|High-resolution record of Northern Hemisphere climate extending into the last interglacial period|
High-resolution record of Northern
Hemisphere climate extending into the
last interglacial period
Nature v.431, No. 7005, pp. 147-151, 9 September 2004.
North Greenland Ice Core Project members*
The NGRIP stable oxygen isotopic record compared to the GRIP record. |
a, The GRIP oxygen isotopic profile (blue) with respect to depth at GRIP. Isotopic values (d18O) are expressed in permil with respect to Vienna Standard Mean Ocean Water (V-SMOW). The measurements have been performed on 55 cm samples with an accuracy of ± 0.1 permil.
b, The NGRIP oxygen isotopic profile (red) with respect to depth at NGRIP. For comparison, the GRIP record (blue) has been plotted on the NGRIP depth scale using the rapid transitions as tie points.
c, The difference between the NGRIP and GRIP oxygen isotopic profiles plotted above on the GRIP2001/ss09sea timescale in 50 yr resolution (black). The record is compared to a record representing sea level changes (green) and a 10-kyr smoothed oxygen isotope profile from NGRIP (red).
Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5°C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.
Download the data from this study from the WDC Paleo Ice Core Gateway.
To read or view the full study, please visit the Nature website.
It was published in Nature v.431, No. 7005, pp. 147-151, 9 September 2004.
* North GRIP ice core project members
K. K. ANDERSEN1, N. AZUMA2, J.-M. BARNOLA3, M. BIGLER4, P. BISCAYE5, N. CAILLON6, J. CHAPPELLAZ3, H. B. CLAUSEN1, D. DAHL-JENSEN1, H. FISCHER7, J. FLÜCKIGER4, D. FRITZSCHE7, Y. FUJII8, K. GOTO-AZUMA8, K. GRONVOLD9, N. S. GUNDESTRUP1,17, M. HANSSON10, C. HUBER4, C. S. HVIDBERG1, S. J. JOHNSEN1, U. JONSELL10, J. JOUZEL6, S. KIPFSTUHL7, A. LANDAIS6, M. LEUENBERGER4, R. LORRAIN11, V. MASSON-DELMOTTE6, H. MILLER7, H. MOTOYAMA8, H. NARITA12, T. POPP13, S. O. RASMUSSEN1, D. RAYNAUD3, R. ROTHLISBERGER4, U. RUTH7, D. SAMYN11, J. SCHWANDER4, H. SHOJI14, M.-L. SIGGARD-ANDERSEN1, J. P. STEFFENSEN1, T. STOCKER4, A. E. SVEINBJÖRNSDÓTTIR15, A. SVENSSON1, M. TAKATA2, J.-L. TISON11, TH. THORSTEINSSON16, O. WATANABE8, F. WILHELMS7 & J. W. C. WHITE13
1 Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
2 Nagaoka University of Technology, 1603-1 Kamitomioka-machi, Nagaoka 940-2188, Japan
3 Laboratoire de Glaciologie et Géophysique de l'Environnement (CNRS), BP 96, 38402 St Martin d'Héres Cedex, France
4 Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
5 Lamont-Doherty Earth Observatory of Columbia University, Rte 9W - PO Box 1000, Palisades, New York 10964-8000, USA
6 Institut Pierre Simon Laplace/Laboratoire des Sciences du Climat et de l'Environnement, UMR CEA-CNRS 1572, CE Saclay, Orme des Merisiers, 91191 Gif-Sur-Yvette, France
7 Alfred-Wegener-Institute for Polar-und Marine Research (AWI), Postfach 120161, D-27515 Bremerhaven, Germany
8 National Institute of Polar Research, Kaga 1-9-10, Itabashi-ku, Tokyo 173-8515 Japan
9 Nordic Volcanological Institute, Grensásvegur 50, 108 Reykjavik, Iceland
10 Department of Physical Geography and Quaternary Geology, Stockholm University, S-106 91 Stockholm, Sweden
11 Département des Sciences de la Terre et de l'Environnement, Faculté des Sciences, CP 160/03, Université Libre de Bruxelles, 50 avenue FD Roosevelt, B1050 Brussels, Belgium
12 Research Institute for Humanity and Nature, 335 Takashima-cho, Marutamachi-dori Kawaramachi nishi-iru, Kamigyo-ku, Kyoto 602-0878, Japan
13 INSTAAR, Campus Box 450, University of Colorado, Boulder, Colorado 80309-0450, USA
14 Kitami Institute of Technology, Koencho 165, Kitami, Hokkaido 090-8507 Japan
15 Raunvísindastofnun Háskólans, Dunhagi 3, Iceland
16 National Energy Authority, Grensásvegur 9, IS-108 Reykjavík, Iceland
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5 October 2004