It's a shame that this thread got waylaid by the discussion on climate change though it is incredibly interesting in and of itself.
[Blatham, back in those middle pages, around 7 or 8, was so dead on track, it was scary. I feel, though I may well be wrong, that some papered over those pages as fast as they possibly could.]
The Wikipedia material is awfully interesting and my opinion as to whether GWing is being caused by us is obviously of little consequence but there are a number of reputable contrarians.
I don't offer the following as conclusive proof, but I will suggest that there have been any number of times in history when the majority of scientists have been spectacularly wrong.
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http://www.co2andclimate.org/wca/2004/wca_29c.html
The phrase "scientific consensus" suggests something approaching unanimous agreement among scientists. However even a rudimentary survey of scientific literature reveals there to be very little agreement on the subject of climate change. The unfortunate and inaccurate characterization of consensus is used as a rhetorical bludgeon of skeptics and is the basis of a push for industrialized nations to "do something" to reduce the atmosphere's greenhouse gas concentration.
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Maybe the perceived effects for our own little corner of the world cause us to be lean rabidly one way or t'other.