NEW : World population could surpass 15 billion by the end of the century , the CNN says . In age 25 , the world 's population was 15 billion . People under this century make up 43 % of the current population . -- Today there are 893 million people over the age of 60 ; by the middle of the century , that number will rise to 2.4 billion . Oceania 's population is expected to more than triple this century .
NEW : World population could surpass 15 billion by the end of the century , the CNN says . In age 25 , the world 's population was 15 billion . People under this century make up 43 % of the current population . Oceania 's population is expected to more than triple this century .