While reading this thread a thought popped into my head about what a person can do, to help the environment. It seems a simple idea that has to do with lawns and mowing. Remember those old push lawn mowers? The ones with the rotating blades? Only energy required was from the person pushing them.
I imagine in well populated areas (cement jungles) that people with the small amount of lawns they have, could reduce air pollution and the use of fossil fuel, just by eliminating gas driven mowers.
A blade of grass takes polluting gases and CO2 from the air and returns pure oxygen, so we need lawns to help us. But... the way we care for our lawns is something to think about. The fertilizing, the watering, the mowing, etc..
Even further on this thought(that popped into my head) was don't mow so damn much!
Sorry A-Mouse, I haven't seen the film.