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Is There an Ice Age on the Horizon?
Reference
Wolff, E.W., Augustin, L., Barbante, C., Barnes, P.R.F., Barnola, J.M., Bigler, M., Castellano, E., Cattani, O., Chappellaz, J., Dahl-Jensen, D., Delmonte, B., Dreyfus, G., Durand, G., Falourd, S., Fischer, H., Fluckiger, J., Hansson, M.E., Huybrechts, P., Jugie, G., Johnsen, S.J., Jouzel, J., Kaufmann, P., Kipfstuhl, J., Lambert, F., Lipenkov, V.Y., Littot, G.C., Longinelli, A., Lorrain, R., Maggi, V., Masson-Delmotte, V., Miller, H., Mulvaney, R., Oerlemans, J., Oerter, H., Orombelli, G., Parrenin, F., Peel, D.A., Petit, J.-R., Raynaud, D., Ritz, C., Ruth, U., Schwander, J., Siegenthaler, U., Souchez, R., Stauffer, B., Steffensen, J.P., Stenni, B., Stocker, T.F., Tabacco, I.E., Udisti, R., van de Wal, R.S.W., van den Broeke, M., Weiss, J., Wilhelms, F., Winther, J.-G. and Zucchelli, M.  2004.  Eight glacial cycles from an Antarctic ice core.  Nature 429: 623-628.

Background
The world was recently treated to Al Gore's version of apocalypse in Hollywood's epic horror movie The Day After Tomorrow, where humanity's enriching of the air with CO2 provokes an instant ice age, the advent of which is attended by all sorts of extreme weather phenomena that punish mankind for the environmental sin of flooding the air with something that makes essentially all plants do almost everything they do far better than they have done for eons (such as produce the food that feeds us and sustains nearly all the rest of the biosphere).  We are thus made to wonder: Is the premise of the movie -- and Al Gore's take on it -- truly prophetic? ? or is it something a whole lot less, like perhaps pathetic?

What was done
The fifty-plus scientists working on the European Project for Ice Coring in Antarctica (EPICA) successfully retrieved an ice core from the Dome C region of the frozen continent that spans nearly three-quarters of a million years, producing from it preliminary histories of atmospheric CO2, CH4 and dust concentrations, along with a concomitant reconstruction of air temperature.

What was learned
One of the more intriguing revelations to come from the study concerns the nature of the glacial-to-interglacial transition of 430,000 ago, which the authors of this first published study of the new ice core call Termination V.  In terms of the observed magnitudes of temperature and greenhouse gas changes that occurred at that time, they say that this termination "resembles the transition into the present interglacial period."  In addition, in an accompanying News and Views article, McManus (2004) says that "a similar orbital configuration to that for MIS 11 [Marine Isotope Stage 11 (the interglacial that followed Termination V)] holds today, and will for some time, making this interglacial a potential analogue for the natural development of earth's climate in the future," citing Loutre and Berger (2003) in this regard.  Also, as the EPICA team continues, "the interglacial stage following Termination V was exceptionally long -- 28,000 years compared to, for example, the 12,000 years recorded so far in the present interglacial period," which observation suggests a most interesting consequence.

What it means
The authors of the EPICA study conclude that "given the similarities between this earlier warm period [MIS 11] and today, our results may imply that without human intervention, a climate similar to the present one would extend well into the future," perhaps as far as another 16,000 years.  Hence, as EPICA's lead author Eric W. Wolff concludes in the 9 June 2004 edition of BBC News Online, it would appear that "the next ice age is not imminent, and greenhouse warming makes it even less likely -- despite what The Day After Tomorrow says."  With respect to the question posed in our background paragraph, therefore, we presume that these findings make Al Gore's strident climate-alarmist claims rather more pathetic than prophetic, which, of course, should come as no surprise to most thinking people.

References
Loutre, M.F. and Berger, A.  2003.  Marine Isotope Stage 11 as an analogue for the present interglacial.  Global and Planetary Change 36: 209-217.

McManus, J.F.  2004.  A great grand-daddy of ice cores.  Nature 429: 611-612.


Reviewed 23 June 2004