World population

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Population density by country

Population by continent as a percentage of world population (1750–2005)

The world population is the total number of living humans on Earth at a given time. As of April 2009, the earth's population is estimated to be about 6.77 billion.^[1] The trend in world population has been of continuous growth since 400 AD, if not earlier,^[2] although during much of the 14th century^[3] there were significant short-term falls (especially in Europe) due to the Black Death. There were also short term falls at other times due to plague, for example in the mid 17th century.^[3][4][2] The fastest rates of world population growth (above 1.8%) were seen briefly during the 1950s then for a longer period during the 1960s and 1970s (see graph). According to population projections, world population will continue to grow until around 2050. The 2008 rate of growth has almost halved since its peak of 2.2% per year, which was reached in 1963. World births have levelled off at about 137-million-per-year, since their peak at 163-million in the late 1990's, and are expected to remain constant. However, deaths are only around 56 million per year, and are expected to increase to 90 million by the year 2050. Since births outnumber deaths, the world's population is expected to reach about 9 billion by the year 2040.^[5][6]

[edit] Population figures

It is estimated that over 57 million people lived in the combined eastern and western Roman Empire (300–400 AD).^[7] 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.^[8] During the Industrial Revolution, the life expectancy of children increased dramatically. The percentage of the children born in London who died before the age of five decreased from 74.5% in 1730-1749 to 31.8% in 1810-1829.^[9] Europe’s population doubled during the 18th century, from roughly 100 million to almost 200 million, and doubled again during the 19th century.^[10]

Below is a table with historical and predicted population figures shown in millions.^{[11][12][13] [14]}
The availability of historical population figures varies by region.

* Northern America comprises the northern countries and territories of North America: Canada, the United States, Greenland, Bermuda, and St. Pierre and Miquelon. Latin America comprises Middle America (Mexico, the nations of Central America, and the Caribbean) and South America.

[edit] Rate of increase

Population evolution in different continents. The vertical axis is logarithmic and is millions of people.

Different regions have different rates of population growth. According to the above table, the growth in population of the different regions from 2000 to 2005 was:

237.771 million in Asia

92.293 million in Africa

38.052 million in Latin America

16.241 million in Northern America

1.955 million in Oceania

-3.264 million in Europe

383.047 million in the whole world

In the 20th century, the world saw the biggest increase in its population in human history due to lessening of the mortality rate in many countries due to medical advances and massive increase in agricultural productivity attributed to the Green Revolution.^[19][20][21]

In 2000, the United Nations estimated that the world's population was growing at the rate of 1.14% (or about 75 million people) per year,^[22] down from a peak of 88 million per year in 1989. In the last few centuries, the number of people living on Earth has increased many times over. By the year 2000, there were 10 times as many people on Earth as there were 300 years ago. According to data from the CIA's 2005–2006 World Factbooks, the world human population increased by 203,800 every day.^[23] The CIA Factbook increased this to 211,090 people every day in 2007, and again to 220,980 people every day in 2009.

Globally, the population growth rate has been steadily declining from its peak of 2.19% in 1963, but growth remains high in Latin America, the Middle East and Sub-Saharan Africa.^[24]

In some countries there is negative population growth (i.e. net decrease in population over time), especially in Central and Eastern Europe (mainly due to low fertility rates) and Southern Africa (due to the high number of HIV-related deaths). Within the next decade, Japan and some countries in Western Europe are also expected to encounter negative population growth due to sub-replacement fertility rates.

The United Nations states that population growth is rapidly declining due to the demographic transition. The world population is expected to peak at 9.2 billion in 2050.[2]

Population (est.) 10,000 BC–2000 AD.

Population (est.) in log y scale

World population 1950–2000

Increase rate 1950–2000

[edit] Milestones

World Population Milestones (Billions - estimated).

There is currently no estimation on the exact day the world's population surpassed both the 1 and 2 billion marks. The day of 3 and 4 billion were not officially celebrated, but the International Database of the U.S. Census Bureau places them around July of 1959, and April of 1974. The United Nations did determine, and celebrate, the "Day of 5 billion" (July 11, 1987), and the "Day of 6 billion" (October 12, 1999). The U.S. Census bureau, International Programs division, currently estimated that the world reached 6 billion on April 21, 1999 (several months earlier than the official UN day). The "Day of 7 billion" has been targeted by the Census Bureau to be in February 2012.^[25]

The day of 350 million for the United States will occur in the year 2023. At this point in time the population growth rate of the USA will equal and then surpass that of Latin America and the Caribbean.

[edit] Years for Population to Double

Including some more estimates (together with an interpolated number for year 950), the world population has been doubled or will double in the following years (with two different starting points). Note how, during the 2nd millennium, each doubling has taken roughly half as long as the previous doubling. However, it is unlikely that there will be another doubling in the current century.^[26]

Years for Population to Double

[edit] Distribution

Population density map of the world in 1994, when the world's population was at 5600 million; Observe the high densities in the Indo-Gangetic and North China Plains, the Sichuan Basin, the Nile river delta, Southern Japan, Western Europe, the Indonesian island of Java, Central America (especially El Salvador, the Americas' most densely populated nation), and the United States' BosWash megalopolis.

