How do you pick experts?

One writer's answer here.

In response to the question:

"Can I ask how you made the judgment on which scientists to believe? I am interested in climate science and just started reading RealClimate, thanks in part to your post. To be honest, I respect your literary work and was surprised to hear you, as a science fiction author, naysay what I thought was serious and substantial scientific study.

L Neil Smith writes:

...lacking other data, I looked at the character of those pushing the idea of Global Warming. They included leftist politicos I knew to be opportunistic liars in other contexts—particularly gun ownership—along with movie stars and other brain-dead celebrities that flock to any cause that attacks private industrial capitalism and individual liberty. Some may criticize me for ad hominem thinking, but when you don't have reliable scientific information (which I didn't back then), what else can you rely on but your understanding of the personalities involved?

There was also my experience with previous predictions of disaster (some which I listed in the blog entry "The Badguys" that we're discussing ), and of conspiracy theories that seemed to me to have a similar structure. The whole "Paul is dead" thing comes to mind. I know a lot about this because I spent a lot of time in the JFK Assassination Conspiracy "movement".

....

I suppose my perception of precisely who stood to benefit from the spreading fear about Global Warming comes into it. Anyone who hates technology, of course, or the present economic system. Also, hordes who will get rich from all of the asinine proposals to reduce Global Warming—anyone who makes solar panels or water heating systems or nasty little cars that go short distances very slowly, carrying almost nothing.

Most persuasive, I suppose, was an anthropological understanding I have (that being my principle field of interest and study in college) of what constitutes a religion. The planet gets transmogrified into a goddess in the minds of the faithful, and all of the entities upon it, the birds and bees and flowers and trees (to quote an old song)—all of the entities, that is, except humans—become sacred objects. Exhaling carbon dioxide becomes Original Sin. Better that a thousand human babies should die than one single snail darter or a furbish lousewort.