1
|
Aguiar W, Meissner KJ, Montenegro A, Prado L, Wainer I, Carlson AE, Mata MM. Magnitude of the 8.2 ka event freshwater forcing based on stable isotope modelling and comparison to future Greenland melting. Sci Rep 2021; 11:5473. [PMID: 33750824 PMCID: PMC7943769 DOI: 10.1038/s41598-021-84709-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/17/2021] [Indexed: 11/10/2022] Open
Abstract
The northern hemisphere experienced an abrupt cold event ~ 8200 years ago (the 8.2 ka event) that was triggered by the release of meltwater into the Labrador Sea, and resulting in a weakening of the poleward oceanic heat transport. Although this event has been considered a possible analogue for future ocean circulation changes due to the projected Greenland Ice Sheet (GIS) melting, large uncertainties in the amount and rate of freshwater released during the 8.2 ka event make such a comparison difficult. In this study, we compare sea surface temperatures and oxygen isotope ratios from 28 isotope-enabled model simulations with 35 paleoproxy records to constrain the meltwater released during the 8.2 ka event. Our results suggest that a combination of 5.3 m of meltwater in sea level rise equivalent (SLR) released over a thousand years, with a short intensification over ~ 130 years (an additional 2.2 m of equivalent SLR) due to routing of the Canadian river discharge, best reproduces the proxy anomalies. Our estimate is of the same order of magnitude as projected future GIS melting rates under the high emission scenario RCP8.5.
Collapse
Affiliation(s)
- Wilton Aguiar
- Laboratório de Estudos dos Oceanos e Clima, Instituto de Oceanografia, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, 96203-900, Brazil.
| | - Katrin J Meissner
- Climate Change Research Center and ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, Australia
| | - Alvaro Montenegro
- Department of Geography, The Ohio State University, Columbus, OH, 43210, USA
| | - Luciana Prado
- Instituto Oceanográfico, Universidade de São Paulo, São Paulo, 05508-120, Brazil.,Instituto de Geociências, Universidade de Brasília, Brasília, 70297-400, Brazil
| | - Ilana Wainer
- Instituto Oceanográfico, Universidade de São Paulo, São Paulo, 05508-120, Brazil
| | | | - Mauricio M Mata
- Laboratório de Estudos dos Oceanos e Clima, Instituto de Oceanografia, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, 96203-900, Brazil
| |
Collapse
|
2
|
Waelbroeck C, Lougheed BC, Vazquez Riveiros N, Missiaen L, Pedro J, Dokken T, Hajdas I, Wacker L, Abbott P, Dumoulin JP, Thil F, Eynaud F, Rossignol L, Fersi W, Albuquerque AL, Arz H, Austin WEN, Came R, Carlson AE, Collins JA, Dennielou B, Desprat S, Dickson A, Elliot M, Farmer C, Giraudeau J, Gottschalk J, Henderiks J, Hughen K, Jung S, Knutz P, Lebreiro S, Lund DC, Lynch-Stieglitz J, Malaizé B, Marchitto T, Martínez-Méndez G, Mollenhauer G, Naughton F, Nave S, Nürnberg D, Oppo D, Peck V, Peeters FJC, Penaud A, Portilho-Ramos RDC, Repschläger J, Roberts J, Rühlemann C, Salgueiro E, Sanchez Goni MF, Schönfeld J, Scussolini P, Skinner LC, Skonieczny C, Thornalley D, Toucanne S, Rooij DV, Vidal L, Voelker AHL, Wary M, Weldeab S, Ziegler M. Consistently dated Atlantic sediment cores over the last 40 thousand years. Sci Data 2019; 6:165. [PMID: 31477737 PMCID: PMC6718518 DOI: 10.1038/s41597-019-0173-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/08/2019] [Indexed: 11/21/2022] Open
Abstract
Rapid changes in ocean circulation and climate have been observed in marine-sediment and ice cores over the last glacial period and deglaciation, highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in climate and ocean circulation are still not fully explained. One obstacle hindering progress in our understanding of the interactions between past ocean circulation and climate changes is the difficulty of accurately dating marine cores. Here, we present a set of 92 marine sediment cores from the Atlantic Ocean for which we have established age-depth models that are consistent with the Greenland GICC05 ice core chronology, and computed the associated dating uncertainties, using a new deposition modeling technique. This is the first set of consistently dated marine sediment cores enabling paleoclimate scientists to evaluate leads/lags between circulation and climate changes over vast regions of the Atlantic Ocean. Moreover, this data set is of direct use in paleoclimate modeling studies.
