variability seen in these properties does not approach the extremes originally inferred from the GRIP ice core, significant climate variability beyond the traditional 5a–e classification exists throughout oxygen isotope stage 5 and significant variability exists even within stage 5e. Arguments based on the supposed climate stability of warm climate periods will need to be rethought based on these emerging results.

Concluding Remarks

The quest for uncovering the LGM SCO2 distribution and its link to deep ocean circulation changes has made significant progress in the Atlantic, northern Indian, and eastern tropical Pacific oceans, but the quest is still stalled regarding the Southern Ocean and the northwest Pacific. The temporal variability of SCO2 and circulation in the North Atlantic is becoming evident, with long-term Milankovitch orbital links as well as century- to millennial-scale variability that may be linked to events seen in Greenland ice cores. Warm climate periods are not as unstable as implied by the original GRIP ice core data, but significant fluctuations occur, and these need to be better understood.

I thank conference organizers for inviting me to this stimulating meeting. I am deeply indebted to Yvon Balut and other key personnel of the Marion Dufresne coring effort: Laurent Labeyrie, chief scientist of IMAGES; Jean-Louie Turon, chief scientist of the ship during our coring efforts; and Yves Lancelot and especially Franck Bassinot for their efforts on our behalf. All of the crew and scientific shipboard personnel were crucial in this effort, especially the Magnetic Suseptibility Track efforts led by Larry Mayer, Kate Jarrett, Frank Rack, and Gavin Dunbar, and my optical team coworkers, especially Lynda Levesque. I thank Todd Sowers for putting the GRIP d18O record on the GISP2 time scale. Graduate student Jess Adkins is thanked both for his shipboard work (along with Jeff Berry) and comments on this manuscript. My continuing collaboration with Lloyd Keigwin on Bermuda Rise cores is a key inspiration in this effort. This research was sponsored by National Science Foundation Grant OCE9402198 and National Oceanic and Atmospheric Administration Grant NA-3GGP0246.

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