An astronomically dated record of Earth’s climate and its predictability over the last 66 million years

TLDR

Understanding of Earth's past climate relies on oxygen and carbon isotope variations in deep‑sea benthic foraminifera, yet existing records lack the temporal resolution and age control needed to fully categorize Cenozoic climate states and dynamics. The study presents a new, highly resolved, astronomically dated, continuous composite of benthic foraminifer isotope records. This composite was developed in our laboratories. Four climate states—Hothouse, Warmhouse, Coolhouse, Icehouse—are distinguished by their distinct responses to astronomical forcing, and statistical analysis shows polar ice volume is key to the predictability of Cenozoic climate dynamics.

Abstract

Much of our understanding of Earth's past climate comes from the measurement of oxygen and carbon isotope variations in deep-sea benthic foraminifera. Yet, long intervals in existing records lack the temporal resolution and age control needed to thoroughly categorize climate states of the Cenozoic era and to study their dynamics. Here, we present a new, highly resolved, astronomically dated, continuous composite of benthic foraminifer isotope records developed in our laboratories. Four climate states-Hothouse, Warmhouse, Coolhouse, Icehouse-are identified on the basis of their distinctive response to astronomical forcing depending on greenhouse gas concentrations and polar ice sheet volume. Statistical analysis of the nonlinear behavior encoded in our record reveals the key role that polar ice volume plays in the predictability of Cenozoic climate dynamics.