re: Steamy Earth? How Come? Greenhouse Gas?
That's what they suggest -- thick CO2, "almost like Venus" one of the authors says.
But, still very hot with a thick CO2 blanket only 2 or even 1 billion years ago? Isn't that inconsistent with other evidence about the composition of the atmosphere at those times? SHouldn't it get taken up into carbonates, especially after the oceans are full of CO2-eating algae and such?