The Global Biodiversity treaty has already decided how many humans should be allowed to live on the planet.
1.An agricultural society - "in which most human beings are
peasants ... should be able to support 5 to 7 billion people..."
2.An industrialized world society - "at the North American standard of living ... would be 1 billion."
3.Semi-industrialized society - As the more frugal European standard of living, 2 to 3 billion would be possible.
The UN's GBA presents the choice of global peonage or mass
genocide, and leaves the details of accomplishing either option to the ingenuity of national governments.
http://www.freerepublic.com/forum/a33916.htm
That's why nothing was done in Rwanda to stop the genocide of nearly a million. They were letting the people thin out the excess of humans.
Man's ingenuity for mass murder is unprecedented.