"Until someone can explain to me how the earth warmed so long ago when man wasn’t around, I will continue to believe that man-made global warming is nonsense and a hoax."

Classic fallacious reasoning. To paraphrase this statement:
Something happened previously when conditions were different than now; therefore, the same thing can not happen now.

Of course, the same result can have several causes. You may sneeze because you have an infection (i.e., a cold) or you may sneeze because you are allergic to grass pollen. 

So lets play! You can have a lot of fun doing this.  Here's one to start off:

People died when hunting Mammoths during the Pleistocene; Mammoths are now, unfortunately, extinct. Therefore, people no longer die.