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Matteucci G. Multiple equilibria in a zonal energy balance climate model: The thin ice cap instability. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/93jd01740] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Joussaume S. Paleoclimatic tracers: An investigation using an atmospheric general circulation model under ice age conditions: 1. Desert dust. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92jd01921] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Plio-Pleistocene East African Pulsed Climate Variability and Its Influence on Early Human Evolution. VERTEBRATE PALEOBIOLOGY AND PALEOANTHROPOLOGY 2009. [DOI: 10.1007/978-1-4020-9980-9_13] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Trauth MH, Maslin MA, Deino AL, Strecker MR, Bergner AGN, Dühnforth M. High- and low-latitude forcing of Plio-Pleistocene East African climate and human evolution. J Hum Evol 2007; 53:475-86. [PMID: 17959230 DOI: 10.1016/j.jhevol.2006.12.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 06/08/2006] [Accepted: 12/15/2006] [Indexed: 11/15/2022]
Abstract
The late Cenozoic climate of East Africa is punctuated by episodes of short, alternating periods of extreme wetness and aridity, superimposed on a regime of subdued moisture availability exhibiting a long-term drying trend. These periods of extreme climate variability appear to correlate with maxima in the 400-thousand-year (kyr) component of the Earth's eccentricity cycle. Prior to 2.7 Ma the wet phases appear every 400 kyrs, whereas after 2.7 Ma, the wet phases appear every 800 kyrs, with periods of precessional-forced extreme climate variability at 2.7-2.5 Ma, 1.9-1.7 Ma, and 1.1-0.9 Ma before present. The last three major lake phases occur at the times of major global climatic transitions, such as the onset of Northern Hemisphere Glaciation (2.7-2.5 Ma), intensification of the Walker Circulation (1.9-1.7 Ma), and the Mid-Pleistocene Revolution (1.0-0.7 Ma). High-latitude forcing is required to compress the Intertropical Convergence Zone so that East Africa becomes locally sensitive to precessional forcing, resulting in rapid shifts from wet to dry conditions. These periods of extreme climate variability may have provided a catalyst for evolutionary change and driven key speciation and dispersal events amongst mammals and hominins in East Africa.
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Affiliation(s)
- Martin H Trauth
- Institut für Geowissenschaften, Universität Potsdam, POB 601553, D-14415 Potsdam, Germany.
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Maslin MA, Christensen B. Tectonics, orbital forcing, global climate change, and human evolution in Africa: introduction to the African paleoclimate special volume. J Hum Evol 2007; 53:443-64. [PMID: 17915289 DOI: 10.1016/j.jhevol.2007.06.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 06/15/2007] [Accepted: 06/28/2007] [Indexed: 11/19/2022]
Abstract
The late Cenozoic climate of Africa is a critical component for understanding human evolution. African climate is controlled by major tectonic changes, global climate transitions, and local variations in orbital forcing. We introduce the special African Paleoclimate Issue of the Journal of Human Evolution by providing a background for and synthesis of the latest work relating to the environmental context for human evolution. Records presented in this special issue suggest that the regional tectonics, appearance of C(4) plants in East Africa, and late Cenozoic global cooling combined to produce a long-term drying trend in East Africa. Of particular importance is the uplift associated with the East African Rift Valley formation, which altered wind flow patterns from a more zonal to more meridinal direction. Results in this volume suggest a marked difference in the climate history of southern and eastern Africa, though both are clearly influenced by the major global climate thresholds crossed in the last 3 million years. Papers in this volume present lake, speleothem, and marine paleoclimate records showing that the East African long-term drying trend is punctuated by episodes of short, alternating periods of extreme wetness and aridity. These periods of extreme climate variability are characterized by the precession-forced appearance and disappearance of large, deep lakes in the East African Rift Valley and paralleled by low and high wind-driven dust loads reaching the adjacent ocean basins. Dating of these records show that over the last 3 million years such periods only occur at the times of major global climatic transitions, such as the intensification of Northern Hemisphere Glaciation (2.7-2.5 Ma), intensification of the Walker Circulation (1.9-1.7 Ma), and the Mid-Pleistocene Revolution (1-0.7 Ma). Authors in this volume suggest this onset occurs as high latitude forcing in both Hemispheres compresses the Intertropical Convergence Zone so that East Africa becomes locally sensitive to precessional forcing, resulting in rapid shifts from wet to dry conditions. These periods of extreme climate variability may have provided a catalyst for evolutionary change and driven key speciation and dispersal events amongst mammals and hominins in Africa. In particular, hominin species seem to differentially originate and go extinct during periods of extreme climate variability. Results presented in this volume may represent the basis of a new theory of early human evolution in Africa.
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Affiliation(s)
- Mark A Maslin
- Environmental Change Research Centre, Department of Geography, University College London, UK.
