ORA Article: "Persistent El Nino-Southern Oscillation variation during the Pliocene Epoch" - uuid:5668e8ee-3791-48c3-a6fa-ca0c3320d738

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Reference: N. Scroxton, S. G. Bonham, R. E. M. Rickaby et al., (2011). Persistent El Nino-Southern Oscillation variation during the Pliocene Epoch. Palaeoceanography, 26, Article: PA2215.

Citable link to this page: http://ora.ox.ac.uk/objects/uuid:5668e8ee-3791-48c3-a6fa-ca0c3320d738
 
Title: Persistent El Nino-Southern Oscillation variation during the Pliocene Epoch

Abstract: There is an urgent requirement to understand how large fluctuations in tropical heat distribution associated with the El Niño-Southern Oscillation (ENSO) will respond to anthropogenic emissions of greenhouse gases. Intervals of global warmth in Earth history provide a unique natural laboratory to explore the behavior of ENSO in a warmer world. To investigate interannual climatic variability, specifically ENSO, in the mid-Piacenzian Warm Period (mPWP) (3.26-3.03 Ma), we integrate observations from the stable isotopes of multiple individual planktonic foraminifera from three different species from the eastern equatorial Pacific with ENSO simulations from the Hadley Centre Coupled Model version 3 (HadCM3), a fully coupled ocean-atmosphere climate model. Our proxy data and model outputs show persistent interannual variability during the mPWP caused by a fluctuating thermocline, despite a deeper thermocline and reduced upswelling. We show that the likely cause of the deeper thermocline is due to warmer equatorial undercurrents rather than reduced physical upswelling. We conclude that the mPWP was characterized by ENSO-related variability around a mean state akin to a modern El Niño event. Furthermore, HadCM3 predicts that the warmer Pliocene world is characterized by a more periodic, regular-amplitude ENSO fluctuation, suggestive that the larger and deeper west Pacific warm pool is more easily destabilized eastward. These conclusions are comparable to the observed trend over the last 40 years to more regular and intense ENSO events. Future research must resolve whether global warming alone, or in concert with tectonic factors, was sufficient to alter ENSO variability during warm intervals of the Pliocene.


Publication status:Published
Peer Review status:Peer reviewed
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About The Authors
institution"University of Oxford", "Australian National University, Acton, ACT, Australia"
facultyMathematical,Physical & Life Sciences Division - Earth Sciences
facultyResearch School of Earth Sciences
 
institutionUniversity of Leeds
facultySchool of Earth and Environment
 
institutionUniversity of Oxford
facultyMathematical,Physical & Life Sciences Division - Earth Sciences
 
institutionUniversity of Oxford
facultyMathematical,Physical & Life Sciences Division - Earth Sciences
 
institutionUniversity of Oxford
facultyMathematical,Physical & Life Sciences Division - Earth Sciences
 
institutionUniversity of Leeds
facultySchool of Earth and Environment
 
Bibliographic Details
Publisher: American Geophysical Union
Host: Palaeoceanography see more from them
Volume: 26
Extent: Article: PA2215
Issue Date: 2011
Copyright Date: 2011
Identifiers
Doi: 10.1029/2010PA002097
Issn: 0883–8305
Urn: uuid:5668e8ee-3791-48c3-a6fa-ca0c3320d738
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Member of collection : ora:articles
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Copyright Holder: American Geophysical Union
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