1
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Riehl S, Karakaya D, Zeidi M, Conard NJ. Contextualizing wild cereal harvesting at Middle Palaeolithic Ghar-e Boof in the southern Zagros. Sci Rep 2024; 14:18748. [PMID: 39138229 PMCID: PMC11322544 DOI: 10.1038/s41598-024-69056-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/31/2024] [Indexed: 08/15/2024] Open
Abstract
A stratigraphic sequence from Ghar-e Boof, a cave site in Iran, covering a period of c. 80,000-30,000 BP and containing more than 20,000 seed and chaff remains, allows a detailed study of the use of annual seed species of Palaeolithic hunter-gatherer groups and its evolution under the influence of changing environmental conditions. Taxonomic changes in the archaeobotanical assemblage and the stable carbon isotope data of pistachio support a considerable change in environmental conditions over the sequence from MIS 5a to MIS 3. The exceptional dominance of wild ancestors of modern crop species, including glume wheat and large-seeded legumes from Middle Palaeolithic layers AH VI (OSL ranges 72-81 ka BP), coincides broadly with the transition from MIS 5a to MIS 4. With the beginning of MIS 4 these taxa are strongly reduced, corresponding with a strong decrease in global CO2 concentrations and in the Δ13C values of Pistacia khinjuk/atlantica from the site. Wild glume wheat completely disappears after Middle Palaeolithic AH Vb and never reappears at the site. We hypothesize that the Middle Palaeolithic niche that allowed the harvesting and consumption of wild cereals and legumes ended with a destabilization of the vegetation in early MIS 4.
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Affiliation(s)
- Simone Riehl
- Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen, Hölderlinstrasse 23, 72070, Tübingen, Germany.
- Institute for Archaeological Sciences, University of Tübingen, Hölderlinstrasse 12, 72070, Tübingen, Germany.
| | - Doğa Karakaya
- Institute for Archaeological Sciences, University of Tübingen, Hölderlinstrasse 12, 72070, Tübingen, Germany
- Department of Cultures, Faculty of Arts, University of Helsinki, Fabianinkatu 24A, 00014, Helsinki, Finland
| | - Mohsen Zeidi
- Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen, Hölderlinstrasse 23, 72070, Tübingen, Germany
- Abteilung für Ältere Urgeschichte und Quartärökologie, Institut für Ur-und Frühgeschichte und Archäologie des Mittelalters, Universität Tübingen, Schloss Hohentübingen, 72070, Tübingen, Germany
| | - Nicholas J Conard
- Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen, Hölderlinstrasse 23, 72070, Tübingen, Germany
- Institute for Archaeological Sciences, University of Tübingen, Hölderlinstrasse 12, 72070, Tübingen, Germany
- Abteilung für Ältere Urgeschichte und Quartärökologie, Institut für Ur-und Frühgeschichte und Archäologie des Mittelalters, Universität Tübingen, Schloss Hohentübingen, 72070, Tübingen, Germany
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2
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Pérez-Jiménez M, Corona H, de la Cruz-Martínez F, Campos J. Donor-Acceptor Activation of Carbon Dioxide. Chemistry 2023; 29:e202301428. [PMID: 37494303 DOI: 10.1002/chem.202301428] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/23/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023]
Abstract
The activation and functionalization of carbon dioxide entails great interest related to its abundance, low toxicity and associated environmental problems. However, the inertness of CO2 has posed a challenge towards its efficient conversion to added-value products. In this review we discuss one of the strategies that have been widely used to capture and activate carbon dioxide, namely the use of donor-acceptor interactions by partnering a Lewis acidic and a Lewis basic fragment. This type of CO2 activation resembles that found in metalloenzymes, whose outstanding performance in catalytically transforming carbon dioxide encourages further bioinspired research. We have divided this review into three general sections based on the nature of the active sites: metal-free examples (mainly formed by frustrated Lewis pairs), main group-transition metal combinations, and transition metal heterobimetallic complexes. Overall, we discuss one hundred compounds that cooperatively activate carbon dioxide by donor-acceptor interactions, revealing a wide range of structural motifs.
