Evidence for warmer interglacials in East Antarctic ice cores
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Material Information

Title:
Evidence for warmer interglacials in East Antarctic ice cores
Series Title:
Nature Magazine Volume 462
Creator:
L.C. Sime
E.W. Wolff
K.I.C. Oliver
J.C. Tindall
Affiliation:
The Open University -- Department of Earth and Environmental Sciences
University of Bristol -- School of Geographical Sciences
Publisher:
Macmillan Publishers Limited
Publication Date:
Language:
English

Notes

Abstract:
Stable isotope ratios of oxygen and hydrogen in the Antarctic ice core record have revolutionized our understanding of Pleistocene climate variations and have allowed reconstructions of Antarctic temperature over the past 800,000 years (800 kyr; refs 1, 2). The relationship between the D/H ratio of mean annual precipitation and mean annual surface air temperature is said to be uniform 610% over East Antarctica3 and constant with time 620% (refs 3–5). In the absence of strong independent temperature proxy evidence allowing us to calibrate individual ice cores, prior general circulation model (GCM) studies have supported the assumption of constant uniform conversion for climates cooler than that of the present day3,5. Here we analyse the three available 340 kyr East Antarctic ice core records alongside input from GCM modelling. We show that for warmer interglacial periods the relationship between temperature and the isotopic signature varies among ice core sites, and that therefore the conversions must be nonlinear for at least some sites. Model results indicate that the isotopic composition of East Antarctic ice is less sensitive to temperature changes during warmer climates. We conclude that previous temperature estimates from interglacial climates are likely to be too low. The available evidence is consistent with a peak Antarctic interglacial temperature that was at least 6K higher than that of the present day —approximately double the widely quoted 361.5K (refs 5, 6). ( English )

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Florida International University
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