Collapse
Affiliation(s)
- Claire Waelbroeck
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France.
| | - Bryan C Lougheed
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
| | - Natalia Vazquez Riveiros
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
- Ifremer, Unité de Geosciences Marines, 29280, Plouzané, France
| | - Lise Missiaen
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
| | - Joel Pedro
- Uni Research, Nygårdsgaten 112, 5008, Bergen, Norway
| | - Trond Dokken
- Uni Research, Nygårdsgaten 112, 5008, Bergen, Norway
| | - Irka Hajdas
- Laboratory of Ion Beam Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Lukas Wacker
- Laboratory of Ion Beam Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Peter Abbott
- School of Earth and Ocean Sciences, Cardiff University, CF10 3AT, Cardiff, UK
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Jean-Pascal Dumoulin
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
- LMC14, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
| | - François Thil
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
| | - Frédérique Eynaud
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | - Linda Rossignol
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | - Wiem Fersi
- LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91191, Orme des Merisiers, France
| | | | - Helge Arz
- Leibniz-Institute for Baltic Sea Research Warnemünde, Seestrasse 15, 18119, Rostock, Germany
| | | | - Rosemarie Came
- University of New Hampshire, 56 College Road, Durham, NH, 03824, USA
| | | | | | | | - Stéphanie Desprat
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
- Ecole Pratique des Hautes Etudes (EPHE, PSL), 4-14 rue Ferrus, 75014, Paris, France
| | - Alex Dickson
- Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Mary Elliot
- LPG-Nantes, Université de Nantes, 44300, Nantes, France
| | | | - Jacques Giraudeau
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | - Julia Gottschalk
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W - PO Box 1000, Palisades, NY, 10964-1000, USA
| | | | - Konrad Hughen
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd., Woods Hole, MA, 02543-1050, USA
| | - Simon Jung
- University of Edinburgh, School of Geosciences, Edinburgh, EH9 3FE, UK
| | - Paul Knutz
- Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350, Copenhagen, Denmark
| | - Susana Lebreiro
- IGME - Instituto Geológico y Minero de España, Calle Ríos Rosas, 23, 28003, Madrid, Spain
| | - David C Lund
- University of Connecticut, 1080 Shennecossett Road, Groton, CT, 06340, USA
| | | | - Bruno Malaizé
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | | | | | | | - Filipa Naughton
- IPMA-DivGM, Avenida Doutor Alfredo Magalhães Ramalho, 6, 1495-165, Alges, Portugal
- CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Silvia Nave
- LNEG, Bairro do Zambujal, 2610-999, Amadora, Portugal
| | | | - Delia Oppo
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd., Woods Hole, MA, 02543-1050, USA
| | - Victoria Peck
- UK British Antarctic Survey, Madingley Road, Cambridge, CB3 0ET, UK
| | - Frank J C Peeters
- Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV, Amsterdam, Netherlands
| | - Aurélie Penaud
- Université de Bretragne Occidentale, Technopôle Brest-Iroise, 29280, Plouzané, France
| | | | | | - Jenny Roberts
- Thermo Fisher Scientific, Hanna-Kunath Straße 11, Bremen, 28199, Germany
| | | | - Emilia Salgueiro
- IPMA-DivGM, Avenida Doutor Alfredo Magalhães Ramalho, 6, 1495-165, Alges, Portugal
- CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Maria Fernanda Sanchez Goni