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Affiliation(s)
- Marina Pérez-Jiménez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Helena Corona
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Felipe de la Cruz-Martínez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Jesús Campos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 49, 41092, Sevilla, Spain
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3
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Zhao C, Rohling EJ, Liu Z, Yang X, Zhang E, Cheng J, Liu Z, An Z, Yang X, Feng X, Sun X, Zhang C, Yan T, Long H, Yan H, Yu Z, Liu W, Yu SY, Shen J. Possible obliquity-forced warmth in southern Asia during the last glacial stage. Sci Bull (Beijing) 2021; 66:1136-1145. [PMID: 36654347 DOI: 10.1016/j.scib.2020.11.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 01/20/2023]
Abstract
Orbital-scale global climatic changes during the late Quaternary are dominated by high-latitude influenced ~100,000-year global ice-age cycles and monsoon influenced ~23,000-year low-latitude hydroclimate variations. However, the shortage of highly-resolved land temperature records remains a limiting factor for achieving a comprehensive understanding of long-term low-latitude terrestrial climatic changes. Here, we report paired mean annual air temperature (MAAT) and monsoon intensity proxy records over the past 88,000 years from Lake Tengchongqinghai in southwestern China. While summer monsoon intensity follows the ~23,000-year precession beat found also in previous studies, we identify previously unrecognized warm periods at 88,000-71,000 and 45,000-22,000 years ago, with 2-3 °C amplitudes that are close to our recorded full glacial-interglacial range. Using advanced transient climate simulations and comparing with forcing factors, we find that these warm periods in our MAAT record probably depends on local annual mean insolation, which is controlled by Earth's ~41,000-year obliquity cycles and is anti-phased to annual mean insolation at high latitudes. The coincidence of our identified warm periods and intervals of high-frequent dated archaeological evidence highlights the importance of temperature on anatomically modern humans in Asia during the last glacial stage.
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Affiliation(s)
- Cheng Zhao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China; School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China.
| | - Eelco J Rohling
- Research School of Earth Sciences, the Australian National University, Canberra ACT 2601, Australia; Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - Zhengyu Liu
- Department of Geography, Ohio State University, Columbus 43210, USA
| | - Xiaoqiang Yang
- Department of Earth Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Enlou Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
| | - Jun Cheng
- Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhonghui Liu
- Department of Earth Sciences, University of Hong Kong, Hong Kong 999077, China
| | - Zhisheng An
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Xiangdong Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaoping Feng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaoshuang Sun
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Can Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Tianlong Yan
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Hao Long
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hong Yan
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Zicheng Yu
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem 18015, USA; Institute for Peat and Mire Research, School of Geographical Sciences, Northeast Normal University, Changchun 130024, China
| | - Weiguo Liu
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Shi-Yong Yu
- School of Geography, Geomatics, and Planning, Jiangsu Normal University, Xuzhou 221116, China
| | - Ji Shen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China.
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4
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He C, Liu Z, Otto-Bliesner BL, Brady EC, Zhu C, Tomas R, Buizert C, Severinghaus JP. Abrupt Heinrich Stadial 1 cooling missing in Greenland oxygen isotopes. SCIENCE ADVANCES 2021; 7:7/25/eabh1007. [PMID: 34134984 PMCID: PMC8208719 DOI: 10.1126/sciadv.abh1007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/29/2021] [Indexed: 05/10/2023]
Abstract
Abrupt climate changes during the last deglaciation have been well preserved in proxy records across the globe. However, one long-standing puzzle is the apparent absence of the onset of the Heinrich Stadial 1 (HS1) cold event around 18 ka in Greenland ice core oxygen isotope δ18 O records, inconsistent with other proxies. Here, combining proxy records with an isotope-enabled transient deglacial simulation, we propose that a substantial HS1 cooling onset did indeed occur over the Arctic in winter. However, this cooling signal in the depleted oxygen isotopic composition is completely compensated by the enrichment because of the loss of winter precipitation in response to sea ice expansion associated with AMOC slowdown during extreme glacial climate. In contrast, the Arctic summer warmed during HS1 and YD because of increased insolation and greenhouse gases, consistent with snowline reconstructions. Our work suggests that Greenland δ18 O may substantially underestimate temperature variability during cold glacial conditions.
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Affiliation(s)
- Chengfei He
- College of Atmospheric Sciences, Nanjing University of Information Science and Technology, Nanjing, China
- Department of Geography, The Ohio State University, Columbus, OH 43210, USA
- Open Studio for Ocean-Climate-Isotope Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhengyu Liu
- Department of Geography, The Ohio State University, Columbus, OH 43210, USA.
