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Atmospheric carbon dioxide linked with Mesozoic and early Cenozoic climate change

Fletcher, B.J., Brentnall, S.J., Anderson, C.W., Berner, R.A. and Beerling, D.J. (2008) Atmospheric carbon dioxide linked with Mesozoic and early Cenozoic climate change. Nature Geoscience, 1 (1). pp. 43-48. ISSN 1752-0908

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Abstract

The relationship between atmospheric carbon dioxide (CO2) and climate in the Quaternary period has been extensively investigated, but the role of CO2 in temperature changes during the rest of Earth's history is less clear. The range of geological evidence for cool periods during the high CO2 Mesozoic 'greenhouse world' of high atmospheric CO2 concentrations, indicated by models and fossil soils, has been particularly difficult to interpret. Here, we present high-resolution records of Mesozoic and early Cenozoic atmospheric CO2 concentrations from a combination of carbon-isotope analyses of non-vascular plant (bryophyte) fossils and theoretical modelling. These records indicate that atmospheric CO2 rose from approx420 p.p.m.v. in the Triassic period (about 200 million years ago) to a peak of approx1,130 p.p.m.v. in the Middle Cretaceous (about 100 million years ago). Atmospheric CO2 levels then declined to approx680 p.p.m.v. by 60 million years ago. Time-series comparisons show that these variations coincide with large Mesozoic climate shifts, in contrast to earlier suggestions of climate–CO2 decoupling during this interval. These reconstructed atmospheric CO2 concentrations drop below the simulated threshold for the initiation of glaciations on several occasions and therefore help explain the occurrence of cold intervals in a 'greenhouse world'.

Item Type: Article
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield)
The University of Sheffield > Faculty of Science (Sheffield) > School of Biological Sciences (Sheffield) > Department of Animal and Plant Sciences (Sheffield)
Depositing User: Mrs Megan Hobbs
Date Deposited: 16 Mar 2010 18:20
Last Modified: 07 Jun 2010 11:10
Published Version: http://dx.doi.org/10.1038/ngeo.2007.29
Status: Published
Publisher: Nature Publishing Group
Identification Number: 10.1038/ngeo.2007.29
URI: http://eprints.whiterose.ac.uk/id/eprint/10598

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