At the start of 2011, the world population was 6,890,646,738 people, according to the US Census Bureau.
The total number of people in the world is expected to top 7 billion by either the end of this year, or the beginning of 2012. (The United Nations thinks the world’s population will reach 7 billion on 21 October 2011, whereas the United States Census Bureau thinks it will be sometime in July 2012).
This video, from the National Geographic, gives you a great idea of just how many people seven billion actually is.
History of Population Growth
Before the introduction of agriculture, when humans lived a primarily hunter-gatherer lifestyle, the world’s human population was low and likely never passed 15 million people in total.
Following the introduction of agriculture, however, the population of the world gradually increased, and had reached around 450 million by 1340AD. At that point, Bubonic Plague began to spread around the world and, combined with wars – notably Mongol expansion – the population of the world fell by more than 20% to between 350 and 375 million by 1400AD.
Once the world had recovered from the plague, however, population began to grow again and 400 years later, in 1800AD, the number of people in the world reached 1 billion.
The industrial revolution contributed to an increase in the speed of population growth – the next big milestone of 2 billion people was reached little more than a century later, in 1927.
Since then, though, the world’s rapid modernisation, improvements in diet and – critically – improvements in healthcare – has led to a rapid increase in global population, as you can see in the chart below.
Imagine – it took millennia for the world’s population to reach 1 billion. For it to go from six billion to seven billion, it took just 12 years.
Prospects for Population Growth
As you can see from the chart, there are wildly varying estimates as to whether, after the world population in 2011 reaches seven billion, the number of people on our planet will continue to grow at such rapid levels, will level off or even begin to decline.
The chart below gives an indication of how population is likely to grow or fall in various parts of the world. As you can see, while growth in Africa, the world’s poorest region is predicted to increase significantly, a population decline in expected in Europe.
Those who argue that growth will slow point to the decline in population in Europe and argue that, as countries become more developed, their population growth slows and can even go into decline. Others, though, argue that the world is consuming so many resources that, as more and more countries develop there will not be enough resources to go around, leading perhaps to a catastrophic decline in global population as a result of war or famine.
The general consensus seems to be that the world’s population will reach around 9 billion sometime in the next 40-50 years but won’t go much beyond that.