Want to stay on top of all the space news? Follow @universetoday on TwitterThe population of Earth has been steadily growing since the end of the plague in the early 1400′s. It is currently estimated to be 6.78 billion people and reach 9 billion by the year 2040. The distribution of people across the face of the Earth has remained fairly consistent over the centuries. Many people have devoted their entire careers to studying the rate of human population growth and the ability of the Earth to sustain that growth. According to population projections, world population will continue to grow until around 2050.
The population of Earth continues to grow even though the rate of births have leveled off at 134-million-per-year. While the birth rate has leveled off it is still nearly twice the death rate. The death rate will top off at 90 million per year in 2050. The increasing life span of humans around the world is causing a continued rise in the population.
The population of Earth has been distributed over the same areas in a consistent way for centuries. Countries like China and India have accounted for as much as 40% of the population of the Earth since before the birth of Christ. The have been closely followed by Africa all along. Currently China and India account for 37% of the world’s population. The birth rates are higher in both countries than the world average at the same time that medical advances are lengthening the life span of the average person.
There are theories that the population of Earth will continue to grow until agriculture can no longer support it. At that time there will have to be a return to subsistence farming which will cause a drop in birth rates and an increase in death rates. This is a very basic translation of the Malthusian theory. How will the population of Earth correct its overburdening of the Earth is another point of debate. Will countries have to go to war in order to feed their populations and provide the basic items of life like oil and gasoline? Have we already seen the first wars for resources in the Middle East?
Wikipedia has the exact numbers and distribution of the population of Earth. While that single link will not let you do any complete research you can do an easy keyword search to get everything else that you need.