Late Pleistocene δ¹¹B based carbon dioxide levels from ODP Site 154-926


Earth's climate cooled markedly during the Late Miocene from 12 to 5 million years ago, with far-reaching consequences for global ecosystems. However, the driving forces of these changes remain controversial. A major obstacle to progress is the uncertainty over the role played by greenhouse gas radiative forcing. Here we present boron isotope compositions for planktonic foraminifera, which record carbon dioxide change for the interval of most rapid cooling, the Late Miocene Cooling event between 7 and 5 Ma. Our record suggests that CO₂ declined by some 100 ppm over this two-million year-long interval to a minimum at approximately 5.9 Ma. Having accounted non-CO₂ greenhouse gasses and slow climate feedbacks, we estimate global mean surface temperature change for a doubling of CO₂ - Equilibrium Climate Sensitivity - to be 3.9˚C (1.8–6.7 ˚C at 95% confidence) based on comparison of our record of radiative forcing from CO₂ with a record of global mean surface temperature change. We conclude that changes in CO₂ and climate were closely coupled during the latest Miocene and that Equilibrium Climate Sensitivity was within range of estimates for the late Pleistocene, other intervals of the Cenozoic, and the 21st century as presented by the Intergovernmental Panel on Climate Change.

Related Identifier
Metadata Access
Creator Brown, Rachel Mary ORCID logo; Wilson, Paul A ORCID logo; Crocker, Anya J ORCID logo; Thomas, Chalk
Publisher PANGAEA
Publication Year 2023
Rights Creative Commons Attribution 4.0 International;
OpenAccess true
Resource Type Dataset
Format text/tab-separated-values
Size 3532 data points
Discipline Jurisprudence; Law; Social and Behavioural Sciences
Spatial Coverage (-42.908W, 3.719S, -42.908E, 3.719N); South Atlantic Ocean
Temporal Coverage Begin 1994-02-19T11:30:00Z
Temporal Coverage End 1994-02-27T16:00:00Z