- EPOC, Université Bordeaux, Allée Geoffroy St Hilaire, 33615, Pessac, France
- Ecole Pratique des Hautes Etudes (EPHE, PSL), 4-14 rue Ferrus, 75014, Paris, France
| | | | - Paolo Scussolini
- Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV, Amsterdam, Netherlands
| | - Luke C Skinner
- University of Cambridge, Godwin Laboratory for Palaeoclimate Research, Cambridge, CB2 3EQ, UK
| | | | | | - Samuel Toucanne
- Ifremer, Unité de Geosciences Marines, 29280, Plouzané, France
| | | | - Laurence Vidal
- Aix-Marseille Université, CNRS, IRD, INRA, Coll France, CEREGE, Europole de l'Arbois, 13545, Aix-en-Provence, France
| | - Antje H L Voelker
- IPMA-DivGM, Avenida Doutor Alfredo Magalhães Ramalho, 6, 1495-165, Alges, Portugal
- CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Mélanie Wary
- ICTA, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Syee Weldeab
- University of California Santa Barbara, Santa Barbara, 1006 Webb Hall, CA, 93106-9630, USA
| | - Martin Ziegler
- University of Utrecht, Princetonlaan 8a, 3584 CB, Utrecht, Netherlands
| |
Collapse
|
3
|
Dutton A, Carlson AE, Long AJ, Milne GA, Clark PU, DeConto R, Horton BP, Rahmstorf S, Raymo ME. SEA-LEVEL RISE. Sea-level rise due to polar ice-sheet mass loss during past warm periods. Science 2015; 349:aaa4019. [PMID: 26160951 DOI: 10.1126/science.aaa4019] [Citation(s) in RCA: 403] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo-sea level records.
Collapse
Affiliation(s)
- A Dutton
- Department of Geological Sciences, University of Florida,Gainesville, FL 32611, USA.
| | - A E Carlson
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - A J Long
- Department of Geography, Durham University, Durham, UK
| | - G A Milne
- Department of Earth Sciences, University of Ottawa, Ottawa, Canada
| | - P U Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - R DeConto
- Department of Geosciences, University of Massachusetts, Amherst, MA 01003, USA
| | - B P Horton
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901, USA. Earth Observatory of Singapore, Nanyang Technological University, Singapore, 639798
| | - S Rahmstorf
- Potsdam Institute for Climate Impact Research, Potsdam, Germany
| | - M E Raymo
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
| |
Collapse
|
4
|
Buizert C, Gkinis V, Severinghaus JP, He F, Lecavalier BS, Kindler P, Leuenberger M, Carlson AE, Vinther B, Masson-Delmotte V, White JWC, Liu Z, Otto-Bliesner B, Brook EJ. Greenland temperature response to climate forcing during the last deglaciation. Science 2014; 345:1177-80. [PMID: 25190795 DOI: 10.1126/science.1254961] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Greenland ice core water isotopic composition (δ(18)O) provides detailed evidence for abrupt climate changes but is by itself insufficient for quantitative reconstruction of past temperatures and their spatial patterns. We investigate Greenland temperature evolution during the last deglaciation using independent reconstructions from three ice cores and simulations with a coupled ocean-atmosphere climate model. Contrary to the traditional δ(18)O interpretation, the Younger Dryas period was 4.5° ± 2°C warmer than the Oldest Dryas, due to increased carbon dioxide forcing and summer insolation. The magnitude of abrupt temperature changes is larger in central Greenland (9° to 14°C) than in the northwest (5° to 9°C), fingerprinting a North Atlantic origin. Simulated changes in temperature seasonality closely track changes in the Atlantic overturning strength and support the hypothesis that abrupt climate change is mostly a winter phenomenon.