Asia accounts for over 60% of the world population with almost 3800 million people. The People's Republic of China and India alone comprise 20% and 17% respectively. Africa follows with 840 million people, 12% of the world's population. Europe's 710 million people make up 11% of the world's population. North America is home to 514 million (8%), South America to 371 million (5.3%), and Australia to 21 million.

[edit] The world's most populous nations

Map of countries by population

The 10 most densely populated countries

Rank	Country	Population	Area (km²)	Density (Pop per km²)	Notes
1	Monaco	32,719	1.95	16,779	[27]
2	Singapore	4,620,657	707.1	6,535
3	Vatican City	824	0.44	1,873	[28]
4	Maldives	385,375	298	1,293
5	Malta	404,032	316	1,279
6	Bahrain	723,967	665	1,089	[29]
7	Bangladesh	155,688,660	147,570	1,055	[30]
8	Palestinian territories	4,223,760	6,020	702
9	Nauru	13,918	21	663
10	Republic of China (commonly, "Taiwan")	22,955,395	36,190	634	[28]

The 16 countries with the largest total population:

Rank	Country / Territory	Population	Date	% of world population	Source
1	China (excluding Hong Kong and Macau)	1,329,740,000	March 25, 2009	19.66%	Chinese Population Clock[31]
2	India	1,145,174,000	02009-03-03 March 3, 2009	16.94%	Indian Population clock
3	United States	305,924,270	02009-03-02 March 2, 2009	4.53%	Official USA Population clock
4	Indonesia	229,631,355	02009-03-03 March 3, 2009	3.4%	Indonesian Population clock
5	Brazil	190,765,170	02009-03-03 March 3, 2009	2.82%	Brazilian Population clock
6	Pakistan	165,772,000	02009-03-03 March 3, 2009	2.45%	Pakistani Population clock
7	Bangladesh	155,688,660	02009-03-02 March 2, 2009	2.3%	Private Bangladeshi Population clock
8	Nigeria	148,235,170		2.19%	UN estimate
9	Russia	141,849,333	02009-03-03 March 3, 2009	2.1%	Russian Population Clock
10	Japan	127,170,110	02009-03-02 March 2, 2009	1.88%	Japanese Statistics Bureau
11	Mexico	111,077,375	02009-03-02 March 2, 2009	1.64%	Private Mexican Population Clock
12	Philippines	93,843,460	02009-03-02 March 2, 2009	1.39%	Private Filipino Population Clock
13	Vietnam	86,709,095	02009-03-02 March 2, 2009	1.28%	Private Vietnamese Population Clock
14	Germany	82,060,000	02008-12 December 2008	1.21%	Federal Statistical Office of Germany
15	Ethiopia	79,221,000	02008-07 July 2008	1.18%	Ethiopia Central Statistics Agency
16	Egypt	75,973,137	02009-03-03 March 3, 2009	1.12%	Egyptian Population Clock
	European Union (includes Germany)	499,673,300	02009-01-01 January 1, 2009	7.39%	Eurostat estimate

Approximately 4.51 billion people live in these 16 countries, representing roughly two-thirds (66.7%) of the world's population as of February 2009. If added together, all nations in the European Union, with approximately 499.7 million people—about 7.4% of world's population as of January 2009—would be third in the list above.

Population by region, 2007

[edit] Ethnicity

The world is made up of thousands of ethnic groups. The single largest ethnic group on the planet by far is Han Chinese, which represents 19.73% of the global population. For comparison 6.06% of the planet's population is of full or partial Spanish ancestry, and on a wider scale 14.2% of earth's population is of Sub-Saharan descent (those identifying as 'Black')^{[citation needed]}.

[edit] Demographics of youth

According to the 2006 CIA World Factbook, around 27% of the world's population is below 15 years of age.^[32]

Before adding mortality rates, the 1990s saw the greatest number of raw births worldwide, especially in the years after 1995, despite the fact that the birth rate was not as high as in the 1960s. In fact, because of the 163 million-per-year raw births after 1995, the time it took to reach the next 10⁹ reached its fastest pace (only 12 years), as world population reached 6000 million people in 1999, when at the beginning of the decade, the reaching was designated for the year 2000, by most demographers. These people aged 9 through 18 make up these births today, and are either from the late Generation Y group, or are in the Generation Z group.

