What if the atmosphere of Titan were like the one on Venus?
If the pressure were the same as the current pressure on Titan, the planet would be slightly warmer for a while, but not for long. The CO2 would soon be frozen out. It is probable that 4 billion years ago the atmospheres of Venus,Earth,Masrs and Titan were much more similar. A hotter Saturn may have warmed Titan in those days. It probably,like the others, had a lot of CO2 in its atmosphere,but that has long ago been frozen out. There is plenty of frozen water on Titan, and if gelogists ever dig down far enough,they are likely to find a layer of frozen CO2 there as well.