Here is my stance/theory/whatever you want to call it on global warming. There are four seasons every year: spring, summer, fall, and winter. The earth seems to have a similar situation, bu it happens over long periods. We have seen multiple ice ages and found multiple periods of a more tropical climate between them. This seems to be happening now. The way I see it, we now are coming out of the ice age and transitioning into a period in which earth is hotter and more tropical. I don't know if anyone of any significance has this stance but it makes the most sence to me and seems rather plausible. Just wanted to put that out there. I know that's not the only thing mentioned but it is relevant.