Overpopulation.

There are over six billion people in the world.  Why are people so adament on saving as many human lives as possible?

I haven't read any of the past 19 posts.
That said, overpopulation fixes itself. As populations grow and resources remain static things like disease and wars break out. Overpopulation which must lead to over consumption has an adverse effect on the environment. This can be seen in ozone layer depletion, melting ice caps, severe weather (e.g., hurricanes).