This planet we live on is the only one in the known Universe that sustains life, therefore it is important that we look after it, if we wish to go on living here for a few more years!
I will add further thoughts at a later time but for now please feel free to watch the film below; Directed by Yann Arthus-Bertrand, and made as a not-for-profit film in 2009.
http://www.youtube.com/watch?v=jqxENMKaeCU&feature=watch-now-button&wide=1