Late Miocene cooling coupled to carbon dioxide with Pleistocene-like climate sensitivity
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https://hdl.handle.net/10037/29226Date
2022-07-25Type
Journal articleTidsskriftartikkel
Peer reviewed
Abstract
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 planktic
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 for 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)
on the basis of 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 twenty-first century as
presented by the Intergovernmental Panel on Climate Change.
Publisher
NatureCitation
Brown RM, Chalk TB, Crocker, Wilson PA, Foster GL. Late Miocene cooling coupled to carbon dioxide with Pleistocene-like climate sensitivity. Nature Geoscience. 2022;15(8):664-670Metadata
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