Toward a Plio CLIMAP Project: Enhanced Astronomical Chronologies and Global Paleoceanographic Mapping of the Pliocene

Assessments by the Intergovernmental Panel on Climate Change (IPCC) indicate that the Earth is experiencing steady warming and that urgent mitigation measures are required. However, climate model simulations continue to show considerable diversity, and discrepancies remain between observational records and model outputs, highlighting the need for improved model validation. Paleoenvironmental data from multiple geological time slices represent an effective means of testing model performance, yet global reconstructions of sea-surface temperature and salinity have largely been restricted to the CLIMAP project for the Last Glacial Maximum.

The Pliocene epoch (≈2.6–5.3 Ma) has emerged as a crucial warm-period analog for future Earth conditions. Despite atmospheric CO₂ concentrations similar to modern values, global temperatures were 2–3°C higher, accompanied by dynamic ice-sheet behavior and transitions in dominant climate-variability periodicities. Comparative studies of Pliocene paleo–oceanographic data and climate simulations have been advanced by the USGS-led PRISM project, focusing primarily on the 3.0–3.3 Ma interval.

Recent geological evidence from IODP Expeditions 318 (Wilkes Land) and 379 (Amundsen Sea) indicates that earlier Pliocene intervals experienced even warmer conditions. Our preliminary work, based on astronomically tuned, high-resolution chronostratigraphic correlations, further suggests distinct responses of the East and West Antarctic Ice Sheets during this time.

We therefore propose a new Pliocene CLIMAP-style initiative grounded in a highly accurate astronomically tuned timescale, aimed at generating improved global paleoceanographic reconstructions to enhance next-generation climate model validation.