File:Ice Age Temperature Rev.png
From Global Warming Art
This figure shows the Antarctic temperature changes during the last several glacial/interglacial cycles of the present ice age and a comparison to changes in global ice volume. The present day is on the right.
The first two curves shows local changes in temperature at two sites in Antarctica as derived from deuterium isotopic measurements (δD) on ice cores (EPICA Community Members 2004, Petit et al. 1999). The final plot shows a reconstruction of global ice volume based on δ18O measurements on benthic foraminifera from a composite of globally distributed sediment cores and is scaled to match the scale of fluctuations in Antarctic temperature (Lisiecki and Raymo 2005). Note that changes in global ice volume and changes in Antarctic temperature are highly correlated, so one is a good estimate of the other, but differences in the sediment record do no necessarily reflect differences in paleotemperature. Horizontal lines indicate modern temperatures and ice volume. Differences in the alignment of various features reflect dating uncertainty and do not indicate different timing at different sites.
The Antarctic temperature records indicate that the present interglacial is relatively cool compared to previous interglacials, at least at these sites. It is believed that the interglacials themselves are triggered by changes in Earth's orbit known as Milankovitch cycles and that the variations in individual interglacials can be partially explained by differences within this process. For example, Overpeck et al. (2006) argues that the previous interglacial was warmer because of increased solar radiation at high latitudes. The Liesecki & Raymo (2005) sediment reconstruction does not indicate significant differences between modern ice volume and previous interglacials, though some other studies do report slightly lower ice volumes / higher sea levels during the 120 ka and 400 ka interglacials (Karner et al. 2001, Hearty and Kaufman 2000).
It should be noted that temperature changes at the typical equatorial site are believed to have been significantly less than the changes observed at high latitude.
|Temperature Record Series|
|This figure is part of series of plots showing changes in Earth's temperature over time.|
|Time Period: 25 yrs | 150 yrs | 1 kyr | 2 kyr | 12 kyr | 450 kyr | 5 Myr | 65 Myr | 500 Myr|
|See also: Future predicted changes | Map of recent warming | Temperature change category|
This figure was produced by Robert A. Rohde from publicly available data.
- [abstract] [ [ EPICA community members (2004). "Eight glacial cycles from an Antarctic ice core". Nature 429 (6992): 623-628.
- [abstract] Hearty, P.J. and Kaufmann, D.S. (2000). "Whole-rock aminostratigraphy and Quaternary sea-level history of the Bahamas". Quaternary Research 54: 63-173.
- [abstract] [ [ Karner, D.B., J. Levine, B.P. Medeiros, and R.A. Muller (2002). "Constructing a Stacked Benthic δ18O Record". Paleoceanography 17 (3).
- [abstract] [ [ Lisiecki, L. E., and M. E. Raymo (2005). "A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records". Paleoceanography 20: PA1003.
- [abstract] [ Overpeck, Jonathan T., Bette L. Otto-Bliesner, Gifford H. Miller, Daniel R. Muhs, Richard B. Alley, Jeffrey T. Kiehl (2006). "Paleoclimatic Evidence for Future Ice-Sheet Instability and Rapid Sea-Level Rise". Science 311 (5768): 1747-1750.
- [abstract] [ Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M. (1999). "Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica". Nature 399: 429-436.
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|current||02:57, 20 February 2006||574×379 (26 KB)||Robert A. Rohde|