Evolution of atmosphere when the earth was formed the sun radiated about 30% energy less than now, and its output goes only gradually up the climate models tell us that the earth would have been completely frozen for about first 2 billions years if it had an atmosphere similar to the current one. however we see evidence of liquid water that existed during that time therefore the early atmosphere must have had much more greenhouse gases, like carbon dioxide and methane that stopped the planet from freezing. (q1) name the molecule or element that is part of the present day atmosphere but would be missing from the original atmosphere of the earth: o carbon dioxide oxygen o methane nitrogen o water vapour o carbon monoxide (q2) which statement describes the geochemical carbon cycle an exchange of carbon between carbon monoxide in the earth and oceans and carbon dioxide in the atmosphere o an exchange of oxygen between carbon monoxide buried in carbonate rocks and carbon dioxide in the atmosphere. o an exchange of carbon between carbon dioxide in the atmosphere and carbon buried in the earth as carbonate rocks