"i've always thought the problem isn't so much population as politics. not children but greed."

Levels of causality....
If we were all suddenly altruistic and reasonable, it is not clear that the situation would improve. Earth will not support 79 trillion people, no matter how nice and sharing they are and no matter whether politicians begin to look beyond their own re-election.

We artificially control deer populations and thin herds of cattle, but the very concept of mandatory birth control on ourselves seems to trigger all sorts of rationalizations. "But the bible says be fruitful and multiply" "I need children to help with the farm" and the simple one.. "I forgot to use..."

Just imagine if a proposal were made to implant timed-release contraceptives in 1/3 of all girls at at puberty....