Human population exhibits an J-shaped growth curve, and is accelerating.              //             Successive cultural revolutions, such as the agricultural revolution, have led to surges in population.             //             Population growth rates are highly dependent upon level of development. Most current and future growth is taking place in developing countries, which have experienced only a partial demographic transition.             //             In 1950 the whole population of the earth—2.5 billion—could have squeezed, shoulder to shoulder, onto the Isle of Wight, a 381-square-kilometre rock off southern England.             //             By 1968 3.5 billion people would have required the Isle of Man, 572 square kilometres in the Irish Sea, for its standing room.             //             7 billion would need a bigger island, like Zanzibar which is 1,554 square kilometres off east Africa.             //             World's population is rising as fast as ever.             //             It took 250,000 years to reach 1 billion, around 1800; over a century more to reach 2 billion in 1927; and 32 years more to reach 3 billion.             //             But to rise from 5 billion (in 1987) to 6 billion took only 12 years; and now, another 12 years later, it is at 7 billion.             //             By 2050 there will be 9.3 billion people, requiring an island the size of Maui or Tenerife to stand on.

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Agriculture was developed at least 10,000 years ago. The total world population probably never exceeded 15 million inhabitants before the invention of agriculture.

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The plague which first emerged during the reign of Justinian caused Europe's population to drop by around 50% between 541 and the 8th century

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The Black Death pandemic in the 14th century may have reduced the world's population from an estimated 450 million to between 350 and 375 million in 1400.

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New crops that had come to Asia and Europe from the Americas via the Spanish colonizers in the 16th century are believed to have contributed to population growth.

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During the Agricultural and Industrial Revolutions, the life expectancy of children increased dramatically.

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Improvements in medicine and sanitation increase population grouth.

world population chart