your life depends on it. with poor air and water quality, comes poor soil and poor food quality. bad food quality means no nutrients and this leads to disease and our body stops functioning. its also important for the sake of the animals. our lives are affected by animals as well. I will give you an example. more and more birds are dying because of air pollution and artificial lighting (city lights) their existence relies on following the earths natural rhythms (like when they fly south) but when everyhting is artificial and polluted they become confused. some birds don't know when to fly south, and mate becuase the weather systems are all messed up. and birds help humans out by eating millions and millions of insects. if the birds go, we will be infested with insects. too many insects also brings about rats, parasites and other forms that can contribute to human and oher animal death. (think about the black/bubonic plague with all the rat infested streets, cows and chickens and other animals we eat all becoming infected any dying) if you destroy the environment, animals die and this hugely affects humans.
keeping the environment is also for future generations and respect for all living creatures. we are all connected, and we are all one, if you want to discuss philosophy or spirituality. when one area on the earth is affected (i.e say man made forest fires) the position exactly opposite on the other side of the world will also face a very similar fate. its already proven human technology, pollution (air, land and water) are all contributing to severe weather changes such as hurricanes and tsunamis occuring more frequently.