Do you really think you want to understand? Again, the irrational histrionics of so many to this discussion (such as the conflation of billions of years with a period of time that is a tiny, tiny sliver of human history, much less periods of the Earth). It is impossible to discuss nuances without the predictable, boorish stomping of feet and announcing of positions. People must make everyone know how firmly and strongly they believe in global warming.
And the funny thing is that I fully and completely believe in and understand AGW. It isn't a religion, however, and I'm not waving a flag or announcing fealty, or angrily posting over the top responses to anything that is other than full-fledged Belief. It is the most toxic, bottom-feeding discussion going.