SpringerLink - Article
: "High CO2 levels are required to warm the primitive earth in the face of decreased solar luminosity. The atmosphere should have had an effective stratospheric cold trap, which would have limited the abiotic production rate of oxygen to relatively low values. Photostimulated oxidation of ferrous iron in the oceans should have been the dominant source of atmospheric H2. Rainout of H2O2 would have kept the atmospheric H2 content high and the O2 content low, even if other sources of H2 were small." Article PubMed ChemPort
James F. Kasting
The evolution of the prebiotic atmosphere
Kasting, J. E. Origins of Life 14, 75−82 (1984).