Collapse
Affiliation(s)
- Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
| | - Vasileios Gkinis
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093, USA
| | - Feng He
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA
| | - Benoit S Lecavalier
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Canada
| | - Philippe Kindler
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Markus Leuenberger
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Anders E Carlson
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Bo Vinther
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark
| | - Valérie Masson-Delmotte
- Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre Simon Laplace (UMR CEA-CNRS-UVSQ 8212), Gif-sur-Yvette, France
| | - James W C White
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Zhengyu Liu
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA. Laboratory for Climate and Ocean-Atmosphere Studies, Peking University, Beijing 100871, China
| | - Bette Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307, USA
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| |
Collapse
|
5
|
He F, Shakun JD, Clark PU, Carlson AE, Liu Z, Otto-Bliesner BL, Kutzbach JE. Northern Hemisphere forcing of Southern Hemisphere climate during the last deglaciation. Nature 2013; 494:81-5. [PMID: 23389542 DOI: 10.1038/nature11822] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/27/2012] [Indexed: 11/09/2022]
Abstract
According to the Milankovitch theory, changes in summer insolation in the high-latitude Northern Hemisphere caused glacial cycles through their impact on ice-sheet mass balance. Statistical analyses of long climate records supported this theory, but they also posed a substantial challenge by showing that changes in Southern Hemisphere climate were in phase with or led those in the north. Although an orbitally forced Northern Hemisphere signal may have been transmitted to the Southern Hemisphere, insolation forcing can also directly influence local Southern Hemisphere climate, potentially intensified by sea-ice feedback, suggesting that the hemispheres may have responded independently to different aspects of orbital forcing. Signal processing of climate records cannot distinguish between these conditions, however, because the proposed insolation forcings share essentially identical variability. Here we use transient simulations with a coupled atmosphere-ocean general circulation model to identify the impacts of forcing from changes in orbits, atmospheric CO(2) concentration, ice sheets and the Atlantic meridional overturning circulation (AMOC) on hemispheric temperatures during the first half of the last deglaciation (22-14.3 kyr BP). Although based on a single model, our transient simulation with only orbital changes supports the Milankovitch theory in showing that the last deglaciation was initiated by rising insolation during spring and summer in the mid-latitude to high-latitude Northern Hemisphere and by terrestrial snow-albedo feedback. The simulation with all forcings best reproduces the timing and magnitude of surface temperature evolution in the Southern Hemisphere in deglacial proxy records. AMOC changes associated with an orbitally induced retreat of Northern Hemisphere ice sheets is the most plausible explanation for the early Southern Hemisphere deglacial warming and its lead over Northern Hemisphere temperature; the ensuing rise in atmospheric CO(2) concentration provided the critical feedback on global deglaciation.
Collapse
Affiliation(s)
- Feng He
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
| | | | | | | | | | | | | |
Collapse
|
6
|
Clark PU, Shakun JD, Baker PA, Bartlein PJ, Brewer S, Brook E, Carlson AE, Cheng H, Kaufman DS, Liu Z, Marchitto TM, Mix AC, Morrill C, Otto-Bliesner BL, Pahnke K, Russell JM, Whitlock C, Adkins JF, Blois JL, Clark J, Colman SM, Curry WB, Flower BP, He F, Johnson TC, Lynch-Stieglitz J, Markgraf V, McManus J, Mitrovica JX, Moreno PI, Williams JW. Global climate evolution during the last deglaciation. Proc Natl Acad Sci U S A 2012; 109:E1134-42. [PMID: 22331892 PMCID: PMC3358890 DOI: 10.1073/pnas.1116619109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of ice sheets caused global mean sea level to rise by approximately 80 m; terrestrial and marine ecosystems experienced large disturbances and range shifts; perturbations to the carbon cycle resulted in a net release of the greenhouse gases CO(2) and CH(4) to the atmosphere; and changes in atmosphere and ocean circulation affected the global distribution and fluxes of water and heat. Here we summarize a major effort by the paleoclimate research community to characterize these changes through the development of well-dated, high-resolution records of the deep and intermediate ocean as well as surface climate. Our synthesis indicates that the superposition of two modes explains much of the variability in regional and global climate during the last deglaciation, with a strong association between the first mode and variations in greenhouse gases, and between the second mode and variations in the Atlantic meridional overturning circulation.
