Geological archives of the Antarctic continent and Southern Ocean during past warmer climates provide important clues as to how this region may respond to future anthropogenic warming scenarios. The ANDRILL drill cores allow us to re-create past environments from beneath the present-day Ross Ice Shelf, including ice sheet advances during past ice ages, but also times when there were open-marine/sea-ice environments during warmer-than-present climates. These studies indicated that the West Antarctic Ice Sheet was greatly reduced in size during the Pliocene epoch (5-2.6 Myr ago), when atmospheric CO2 concentrations and global temperatures were 2-3°C warmer than present, similar to those projected by the end of the century. I was also involved in a drilling expedition to a previously undrilled sector off East Antarctica (Wilkes Land continental margin), as part of the Integrated Ocean Drilling Program (IODP), the world’s premier geomarine research programme. Located in the open ocean, the IODP cores compliment the ANDRILL cores by providing Antarctic margin and Southern Ocean water mass response to ice advance and retreat cycles. This temporal overlap of ANDRILL and IODP records will help us identify oceanic thresholds for past ice sheet retreat. The Wilkes Land IODP sites were drilled beneath one of the three main bottom water production zones off Antarctica, a critical component of the global ocean circulation that distributes heat, gases and nutrients around the planet. To investigate this link to the global climate system, our research team is reconstructing an ocean-climate history from Ocean Drilling Program cores collected from offshore eastern NZ to investigate Antarctic water masses entering the Pacific Ocean basin, and how these changes may influence global climate.

anthropogenic ,oceanic thresholds,geomarine