Estimating latest Cretaceous and Tertiary atmospheric CO2 from stomatal indices
by Royer D. L. (2003)
Dana L. Royer,
Department of Geology and Geophysics, Yale University, P.O. Box 208109, New Haven, Connecticut 06520-8109, USA.
in Wing, S.L., Gingerich, P.D., Schmitz, B., and Thomas, E., eds., Causes and Consequences of Globally Warm Climates in the Early Paleogene: Boulder, Colorado, Geological Society of America Special Paper 369: 79–93 –
A quantitative understanding of the levels of atmospheric CO2 in the geologic past sheds light on the operation of the carbon cycle and the biosphere, and aids in the prediction of future climate change.
Here I present a CO2 reconstruction for the very latest Cretaceous to early Eocene and middle Miocene based on the stomatal distributions in fossil and extant Ginkgo and Metasequoia cuticles.
Although both of these intervals are representative of globally warm climates, my CO2 reconstruction indicates near present-day values (300–450 ppmV) for both times. Although these data do not cast doubt on the theory of the greenhouse effect, they do suggest that other thermal forcings were more important during these intervals than they are today