Global Warming

Just wondering - did any of you, like me, learn about the Ice Age??? I'm thinkin it was waaay back there... so far back that there were not any cars, factorys, buses and all the other 'stuff' that causes this heah global warming.... umm, so as a dumb kid from North West Iowa, I'm jus wonderin what warmed the earth enuff to git rid of the ice age.... umm, could it just be that we have cycles? Hmmmm????? Just wondering and a wandering down life's path.