National Geographic: Warning: The 21st century may get a lot more crowded than previously thought.
In a paper published Thursday in Science, demographers from several universities and the United Nations Population Division conclude that instead of leveling off in the second half of the 21st century, as the UN predicted less than a decade ago, the world's population will continue to grow beyond 2100. (Read "Population Seven Billion" in National Geographic magazine.)
And for the first time, through the use of a "probabilistic"...