October 31, 2011
World Population Nears Seven Billion People
Many estimates suggest that the world population will hit 7 billion by the end of this year. The United Nations Population Division has estimated that the 7 billion number will be hit on or around October 31, 2011. Happy Halloween to all seven billion of you!
It took thousands of years of human civilization for the population to first hit the one billion mark. However, the world's population has grown dramatically over the past few hundred years. It was just a little over two hundred years ago, in 1804, when the world's population first reached 1 billion people. The second billion was reached in 1927, just 123 years later. However, the past 84 years has seen even faster growth with another 5 billion people added to make the total population 7 billion this year.
The future population of the Earth is uncertain. One United Nations estimate shows the population growing to as much as 14 billion by the year 2100. This is just an estimate, however, and some estimates show that the world's population could even shrink to be as low as 5.5 billion in 2100.
There are many factors that will impact how many people live on the planet in the future. These include birth rates, diseases, and the development of third world countries. As countries develop, they often have lower growth rates. Many European countries are very close to zero growth rates, with some even shrinking in size.
How do they know the population?
The UN doesn't know exactly how many people there are in the world. What they do is take data from all the world's countries and make an estimate. The main information they use is government censuses. A census is a count of the country's population. However, censuses are never entirely accurate and have an error rate of around 2-3 percent.
They also have to take in account people moving from country to country, people being born, as well as people dying. All of these factors make the censuses from each country less accurate as time passes. As a result they develop growth curves for each country so they can guess around how many people are in each country at a given point in time.
The top 10 Most Populous Countries