Sometime around Halloween 2011, the global population topped seven billion. That’s a staggering number of people. In fact, linked arm to arm, a human chain would wrap around the equator roughly 175 times or extend to the moon and back about nine times, according to CBC/Radio-Canada.
Bearing this image in mind, we can be forgiven for believing that there are more humans roaming the Earth today than during all of history and prehistory combined. But is it true?
Phoenix, Ariz., is a sprawling desert city with twice the population of Portland, Ore., and one-fifth its annual rainfall. The Valley of the Sun irrigates its golf courses with water channeled from the Salt, Verde and Colorado Rivers, while the City of Roses guzzles winter rains and stores the remainder in the reservoirs of the Bull Run Watershed.
What could these two cities possibly have in common? Simple. They both face seasonal water shortages if projections of population growth and climate change hold true.