Canie (and Barbara),
yes, the sudden climate changes were pre-industrial: not man-induced. The reason to mention these is that they are possible. There are theories (stronger word than hypotheses) that man-induced warming can set these off. From what I saw the other day, these sudden changes tended to occur coming out of ice ages. We have been out of the last ice age for about 11,000 years. So, one could question whether the earth's climate system can be capable of additional sudden (10 to 100 years) major (catastophic given the earth's population now) change. This would be a reasonable topic of debate. But, saying that man (and woman) cannot affect the global climate is not reasonable: it is well understood that we can.

And, Barbara, OK, most of the posts on this thread did not attack the reality of man-induced climate change. Canie's last sentence is ambiguous on that, but she has posted in the past what I understood to mean we cannot significantly affect the climate.

Since you posted attacking (or some other milder word) one effort to combat the release of greenhouse gasses, whether some control on CO2/methane is important is certainly relevant. If there is no problem, then no cap and trade is needed. If there is a problem (there is), then what is your solution? You just complained about a solution without offering one of your own (I think: I did not read all the letters you pasted...still too busy). Just keep on keeping on and buy shorts and a t-shirt? Stockpile food? (OK, plants grow better with more CO2 if everthing else is held constant...but...)
Chris