Climate Change Doubters

In the dog park on Sunday speaking with someone young and fairly intelligent who admitted to me that he doesn't really believe in global warming. He believes that the earth is getting warmer and humans merely speeding up a natural process.

It got me thinking, what would the earth be like without humans. Would it be heating up if we took us all out of the equation?

Animals would not be knocking down trees, deforesting the earth, destroying the ozone layer with fluorocarbons, laying down black asphalt, polluting the ocean, burning oil to keep warm and drive our cars and so on? How is it possible that we are not affecting the earth in every way.

It is logic, pure and simple logic.