While sitting in my dentist's chair today waiting for his recommendation on whether or not to proceed with a root canal, my mind wandered to something I had read in Skeptical Science earlier today. The blogger was discussing the tendency of some who have expertise in one area to assume that they are experts in other fields as well. Thus, you might have, to use one of his examples, a perfectly competent gardener who claims to be expert in ichthyology, even though he has never studied the biology of fish.
This tendency seems very prevalent in the field of climate science. You have all kinds of people who may be knowledgeable in one field of study claiming expertise in regard to what the real climate scientists refer to as global climate change or anthropogenic (man-made) global warming.
Most often, these people from other fields who bill themselves as experts on climate science are global climate change deniers. They are absolutely certain (or claim to be) that the whole thing is a hoax perpetrated by liberals to make us give up our gas-guzzling cars and our air-polluting factories. They maintain this certainty even though more than 95% of climate scientists - i.e., the people who have studied this and have ACTUAL expertise as opposed to PRETEND expertise - state unequivocally that global climate change is happening and that it is largely caused by human activity.
I can't think of any other subject matter where this would be acceptable to a large number, perhaps even a majority, of Americans. How many of them do you suppose would allow their plumber to perform a root canal for them? And yet, in regard to this one topic, they will listen to and accept opinions from people who are absolute idiots on the subject.
As for myself, I prefer to listen to the people who actually know what they are talking about and are not receiving financial inducements from Big Oil and other notorious polluters to say what they say.
I wouldn't let my plumber or Glenn Beck do my root canal, either.