Collapse
Affiliation(s)
- Peter U. Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Jeremy D. Shakun
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Paul A. Baker
- Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708
| | | | - Simon Brewer
- Department of Geography, University of Utah, Salt Lake City, UT 84112
| | - Ed Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Anders E. Carlson
- Department of Geoscience, University of Wisconsin, Madison, WI 53706
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Hai Cheng
- Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China
- Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
| | - Darrell S. Kaufman
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Zhengyu Liu
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Laboratory for Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China
| | - Thomas M. Marchitto
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309
| | - Alan C. Mix
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Carrie Morrill
- National Oceanic and Atmospheric Administration National Climatic Data Center, Boulder, CO 80305
| | - Bette L. Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307
| | - Katharina Pahnke
- Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822
| | - James M. Russell
- Department of Geological Sciences, Brown University, Providence, RI 02912
| | - Cathy Whitlock
- Department of Earth Sciences, Montana State University, Bozeman, MT 97403
| | - Jess F. Adkins
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Jessica L. Blois
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Department of Geography, University of Wisconsin, Madison, WI 53706
| | - Jorie Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Steven M. Colman
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - William B. Curry
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Ben P. Flower
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701
| | - Feng He
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Thomas C. Johnson
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - Jean Lynch-Stieglitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332
| | - Vera Markgraf
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Jerry McManus
- Lamont-Doherty Earth Observatory, Palisades, NY 10964; and
| | - Jerry X. Mitrovica
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Patricio I. Moreno
- Institute of Ecology and Biodiversity and Department of Ecological Sciences, Universidad de Chile, Santiago 1058, Chile
| | - John W. Williams
- Department of Geography, University of Wisconsin, Madison, WI 53706
| |
Collapse
|
7
|
Abstract
We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level approximately 14.5 ka.
Collapse
Affiliation(s)
- Peter U Clark
- Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Liu Z, Otto-Bliesner BL, He F, Brady EC, Tomas R, Clark PU, Carlson AE, Lynch-Stieglitz J, Curry W, Brook E, Erickson D, Jacob R, Kutzbach J, Cheng J. Transient simulation of last deglaciation with a new mechanism for Bolling-Allerod warming. Science 2009; 325:310-4. [PMID: 19608916 DOI: 10.1126/science.1171041] [Citation(s) in RCA: 688] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We conducted the first synchronously coupled atmosphere-ocean general circulation model simulation from the Last Glacial Maximum to the Bølling-Allerød (BA) warming. Our model reproduces several major features of the deglacial climate evolution, suggesting a good agreement in climate sensitivity between the model and observations. In particular, our model simulates the abrupt BA warming as a transient response of the Atlantic meridional overturning circulation (AMOC) to a sudden termination of freshwater discharge to the North Atlantic before the BA. In contrast to previous mechanisms that invoke AMOC multiple equilibrium and Southern Hemisphere climate forcing, we propose that the BA transition is caused by the superposition of climatic responses to the transient CO(2) forcing, the AMOC recovery from Heinrich Event 1, and an AMOC overshoot.
Collapse
Affiliation(s)
- Z Liu
- Key Laboratory of Meteorological Disaster, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Carlson AE, Clark PU, Haley BA, Klinkhammer GP, Simmons K, Brook EJ, Meissner KJ. Geochemical proxies of North American freshwater routing during the Younger Dryas cold event. Proc Natl Acad Sci U S A 2007; 104:6556-61. [PMID: 17420461 PMCID: PMC1871824 DOI: 10.1073/pnas.0611313104] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from approximately 12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (DeltaMg/Ca, U/Ca, and (87)Sr/(86)Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic delta(18)O(seawater) and delta(13)C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 +/- 0.02 Sverdrup (1 Sverdrup = 10(6) m(3).s(-1)). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of approximately 0.06-0.12 Sverdrup, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.
Collapse
Affiliation(s)
- Anders E Carlson
- Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
| | | | | | | | | | | | | |
Collapse
|