Asynchrony of
Antarctic and Greenland Climate Change
During the Last Glacial Period

T. Blunier, J. Chappellaz, J. Schwander, A. Dällenbach, B. Stauffer, T. F. Stocker, D. Raynaud, J. Jouzel, H. B. Clausen, C. U. Hammer, S. J. Johnsen

 

Links to Paper Sources:
Published August 20, 1998, Nature, 394: 739-743.
www.nature.com
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Abstract:
A central issue in climate dynamics is to understand how the Northern and Southern hemisphere couple during climate events. The strongest of the fast temperature changes observed in Greenland (so called Dansgaard-Oeschger events) during the last glaciation have an analogue in the temperature signal of Antarctica. A comparison of the global atmospheric concentration of methane as recorded in ice cores from Antarctica and Greenland permits a determination of the phase relationship (in leads or lags) of these temperature variations. Greenland warming events around 36 and 45 kyr before present lag their Antarctic counterpart by more than 1 kyr. On average, Antarctic climate change leads that of Greenland by 1-2.5 kyr over the period 47-23 kyr before present.

Figure 1:
10Be fluxes from Byrd32, Vostok33 and GRIP31 ice cores. Byrd was reduced by 15% accounting for a difference in standards used for the measurements on the Byrd and the GRIP/Vostok cores (Jürg Beer personnel communication). Dating of the GRIP core after Ref. 21. For Byrd two dating scenarios were used: solid line with lower temperature and accumulation; dashed line with higher temperature and accumulation (see methods for details). Vostok dated as described in methods. The hatched area indicates the 10Be peak area deduced from the GRIP core.

 

Figure 2:
GRIP1, Byrd15 and Vostok16 isotopic and CH4 records on the common time scale (GRIP time scale in year before 1989). Byrd: solid line for the lower temperature scenario, shaded area indicates the range of (Delta) age for the two temperature scenarios discussed in the methods.
The CH4 scale corresponds to the GRIP values. Byrd and Vostok values were lowered by 200 and 400 ppbv respectively for better visibility.
Numbers on top of the GRIP isotopic record indicate the location of Dansgaard-Oeschger events. ACR is the location of the Antarctic Cold Reversal as described by Jouzel et al.34. Antarctic warmings are indicated by A1 and A2. Dotted lines show the location of Greenland warmings 1, 8 and 12 in the Antarctic cores.
The Byrd (delta)18O variation between 25-17 kyr BP show most likely local climate characteristics since:
  • 1) it is not seen in the Vostok or in the Dome C record51.
  • 2) it is not compatible with the climate mechanism seen during events A1, A2 and also the ACR present in all Antarctic records.

     

Figure 3:
(Delta) Age versus Ice Age: Solid line for GRIP5, the shaded area gives the range of Dage for the Byrd core covered by the temperature scenarios discussed in methods, calculated with the same model as the GRIP (Delta) age.

 

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