Past gasps

Ancient atmosphere not as oxygen-poor as once thought

Normal 0 false false false MicrosoftInternetExplorer4 Earth’s atmosphere during some past geological ages wasn’t as oxygen-deprived as previously thought, new experiments suggest.

Results of the new lab work — conducted in climate-controlled chambers large enough to walk inside — indicate that combustion of natural materials such as moss and wood takes place only when atmospheric concentrations of oxygen exceed 15 percent.