- College of Geography Sciences, Nanjing Normal University, Nanjing, China
| | - Bette L Otto-Bliesner
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Esther C Brady
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Chenyu Zhu
- Open Studio for Ocean-Climate-Isotope Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, China
| | - Robert Tomas
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA
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5
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Vegetation feedback causes delayed ecosystem response to East Asian Summer Monsoon Rainfall during the Holocene. Nat Commun 2021; 12:1843. [PMID: 33758179 PMCID: PMC7988120 DOI: 10.1038/s41467-021-22087-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 02/26/2021] [Indexed: 12/25/2022] Open
Abstract
One long-standing issue in the paleoclimate records is whether East Asian Summer Monsoon peaked in the early Holocene or mid-Holocene. Here, combining a set of transient earth system model simulations with proxy records, we propose that, over northern China, monsoon rainfall peaked in the early Holocene, while soil moisture and tree cover peaked in the mid-Holocene. The delayed ecosystem (soil moisture and tree cover) response to rainfall is caused by the vegetation response to winter warming and the subsequent feedback with soil moisture. Our study provides a mechanism for reconciling different evolution behaviors of monsoon proxy records; it sheds light on the driving mechanism of the monsoon evolution and monsoon-ecosystem feedback over northern China, with implications to climate changes in other high climate sensitivity regions over the globe.
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6
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Brown SC, Wigley TML, Otto-Bliesner BL, Fordham DA. StableClim, continuous projections of climate stability from 21000 BP to 2100 CE at multiple spatial scales. Sci Data 2020; 7:335. [PMID: 33046711 PMCID: PMC7550347 DOI: 10.1038/s41597-020-00663-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/31/2020] [Indexed: 11/17/2022] Open
Abstract
Paleoclimatic data are used in eco-evolutionary models to improve knowledge of biogeographical processes that drive patterns of biodiversity through time, opening windows into past climate–biodiversity dynamics. Applying these models to harmonised simulations of past and future climatic change can strengthen forecasts of biodiversity change. StableClim provides continuous estimates of climate stability from 21,000 years ago to 2100 C.E. for ocean and terrestrial realms at spatial scales that include biogeographic regions and climate zones. Climate stability is quantified using annual trends and variabilities in air temperature and precipitation, and associated signal-to-noise ratios. Thresholds of natural variability in trends in regional- and global-mean temperature allow periods in Earth’s history when climatic conditions were warming and cooling rapidly (or slowly) to be identified and climate stability to be estimated locally (grid-cell) during these periods of accelerated change. Model simulations are validated against independent paleoclimate and observational data. Projections of climatic stability, accessed through StableClim, will improve understanding of the roles of climate in shaping past, present-day and future patterns of biodiversity. Measurement(s) | climate change • climate • temperature of air • volume of hydrological precipitation | Technology Type(s) | computational modeling technique • digital curation | Factor Type(s) | timing of temperature and precipitation estimates | Sample Characteristic - Environment | climate system | Sample Characteristic - Location | Earth (planet) |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12831935
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Affiliation(s)
- Stuart C Brown
- The Environment Institute and School of Biological Sciences, University of Adelaide, South Australia, 5005, Australia.
