Re: "which was supposedly a lot thicker"
Liquid water is not always entirely water.
I seem to recall that water heavily doped with perchlorates can remain liquid(-ish) even in martian-type environments, and a fair bit of perchlorate-type chemistry had been discovered on Mars.
I find myself wondering if there could have been some Chlorine-based gasses that could act as a warming blanket.
Biting the hand that feeds IT
