The relative roles of CO<sub>2</sub> and palaeogeography in determining late Miocene climate: results from a terrestrial model–data comparison
The late Miocene palaeorecord provides evidence for a warmer and wetter climate than that of today, and there is uncertainty in the palaeo-CO<sub>2</sub> record of at least 200 ppm. We present results from fully coupled atmosphere-ocean-vegetation simulations for the late Miocene that ex...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2012-08-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/8/1257/2012/cp-8-1257-2012.pdf |
| Summary: | The late Miocene palaeorecord provides evidence for a warmer and wetter climate than that of today, and there is uncertainty in the palaeo-CO<sub>2</sub> record of at least 200 ppm. We present results from fully coupled atmosphere-ocean-vegetation simulations for the late Miocene that examine the relative roles of palaeogeography (topography and ice sheet geometry) and CO<sub>2</sub> concentration in the determination of late Miocene climate through comprehensive terrestrial model-data comparisons. Assuming that these data accurately reflect the late Miocene climate, and that the late Miocene palaeogeographic reconstruction used in the model is robust, then results indicate that: <br><br> 1. Both palaeogeography and atmospheric CO<sub>2</sub> contribute to the proxy-derived precipitation differences between the late Miocene and modern reference climates. However these contributions exibit synergy and so do not add linearly. <br><br> 2. The vast majority of the proxy-derived temperature differences between the late Miocene and modern reference climates can only be accounted for if we assume a palaeo-CO<sub>2</sub> concentration towards the higher end of the range of estimates. |
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| ISSN: | 1814-9324 1814-9332 |