| | - Tom M L Wigley
- The Environment Institute and School of Biological Sciences, University of Adelaide, South Australia, 5005, Australia.,Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, 80307-3000, USA
| | - Bette L Otto-Bliesner
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, 80307-3000, USA
| | - Damien A Fordham
- The Environment Institute and School of Biological Sciences, University of Adelaide, South Australia, 5005, Australia
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7
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Oceanic forcing of penultimate deglacial and last interglacial sea-level rise. Nature 2020; 577:660-664. [PMID: 31996820 DOI: 10.1038/s41586-020-1931-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 11/09/2019] [Indexed: 11/08/2022]
Abstract
Sea-level histories during the two most recent deglacial-interglacial intervals show substantial differences1-3 despite both periods undergoing similar changes in global mean temperature4,5 and forcing from greenhouse gases6. Although the last interglaciation (LIG) experienced stronger boreal summer insolation forcing than the present interglaciation7, understanding why LIG global mean sea level may have been six to nine metres higher than today has proven particularly challenging2. Extensive areas of polar ice sheets were grounded below sea level during both glacial and interglacial periods, with grounding lines and fringing ice shelves extending onto continental shelves8. This suggests that oceanic forcing by subsurface warming may also have contributed to ice-sheet loss9-12 analogous to ongoing changes in the Antarctic13,14 and Greenland15 ice sheets. Such forcing would have been especially effective during glacial periods, when the Atlantic Meridional Overturning Circulation (AMOC) experienced large variations on millennial timescales16, with a reduction of the AMOC causing subsurface warming throughout much of the Atlantic basin9,12,17. Here we show that greater subsurface warming induced by the longer period of reduced AMOC during the penultimate deglaciation can explain the more-rapid sea-level rise compared with the last deglaciation. This greater forcing also contributed to excess loss from the Greenland and Antarctic ice sheets during the LIG, causing global mean sea level to rise at least four metres above modern levels. When accounting for the combined influences of penultimate and LIG deglaciation on glacial isostatic adjustment, this excess loss of polar ice during the LIG can explain much of the relative sea level recorded by fossil coral reefs and speleothems at intermediate- and far-field sites.
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8
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Calder WJ, Shuman B. Detecting past changes in vegetation resilience in the context of a changing climate. Biol Lett 2019; 15:20180768. [PMID: 30836887 DOI: 10.1098/rsbl.2018.0768] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Anthropogenic climate change is continuously altering ecological responses to disturbance and must be accounted for when examining ecological resilience. One way to measure resilience in ecological datasets is by considering the amount and duration of change from a baseline created by perturbations, such as disturbances like wildfire. Recovery occurs when ecological conditions return to equilibrium, meaning that no subsequent changes can be attributed to the effects of the disturbance, but climate change often causes the recovered state to differ from the previous baseline. The palaeoecological record provides an opportunity to examine these expectations because palaeoclimates changed continuously; few periods existed when environmental conditions were stationary. Here we demonstrate a framework for examining resilience in palaeoecological records against the backdrop of a non-stationary climate by considering resilience as two components of (i) resistance (magnitude of change) and (ii) recovery (time required to return) to predicted equilibrium values. Measuring these components of resilience in palaeoecological records requires high-resolution fossil (e.g. pollen) records, local palaeoclimate reconstructions, a model to predict ecological change in response to climate change, and disturbance records measured at the same spatial scale as the ecological (e.g. vegetation history) record. Resistance following disturbance is measured as the deviation of the fossil record from the ecological state predicted by the palaeoclimate records, and recovery time is measured as the time required for the fossil record to return to predicted values. We show that some cases may involve nearly persistent equilibrium despite large climate changes, but that others can involve a shift to a new state without any complete recovery.
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Affiliation(s)
- W John Calder
- 1 Department of Botany, University of Wyoming , Laramie, WY , USA
| | - Bryan Shuman
- 2 Department of Geology and Geophysics, University of Wyoming , Laramie, WY , USA
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9
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Hudson AM, Hatchett BJ, Quade J, Boyle DP, Bassett SD, Ali G, De Los Santos MG. North-south dipole in winter hydroclimate in the western United States during the last deglaciation. Sci Rep 2019; 9:4826. [PMID: 30886192 PMCID: PMC6423015 DOI: 10.1038/s41598-019-41197-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 03/05/2019] [Indexed: 11/30/2022] Open
Abstract
During the termination of the last glacial period the western U.S. experienced exceptionally wet conditions, driven by changes in location and strength of the mid-latitude winter storm track. The distribution of modern winter precipitation is frequently characterized by a north-south wet/dry dipole pattern, controlled by interaction of the storm track with ocean-atmosphere conditions over the Pacific and Atlantic Oceans. Here we show that a dipole pattern of similar geographic extent persisted and switched sign during millennial-scale abrupt climate changes of the last deglaciation, based on a new lake level reconstruction for pluvial Lake Chewaucan (northwestern U.S.), and a compilation of regional paleoclimate records. This suggests the dipole pattern is robust, and one mode may be favored for centuries, thereby creating persistent contrasting wet/dry conditions across the western U.S. The TraCE-21k climate model simulation shows an equatorward enhancement of winter storm track activity in the northeastern Pacific, favoring wet conditions in southwestern U.S. during the second half of Heinrich Stadial 1 (16.1–14.6 ka) and consistent with paleoclimate evidence. During the Bølling/Allerød (14.6–12.8 ka), the northeastern Pacific storm track contracted poleward, consistent with wetter conditions concentrated poleward toward the northwest U.S.
