Population growth

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In human biology or geography, population growth is an increase in the number of individuals in a population.

Global human population growth amounts to about 83 million per year, or 1.1% per year. The global population has grown from 1 billion in 1800 to 7.616 billion in 2018. This is forecast to continue growing, and estimates have put the total population at 8.6 billion by mid-2030, 9.8 billion by mid-2050 and 11.2 billion in year 2100. Many countries with rapid population growth have low standards of living, while many countries with low population growth rates have a high standard of living.

Video Population growth

Histori

The population began to grow rapidly in the Western world at the beginning of the industrial revolution at the end of the 18th century. The reasons for "Modern Rise of Population" were specifically investigated by British health scientist Thomas McKeown (1912-1988). In his publication, McKeown challenged four theories about population growth: McKeown states that the growth of Western populations, especially those soaring in the nineteenth century, is not so much due to the increase in fertility, but mainly by the decrease in mortality, especially the deaths of children followed by infant mortality,

Decrease in mortality can largely be attributed to improved living standards, where McKeown emphasizes on improving nutritional status,

His most controversial idea, at least his most disputed idea, is that it questions the effectiveness of public health measures, including sanitation, vaccination and quarantine reform,

The fierce disputes published around his "McKeown thesis," have overshadowed his more important and unrivaled argument that curative treatment acts play a minor role in mortality reduction, not only before the mid-20th century but also into the century -20.

Although McKeown's thesis has been heavily debated, recent research has confirmed the value of his ideas. His work is vital to current thinking about population growth, birth control, public health and medical care. McKeown has a major influence on many population researchers, such as health economist and Nobel Prize winner Robert W. Fogel (1993) and Angus Deaton (2015). The latter regard McKeown as the 'founder of social medicine'.

Maps Population growth

Population growth rate

"Population growth rate" is the rate at which the number of individuals in a population increases within a given period of time, expressed as a fraction of the initial population. In particular, the rate of population growth refers to population changes during the unit time period, often expressed as a percentage of the number of individuals in the population at the beginning of the period. This can be written as a formula, valid for a fairly small time interval:

              -               P               ()                               t                                   1                                                                     P               ()                               t                                   1                                             ()                               t                                   2                                             -                               t                                   1                                                                       {P (t_ {p (t_ {2}) - P (t_ {1})} {P (t_ { 1}) (t_ {2} -t_ {1})}}}  Â

A positive growth rate indicates that the population is increasing, while a negative growth rate indicates that the population is declining. The zero growth ratio shows that there are the same number of individuals at the beginning and end of the period - growth rates may be zero even when there are significant changes in birth rates, mortality rates, immigration rates, and age distribution between two times.

Related size is the net reproduction rate. In the absence of migration, a net reproduction rate of more than 1 indicates that the female population increases, while a net reproduction rate of less than one (fertility sub-substitute) indicates that the female population declines.

Most populations do not grow exponentially, but they follow the logistics model. Once the population has reached its carrying capacity, it will stabilize and the exponential curve will travel to the carrying capacity, which is usually when the population has spent most of its natural resources.

Logistics equation

Pertumbuhan populasi sering dapat dimodelkan oleh persamaan logistik

${\ displaystyle {\ frac {dP} {dt}} = kP \ left (1 - {\ frac {P} {K}} \ right),}  ÂÂ$

dimana

• ${\ displaystyle P (t)}  ÂÂ$ = populasi setelah waktu t;
• ${\ displaystyle t}  ÂÂ$ = waktu populasi bertambah;
• ${\ displaystyle k}  ÂÂ$ = koefisien laju pertumbuhan relatif;
• ${\ displaystyle K}  ÂÂ$ = daya dukung populasi; didefinisikan oleh ahli ekologi sebagai ukuran populasi maksimum yang dapat dipertahankan oleh lingkungan tertentu.

Karena ini adalah persamaan diferensial yang dapat dipisahkan, populasi dapat diselesaikan secara eksplisit, menghasilkan fungsi logistik:

${\ displaystyle P (t) = {\ frac {K} {1 Ae ^ {- rt}}}}  ÂÂ$ ,

di mana ${\ displaystyle A = {\ frac {K-P_ {0}} {P_ {0}}}}  ÂÂ$ dan ${\ displaystyle P_ {0}}  ÂÂ$ adalah populasi awal pada saat 0.

