ACE Pleistocene Subcommittee

Pleistocene ACE subcommittee

Rationale:

Studies of Antarctic ice cores show that Pleistocene climate variability between hemispheres has occurred out of phase. This variability raises questions about the response of the southern high latitudes to external climate drivers, such as orbital insolation, solar variability, and internal amplifiers such as thermohaline circulation and carbon-cycle changes that operate at both Milankovitch and millennial-decadal time scales. Answers to these questions will improve our understanding of the vulnerability of the ice sheet during Pleistocene climatic optima and its potential impact on (1) global thermohaline circulation as a southern source of melt water discharge, and (2) sea level rise well beyond the present sea level stand. The Pleistocene sub-committee will facilitate Antarctic and global environmental research investigating:

The interval of Late-Pliocene global cooling co-incident with development of a bi-polar cryosphere (working jointly with the Mid-Miocene Pliocene sub-committee).
The period of Mid-Pleistocene reorganisation of the climate system (1.0-0.4 Ma) – Mid-Pleistocene Climate Transition (MPCT).
Major glacial terminations and super-interglacial periods (e.g. marine isotope stages 31, 11, 9 and 5) of extreme climatic warmth.

Focus:

The primary focus of this sub-committee is to provide new knowledge of the role the Antarctic in the bi-polar cryosphere. It will take an integrated approach which combines atmospheric (ice core), proximal marine (SHALDRILL, ANDRILL, ODP), distal deep marine (ODP), and far-field seal-level (Wanganui Basin, Huon Peninsula etc.) records to provide boundary conditions and constraints for Earth system and climate modelling studies. In particular the committee is interested in the influence of Pleistocene Antarctic ice cover on global sea-level and ocean circulation. To achieve these scientific ambitions the committee will:

Integrate existing datasets with new proximal datasets from EPICA, SHALDRILL, ANDRILL and ODP/IODP to determine ice sheet/shelf responses to climate forcing, including variability at a range of temporal scales (10 2-10 4 years), and possible collapses.
Relate Antarctic ice variability to thermohaline circulation as expressed by variations in abyssal Pacific inflow along eastern New Zealand to the Pacific Ocean (ODP Leg 181 datasets)
Synthesise global proxy data for key climatic transitions (Late Pliocene, Mid-Pleistocene, Late Pleistocene termination-interglacial)
Undertake numerical modelling studies of ice sheet dynamics and global climate for these transitions

Committee Membership:

Tim Naish (chair, NZ); Lionel Carter (NZ); Eric Wolff (UK); Andrew Mackintosh (NZ); Ross Powell (US); Rainer Gersonde (Germany); Gary Clarke (Canada); John Chappell (AUS); Stuart Henrys (NZ); Reed Scherer (US); David Pollard (US); Ian Hall (UK).