Pleistocene millennial-scale climate cycles. Geochemical and geochronologic data provide evidence for opal formation during cold periods via cryoconcentration of subglacial brine, and calcite formation during warm periods through the addition of subglacial meltwater originating from the ice sheet interior. These freeze-flush cycles represent cyclic changes in subglacial hydrologic-connectivity driven by ice sheet velocity fluctuations. Our findings imply that oscillating Southern Ocean temperatures drive a dynamic response in the Antarctic ice sheet on millennial timescales, regardless of the background climate state. Piccione et al find evidence for Antarctic ice sheet instability driven by millennial cycles in Southern Ocean temperature, providing clues for the mechanisms that link climate change and rapid Antarctic ice loss events.
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5
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Scientists have unearthed what could be the world's oldest ice core. Nature 2022; 609:22-23. [PMID: 35948685 DOI: 10.1038/d41586-022-02129-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Thomas NC, Bradbury HJ, Hodell DA. Changes in North Atlantic deep-water oxygenation across the Middle Pleistocene Transition. Science 2022; 377:654-659. [PMID: 35926027 DOI: 10.1126/science.abj7761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The oxygen concentrations of oceanic deep-water and atmospheric carbon dioxide (pCO2) are intrinsically linked through organic carbon remineralization and storage as dissolved inorganic carbon in the deep sea. We present a high-resolution reconstruction of relative changes in oxygen concentration in the deep North Atlantic for the past 1.5 million years using the carbon isotope gradient between epifaunal and infaunal benthic foraminifera species as a proxy for paleo-oxygen. We report a significant (>40 micromole per kilogram) reduction in glacial Atlantic deep-water oxygenation at ~960 thousand to 900 thousand years ago that coincided with increased continental ice volume and a major change in ocean thermohaline circulation. Paleo-oxygen results support a scenario of decreasing deep-water oxygen concentrations, increased respired carbon storage, and a reduction in glacial pCO2 across the Middle Pleistocene Transition.
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Affiliation(s)
- Nicola C Thomas
- Department of Earth Science, University of Cambridge, Cambridge, UK
| | | | - David A Hodell
- Department of Earth Science, University of Cambridge, Cambridge, UK
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7
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Abstract
Massive carbon (C) release with abrupt warming has occurred repeatedly during greenhouse states, and these events have driven episodes of ocean deoxygenation and extinction. Records from these paleo events, coupled with biogeochemical modeling, provide clear evidence that with continued warming, the modern oceans will experience substantial deoxygenation. There are, however, few constraints from the geologic record on the effects of rapid warming under icehouse conditions. We document a C-cycle perturbation that occurred under an Earth system state experiencing recurrent glaciation. A suite of proxies suggests increased seafloor anoxia during this event in step with abrupt increase in CO2 partial pressure and a biodiversity nadir. Warming-mediated increases in marine anoxia may be more pronounced in a glaciated versus unglaciated climate state. Piecing together the history of carbon (C) perturbation events throughout Earth’s history has provided key insights into how the Earth system responds to abrupt warming. Previous studies, however, focused on short-term warming events that were superimposed on longer-term greenhouse climate states. Here, we present an integrated proxy (C and uranium [U] isotopes and paleo CO2) and multicomponent modeling approach to investigate an abrupt C perturbation and global warming event (∼304 Ma) that occurred during a paleo-glacial state. We report pronounced negative C and U isotopic excursions coincident with a doubling of atmospheric CO2 partial pressure and a biodiversity nadir. The isotopic excursions can be linked to an injection of ∼9,000 Gt of organic matter–derived C over ∼300 kyr and to near 20% of areal extent of seafloor anoxia. Earth system modeling indicates that widespread anoxic conditions can be linked to enhanced thermocline stratification and increased nutrient fluxes during this global warming within an icehouse.
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8
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Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years. Nat Commun 2022; 13:2044. [PMID: 35440628 PMCID: PMC9018689 DOI: 10.1038/s41467-022-29642-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 03/25/2022] [Indexed: 11/08/2022] Open
Abstract
The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.
