Skeptics discount science by casting doubts on scientist expertise

However, the _predictive_ claims of climate scientists only follow from the historical facts through the means of statistical, computerized models that are, AFAIK, essentially unproven. In fact, exact quantitative predictions have consistently failed for the last two decades. There is no more science in _predictive_ climatology, I believe, than there is in forecasting the stock market (where the same kind of computer models are also used extensively).

Yes, few informed people would disagree. The problem, however, is with how the debate is presented to the public. Watching CNN or MSNBC someone would come away with the impression that the debate is between the political conservative position (either wait and see, or it's not a problem), and the IPCC.

In reality, the scientific debate is centered around the IPCC[1], with some scientists being more conservative in future projections, and some being more dire. The scientific uncertainty that you speak of cuts both ways, and could also end up revealing a nightmare scenario of climate feedbacks. See:http://web.mit.edu/newsoffice/2009/roulette-0519.html

[1] http://www.pnas.org/content/early/2010/06/04/1003187107.full...

Then the same politicians and the same media trot out "scientists" in support of various measures. Sometimes the scientists are legit, and sometimes they're cranks. Sometimes the scientists are legit, but are talking about policy preferences rather than science. And most of the time, the politician or media member giving the "scientist" the podium doesn't have the expertise necessary to understand if the person is legit or totally nuts. And all of this gets ratings, so the media keeps it coming.

Throw in a little confirmation bias -- where people remember their side's successes and the other side's failures, and therefore trust of their side's experts and distrust of the other side's experts -- and you have a recipe for divided opinion even where there shouldn't be.

Consider, for instance, the distribution of human intelligence. There is quite a bit of solid data on this (how valid is the measurement of g, how g varies amongst different human subgroups), and yet most people want to ignore it. A much smaller subset want to exaggerate it. I can't see any action people could reasonably take based on this data (except for a very small subset of people, namely judges and HR departments).

Creationists doubt the evidence for evolution, but what do they want to do? Similarly the Holocaust "deniers". (Most don't actually deny the Holocaust, they dispute the scale.)

I've yet to see somebody say that scientists are divided on general relativity and therefore I don't need to worry about falling off this cliff.

I have known people who denied Einstein's theory of special relativity. They don't seem to want anything other than to argue about it. In fact annoyance over that was why I stopped reading James P. Hogan. (This was before he expressed his more controversial views.)

There are also a number of scientists who have doubted general relativity, and they are generally credited with moving the discussion forward by providing something concrete to test. GR has done well under those tests, but it was important to have reasonable alternatives presented. (It is worth noting that 2 of the 3 classical tests of GR match the first order predictions of any theory that reconciles gravity with special relativity, and gravitational redshift falls out of quantum mechanics. So the classical tests didn't actually test the theory very well.)

Nobody sane doubts the reality of gravity though. People who are prone to walking off cliffs because they think gravity is not real generally end up dead or institutionalized for good reason.

While I agree with you in principle that healthy skepticism is good, this is not that. Whether there is a scientific consensus is a fact that people reasonably are not free to be skeptics about.