Recycle. Compost. Drive less. Use less energy. Use less water. We are fast approaching the point (if we've not already passed it) that everyone on this planet will be an environmentalist by default. Until Pandora or Endor are found, Earth is all we've got.
Trash and energy notwithstanding, there is something extremely simple that most everyone has the capability of doing in order to help Mother Earth and Mother Nature along their ways. What is it? Well, I'll tell you...
No, I'm not advocating those who live in concrete jungles to do so, but people who still have the luxuries of yards and other wildernesses about should do it. I mean, why not? It's no accident that the salt content of the oceans matches the salt content of our blood (and, hence, our piss). Urine is supposed to be returned to the water table or evaporated into the air. The animal kingdom does it and they've never had a problem with it, no? And think about it... that "purified" water you're drinking probably had piss in it at some point. Hell, it probably WAS piss at some point.
Quick aside: this reminds me of that god-awful scene in Waterworld in which Kevin Costner, surrounded by nothing but ocean, pisses in some sort of recycling device in order to obtain drinking water. What the fuck? If that thing's good enough to recycle piss into potable water, shouldn't it be good enough to recycle... I dunno... seawater???
Anyway... piss outside. Not only does that ensure the water goes directly back into nature, it'll cut your water/sewage bill down by eliminating many of your toilet flushes during the day. Not only that, it keeps your piss from returning to reclamation and sewage plants which are filled with water far more disgusting than any pool you've ever pissed in.
I also advocate not being buried in caskets and coffins (don't get me started on the fallacy of cremation), since that also allows our water and tissue to return to the environment more efficiently, but that's another story.