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9
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Yan Y, Brook EJ, Kurbatov AV, Severinghaus JP, Higgins JA. Ice core evidence for atmospheric oxygen decline since the Mid-Pleistocene transition. SCIENCE ADVANCES 2021; 7:eabj9341. [PMID: 34910502 PMCID: PMC8673763 DOI: 10.1126/sciadv.abj9341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
The history of atmospheric oxygen (PO2) and the processes that act to regulate it remain enigmatic because of difficulties in quantitative reconstructions using indirect proxies. Here, we extend the ice-core record of PO2 using 1.5-million-year-old (Ma) discontinuous ice samples drilled from Allan Hills Blue Ice Area, East Antarctica. No statistically significant difference exists in PO2 between samples at 1.5 Ma and 810 thousand years (ka), suggesting that the Late-Pleistocene imbalance in O2 sources and sinks began around the time of the transition from 40- to 100-ka glacial cycles in the Mid-Pleistocene between ~1.2 Ma and 700 ka. The absence of a coeval secular increase in atmospheric CO2 over the past ~1 Ma requires negative feedback mechanisms such as Pco2-dependent silicate weathering. Fast processes must also act to suppress the immediate Pco2 increase because of the imbalance in O2 sinks over sources beginning in the Mid-Pleistocene.
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Affiliation(s)
- Yuzhen Yan
- Department of Geosciences, Princeton University, Princeton, NJ, USA
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA
| | - Edward J. Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | | | | | - John A. Higgins
- Department of Geosciences, Princeton University, Princeton, NJ, USA
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10
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Rohling EJ, Yu J, Heslop D, Foster GL, Opdyke B, Roberts AP. Sea level and deep-sea temperature reconstructions suggest quasi-stable states and critical transitions over the past 40 million years. SCIENCE ADVANCES 2021; 7:7/26/eabf5326. [PMID: 34172440 PMCID: PMC8232915 DOI: 10.1126/sciadv.abf5326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 05/12/2021] [Indexed: 06/13/2023]
Abstract
Sea level and deep-sea temperature variations are key indicators of global climate changes. For continuous records over millions of years, deep-sea carbonate microfossil-based δ18O (δc) records are indispensable because they reflect changes in both deep-sea temperature and seawater δ18O (δw); the latter are related to ice volume and, thus, to sea level changes. Deep-sea temperature is usually resolved using elemental ratios in the same benthic microfossil shells used for δc, with linear scaling of residual δw to sea level changes. Uncertainties are large and the linear-scaling assumption remains untested. Here, we present a new process-based approach to assess relationships between changes in sea level, mean ice sheet δ18O, and both deep-sea δw and temperature and find distinct nonlinearity between sea level and δw changes. Application to δc records over the past 40 million years suggests that Earth's climate system has complex dynamical behavior, with threshold-like adjustments (critical transitions) that separate quasi-stable deep-sea temperature and ice-volume states.
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Affiliation(s)
- Eelco J Rohling
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia.
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - Jimin Yu
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - David Heslop
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Gavin L Foster
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - Bradley Opdyke
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
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11
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Biller-Celander N, Shakun JD, McGee D, Wong CI, Reyes AV, Hardt B, Tal I, Ford DC, Lauriol B. Increasing Pleistocene permafrost persistence and carbon cycle conundrums inferred from Canadian speleothems. SCIENCE ADVANCES 2021; 7:7/18/eabe5799. [PMID: 33910910 PMCID: PMC8081356 DOI: 10.1126/sciadv.abe5799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Permafrost carbon represents a potentially powerful amplifier of climate change, but little is known about permafrost sensitivity and associated carbon cycling during past warm intervals. We reconstruct permafrost history in western Canada during Pleistocene interglacials from 130 uranium-thorium ages on 72 speleothems, cave deposits that only accumulate with deep ground thaw. We infer that permafrost thaw extended to the high Arctic during one or more periods between ~1.5 million and 0.5 million years ago but has been limited to the sub-Arctic since 400,000 years ago. Our Canadian speleothem growth history closely parallels an analogous reconstruction from Siberia, suggesting that this shift toward more stable permafrost across the Pleistocene may have been Arctic-wide. In contrast, interglacial greenhouse gas concentrations were relatively stable throughout the Pleistocene, suggesting that either permafrost thaw did not trigger substantial carbon release to the atmosphere or it was offset by carbon uptake elsewhere on glacial-interglacial time scales.
