Have you heard of this film?
HOME, by photographer Yann Arthus-Bertrand (click on his name sends you to his very complete website, or go to wikipedia biography).
I just saw it after lunch, a friend brought the dvd over... perhaps a wee bit slow for "siesta" time (very poetic, lovely music and images can soothe you a bit too much). It's WONDERFUL! The story just flows from one sequence to the next like water down a stream to the river and on to the ocean. Via a bird's eye view we're told the history of our planet, from the first appearance of water, oxygen, living organisms, to man's rise and evolution from hunter-gatherer to farmer to city-dweller. We see from above the impact our actions have had on certain ecosystems. And we get to see certain actions already in place to alleviate some of it.
Amazingly enough you can see the whole film on their YouTube page!!! Click here. Set some time aside, it lasts almost 2h, but is well worth it!