[Mercadante]

Of course the climate changes naturally - nobody has ever said otherwise. Similarly, people die naturally. But if I ran over someone in my car and then said, "It's not murder, deaths are perfectly natural! Napoleon died, and there weren't any cars around then!", I think you'd realize that that was wrong.

There is a lot of evidence now that human activities, not just natural processes, are now having a warming effect on the planet. That is the overwhelming consensus among climate scientists, not governments.

To put it at its simplest: carbon dioxide has a insulating effect (which is used commercially). We have put a great deal of it in the air, dramatically increasing its concentration in the atmosphere. People who deny that this is warming the planet are essentially saying that a mysterious process has suspended the laws of physics, and that the warming we actually see happening is a marvellous coincidence. My faith in miracles doesn't stretch quite that far.