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What Is the Likelihood of the Antarctic Ice Sheet Collapsing Sometime Soon?
Reference
Cofaigh, C.O., Dowdeswell, J.A. and Pudsey, C.J. 2001. Late Quaternary iceberg rafting along the Antarctic Peninsula continental rise in the Weddell and Scotia Seas. Quaternary Research 56: 308-321.

What was done
Five sediment cores from the continental rise west of the Antarctic Peninsula and six from the Weddell and Scotia Seas were investigated for their ice rafted debris (IRD) content in an attempt to determine if there are Antarctic analogues of the Heinrich layers of the North Atlantic Ocean, which testify of the repeated collapse of the eastern margin of the Laurentide Ice Sheet and the concomitant massive discharge of icebergs. If such IRD layers exist around Antarctica, the authors reasoned, they would be evidence of "periodic, widespread catastrophic collapse of basins within the Antarctic Ice Sheet," which could obviously occur again.

What was learned
After carefully analyzing their data, the authors concluded that "the ice sheet over the Antarctic Peninsula did not undergo widespread catastrophic collapse along its western margin during the late Quaternary." They also say their evidence "argues against pervasive, rapid ice-sheet collapse around the Weddell embayment over the last few glacial cycles."

What it means
If there was no dramatic break-up of the Antarctic Ice Sheet "over the last few glacial cycles," as the authors say, there's a good chance there will also be none before the current interglacial ends. And since the data of Petit et al. (1999) indicate that each of the last four intergalcials were warmer than the current one - and by an average of more than 2C - there's an extremely good chance there will be no such break-up this time around.

Reference
Petit, J.R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, L., Ritz, C., Saltzman, E., and Stievenard, M. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399: 429-436.


Reviewed 2 January 2002