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Affiliation(s)
| | - Benjamin J Hatchett
- Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA.,Western Regional Climate Center, Reno, Nevada, USA
| | - Jay Quade
- Department of Geosciences, University of Arizona, Tucson, Arizona, USA
| | - Douglas P Boyle
- Department of Geography, University of Nevada-Reno, Reno, Nevada, USA
| | - Scott D Bassett
- Department of Geography, University of Nevada-Reno, Reno, Nevada, USA
| | - Guleed Ali
- Climate Change Institute, University of Maine, Orono, Maine, USA
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10
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Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period. Proc Natl Acad Sci U S A 2019; 116:4099-4104. [PMID: 30760586 PMCID: PMC6410777 DOI: 10.1073/pnas.1807261116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Dansgaard–Oeschger events contained in Greenland ice cores constitute the archetypal record of abrupt climate change. An accurate understanding of these events hinges on interpretation of Greenland records of oxygen and nitrogen isotopes. We present here the important results from a suite of modeled Dansgaard–Oeschger events. These simulations show that the change in oxygen isotope per degree of warming becomes smaller during larger events. Abrupt reductions in sea ice also emerge as a strong control on ice core oxygen isotopes because of the influence on both the moisture source and the regional temperature increase. This work confirms the significance of sea ice for past abrupt warming events. Greenland ice cores provide excellent evidence of past abrupt climate changes. However, there is no universally accepted theory of how and why these Dansgaard–Oeschger (DO) events occur. Several mechanisms have been proposed to explain DO events, including sea ice, ice shelf buildup, ice sheets, atmospheric circulation, and meltwater changes. DO event temperature reconstructions depend on the stable water isotope (δ18O) and nitrogen isotope measurements from Greenland ice cores: interpretation of these measurements holds the key to understanding the nature of DO events. Here, we demonstrate the primary importance of sea ice as a control on Greenland ice core δ18O: 95% of the variability in δ18O in southern Greenland is explained by DO event sea ice changes. Our suite of DO events, simulated using a general circulation model, accurately captures the amplitude of δ18O enrichment during the abrupt DO event onsets. Simulated geographical variability is broadly consistent with available ice core evidence. We find an hitherto unknown sensitivity of the δ18O paleothermometer to the magnitude of DO event temperature increase: the change in δ18O per Kelvin temperature increase reduces with DO event amplitude. We show that this effect is controlled by precipitation seasonality.
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11
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Buizert C, Sigl M, Severi M, Markle BR, Wettstein JJ, McConnell JR, Pedro JB, Sodemann H, Goto-Azuma K, Kawamura K, Fujita S, Motoyama H, Hirabayashi M, Uemura R, Stenni B, Parrenin F, He F, Fudge TJ, Steig EJ. Abrupt ice-age shifts in southern westerly winds and Antarctic climate forced from the north. Nature 2018; 563:681-685. [DOI: 10.1038/s41586-018-0727-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/12/2018] [Indexed: 11/09/2022]
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12
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Instability of the Northeast Greenland Ice Stream over the last 45,000 years. Nat Commun 2018; 9:1872. [PMID: 29760384 PMCID: PMC5951810 DOI: 10.1038/s41467-018-04312-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/20/2018] [Indexed: 11/16/2022] Open
Abstract
The sensitivity of the Northeast Greenland Ice Stream (NEGIS) to prolonged warm periods is largely unknown and geological records documenting such long-term changes are needed to place current observations in perspective. Here we use cosmogenic surface exposure and radiocarbon ages to determine the magnitude of NEGIS margin fluctuations over the last 45 kyr (thousand years). We find that the NEGIS experienced slow early Holocene ice-margin retreat of 30–40 m a−1, likely as a result of the buttressing effect of sea-ice or shelf-ice. The NEGIS was ~20–70 km behind its present ice-extent ~41–26 ka and ~7.8–1.2 ka; both periods of high orbital precession index and/or summer temperatures within the projected warming for the end of this century. We show that the NEGIS was smaller than present for approximately half of the last ~45 kyr and is susceptible to subtle changes in climate, which has implications for future stability of this ice stream. The outlet glaciers that comprise the Northeast Greenland Ice Stream (NEGIS) have experienced accelerated retreat in recent years, yet their longterm stability remains unclear. Here, via cosmogenic surface exposure and radiocarbon ages, the authors investigate the stability of the NEGIS for the past 45 kyr.
