Emulating Climate and δ18O of Precipitation over the Antarctic Ice Sheet During the Pliocene

The Pliocene Epoch (5.3-2.6 Ma) serves as a potential analogue for future climate because of its comparable atmospheric CO2 levels to present-day. Attempts to reconstruct Pliocene sea-level thus far remain poorly constrained, with estimates ranging from 0 to 50 m above present-day. Such uncertainties in sea level reconstructions during the Pliocene can be partly attributed to uncertainties in the δ18O of Antarctic ice and its relationship to δ18O of benthic foraminifera (δ18Oben). Studies indicate that differences in the δ18O of ice from changes in δ18O of precipitation in addition to ice sheet geometry and flow can alter the relationship between the δ18O of sea water and ice volume, and may contribute to sea level estimates by greater than 15 m. However, these studies have not explored the range of Pliocene climate conditions. Here, we utilize the fully-coupled water isotope tracer enabled Earth system model (iCESM1) and an emulator to investigate climate over the Antarctic ice sheet during the Pliocene, including δ18O of precipitation and surface mass balance. Preliminary results derived from iCESM and emulator outputs suggest that δ18O of precipitation, temperature, and precipitation over the Antarctic ice sheet vary significantly under different orbital and CO2 configurations. These preliminary results can help us investigate the validity of δ18Oben based reconstructions of Pliocene sea level.