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Science 4 August 1978:
Vol. 201. no. 4354, pp. 401 - 406
DOI: 10.1126/science.201.4354.401
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Articles

A Terminal Mesozoic "Greenhouse": Lessons from the Past

Dewey M. McLean 1

1 Associate professor of geology in the Department of Geological Sciences at the Virginia Polytechnic Institute and State University, Blacksburg 24061

The late Mesozoic rock and life records implicate short-term (up to 105 to 106 years) global warming resulting from carbon dioxide—induced "greenhouse" conditions in the late Maestrichtian extinctions that terminated the Mesozoic Era. Oxygen isotope data from marine microfossils suggest late Mesozoic climatic cooling into middle Maestrichtian, and warming thereafter into the Cenozoic. Animals adapting to climatic cooling could not adapt to sudden warming. Small calcareous marine organisms would have suffered solution effects of carbon dioxide—enriched waters; animals dependent upon them for food would also have been affected. The widespread terrestrial tropical floras would likely not have reflected effects of a slight climatic warming. In late Mesozoic, the deep oceanic waters may have been triggered into releasing vast amounts of carbon dioxide into the atmosphere in a chain reaction of climatic warming and carbon dioxide expulsion. These conditions may be duplicated by human combustion of the fossil fuels and by forest clearing.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Impacts and marine invertebrate extinctions.
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Mass Mortality and Its Environmental and Evolutionary Consequences.
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Extraterrestrial Cause for the Cretaceous-Tertiary Extinction.
L. W. Alvarez, L. W. Alvarez, W. Alvarez, F. Asaro, and H. V. Michel (1980)
Science 208, 1095-1108
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Terminal Cretaceous Extinction Scenario for a Catastrophe.
S. Gartner, S. Gartner, and J. P. McGuirk (1979)
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Biogeography.
D.R. Stoddart (1978)
Progress in Physical Geography 2, 514-528
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