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Schenk F, Väliranta M, Muschitiello F, Tarasov L, Heikkilä M, Björck S, Brandefelt J, Johansson AV, Näslund JO, Wohlfarth B. Warm summers during the Younger Dryas cold reversal. Nat Commun 2018; 9:1634. [PMID: 29691388 PMCID: PMC5915408 DOI: 10.1038/s41467-018-04071-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 03/29/2018] [Indexed: 11/26/2022] Open
Abstract
The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons. Mechanisms causing the Younger Dryas cold reversal have been questioned by inconsistencies between proxy and modelling results. Here, the authors show that the concept of a strong North Atlantic Ocean cooling event as major driver is consistent with warm European summers caused by intensified atmospheric blocking.
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Affiliation(s)
- Frederik Schenk
- Bolin Centre for Climate Research and Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, SE106-91, Stockholm, Sweden. .,Department of Mechanics, Linné FLOW Centre, KTH Royal Institute of Technology, Osquars backe 18, SE100-44, Stockholm, Sweden.
| | - Minna Väliranta
- Environmental Change Research Unit (ECRU), Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, P.O. Box 65, 00014, Helsinki, Finland
| | - Francesco Muschitiello
- Bolin Centre for Climate Research and Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, SE106-91, Stockholm, Sweden.,Department of Geography, University of Cambridge, Cambridge, CB2 3EN, UK.,Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9 W, Palisades, New York, NY, 10964-8000, USA
| | - Lev Tarasov
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada
| | - Maija Heikkilä
- Environmental Change Research Unit (ECRU), Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, P.O. Box 65, 00014, Helsinki, Finland
| | - Svante Björck
- Bolin Centre for Climate Research and Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, SE106-91, Stockholm, Sweden.,Department of Geology, Quaternary Sciences, Lund University, Box 117, SE221-00, Lund, Sweden
| | - Jenny Brandefelt
- Swedish Nuclear Fuel and Waste Management Company (SKB), Box 250, SE101-24, Stockholm, Sweden
| | - Arne V Johansson
- Department of Mechanics, Linné FLOW Centre, KTH Royal Institute of Technology, Osquars backe 18, SE100-44, Stockholm, Sweden
| | - Jens-Ove Näslund
- Swedish Nuclear Fuel and Waste Management Company (SKB), Box 250, SE101-24, Stockholm, Sweden.,Department of Physical Geography and Quaternary Geology, Stockholm University, Svante Arrhenius väg 8, SE106-91, Stockholm, Sweden
| | - Barbara Wohlfarth
- Bolin Centre for Climate Research and Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, SE106-91, Stockholm, Sweden
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14
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Gregoire LJ, Otto‐Bliesner B, Valdes PJ, Ivanovic R. Abrupt Bølling warming and ice saddle collapse contributions to the Meltwater Pulse 1a rapid sea level rise. GEOPHYSICAL RESEARCH LETTERS 2016; 43:9130-9137. [PMID: 27773954 PMCID: PMC5053285 DOI: 10.1002/2016gl070356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/11/2016] [Accepted: 08/19/2016] [Indexed: 06/06/2023]
Abstract
Elucidating the source(s) of Meltwater Pulse 1a, the largest rapid sea level rise caused by ice melt (14-18 m in less than 340 years, 14,600 years ago), is important for understanding mechanisms of rapid ice melt and the links with abrupt climate change. Here we quantify how much and by what mechanisms the North American ice sheet could have contributed to Meltwater Pulse 1a, by driving an ice sheet model with two transient climate simulations of the last 21,000 years. Ice sheet perturbed physics ensembles were run to account for model uncertainties, constraining ice extent and volume with reconstructions of 21,000 years ago to present. We determine that the North American ice sheet produced 3-4 m global mean sea level rise in 340 years due to the abrupt Bølling warming, but this response is amplified to 5-6 m when it triggers the ice sheet saddle collapse.
