World population

The United Nations Department of Economic and Social Affairs tells us that some time today the world’s human population will reach 8 billion, double that of 1970.

Here are the previous milestones on our journey to overpopulation:

one billion for the first time in 1804;
two billion in 1927;
three billion in 1960;
four billion in 1974;
five billion in 1987;
six billion in 1999;
seven billion in October 2011.

World population by country by Hadrian Oliver (CC BY-SA 3.0) via Wikimedia Commons

Since 1974, Earth’s human population has doubled from 4 to 8 billion. This is a scarily convenient metric because the rapid loss of the planet’s biodiversity is also measured from the 1970s. So, as our own population has doubled in just fifty years, the WWF found that, in exactly the same amount of time, populations of wild mammals, birds, amphibians reptiles and fish fell by 69%, and insect populations by 50%. While we accept that correlation doesn’t prove cause, it’s difficult not to conclude that the two sets of numbers are linked in some way.

Human population growth is slowing but is not expected to peak, at around 10 billion, until some time in the 2080s. Unless we learn to share our planet, we could be in real trouble by then.