Earlier today, we spotlighted National Geographic‘s Great Migrations — a fascinating look at how large numbers of animals move as one. But perhaps even more fascinating, often in a troublesome kind of way, is how humanity’s ever-growing legions adapt to inhabiting a planet that seems to shrink. This preview for 7 Billion, a year-long series National Geographic is doing on overpopulation — an issue so enormous and far-reaching few of us truly grasp its gravity, and also one of the “elements” in yesterday’s A Is for Armageddon: An Illustrated Catalogue of Disasters — delivers some jaw-dropping facts in beautifully animated kinetic typography.

In 1975, there were 3 megacities — Tokyo, Mexico City and New York City. Right now, there are 21. By 2050, 70% of us will be living in urban areas.”

Standing shoulder to shoulder, all 7 billion of us would fill the city of Los Angeles.”

For an intelligent take on overpopulation, its implications for our not-at-all distant future and the opportunities that lie in it, we highly recommend David Christensen’s Two Elephants in the Room: Overpopulation and Opportunities We Overlook at Our Peril.