The Ecology of Population Growth
Throughout most of human existence, population growth has been so slow as to be imperceptible within a single generation. Reaching a global population of 1 billion in 1804 required the entire time since modern humans appeared on the scene. To add the second billion, it took until 1927, just over a century. Thirty-three years later, in 1960, world population reached 3 billion. Then the pace sped up, as we added another billion every 13 years or so until we hit 7 billion in late 2011.
One of the consequences of this explosive growth in human numbers is that human demands have outrun the carrying capacity of the economy’s natural support systems-its forests, fisheries, grasslands, aquifers, and soils. Once demand exceeds the sustainable yield of these natural systems, additional demand can only be satisfied by consuming the resource base itself. We call this overcutting, overfishing, overgrazing, overpumping, and overplowing. It is these overages that are undermining our global civilization.
The exponential growth that has led to this explosive increase in our numbers is not always an easy concept to grasp. As a result, not many of us-including political leaders-realize that a 3 percent annual rate of growth will actually lead to a 20-fold growth in a century.
Current World Population
Net Growth During Your Visit