Digital Explorations Project

Population Doubling

A key notion in biology and ecology is doubling time. How long does it take a given population to double in size? The doubling time for the human population on Earth is one of the most prominent features of the past few centuries. Whereas thousands of years characterized doubling times for many thousands of years, since 1900 the human population had doubled twice, first from 1 to 2 billion, then from 2 to 4 billion. During the early decades of the twenty-first century, it is expected to double once again.