what? you think were going to strip the oxygen out of the air or something, we might make it less pleasent, but short of the discussion in the other thread about colapseing the planet into a miniture black hole, there is no way were going to destroy all life on earth, or "break" it.
were just doing what come natural to us like every other liveing thing on the planet. just for some reason a few people in the last few decades have decided thats a reason to hate our selves over. animals go extinct all the time, oftine becase a new animal comes about and alters the environment, those animals incapable of adapting to the new environment die out, that's evolution, that's nature.