With grand plans of connecting Antarctic sea ice and the Circumpolar Current to not only climate change but geomagnetic field reversals, there needs to be a solid reference to trace events back through time. Bantanja and van de Wal provide a remarkable well constructed set of data for 45N to the pole. But 45N to the pole is not "Global".
Note: Core ODP 846 is actually tropical eastern Pacific not sub-Antarctic. Text below revised.
Martinez-Garcia et al. 2010, Subantarctic Atlantic and Subarctic Pacific 3.6 Ma Alkenone SST Reconstructions. (DOI:10.1126/science.1184480) has an interesting fit with the scaled CO2. The scaled CO2 does not fit either data set perfectly but does tend to follow the combined sets with emphasis more on one than the other at some points. The slope of the scaled CO2 is nearly a perfect match of the slopes of the sub-Antarctic and Eastern Pacific temperature reconstructions. The oscillations between the two temperature sets should provide some information on changes in the ACC and its impact on the THC.
Since the EPICA core does not extend far enough back in time for a continuous "standard", a combination of the BW Tdo and the Herbert et al. Tropical Oceans may be required for the next step back in time.