Posted 21 September 2011, by Staff, CO2 Science (Center for the Study of Carbon Dioxide and Global Change), co2science.org
McInerney, F.A. and Wing, S.L. 2011. The Paleocene-Eocene Thermal Maximum: A perturbation of carbon cycle, climate, and biosphere with implications for the future. Annual Review of Earth and Planetary Sciences 39: 489-516.
During the Paleocene-Eocene Thermal Maximum, or PETM, of some 56 million years ago, it is believed that large amounts of carbon were released to the ocean-atmosphere system and that global temperatures may have risen by 5-8°C. Thus, the authors write that study of the PETM may provide “valuable insights into the carbon cycle, climate system and biotic responses to environmental change that are relevant to long-term future global changes.”
What was done
McInerney and Wing reviewed much of the scientific literature pertaining to the insights being sought by biologists concerned about potential species extinctions due to CO2-induced global warming; and they give their assessment of the current status of the grand enterprise in which many scientists have been involved since the early 1990s, when the PETM and its significance first began to be recognized (Kennett and Stott, 1991; Koch et al., 1992).
What was learned
In summarizing their findings, the two researchers write that although there was a major extinction of benthic foraminifera in the world’s oceans, “most groups of organisms did not suffer mass extinction.” In fact, they say “it is surprising that cool-adapted species already living at higher latitudes before the onset of the PETM are not known to have experienced major extinctions,” and they remark that “this absence of significant extinction in most groups is particularly interesting in light of the predictions of substantial future extinction with anthropogenic global warming.” In addition, they note that “low levels of extinction in the face of rapid environmental change during the Quaternary pose a similar challenge to modeled extinctions under future greenhouse warming,” citing Botkin et al. (2007). And, last of all, they indicate that “rapid morphological change occurred in both marine and terrestrial lineages, suggesting that organisms adjusted to climate change through evolution as well as dispersal.”
What it means
McInerney and Wing wrap up their review by noting that “research on the PETM and other intervals of rapid global change has been driven by the idea that they provide geological parallels to future anthropogenic warming.” And in this regard, the many research results they review seem to suggest that earth’s plants and animals, both on land and in the sea, may be much better equipped to deal with the environmental changes that climate alarmists claim are occurring in response to anthropogenic CO2 emissions than what many students of the subject have long believed to be possible.
Botkin, D.B., Saxe, H., Araujo, M.B., Betts, R, Bradshaw, R.H.W., Cedhagen, T., Chesson, P., Dawson, T.P., Etterson, J.R., Faith, D.P., Ferrier, S., Guisan, A., Skjoldborg-Hansen, A., Hilbert, D.W., Loehle, C., Margules, C., New, M., Sobel, M.J. and Stockwell, D.R.B. 2007. Forecasting the effects of global warming on biodiversity. BioScience 57: 227-236.
Kennett, J.P. and Stott, L.D. 1991. Abrupt deep-sea warming, palaeoceanographic changes and benthic extinctions at the end of the Palaeocene. Nature 353: 225-229.
Koch, P.L., Zachos, J.C. and Gingerich, P.D. 1992. Correlation between isotope records in marine and continental carbon reservoirs near the Paleocene/Eocene boundary. Nature 358: 319-322.