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Affiliation(s)
- Nicole Biller-Celander
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA 02467, USA
| | - Jeremy D Shakun
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA 02467, USA.
| | - David McGee
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Corinne I Wong
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA 02467, USA
| | - Alberto V Reyes
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
| | - Ben Hardt
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Irit Tal
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Derek C Ford
- Department of Geography and Earth Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Bernard Lauriol
- Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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12
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Sherwood SC, Webb MJ, Annan JD, Armour KC, Forster PM, Hargreaves JC, Hegerl G, Klein SA, Marvel KD, Rohling EJ, Watanabe M, Andrews T, Braconnot P, Bretherton CS, Foster GL, Hausfather Z, von der Heydt AS, Knutti R, Mauritsen T, Norris JR, Proistosescu C, Rugenstein M, Schmidt GA, Tokarska KB, Zelinka MD. An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2020; 58:e2019RG000678. [PMID: 33015673 PMCID: PMC7524012 DOI: 10.1029/2019rg000678] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 04/22/2020] [Accepted: 06/24/2020] [Indexed: 05/10/2023]
Abstract
We assess evidence relevant to Earth's equilibrium climate sensitivity per doubling of atmospheric CO2, characterized by an effective sensitivity S. This evidence includes feedback process understanding, the historical climate record, and the paleoclimate record. An S value lower than 2 K is difficult to reconcile with any of the three lines of evidence. The amount of cooling during the Last Glacial Maximum provides strong evidence against values of S greater than 4.5 K. Other lines of evidence in combination also show that this is relatively unlikely. We use a Bayesian approach to produce a probability density function (PDF) for S given all the evidence, including tests of robustness to difficult-to-quantify uncertainties and different priors. The 66% range is 2.6-3.9 K for our Baseline calculation and remains within 2.3-4.5 K under the robustness tests; corresponding 5-95% ranges are 2.3-4.7 K, bounded by 2.0-5.7 K (although such high-confidence ranges should be regarded more cautiously). This indicates a stronger constraint on S than reported in past assessments, by lifting the low end of the range. This narrowing occurs because the three lines of evidence agree and are judged to be largely independent and because of greater confidence in understanding feedback processes and in combining evidence. We identify promising avenues for further narrowing the range in S, in particular using comprehensive models and process understanding to address limitations in the traditional forcing-feedback paradigm for interpreting past changes.
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Affiliation(s)
- S C Sherwood
- Climate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney Sydney New South Wales Australia
| | - M J Webb
- Met Office Hadley Centre Exeter UK
| | | | | | - P M Forster
- Priestley International Centre for Climate University of Leeds Leeds UK
| | | | - G Hegerl
- School of Geosciences University of Edinburgh Edinburgh UK
| | | | - K D Marvel
- Department of Applied Physics and Applied Math Columbia University New York NY USA
- NASA Goddard Institute for Space Studies New York NY USA
| | - E J Rohling
- Research School of Earth Sciences Australian National University Canberra ACT Australia
- Ocean and Earth Science, National Oceanography Centre University of Southampton Southampton UK
| | - M Watanabe
- Atmosphere and Ocean Research Institute The University of Tokyo Tokyo Japan
| | | | - P Braconnot
- Laboratoire des Sciences du Climat et de l'Environnement, unité mixte CEA-CNRS-UVSQ Université Paris-Saclay Gif sur Yvette France
| | | | - G L Foster
- Ocean and Earth Science, National Oceanography Centre University of Southampton Southampton UK
| | | | - A S von der Heydt
- Institute for Marine and Atmospheric Research, and Centre for Complex Systems Science Utrecht University Utrecht The Netherlands
| | - R Knutti
- Institute for Atmospheric and Climate Science Zurich Switzerland
| | - T Mauritsen
- Department of Meteorology Stockholm University Stockholm Sweden
| | - J R Norris
- Scripps Institution of Oceanography La Jolla CA USA
| | - C Proistosescu
- Department of Atmospheric Sciences and Department of Geology University of Illinois at Urbana-Champaign Urbana IL USA
| | - M Rugenstein
- Max Planck Institute for Meteorology Hamburg Germany
| | - G A Schmidt
- NASA Goddard Institute for Space Studies New York NY USA
| | - K B Tokarska
- School of Geosciences University of Edinburgh Edinburgh UK
- Institute for Atmospheric and Climate Science Zurich Switzerland
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Köhler P, van de Wal RSW. Interglacials of the Quaternary defined by northern hemispheric land ice distribution outside of Greenland. Nat Commun 2020; 11:5124. [PMID: 33046715 PMCID: PMC7550566 DOI: 10.1038/s41467-020-18897-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/18/2020] [Indexed: 11/16/2022] Open
Abstract
Glacial/interglacial dynamics during the Quaternary were suggested to be mainly driven by obliquity (41-kyr periodicity), including irregularities during the last 1 Myr that resulted in on average 100-kyr cycles. Here, we investigate this so-called Mid-Pleistocene Transition via model-based deconvolution of benthic δ18O, redefining interglacials by lack of substantial northern hemispheric land ice outside of Greenland. We find that in 67%, 88% and 52% of the obliquity cycles during the early, middle and late Quaternary, respectively, a glacial termination is realized leading to irregular appearances of new interglacials during various parts of the last 2.6 Myr. This finding suggests that the proposed idea of terminations leading to new interglacials in the Quaternary as obliquity driven with growing influence of land ice volume on the timing of deglaciations during the last 1 Myr might be too simple. Alternatively, the land ice-based definition of interglacials needs revision if applied to the entire Quaternary. This study presents a new definition of interglacials during the Quaternary. The authors find the appearance of interglacials is in general following the 41-kyr cycle of obliquity with various exceptions, suggesting a more complex physical mechanism triggering glacial terminations.
