Provide us the mathematical formula that if you put this much "gas" (whichever kind or concentration you want to use) over said period of time it will raise the earth's temperature "x" degrees. Now once you produce that formula go back and apply it to history and let me know the results. If you can prove it this way I will believe you.
That said, I for one believe the "ice age" theory 60s/70s way more then the "global warming" theory of the 80s/90s. Cool thing is that it was the same scientist who supported the beginnings of both theories. (blocking > trapping in my eyes) Unless of course you can prove it mathematically and not by selectively picking charts and graphs which are the results of only half the data.
If you don't have to be accountable for your beliefs it is easy to believe anything.