The causes of fertility decline are no longer mysterious, and the previous chapters have considered what might help reverse it. We still have to live through the future already taking shape. Some countries may recover. Others may learn to manage contraction, while a few remain at ultra-low fertility long enough to become societies we have never seen before.
These are scenarios rather than forecasts. They follow the same demographic forces until the paths separate and adaptation may cease to be enough. The first begins with the hopeful case: births recover, while the population continues aging anyway.