Studies of Cretaceous Climate
- A. Berger,
- R. E. Dickinson and
- John W. Kidson
Published Online: 18 MAR 2013
Copyright 1989 by the American Geophysical Union
Understanding Climate Change
How to Cite
Barron, E. J. (1989) Studies of Cretaceous Climate, in Understanding Climate Change (eds A. Berger, R. E. Dickinson and J. W. Kidson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM052p0149
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1989
Print ISBN: 9780875904573
Online ISBN: 9781118666517
- Climate changes—Congresses
The warm Cretaceous climate is characterized by (1) warm oceanic deep water, >12°C, (2) tropical surface ocean temperatures similar or slightly warmer than today's values, (3) warm poles as evidenced by abundant high latitude floras and faunas and no direct evidence for permanent ice, (4) continental interiors with a smaller degree of seasonality, (5) a globally averaged surface temperature 6–12°C higher than the present day value, and (6) unusually abundant coals, evaporites, bauxites, black shales and other rock types.
A significant role by external forcing factors is required to explain the Cretaceous warmth. The leading candidates for explaining warm global temperatures are the very different Cretaceous continental geometry, the decrease in continental area due to high eustatic sea level, higher atmospheric CO2 concentrations in the Cretaceous atmosphere, ana amplification of these factors through a greater role of the ocean in poleward heat transport.
A variety of climate models, including Energy Balance models, mean annual atmospheric General Circulation Models (GCM's), annually varying atmospheric GCMs with simple coupled oceans and ocean GCMs have been utilized to study Cretaceous climate. Among many different insights from model simulations, several are notable: (1) multiple forcing factors including a higher atmospheric CO2 level are required to achieve Cretaceous warmth if the spectrum of simulations are reasonable estimators of climate sensitivity, (2) a dramatic change in the role of the ocean would create additional problems rather than solutions to the question of Cretaceous warmth, (3) some permanent ice in Antarctica may be easier to justify than the assumption that the globe was entirely ice free and (4) in focusing attention solely on temperature considerable climate variation has been ignored which will provide important constraints on understanding the record of Cretaceous climate.