We've had warming periods in the past. Tis the natural cycles of the earth that were here before we were born and will be here long after we're gone. We are but a flea on this earth, and don't you think it is the epitomy of arrogance to assume we humans have that much of an effect on this great planet? The Al Gore movie is somewhat propagandist in nature, but isn't that the point? To further political agendas? It is the case with all media and films. I predict in another 20 years we'll still be arguing about all this.