The title of that article does not match the rest. He is not suggesting as you are that global warming has stopped. Even if he was, the assertion that lack of change over an 8 year period represents sound evidence that man made factors have no effect would be incorrect, primarily for no other reason then the simple fact that everything has an effect. You cannot change something (increase emissions) without an effect. The reason for the use of "might", "could", "perhaps" is because nobody knows with certainty what effect it will be, however scientific data suggests that pollution from man made sources has the potential to increase average temperature, leading to problems that humans would consider adverse. Naturally people who perceive this hypothesis as requiring them to "give up" something like their SUV tend to reject it.