Well, whether you believe Al Gore, which all the Nobel Prize winning, smartest scientist do, or you believe in other causes including religion or sun spots is probably moot. It's moot because even if Al baby is right there's no way the people of Earth are going to get together and start acting responcibly to reverse it. I keep telling my wife that if the people on our street can't even all recycle then how can you expect all of us to get together and change things like Al suggests. It's going to take at least 2/3rds of us doing the right thing to make any changes. I believe that you may get about 10% of the population to change their habits enough to matter and that little bit is just not going to do it. So whoever is right on the cause the effect will be the same and it will not be reversed by man.