I guess I need to be even clearer? I don't even know why I am bothering to explain but here goes..
The term "global warming" is a misnomer. The planet has heated and cooled for 4 billion years. This is an undisputed fact. We have gone through ice ages and thaws in the past. Still facts which no one disputes.
The argument is whether green house gasses are leading to "global warming". There is no argument that the climate is actually changing. The argument is why it's changing. If you think I am wrong, please post one link to anyone saying the planet's climate is not actually changing.
If you still don't agree with the FACT the climate is changing, why are the ice caps melting? Why is the sea level rising?
http://earthobservatory.nasa.gov/IOTD/view.php?id=6638
I am not going to say its a FACT that green house gases are causing "global warming" because it hasn't been proven without a doubt like you said. However I would say that it's a damn good possibility/contributing factor and we should be working on ways to lower the green house gas emissions.
Now ask yourself this.. Why would anyone be against lowering green house gasses? Because it's not cost effective and unfortunately many people in this world are more concerned about their profits than the future of our race. Believe it our not.. nothing we do will destroy the planet. It will still be here long after humans.. It's human beings and other life forms that we should be trying to save in future generations.