"The vast majority of scientists in the world believe that global warming is a real and imminent threat."
The oft-referenced letter signed by 1600 U.N. scientists "confirming" global warming? Did you know the chairman of the committee that drafted it has disavowed the executive summary that the U.N. put out? He said the findings showed the opposite. In fact, he is one of 17,000 scientists who signed the letter saying that there is no compelling evidence.
Not that the 1600 may not be the ones who are right, but if we're going to do "argument from authority" we should at least make sure the "authority" we quote said what we think he did.