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Affiliation(s)
- Peter Köhler
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung (AWI), P.O. Box 12 01 61, Bremerhaven, 27515, Germany.
| | - Roderik S W van de Wal
- Institute for Marine and Atmospheric Research Utrecht (IMAU) and Faculty of Geosciences, Department of Physical Geography, Utrecht University, Princetonplein 5, Utrecht, 3584 CC, The Netherlands
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14
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Modelling the effects of CO 2 on C 3 and C 4 grass competition during the mid-Pleistocene transition in South Africa. Sci Rep 2020; 10:16234. [PMID: 33004831 PMCID: PMC7530989 DOI: 10.1038/s41598-020-72614-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/02/2020] [Indexed: 11/25/2022] Open
Abstract
Palaeoenvironmental reconstructions of the interior of South Africa show a wetter environment than today and a non-analogous vegetation structure in the Early Pleistocene. This includes the presence of grasses following both C3 and C4 photosynthetic pathways, whereas C3 grasses decline after the mid-Pleistocene transition (MPT, c. 1.2–0.8 Ma). However, the local terrestrial proxy record cannot distinguish between the potential drivers of these vegetation changes. In this study we show that low glacial CO2 levels, similar to those at the MPT, lead to the local decline of C3 grasses under conditions of decreased water availability, using a vegetation model (LPX) driven by Atmosphere–Ocean coupled General Climate Model climate reconstructions. We modelled vegetation for glacial climates under different levels of CO2 and fire regimes and find evidence that a combination of low CO2 and changed seasonality is driving the changes in grass cover, whereas fire has little influence on the ratio of C3:C4 grasses. Our results suggest the prevalence of a less vegetated landscape with limited, seasonal water availability, which could potentially explain the much sparser mid-Pleistocene archaeological record in the southern Kalahari.
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15
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de la Vega E, Chalk TB, Wilson PA, Bysani RP, Foster GL. Atmospheric CO 2 during the Mid-Piacenzian Warm Period and the M2 glaciation. Sci Rep 2020; 10:11002. [PMID: 32647351 PMCID: PMC7347535 DOI: 10.1038/s41598-020-67154-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/18/2020] [Indexed: 11/28/2022] Open
Abstract
The Piacenzian stage of the Pliocene (2.6 to 3.6 Ma) is the most recent past interval of sustained global warmth with mean global temperatures markedly higher (by ~2–3 °C) than today. Quantifying CO2 levels during the mid-Piacenzian Warm Period (mPWP) provides a means, therefore, to deepen our understanding of Earth System behaviour in a warm climate state. Here we present a new high-resolution record of atmospheric CO2 using the δ11B-pH proxy from 3.35 to 3.15 million years ago (Ma) at a temporal resolution of 1 sample per 3–6 thousand years (kyrs). Our study interval covers both the coolest marine isotope stage of the mPWP, M2 (~3.3 Ma) and the transition into its warmest phase including interglacial KM5c (centered on ~3.205 Ma) which has a similar orbital configuration to present. We find that CO2 ranged from \documentclass[12pt]{minimal}
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\begin{document}$${{\bf{394}}}_{{\boldsymbol{-}}{\bf{9}}}^{{\boldsymbol{+}}{\bf{34}}}$$\end{document}394−9+34 ppm to \documentclass[12pt]{minimal}
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\begin{document}$${{\bf{330}}}_{{\boldsymbol{-}}{\bf{21}}}^{{\boldsymbol{+}}{\bf{14}}}$$\end{document}330−21+14 ppm: with CO2 during the KM5c interglacial being \documentclass[12pt]{minimal}
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\begin{document}$${{\bf{391}}}_{{\boldsymbol{-}}{\bf{28}}}^{{\boldsymbol{+}}{\bf{30}}}$$\end{document}391−28+30 ppm (at 95% confidence). Our findings corroborate the idea that changes in atmospheric CO2 levels played a distinct role in climate variability during the mPWP. They also facilitate ongoing data-model comparisons and suggest that, at present rates of human emissions, there will be more CO2 in Earth’s atmosphere by 2025 than at any time in at least the last 3.3 million years.
