Not to derail, but we're currently overdue for an ice age, not a tropical season, and many of the signs we are seeing are NOT the normal signs of normal planetwide climate cycles. For example, the current spike in carbon in the atmosphere isn't equaled at any point in the ice record, and we've taken the ice record back quite a ways. If you haven't yet, watch An Inconvenient Truth, even (or especially) with a jaded and critical eye; it does a good job of summarizing the science behind the "global warming scare" without getting too technical. Frankly, if I had to try and explain it, I'd probably get it wrong, just like I have trouble explaining Schroedinger's Cat properly; I'm just not trained for this sort of thing.