I have recently had quite a few people express a lot of skepticism about an issue which to me seems pretty clear. The link at the bottom of this post, goes to a webpage which summarizes (vastly condensed) my position.

But first, let me preface my stance on this, with a few caveats: I have always considered myself to be completely open minded. I am willing to doubt my own existence in fact, and …. well, I think that such radical doubt is a good place to start when asking yourself exactly what is the nature of the thing we call “knowledge”.

Notwithstanding this predicament (that I am less a believer in particular statements, than in the processes by which you arrive at statements), I feel at times it is safe, or at least appealing to common sense, to say with some confidence certain statements, as long as one does not overstate the evidence and means of having acquired such evidence which supports the statement. It is not an overstatement of the evidence I have at my disposal, nor of the method by which I have arrived at such evidence (my manner of thought, and the thought itself, that “I exist”), that I do in fact exist.

However, I have no possession of evidence, nor by any sound method that I have attempted, the ability to arrive at any evidence, which would lead to an equal level of certainty (near enough to be called “knowledge”) that aliens from another planet, are any more likely the true cause and explanation, than one based on the existence of spiritual entities from another dimension, or even some other unknown phenomenal explanation based on the combined power of social beliefs to manifest material existences, for the growing popularity of experiences labeled UFOs. The scientific method is one way of arriving at a higher degree of certainty of a matter, as are many other methods (appeal to authority, majority, logic, divine inspiration, practicality, etc.) – and there simply isn’t any one position on UFOs, which seems to creates a high degree of “proof”, “knowledge”, or “certainty”. In the casual, common sense, as well as the scientific and logically necessary way however, some things can be said with some confidence about global warming.

http://www.norvig.com/oreskes.html

UPDATE: Below are two rather interesting responses I received from friends whom I emailed this information to:

Comment #1:

Thanks, Paul.

I have Al Gore’s “Inconvenient Truth” DVD if you would be interested in seeing it. I was totally enthralled and stunned when I watched it.
My simple opinion: global warming IS.
My other simple opinion: Any refutes to it’s existence stem ultimately out of a political point of view rather than a scientific one.

Comment #2:

That is a good summary. I don’t even consider it a question any more. The
question is are we going to do any thing about it.