The world population explosion is synonymous with a consumer explosion. Each person on the face of the planet consumes natural resources directly, as food (unless they are starving), and indirectly as processed or manufactured products (unless they are destitute).

Have you ever seen estimates of the world population in ancient times and wondered where they came from? Sources include reference books containing data collected by historians. The first chart on the right shows the upper and lower estimates from a variety of sources as compiled by the U.S. Census Bureau. The data is available online in tabular form: Historical Estimates of World Population. The second chart shows the population explosion since the industrial revolution got underway.

In the first chart there is a dip corresponding to the plague outbreak known as the Black Death. It first struck Europe in the mid-14th century, killing up to a third of the population. Around the same time there were plague epidemics across large swathes of Asia and the Middle East.

Before the period in which European countries began to keep parish records of births, deaths and marriages, any population estimates can be no more than informed guesses. There’s a listing of sources used in historical population assumptions on the website of the University of Tennessee at Knoxville: Population Data Sources. However, after the spread of the industrial revolution to developing countries, governments began to organize censuses which provide historians with increasingly accurate worldwide population data from the early 19th century onwards.

Just one lifetime ago, no person had ever lived through a doubling of the world population. Now some have lived through a tripling.

What’s the margin for error?

The margin for error in present day world population figures is certainly less than 0·1% — 6 million people couldn’t go unnoticed anywhere on this planet. Satellites are constantly beaming back updated images of every part of the world’s surface. You can see examples at NASA’s Visible Earth website. Estimates of future population levels have a wider margin for error because birth rates may change.

Consuming the environment to death

 
“Collapse” is one of three bestselling books by Jared Diamond, Professor of Geography at University of California, Los Angeles (see “Jared Diamond’s Themes,” on this site). After an in-depth survey of societies that collapsed as a result of resource depletion, the final chapter addresses the question “What Does It All Mean to Us Today?”

The per-capita impact of individuals — the resources consumed and wastes put out by each person — varies greatly around the world. Low-impact inhabitants of Third World countries are fast becoming high-impact people because they see and covet First World lifestyles. Immigration from low-impact countries is the main driving force behind population increases in the United States and Europe. Jared Diamond quotes some alarming statistics:

On the average, each citizen of the U.S., western Europe, and Japan consumes 32 times more resources such as fossil fuels, and puts out 32 times more wastes, than do inhabitants of the Third World.
. . .   . . .
 
Even if the people of China alone achieved a First World living standard while everyone else’s living standard remained constant, that would double our human impact on the world.

 
According to Diamond, advocates of business-as-usual are contributing to the problems of environmental overload:

People in the Third World aspire to First World living standards. They develop that aspiration through watching television, seeing advertisements for First World consumer products sold in their countries, and observing First World visitors to their countries. Even in the most remote villages and refugee camps today, people know about the outside world. Third World citizens are encouraged in that aspiration by First World and United Nations development agencies, which hold out to them the prospect of achieving their dream if they will only adopt the right policies, like balancing their national budgets, investing in education and infrastructure, and so on. But no one at the U.N. or in First World governments is willing to acknowledge the dream’s impossibility: the unsustainability of a world in which the Third World’s large population were to reach and maintain current First World living standards.

 
The consequences of overpopulation also seem to have gone unnoticed by religious groups opposed to family planning. They are inadvertently urging humanity towards an apocalyptic descent into chaos worse than the Biblical story of Adam & Eve’s expulsion from the Garden of Eden. If Satan exists, he must be delighted at how well he has deceived them.

More to read:
Collapse: How Societies Choose to Fail or Succeed.