Throughout history, human population was relatively low. It took until 1850 to reach a population of one billion humans. Then, in the course of only five generations, we went from 1 billion people to 7 billion people!
So how could a problem like this sneak up on us — as if it were possible for 7 billion people to sneak up on anything! — so suddenly? Of course, the industrial revolution and modern medicine played a huge role, but the answer also lies in basic mathematics.
Today in class, students took part in a simulation that modeled population growth. They used dice to play the role of reproducing humans; if they rolled a 1, it meant that a person died; if they rolled a 5 or a 6 it meant that a person had a child. Just like in real life, the birth rate was roughly double the death rate. During each decade, they rolled dice for each member of their population. Before long, a population that started with only six members was well into the hundreds. In fact, if this simulation were carried out further, a population of six would reach about 7 billion after only 136 generations. I guess we’re going to need some more dice…
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