First of all, Michael Crichton is an excellent novelist, and I've read a number of his books.
State of Fear is not one of his best works, but it is still good. He is a novelist, and
State of Fear is not intended to be a text book.
Second, the WU criticizes what a
character in his book says. That is fiction and it isn't claimed as being anything else.
Crichton also includes a nonfiction appendix at the end, where does offer his opinions. Some of his opinions are, that "part of the observed surface will ultimately be attributable to human activity (paperback p. 626)." He also notes that there has been no real study of "wilderness (p. 628)," and that we don't have good modeling of climate changes (p. 626).
Some of observations (and I will not call the opinions) is that the level of CO2 is increasing, and that temperatures have rising since c. 1850, since the cooling period known as the "Little Ice Age." How much is natural and how much man-made is the question.
He then goes to talk about more systematic and more non partisan funded research on climate change issues (pp. 628-9). The particular problem here is that 99% of the scientific community are
not certain of the amount of increase in global temperature is being caused by human activity in general or by CO2 in particular.
Look at these two examples. First, the world got go warmer in the between AD 800-1400, to a point where it was
warmer (1300's) than any time until the 20th Century. Second, global temperature dropped between 1400-1850. The only thing we can say about this is that it was
not due to industrialization; there was none. There was some other cause and we do not know the mechanisms that caused either.
http://en.wikipedia.org/wiki/Medieval_warm_period