Professor Owen Toon, co-author of the paper, said, "This study indicates that the carbon dioxide-rich, hydrogen-poor Mars and Venus-like model of Earth's early atmosphere that scientists have been working with for the last 25 years is incorrect." The researchers claim that there was an estimated 40 percent of hydrogen in the early earth atmosphere.More info at EarthTimes
Early Earth's atmosphere was hydrogen rich

A new research by scientists at the University of Colorado found that there was a lot more hydrogen in Earth's early atmosphere than was previously thought. They estimate that hydrogen accounted for 40 percent of the Earth's atmosphere during its infancy.