With the mortality rate at zero and the birth-rate at non-zero, the world was inexorably accreting a dense carpet of people, even with the migratory and deadhead drains on the population.
"Down and Out in the Magic Kingdom"
Cory Doctorow
Carlos, the island, had crawled out of their mother's womb and pulled himself to the cave mouth and up the face of their father, lying there for ten years, accreting until he was ready to push off on his own.
"Someone Comes to Town, Someone Leaves Town"
Cory Doctorow