Global Warming

I don't think anybody can dispute the fact that global warming has happened, just a few years ago, about 20,000, the earth was covered in ice. Since that time the earth has gradually warmed to the point that the ice started to melt, hence "Global Warming". The big debate now is to what effect does man have on it.
Here is a link to an article that talks about the theory that the earths temperatures are based upon cycles. What happened to global warming? The author states that we have not seen any temperature increase in 11 years. Two theories in the article for the rise in temperates are solar cycles and ocean cycles. Both of which are said to be changing.
I must admit that I am not upon all the science behind global warming, I don't believe that man is causing it and here is why I believe that. The last ice age ended about 20,000 years ago, notice I said last ice age because there have been at least 4 major ice ages. All of them before man was around. If man was the cause of all of the earths problems how did we cause the problems before we were around.