Maddus Mattus said:
Fact of the matter is, they dont know what CO2 does, period. Oh they have theories and simulations, but that's it.
Sorry if this has already been mentioned, I've skipped a lot of the thread, but that statement isn't entirely true.
We know very well what CO2 does and the science behind it, particularly on an individual molecule basis, is well understood. It is, for instance, essentially the same science as Infrared Spectroscopy.
What is not so well understood the macroscopic effect in the highly complicated system that is the world. You should not discredit the theories and simulations so quickly - can you tell me some specific shortcomings of specific simulations? Sure, they won't be perfect, they may even be wide of the mark, but that doesn't mean they're bunkum.
In fact lots of science is juts "simulations" and "models". Most of the thermodynamics and statistical mechanics that can be usefully applied, for instance, is essentially based on modelled systems. The fact that they're models doesn't mean they don't work, these particular models do work. What is important is knowing where the limitations lie - what the limits of accuracy are, what the information is actually telling you and which scenarios it's valid in.
The same is entirely true of climate models.
There are some things we can be sure of. Think of the earth as if it were a giant chemical reaction. The earth and its atmosphere can be considered as a large system constantly maintaining, and repositioning, and equilibrium. When we start p**sing about with the system - for instance by adding large amounts of CO2 to the atmosphere we will move the equilibrium of the system to another point. Other factors in the system (e.g. "conditions" such as temperature) will have to change to match this equilibrium point. A la Le Chatelier's principle on a larger scale. Whatever the new equilibrium, we probably won't like it because it won't be what we're used to.
Finally I think it good to remember the words of my physical chemistry tutor, when discussing atmospheric modelling (specifically ozone depletion): "The first rule of atmospheric chemistry is that everything that happens is bad."