Issue
Table of Contents

Miocene Climate Modelling:
MICHEELS, BRUCH, & MOSBRUGGER

Plain-Language &
Multilingual  Abstracts

Abstract

Introduction

The Model and Experimental Setup

Results

Discussion

Summary and Conclusions

Acknowledgements

References

 

Print article

 

 
 

Miocene climate modelling sensitivity experiments
for different CO2 concentrations

ABSTRACT

Throughout the Cenozoic the global climate cooled, but until the Pliocene, temperatures in polar regions seem to have been higher than at present, and it is not yet clear if the Arctic Ocean was already ice-covered in the Miocene. Reconstructions for Miocene atmospheric carbon dioxide concentration do not give a coherent climatic picture: intervals of ice-free conditions in the Arctic region appear to correspond to low CO2, and intervals during which the Arctic Ocean was ice-covered had high CO2 levels. Here we present the results of climate modelling sensitivity experiments for the Late Miocene, considering different CO2 concentrations. In order to get ice-free conditions in the Arctic Ocean, a CO2 concentration of at least 1500 ppm is necessary. Concentrations this high are unlikely for the Miocene, and our results support onset of Northern Hemisphere glaciation earlier than Late Miocene. Compared to future climate change scenarios with enhanced CO2, the modelled temperature response to CO2 increase is slightly weaker in our Miocene sensitivity experiments. This dampened response is due to the decreased sea ice volume in the Miocene and the reduced ice-albedo feedback. Comparing our sensitivity experiments with quantitative terrestrial proxy data to give an estimation for pCO2 in the Late Miocene we find that model runs with 360 ppm and 460 ppm are most consistent with proxy data. This validation thus suggests that Late Miocene CO2 concentrations were higher than present but lower than 500 ppm.

Arne Micheels. Senckenberg Forschungsinstitut und Naturmuseum, Biodiversitšt und Klima Forschungszentrum (LOEWE BiK-F), Senckenberganlage 25, D-60325 Frankfurt/Main, Germany
c. Forschungsstelle "The role of culture in early expansions of humans" der Heidelberger Akademie der Wissenschaften, Senckenberg Forschungsinstitut und Naturmuseum, Senckenberganlage 25, D-60325 Frankfurt/Main, Germany
Volker Mosbrugger. Senckenberg Forschungsinstitut und Naturmuseum, Biodiversitšt und Klima Forschungszentrum (LOEWE BiK-F), Senckenberganlage 25, D-60325 Frankfurt/Main, Germany.

Keywords: Miocene, Late; climate modelling; sensitivity experiment; CO2; proxy data comparison

PE Article Number: 12.2.5A
Copyright: Palaeontological Association August 2009
Submission: 9 October 2008 Acceptance: 28 April 2009

 

Next Section

Miocene Climate Modelling
Plain-Language & Multilingual  Abstracts | Abstract | Introduction | The Model and Experimental Setup
Results | Discussion | Summary and Conclusions | Acknowledgements | References
Print article