I'm pretty sure Global warming is now a well proven fact, also that humans had a hand in this one, since the Earth constantly warms and cools over millions of years, the changes get more or less drastic, here's the thing, humanity is just seeing the beginning of it, if an ice age did kill the dinosaurs, then either we're heading for some hot/dry times, or aome really cold frigging times. Either way, it's not for another million years or so, we'll all die of cancer first.