Web Topic 2.3 History of Conditions on Earth
Atmospheric oxygen and carbon dioxide concentrations (%) during the Phanerozoic-eon in millions of years ago (Ma). Atmospheric oxygen and carbon dioxide concentrations are plotted as a function of time. The values are based on models of global oxygen and carbon cycling. Estimated errors are ± 7% for O2 and ± 50% for CO2.
(Berner, R. A. (2003) The long-term carbon cycle, fossil fuels and atmospheric composition. Nature 426:323–326. http://www.nature.com/nature/journal/v426/n6964/abs/nature02131.html)
(Royer, D. L., R. A. Berner, I. P. Montañez, N. J. Tabor, and D. J. Beerling (2004) CO2 as a primary driver of Phanerozoic climate. GSA Today 14:4–10. http://www.geosociety.org/gsatoday/archive/14/3/)