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Science 29 August 2008:
Vol. 321. no. 5893, pp. 1197 - 1200
DOI: 10.1126/science.1160978
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Reports

Limits for Combustion in Low O2 Redefine Paleoatmospheric Predictions for the Mesozoic

C. M. Belcher* and J. C. McElwain

Several studies have attempted to determine the lower limit of atmospheric oxygen under which combustion can occur; however, none have been conducted within a fully controlled and realistic atmospheric environment. We performed experimental burns (using pine wood, moss, matches, paper, and a candle) at 20°C in O2 concentrations ranging from 9 to 21% and at ambient and high CO2 (2000 parts per million) in a controlled environment room, which was equipped with a thermal imaging system and full atmospheric, temperature, and humidity control. Our data reveal that the lower O2 limit for combustion should be increased from 12 to 15%. These results, coupled with a record of Mesozoic paleowildfires, are incompatible with the prediction of prolonged intervals of low atmospheric O2 levels (10 to 12%) in the Mesozoic.

School of Biology and Environmental Science, University College Dublin (UCD), Belfield, Dublin 4, Ireland.

* To whom correspondence should be addressed. E-mail: claire.belcher{at}ucd.ie

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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