One sure sign that you are dealing with a crank is their use of outdated information. In cutting edge science, anything older than 10 years is going to be suspect, and 20 years is really pushing it unless you are talking about something really basic. So if you see someone constantly quoting scientists from 50+ years ago, your bullshit alarms should be screaming.
Enter Walter Williams, economist, explaining to us why we shouldn't believe the worldwide consensus of science on global warming. Funny, I haven't heard of Williams submitting papers on his alternate theories to the peer-reviewed literature. Funny how the denialists yap on about how they can win the game, but refuse to step on the playing field.
Williams' reasoning runs roughly as follows: Paul Erlich was a mentor to Al Gore, and made some incorrect predictions, and some other scientists and government bodies have made incorrect statements as far back as 1885, therefore the scientific consensus is wrong on global warming. I'm not kidding.
Don't believe me? Check out the article. Here are the dates and people/organizations he quotes:
1969, environmentalist Nigel Calder
1968, Professor Paul Ehrlich
1972, a report was written for the Club of Rome
1970, Gordon Taylor
1975, the Environmental Fund
1970, Harvard University biologist George Wald
1970, Sen. Gaylord Nelson
1885, the U.S. Geological Survey
1939, the U.S. Department of the Interior
1949, the Secretary of the Interior
1974, the U.S. Geological Survey
So, in summary, Walter Williams is asking you to reject the views of the climate scientists based on the fact that 4 scientists, 2 environmentalist groups, 2 politicians, and 3 government agencies said incorrect things, anywhere from 33 to 123 years ago. That's right, the most recent example Williams gives us is so long ago that most of the scientists he says we should doubt about climate change weren't even born yet! And finally, notice that there is not a single scientific organization mentioned in Williams crimped history. So what relevance does any of this have to the current global warming problem? That's right, not a damned thing.
This is why you shouldn't get your science from economists, especially those who moonlight as political hacks.