Comment It is inevitable (Score 3, Interesting) 125
It is possible to list a myriad of reasons for the population decline, and therein lies the answer, too. The more freedom people have, the fewer people choose to have children. There is no magic bullet to fix it without dismantling a free society. Reduced population growth is a feature of a more advanced human civilisation.
The decline of the world population is inevitable, and it would be wise to prepare for that while providing support structures for children too.
Countries will end up competing for immigrants. My kind wish is that nationalism would start to crumble, but it might not be pretty.