Temperatures at the last interglacial simulated by a coupled ocean-atmosphere climate model

© 1998 by the American Geophysical Union. We thank D. Schriever for supporting us with the simulations for the last interglacial and M. Lautenschlager for helping us to set up the experiment. M. Montoya thanks also E. Zorita, V. Kharin, S. Lorenz, and V. Ocafia for advice and discussion. Finally, we thank the reviewers (C. Covey, P. Fawcett, and G. Vailis) for their valuable comments. M. Montoya was supported by a grant of the Dirección General de Investigación Científica y Técnica (Spain). T. J. Crowley was supported by National Science Foundation grant ATM-9529109. H. yon Storch was supported by BMBF grant 07VKV01/1.
The last interglacial (Eemian, 125,000 years ago) has generally been considered the warmest time period in the last 200,000 years and thus sometimes been used as a reference for greenhouse projections. Herein we report results from a coupled ocean-atmosphere climate model of the surface temperature response to changes in the radiative forcing at the last interglacial. Although the model generates the expected summer warming in the northern hemisphere, winter cooling of a comparable magnitude occurs over North Africa and tropical Asia. The global annual mean temperature for the Eemian run is 0.3 degrees C cooler than the control run. Validation of simulated sea surface temperatures (SSTs) against reconstructed SSTs supports this conclusion and also the assumption that the flux correction, fitted for the present state, operates satisfactorily for modest perturbations. Our results imply that contrary to conventional expectations, Eemian global temperatures may already have been reached by the mid 20th century.
Dirección General de Investigación Científica y Técnica (DGICYT), España
National Science Foundation (NSF)
Bundesministeriums für Bildung und Forschung (BMBF), Alemania
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
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