New insights to the middle Miocene pCO 2 problem
The climate of the middle Miocene was substantially different to today with a much warmer world with boundary conditions (plate configurations, ocean circulation etc) that were very different to the present. The sustained warmth of the “Middle Miocene Climate Optimum” prevailed prior to the second s...
| Main Authors: | , , , , , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2013
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| Subjects: | |
| Online Access: | https://oro.open.ac.uk/46030/ http://abstractsearch.agu.org/meetings/2013/FM/PP34A-06.html |
| Summary: | The climate of the middle Miocene was substantially different to today with a much warmer world with boundary conditions (plate configurations, ocean circulation etc) that were very different to the present. The sustained warmth of the “Middle Miocene Climate Optimum” prevailed prior to the second step of the descent into the ice-house - with the major expansion of Antarctic ice sheet and global cooling at the middle Miocene Climate Transition. Coincident with these major changes in global temperatures and the cryosphere were substantial perturbations of the carbon cycle, as documented by the large fluctuations in oceanic carbonate δ 13 C values during the “Monterey Excursion” as well as the various “CM” events superimposed upon it. Critical to our understanding of Miocene climate and carbon cycle dynamics is a full understanding of atmospheric pCO 2 during this fascinating time. A number of Miocene atmospheric pCO 2 estimates are now available (Kürschner, Kvaček and Dilcher, 2008; Foster, Lear and Rae, 2012; Badger et al., 2013) that help to better understand this relationship but differences between these new records and older published records (ie Pagani et al., 1999; Pearson and Palmer, 2000) raise interesting questions as to the drivers of Miocene climate and carbon cycling. Here we will discuss the implications of our records for the Monterey Excursion and the CM events, as well as presenting a novel probabilistic re-assessment of new and existing atmospheric pCO 2 records. The combination of a larger dataset and more quantitative approach allows us to answer some of the outstanding questions about the operation of the Miocene climate system, and help to explain the apparent disparity between atmospheric pCO 2 records and proxy temperature estimates. |
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