1. Michael Crichton is a pseudo-intellectual hack who doesn't understand anything about the science.
Linky dink
The link includes indepth criticisms of it and the way it was written along with a scientific debunking of the book from Gavin Schmidt of the NASA Goddard Institute for Space Studies.
2. It's very simple.
-CO2 and world temperature are intricately linked.
-There is a very specific heat capacity that CO2 has
That said:
--We
know that we are pouring CO2 into the atmosphere.
--We
know that it is building up and not being absorbed by sinks in any substantial capacity
--We
know that the earth is heating up in line with the heat absorbing capacity of the extra CO2 we have introducted to the atmosphere.
We. Are. Doing. It.
What will happen as a result of our unplanned heating, there are plenty of models. None of them are anywhere remotely close to being appealing.