The total number of living humans on Earth is known as the World population. The method of calculation of the number of living persons is known as census taking. Although the calculations cannot be exactly correct they give a fairly good estimate of the population at a particular point of time. The census of all the countries of the world is put together to get the world population. The world population at present is estimated to be slightly over 7 billion.
Asia is the most populous continent with over 60% of the world population. It has 4.2 billion inhabitants. The two Asian countries, China and India alone make up for 37% of the world population. Africa is the second most populated continent with over 15% of the world population of around 1 billion people. Europe ranks with 11% and North America with 5% hold 3rd and 4th places in the world population. The Australian continent has just over 4% of the world population. Antarctica doesnâ€™t have any permanent inhabitants.
The number of births, as well as the number of deaths, affects the world population. As the world population increases, the pressure on the environment, the food supplies, and other resources of the earth including energy also increases. It is estimated that the world population first reached the 1 billion mark in 1804. It took 123 years for it to become 2 billion. But in the next just 33 years, in 1960, it reached the 3 million mark. Thereafter it began increasing very rapidly. It is estimated that by 2030 the world population will cross the 8 billion mark.