Ubiq: you are right about breathing being part of a cycle, yet water usage is part of a cycle as well, which still doesn’t prevent these wise environmentalists from warning us not to consume too much water even in places with ample water supply.
And you’d be hard pressed to find an environmentalist that doesn’t believe exponential population growth is a problem, because no matter how much some may try to reduce emissions humans definetely add to the “carbon footprint” in the course of even modest living. We cook, travel, heat our homes, build these homes – in addition to producing all necessary items as well as comforts we desire. And this is all part of our task of living in and enjoying Hashem’s world.