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Affiliation(s)
| | | | | | - Ruza Ivanovic
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
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15
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Wen X, Liu Z, Wang S, Cheng J, Zhu J. Correlation and anti-correlation of the East Asian summer and winter monsoons during the last 21,000 years. Nat Commun 2016; 7:11999. [PMID: 27328616 PMCID: PMC4917960 DOI: 10.1038/ncomms11999] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 05/19/2016] [Indexed: 11/10/2022] Open
Abstract
Understanding the past significant changes of the East Asia Summer Monsoon (EASM) and Winter Monsoon (EAWM) is critical for improving the projections of future climate over East Asia. One key issue that has remained outstanding from the paleo-climatic records is whether the evolution of the EASM and EAWM are correlated. Here, using a set of long-term transient simulations of the climate evolution of the last 21,000 years, we show that the EASM and EAWM are positively correlated on the orbital timescale in response to the precessional forcing, but are anti-correlated on millennial timescales in response to North Atlantic melt water forcing. The relation between EASM and EAWM can differ dramatically for different timescales because of the different response mechanisms, highlighting the complex dynamics of the East Asian monsoon system and the challenges for future projection. Future projection of changes in the East Asia Summer and Winter Monsoon are hindered by a lack of understanding of past variability. Here, using longterm transient simulations, the authors show that the monsoons respond in phase to precessional forcing, yet out of phase millennial-scale North Atlantic forcing.
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Affiliation(s)
- Xinyu Wen
- Department of Atmospheric and Oceanic Sciences &Laboratory for Climate and Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China
| | - Zhengyu Liu
- Department of Atmospheric and Oceanic Sciences &Laboratory for Climate and Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China.,Department of Atmospheric and Oceanic Sciences &Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, WI 53706, USA
| | - Shaowu Wang
- Department of Atmospheric and Oceanic Sciences &Laboratory for Climate and Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China
| | - Jun Cheng
- Polar Climate System and Global Change Laboratory, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Jiang Zhu
- Department of Atmospheric and Oceanic Sciences &Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, WI 53706, USA
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16
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Otto-Bliesner BL, Russell JM, Clark PU, Liu Z, Overpeck JT, Konecky B, deMenocal P, Nicholson SE, He F, Lu Z. Coherent changes of southeastern equatorial and northern African rainfall during the last deglaciation. Science 2014; 346:1223-7. [PMID: 25477460 DOI: 10.1126/science.1259531] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
During the last deglaciation, wetter conditions developed abruptly ~14,700 years ago in southeastern equatorial and northern Africa and continued into the Holocene. Explaining the abrupt onset and hemispheric coherence of this early African Humid Period is challenging due to opposing seasonal insolation patterns. In this work, we use a transient simulation with a climate model that provides a mechanistic understanding of deglacial tropical African precipitation changes. Our results show that meltwater-induced reduction in the Atlantic meridional overturning circulation (AMOC) during the early deglaciation suppressed precipitation in both regions. Once the AMOC reestablished, wetter conditions developed north of the equator in response to high summer insolation and increasing greenhouse gas (GHG) concentrations, whereas wetter conditions south of the equator were a response primarily to the GHG increase.
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Affiliation(s)
- Bette L Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307-3000, USA.
| | - James M Russell
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, USA
| | - Peter U Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Zhengyu Liu
- Center for Climatic Research and Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA. Laboratory for Climate, Ocean and Atmosphere Studies, School of Physics, Peking University, Beijing 100871, P. R. China
| | - Jonathan T Overpeck
- Department of Geosciences and Institute of the Environment, University of Arizona, Tucson, AZ 85721, USA
| | - Bronwen Konecky
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA. Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Peter deMenocal
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - Sharon E Nicholson
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Feng He
- Center for Climatic Research and Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zhengyao Lu
- Laboratory for Climate, Ocean and Atmosphere Studies, School of Physics, Peking University, Beijing 100871, P. R. China
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17
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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] [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.
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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
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18
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Sime LC. Climate. Greenland deglaciation puzzles. Science 2014; 345:1116-7. [PMID: 25190777 DOI: 10.1126/science.1257842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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