Demographic history

Demographic history is the reconstructed record of human population in the past. Given the lack of population records prior to the 1950s, there are many gaps in our record of demographic history. Historical demographers must make do with estimates. models and extrapolations. For the methodology, see Historical demography Demographic history is the reconstructed record of human population in the past. Given the lack of population records prior to the 1950s, there are many gaps in our record of demographic history. Historical demographers must make do with estimates. models and extrapolations. For the methodology, see Historical demography Estimating the ancestral population of anatomically modern humans, Colin McEvedy and Richard Jones chose bounds based on gorilla and chimpanzee population densities of 1/km² and 3-4/km², respectively, then assumed that as Homo erectus moved up the food chain, they lost an order of magnitude in density. With a habitat of 68 million km² ('the Old World south of latitude 50° north, minus Australia'), Homo erectus could have numbered around 1.7 million individuals. After being replaced by Homo sapiens and moving into the New World and de-glaciated territory, by 10,000 BC world population was approaching four million people. McEvedy and Jones argue that, after populating the maximum available range, this was the limit of our food-gathering ancestors, with further population growth requiring food-producing activities. The initial population 'upswing' began around 5000 BC. Global population gained 50% in the 5th millennium BC, and 100% each millennium until 1000 BC, reaching 50 million people. After the beginning of the Iron Age, growth rate reached its peak with a doubling time of 500 years. However, growth slackened between 500 BC and 1 AD, before ceasing around 200 AD. This 'primary cycle' was, at this time in history, confined to Europe, North Africa, and mainland Asia. McEvedy and Jones describe a secondary, 'medieval cycle' being led by feudal Europe and Song China from around 900 AD. During the period from 500 to 900 world population grew slowly but the growth rate accelerated between 900 and 1300 when the population doubled. During the 14th century, there was a fall in population associated with the Black Death that spread from Asia to Europe. This was followed by a period of restrained growth for 300 years. In the 18th century world population entered a period of accelerated growth. European population reached a peak growth rate of 10 per thousand per year in the second half of the 19th century. During the 20th century, the growth rate among the European populations fell and was overtaken by a rapid acceleration in the growth rate in other continents, which reached 21 per thousand per year in the last 50 years of the millennium. Between 1900 and 2000, the population of the world increased by 277%, a fourfold increase from 1.5 billion to 6 billion. The European component increased by 124%, and the remainder by 349%. The Indian population was about 100 million in 1500. Under the Mughal Empire, the population rose to 160 million in 1700. Mughal India had a relatively high degree of urbanization for its time, with 15% of its population living in urban centres, higher than the percentage of the urban population in contemporary Europe at the time and higher than that of British India in the 19th century. Under the British Raj, the population reached 255 million according to the census taken in 1881. Studies of India's population since 1881 have focused on such topics as total population, birth and death rates, growth rates, geographic distribution, literacy, the rural and urban divide, cities of a million, and the three cities with populations over eight million: Delhi, Greater Mumbai (Bombay), and Kolkata (Calcutta). Mortality rates fell in 1920-45 era, primarily due to biological immunization. Other factors included rising incomes and better living conditions, improved better nutrition, a safer and cleaner environmental, and better official health policies and medical care. Severe overcrowding in the cities caused major public health problems, as noted in an official report from 1938: