Not quite, there are major evidences being found of even more drastic,sudden and catastrophic climatechanges than what we are experiencing now.http://www.scotese.com/
this site, although old in internet terms has some interesting data and stuff about what happened during the ages with this planet.
About Venus, nobody knows 100% what happened to her, and why she is in this state. But I am pretty sure it got tidal locked by the suns gravity and warmed up due to the forces exerted on her. I am pretty damn sure it wasn't this.
And one more thing, in the one shot, people were able to send a cargo probe 1.27 Million light years to land on distant exoplanet. Why the hell didn't they built spacecolonies instead and at least tried to survive.
Fiction is a strange, so is reality, I will probably die without seeing a spacecolony, even though those fuckers plan on having wireless broadband Internet with Optic-Fibre speeds on the moon in 2014, which is fucking useless.