An ice-free cretaceous? Results from climate model simulations.

We have quantitatively investigated the mechanisms that could explain the warm, equable climate that is believed to have been typical of the mid-Cretaceous (100 million years ago). By performing simulations with a climate model based on zonal energy balance, we demonstrate that past changes in geography were important in bringing about climatic change. However, the meridional distribution of Cretaceous temperatures cannot be successfully simulated unless additional physical "feedback mechanisms" are included in the model. These mechanisms may involve cloud and meridional heat transport changes. We also conclude that paleoclimatologists should reexamine carefully both existing data and their interpretations with regard to reconstruction of Cretaceous tropical and polar surface temperatures.

[1]  S. Margolis,et al.  Purified reduced nicotinamide adenine dinucleotide: responses to lactate dehydrogenase isozymes from three cell sources. , 1981, Science.

[2]  D. Corson,et al.  Excitation of Limulus photoreceptors by vanadate and by a hydrolysis-resistant analog of guanosine triphosphate. , 1981, Science.

[3]  T. Osborn,et al.  Control of equatorial ocean currents by turbulent dissipation. , 1981, Science.

[4]  W. J. Barcellona,et al.  Ctenidial autotomy in Corbicula fluminea in response to massive granulomas. , 1981, Science.

[5]  M. Resnick,et al.  Changes in DNA during meiosis in a repair-deficient mutant (rad 52) of yeast. , 1981, Science.

[6]  S. Smith,et al.  Tritiated thymidine incorporation does not measure DNA synthesis in ribavirin-treated human cells. , 1981, Science.

[7]  C. A. Wagner,et al.  Evidence for endomycorrhizae in pennsylvanian age plant fossils. , 1981, Science.

[8]  R. Wurtman,et al.  Tyrosine increases blood pressure in hypotensive rats. , 1981, Science.

[9]  W. Cade,et al.  Alternative male strategies: genetic differences in crickets. , 1981, Science.

[10]  J. Jarvis.  Eusociality in a mammal: cooperative breeding in naked mole-rat colonies. , 1981, Science.

[11]  S. Thompson,et al.  Comparison of Cretaceous and Present Earth Albedos: Implications for the Causes of Paleoclimates , 1981, The Journal of Geology.

[12]  Syukuro Manabe,et al.  Sensitivity of a global climate model to an increase of CO2 concentration in the atmosphere , 1980 .

[13]  Stephen H. Schneider,et al.  Cosmic conclusions from climatic models: Can they be justified? , 1980 .

[14]  O. White.  The Solar Output and Its Variation , 1977 .

[15]  W. Donn,et al.  Model of climate evolution based on continental drift and polar wandering , 1977 .

[16]  E. M. Kemp,et al.  Influence of Continental Positions on Early Tertiary Climates , 1972, Nature.

[17]  D. L. Clark.  Arctic Ocean Ice Cover and Its Late Cenozoic History , 1971 .

[18]  W. Donn,et al.  A Theory of Ice Ages III. , 1966, Science.

[19]  E. Barron,et al.  Potential significance of land—sea distribution and surface albedo variations as a climatic forcing factor; 180 m.y. to the present , 1980 .

[20]  D. Cullen.  Implications of continental drift to the earth sciences , 1974 .