Venus May Not Have Been So Bad, A Couple Of Billion Years Ago

There was a time not that long ago when the planet Venus was thought of as Earth's twin in some ways. Science fiction stories and movies would depict visits to Mars and Venus as a matter of course. More recently, both planets have revealed themselves to be much less hospitable, with Venus actually being the bleakest of the two, with high temperatures and a toxic, stormy atmosphere.

And yet, if computer models are actually to be trusted for things like this (and I personally am a little dubious), Venus may have been close to habitable one or two billion years ago.
“It’s one of the big mysteries about Venus. How did it get so different from Earth when it seems likely to have started so similarly?” says David Grinspoon at the Planetary Science Institute in Tucson, Arizona. “The question becomes richer when you consider astrobiology, the possibility that Venus and Earth were very similar during the time of the origin of life on Earth.”
Yeah, not so much