The United Nations estimates that the world population will reach seven billion this year, making the population almost quarter what it was in 1960. It is projected that the growth will continue to nine billion by 2050 and 10 billion by 2100.

An astronomical 97 percent of the growth is expected to come from developing countries. Africa is expected to contribute 1.1 billion people or 49 percent, to the growth. The demand for housing, roads, schools and health clinics will be greatly strained in some areas, with the population possibly doubling every 20 years.

In the meanwhile, rich countries like Japan or Germany may see no growth or a decline in their population. This creates the problem of possibly not having enough able-bodied adults to take care of the aging population.

It is anticipated that the developed world will contribute to only three percent of the growth.

The Earth continually has the largest human populations that it has ever had. Major population growth began in 1750 with the Industrial Revolution, reaching one billion in 1800 and two billion by 1920. The population spiked to 3.5 billion in the 1960’s and has grown steadily at a rate of approximately two percent a year until it reached the level it is today.

“In the 1960’s and 1970’s people expected a population bomb. Now we have mini-bombs going off in the most fragile parts of the world. Issues of inequality and poverty may spill over from less-developed countries, which will not be good for their neighbors or the rest of the world,” David Bloom, a professor of economics and demography at Harvard School of Public Health, told Bloomberg.

Higher birth rates and life expectancies as well lower death rates are the main cause for population surges. Researchers estimate that 135 million people will be born and 57 million people will die in 2011, which is a net increase of 78 million people.

In addition, the worldwide left expectancy is projected to grow from 69 today to 76 by 2050. The population of people over 60 will double.

“The demographic picture is indeed complex and poses some formidable challenges. Those challenges are not insurmountable, but we cannot deal with them by sticking our heads in the sand,” Bloom said.

Unavoidable issues such as infectious disease, war, scientific advance, political change and the capacity for global cooperation will all be affected by the continually growing population, making it impossible to estimate what the global outlook will be.

“Every billion people we add to the planet makes life difficult for everyone and will do more damage to the environment,” demographer for New York’s Population Council John Bongaarts said.

“Can we support 10 billion people? Probably. But we would all be better off with a smaller population.”

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