biology or human geography, population growth is the increase in the number of individuals in a population. Many of the world's countries, including many in Sub-Saharan Africa, the Middle East, South Asia and South East Asia, have seen a sharp rise in population since the end of the Cold War. The fear is that high population numbers are putting further strain on natural resources, food supplies, fuel supplies, employment, housing, etc. in some of the less fortunate countries. For example, the population of Chad has ultimately grown from 6,279,921 in 1993 to 10,329,208 in 2009,[1] further straining its resources. Vietnam, Mexico, Nigeria, Egypt, Ethiopia, and the DRC are witnessing a similar growth in population.
Global human population growth amounts to around 83 million annually,[2] or 1.1% per year. The global population has grown from 1 billion in 1800 to 7.616 billion[3] in 2018. It is expected to keep growing, and estimates have put the total population at 8.6 billion by mid-2050, then start declining until 2100.[4] Many nations with rapid population growth have low standards of living, whereas many nations with low rates of population growth have high standards of living
History
Population began growing rapidly in the Western world early in the industrial revolution of the late 18th century. The reasons for the "Modern Rise of Population"[7] were particularly investigated by the British health scientist Thomas McKeown (1912-1988). In his publications, McKeown challenged four theories about the population growth:
McKeown stated that the growth in Western population, particularly surging in the 19th century, was not so much caused by an increase in fertility, but largely by a decline of mortality particularly of childhood mortality followed by infant mortality,[8][9]
The decline of mortality could largely be attributed to rising standards of living, whereby McKeown put most emphasis on improved nutritional status,
His most controversial idea, at least his most disputed idea, was that he questioned the effectiveness of public health measures, including sanitary reforms, vaccination and quarantine,[10]
The sometime fierce disputes that his publication provoked around the "McKeown thesis", have overshadowed his more important and largely unchallenged argument that curative medicine measures played little role in mortality decline, not only prior to the mid-20th century[8] but also until well into the 20th century.[11]
Although the McKeown thesis has been heavily disputed, recent studies have confirmed the value of his ideas.[12] His work is pivotal for present day thinking about population growth, birth control, public health and medical care. McKeown had a major influence on many population researchers, such as health economists and Nobel prize winners Robert W. Fogel (1993) and Angus Deaton (2015). The latter considered McKeown as 'the founder of social medicine