I occasionally hear or read that computer modelling has “proved” something about Anthropogenic Global warming (AGW) or that computer models provide “evidence” of warming.
This is impossible. I have worked with computers for 40 years at all levels of programming.
I understand how they work and what they can, and can’t do.
It is best to think of a computer as a very literal, and obedient clerk. The computer will do exactly what you tell it regardless of whether it makes sense. For example, if you enter topographic information into a computer and program it to redraw the map of the world if the sea level were to rise, say, 50 miles, it will produce wonderful pictures of a globe of water. The “computer” will not, and can not, ask if it is true. And, it certainly can not care.
Even with the best of intentions, a computer model is a set of calculations based on a set of assumptions. This is not evidence of, or proof of, anything.
DalesIdeas.COM 
Good point that was also well explored by Michael Crichton: >> Increasingly it seems facts aren’t necessary, because the tenets of environmentalism are all about belief. It’s about whether you are going to be a sinner, or saved. Whether you are going to be one of the people on the side of salvation, or on the side of doom. Whether you are going to be one of us, or one of them.>> Environmentalism as Religionhttp://mayogenuine.com/blog/dogma-danger/ Michael Crichton, M.D.
My later article “Computers and Scientific Proofs” is a more detailed discussion of this.