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Vizy EK. Evaluation of Last Glacial Maximum sea surface temperature reconstructions through their influence on South American climate. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005415] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hubert-Ferrari A, Armijo R, King G, Meyer B, Barka A. Morphology, displacement, and slip rates along the North Anatolian Fault, Turkey. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2001jb000393] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aurélia Hubert-Ferrari
- Laboratoire de Tectonique; IPGP; Paris France
- Department of Geosciences; Princeton University; Princeton New Jersey USA
| | - Rolando Armijo
- Laboratoire de Tectonique, Mécanique de la Lithosphère, UMR 7578, CNRS; IPGP; Paris France
| | - Geoffrey King
- Laboratoire de Tectonique, Mécanique de la Lithosphère, UMR 7578, CNRS; IPGP; Paris France
| | - Bertrand Meyer
- Laboratoire de Tectonique, Mécanique de la Lithosphère, UMR 7578, CNRS; IPGP; Paris France
| | - Aykut Barka
- Eurasian Earth Sciences Institute, ITU, Ayazaga; Istanbul Turkey
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Fieg K, Gerdes R. Sensitivity of the thermohaline circulation to modern and glacial surface boundary conditions. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/1999jc000102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Weaver AJ, Eby M, Fanning AF, Wiebe EC. Simulated influence of carbon dioxide, orbital forcing and ice sheets on the climate of the Last Glacial Maximum. Nature 1998. [DOI: 10.1038/29695] [Citation(s) in RCA: 179] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Maslin M. Equatorial western Atlantic Ocean circulation changes linked to the Heinrich events: deep-sea sediment evidence from the Amazon Fan. ACTA ACUST UNITED AC 1998. [DOI: 10.1144/gsl.sp.1998.131.01.09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Saltzman ES, Whung PY, Mayewski PA. Methanesulfonate in the Greenland Ice Sheet Project 2 Ice Core. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jc01377] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Crowley TJ, Baum SK. Effect of vegetation on an ice-age climate model simulation. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jd00536] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Seidov D, Sarnthein M, Stattegger K, Prien R, Weinelt M. North Atlantic ocean circulation during the last glacial maximum and subsequent meltwater event: A numerical model. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96jc01079] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Chu S, Ledley TS. Hydrologic cycle parameterization for energy balance climate models. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/95jd01462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Modelling the response of the climate system to astronomical forcing. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0168-6321(06)80025-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
A gravitationally self-consistent theory of postglacial relative sea level change is used to infer the variation of surface ice and water cover since the Last Glacial Maximum (LGM). The results show that LGM ice volume was approximately 35 percent lower than suggested by the CLIMAP reconstruction and the maximum heights of the main Laurentian and Fennoscandian ice complexes are inferred to have been commensurately lower with respect to sea level. Use of these Ice Age boundary conditions in atmospheric general circulation models will yield climates that differ significantly from those previously inferred on the basis of the CLIMAP data set.
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Esser G, Lautenschlager M. Estimating the change of carbon in the terrestrial biosphere from 18 000 BP to present using a carbon cycle model. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 1994; 83:45-53. [PMID: 15091749 DOI: 10.1016/0269-7491(94)90021-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The authors used a global High Resolution Biosphere Model (HRBM), consisting of a biome model and a carbon cycle model, to estimate the changes of carbon storage in the major pools of the terrestrial biosphere from 18 000 BP to present. The climate change data to drive the biosphere for 18 000 BP were derived from an Atmospheric General Circulation Model. Using the AGCM anomalies interpolated to a 0.5 degrees grid, the HRBM data base of the present climate was recalculated for 18 000 BP. The most important processes which influenced the carbon storage include (1) climate-induced changes in biospheric processes and vegetation distribution, (2) the CO(2) fertilization effect, (3) the inundation of lowland areas resulting from the sea level rise of 100 m. Two scenarios were investigated. The first scenario, which ignored the CO(2) fertilization effect, led to total carbon losses from the terrestrial biosphere of -460 x 10(9) t. Scenario 2, which assumed that the model formulation of the CO(2) fertilization effect as used for preindustrial to present could be extrapolated to the glacial 200 microl litre(-1) (ppmv, parts per million per volume), gave a carbon fixation in the terrestrial biosphere of +213 x 10(9) t. The two scenarios were compared with CO(2) concentration data and isotopic ratios from air in ice cores. The results of Scenario 1 are not in agreement with the data. Scenario 2 gives realistic delta(13)C shifts in the atmosphere but the biospheric carbon storage at the end of the glacial period seems too large. The authors suggest that the low atmospheric CO(2) concentration may have favoured the C-4 plants in ice age vegetation types. As a consequence the influence of the low CO(2) concentration was eventually reduced and the glacial carbon storage in vegetation, litter, and soil was increased.
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Affiliation(s)
- G Esser
- Institute for Plant Ecology, Justus-Liebig-University, Heinrich-Buff-Ring 38, D-6300 Giessen, Germany
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Prentice IC, Guiot J, Harrison SP. Mediterranean vegetation, lake levels and palaeoclimate at the Last Glacial Maximum. Nature 1992. [DOI: 10.1038/360658a0] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gallée H, Van Yperselb JP, Fichefet T, Marsiat I, Tricot C, Berger A. Simulation of the last glacial cycle by a coupled, sectorially averaged climate-ice sheet model: 2. Response to insolation and CO2variations. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/92jd01256] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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