Saving the environment is a task that's too difficult for one person to understand, so anything that seems slightly inconvenient is good enough to satisfy most people's "needs". Changing when you charge your cell phone is a lot easier than planning your life to be lower-impact.

(I love all the SUVs filled with one grocery bag at Whole Foods. Do you really think that buying some locally-grown organic carrots offsets the energy you spent driving your military vehicle 3 blocks?)