In the recent issue of fortune magazine, there was a report on population growth on planet earth. Standing at 6 billion, there won't be the doomsday szenario of this number beeing doubled.
The estimates are, that earth's population will reach its peak at 9 billion, somewhen 20 years down the road and then start to shrink. This has a lot of implications (read the article for details).
One I found specifically frightening: while most people would reduce the number of children (if they have any) in favor of personal well beeing, religious conservatives (of any religion) would outbreed (be fruitful!) the more liberal minded population.
So withing 3-4 generations we could be back at the mindset, that made the middle ages the "dark ages". So will all progress in civil development, most notably the right of self expression, go down the drain?]