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Tingkat pertumbuhan populasi manusia

In 2017, the estimated annual growth rate is 1.1%. The CIA World Factbook provides annual birth rates, mortality rates, and world growth rates of 1.86%, 0.78%, and 1.08%, respectively. The last 100 years have experienced a fourfold increase in the population, due to medical advances, lower mortality rates, and increased agricultural productivity made possible by the Green Revolution.

The annual increase in human numbers reached 88.0 million in 1989, then slowly decreased to 73.9 million in 2003, then rising again to 75.2 million in 2006. In 2017, the human population increased by 83 million. Generally, developed countries have seen a decline in their growth rates in recent decades, although annual growth rates remain above 2% in countries with poverty in the Middle East and Sub-Saharan Africa, as well as in South Asia, Southeast Asia , and Latin America.

In some countries the population declines, especially in Eastern Europe, mainly due to low fertility rates, high mortality rates and emigration. In South Africa, growth slowed due to high AIDS-related deaths. Some Western European countries may also experience a decline in population. Japan's population began to decline in 2005; now has the highest standard of living in the world.

The UN Population Division projected the world population to reach 11.2 billion by the end of the 21st century, but Sanjeev Sanyal believes that global fertility will fall below replacement levels by the 2020s and the world population will reach below 9 billion by 2050, followed by a long decline. A 2014 study at Science concluded that the global population would reach 11 billion by 2100, with a possible 70% to continue growth into the 22nd century.

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Growth by country

According to United Nations population statistics, the world population grew by 30%, or 1.6 billion people, between 1990 and 2010. In some people, the highest increase occurred in India (350 million) and China (196 million). Population growth was the highest in the United Arab Emirates (315%) and Qatar (271%).

Notes

* Eritrea left Ethiopia in 1991.

Separate to Sudan and South Sudan during 2011.

? Japan and the Ryukyu Islands joined in 1972.

# India and Sikkim joined in 1975.

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Growth by region

Population growth rates vary by region of the world, with the highest growth rates in Sub-Saharan Africa and the lowest in Europe. For example, from 1950 to 2010, Sub-Saharan Africa grew more than three and a half times, from about 186 million to 856 million. On the other hand, Europe only increased by 35%, from 547 million in 1950 to 738 million in 2010. As a result of this diverse population growth, Sub-Saharan Africa changed from 7.4% of the world's population in 1950 to 12 , 4% in 2010., while Europe decreased from 22% to 11% within the same time period.

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Go to the future

According to the United Nations 2017 revision to its population projection, the world's population is projected to reach 11.2 billion by 2100 compared with 7.6 billion in 2017. In 2011, Indian economist Sanjeev Sanyal debated the UN figures and argued that birth rates would fall below the replacement level in the 2020s. According to projections, population growth will only last until the 2040s with increasing longevity, but will reach below 9 billion by 2050. By contrast, a 2014 paper by demographics from several universities and the UN Population Division projected that the world population would reach about 10.9 billion in 2100 and continues to grow thereafter. One of its authors, Adrian Raftery, a professor of statistics and sociology at the University of Washington, said: "The consensus over the past 20 years or so is that the world's population, which is currently around 7 billion, will rise to 9 billion and levels or may decline. probably 70 percent of the world's population will not stabilize in this century, the population, which has fallen from the global agenda, remains a very important issue. "

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See also

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References

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External links

• World Population Prospects, Website of the United Nations Population Division
• Probabilistic Population Projection, 2nd Revision, Website of United Nations Population Division
• 2008 essay on Population Growth Blue Planet Unity - Population Press
• Growth in world population and trends from 1950-2050 US Census
• World population: focus on youth, Annual World Population Data Sheet, Population Reference Bureau
• The UN University's annual "Country of the Future" report, including updates on the Millennium Project goals including balancing global population growth & resources
• Population Growth Rate by Country, aggregate timeframe data from 1960 to present
• BBC News - Birth rate 'destroys poverty target' - 08/12/06
• Tsirel, S. V. 2004. On Possible Reasons for the Hyperexponential Growth of the Earth Population. Mathematical Modeling of Social and Economic Dynamics /Ed. by M. G. Dmitriev and A. P. Petrov, pp.Ã, 367-9. Moscow: Russian State Social University, 2004.
• Rosling, Hans (January 25, 2009). "What's stopping population growth?". Gapminder . Retrieved 2009-07-06 .

Source of the article : Wikipedia