I can't comment personally on the validity of the climate modeler's computer programs. I'm not a programmer, not a mathematician, statistician, or magician. I do know the meaning of the saying about computer programs, "garbage in...garbage out". I know enough about those things to know lots of games can be played with numbers in order to arrive at a pre-conceived notions. And as sure as I know the Earth revolves around the sun I think they're wrong about the causes of climate change and global warming.
I listen to scientists who have studied global climate for a long time, and I trust what I've seen with my own eyes.....(the history of the rocks and sediments and landforms around us and around the world, on all continents). Computer models are just that, models, ideas, what-ifs...... In my opinion, along with many others, it is ridiculous and dangerous to make public policy on such flimsy so-called science. And to ram it down people's throats through scare tactics and with politicians and celebrities making a circus out of it is absurd. Time will tell, truth will prevail. Make sure you have a lifeboat when the ship of man-made global warming starts to flounder.