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Affiliation(s)
- Elwyn de la Vega
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton,Waterfront Campus Southampton, Southampton, SO14 3ZH, UK.
| | - Thomas B Chalk
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton,Waterfront Campus Southampton, Southampton, SO14 3ZH, UK
| | - Paul A Wilson
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton,Waterfront Campus Southampton, Southampton, SO14 3ZH, UK
| | - Ratna Priya Bysani
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton,Waterfront Campus Southampton, Southampton, SO14 3ZH, UK
| | - Gavin L Foster
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton,Waterfront Campus Southampton, Southampton, SO14 3ZH, UK
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Zhao Y, Tzedakis PC, Li Q, Qin F, Cui Q, Liang C, Birks HJB, Liu Y, Zhang Z, Ge J, Zhao H, Felde VA, Deng C, Cai M, Li H, Ren W, Wei H, Yang H, Zhang J, Yu Z, Guo Z. Evolution of vegetation and climate variability on the Tibetan Plateau over the past 1.74 million years. SCIENCE ADVANCES 2020; 6:eaay6193. [PMID: 32494698 PMCID: PMC7202886 DOI: 10.1126/sciadv.aay6193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 02/13/2020] [Indexed: 05/22/2023]
Abstract
The Tibetan Plateau exerts a major influence on Asian climate, but its long-term environmental history remains largely unknown. We present a detailed record of vegetation and climate changes over the past 1.74 million years in a lake sediment core from the Zoige Basin, eastern Tibetan Plateau. Results show three intervals with different orbital- and millennial-scale features superimposed on a stepwise long-term cooling trend. The interval of 1.74-1.54 million years ago is characterized by an insolation-dominated mode with strong ~20,000-year cyclicity and quasi-absent millennial-scale signal. The interval of 1.54-0.62 million years ago represents a transitional insolation-ice mode marked by ~20,000- and ~40,000-year cycles, with superimposed millennial-scale oscillations. The past 620,000 years are characterized by an ice-driven mode with 100,000-year cyclicity and less frequent millennial-scale variability. A pronounced transition occurred 620,000 years ago, as glacial cycles intensified. These new findings reveal how the interaction of low-latitude insolation and high-latitude ice-volume forcing shaped the evolution of the Tibetan Plateau climate.
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Affiliation(s)
- Yan Zhao
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Polychronis C. Tzedakis
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
| | - Quan Li
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Feng Qin
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaoyu Cui
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Chen Liang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - H. John B. Birks
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
- Department of Biological Sciences and Bjerknes Centre for Climate Research, University of Bergen, PO Box 7803, N-5020 Bergen, Norway
| | - Yaoliang Liu
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiyong Zhang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang 332900, China
| | - Junyi Ge
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Hui Zhao
- Key Laboratory of Desert and Desertification, Cold and Arid Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Vivian A. Felde
- Department of Biological Sciences and Bjerknes Centre for Climate Research, University of Bergen, PO Box 7803, N-5020 Bergen, Norway
| | - Chenglong Deng
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Maotang Cai
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Huan Li
- Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands
| | - Weihe Ren
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Haicheng Wei
- Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
| | - Hanfei Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Jiawu Zhang
- MOE Key Laboratory of Western China’s Environmental Systems, Lanzhou University, Lanzhou 730000, China
| | - Zicheng Yu
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, PA 18015, USA
- Northeast Normal University, Changchun, China
| | - Zhengtang Guo
- University of Chinese Academy of Sciences, Beijing 100049, China
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
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Ancient air challenges prominent explanation for a shift in glacial cycles. Nature 2019; 574:636-637. [DOI: 10.1038/d41586-019-03199-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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