1985–1990 marked the period with the fastest yearly population change in world history. Even though the early 1960s had a greater growth rate than in the mid and late 1980s, the population change hovered around 83 million people in the five-year period, with an all-time growth change of nearly 88 million in 1990. The reason is that the world's population was greater in the mid- and late-1980s (around 5 billion) than in the early 1960s (around 3 billion), which meant that the growth rate in the 1980s was no factor on the dramatic population change. People aged 19 to 24 make up these births today, and are a part of Generation Y.

[edit] Forecast

In the long run, the future population growth of the world is difficult to predict and the UN and US Census Bureau give different estimates. Birth rates are declining slightly on average, but vary greatly between developed countries (where birth rates are often at or below replacement levels), developing countries, and different ethnicities. Death rates can change unexpectedly due to disease, wars and catastrophes, or advances in medicine. The UN itself has issued multiple projections of future world population, based on different assumptions. Over the last 10 years, the UN had consistently revised these projections downward, until the 2006 revision issued March 14, 2007 revised the 2050 mid-range estimate upwards by 273 million.

The United States Census Bureau issued a revised forecast for world population that increased its projection for the year 2050 to above 9.4 billion people (which was the UN's 1996 projection for 2050), up from 9.1 billion people. A new US Census Bureau revision from June 18, 2008 has increased its projections further, to beyond 9.5 billion in 2050.

Other projections are that the world's population will eventually crest, though it is uncertain when or how. In some scenarios, it will crest as early as around 2050 at under 9 billion, or 10 to 11 billion, due to gradually decreasing birth rates.^[11]

In other scenarios, disasters triggered by the growing population's demand for scarce resources will eventually lead to a sudden population crash, or even a Malthusian catastrophe (also see overpopulation and food security).

[edit] Predictions based on population growth

In 1798 Thomas Malthus incorrectly predicted that population growth would outrun food supply by the mid 19th century. In 1968, Paul R. Ehrlich reprised this argument in The Population Bomb, predicting famine in the 1970s and 1980s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Lincoln Simon. Agricultural research already under way, such as the green revolution, led to dramatic improvements in crop yields. Food production has kept pace with population growth, but Malthusians point out the green revolution relies heavily on petroleum-based fertilizers, and that many crops have become so genetically uniform that a crop failure would be very widespread. Food prices in the early 21st century are rising sharply on a global scale, and causing serious malnutrition to spread widely.^[36]

From 1950 to 1984, as the Green Revolution transformed agriculture around the world; grain production increased by 250%. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (natural gas), pesticides (oil), and hydrocarbon-fueled irrigation.^[37] The peaking of world hydrocarbon production (Peak oil) may test Malthus and Ehrlich critics.^[38][39] As of May 2008, the price of grain has been pushed up by increased farming for use in biofuels,^[40] world oil prices at over $140 per barrel,^[41] global population growth,^[42] climate change,^[43] loss of agricultural land to residential and industrial development,^[44][45] and growing consumer demand in China and India^[46][47]. Food riots have recently occurred in many countries across the world.^[48][49][50]

The world population has grown by about four billion since the beginning of the Green Revolution and most believe that, without the Revolution, there would be greater famine and malnutrition than the UN presently documents (approximately 850 million people suffering from chronic malnutrition in 2005).^[51]

Child poverty has been linked to people having children before they have the means to care for them.^[52]

[edit] Number of humans who have ever lived

In the 1970s it was popular to believe that 75% of all the people who had ever lived were alive in the 1970s, which would have put the total number of people who ever lived as of the 1970s as less than the current number of people alive today. This view was eventually debunked as a myth.^[53] A more recent estimate of the total number of people who have ever lived was prepared by Carl Haub of the Population Reference Bureau in 1995 and subsequently updated in 2002; the updated figure was approximately 106 billion.^[54][55] Haub characterized this figure as an estimate which required "selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period".^[55] Given an estimated global population of 6.2 billion in 2002, it could be inferred that about 6% of all people who had ever existed were alive in 2002.^[54]

Other estimates of the total number of people who have ever lived range approximately from 45 billion to 125 billion, with the more robust of these falling in the 90–110 billion range.^{[citation needed]} It is difficult to estimate for the following reasons:^{[citation needed]}

• The set of specific characteristics which define a human being and distinguish early Homo sapiens from earlier or related species continues to be a subject of intense research and debate. It is thus not possible to know when to begin the count, nor which hominids to include. See in this regard also Sorites paradox.
• Even if the scientific community reached wide consensus regarding which characteristics distinguished human beings, it would be nearly impossible to pinpoint the time of their first appearance to even the nearest millennium because the fossil record is simply too sparse. Only a few thousand fossils of early humans have been found, most no bigger than a tooth or a knucklebone. These bone fragments are used to extrapolate the population distribution of millions of early human beings spread across the continents.
• Robust statistical data only exist for the last two or three centuries. Until the late 18th century, few nations, kingdoms, or empires had ever performed an accurate census. In many early attempts, the focus was on counting merely a subset of the people for purposes of taxation or military service.^{[citation needed]} All claims of population sizes preceding the 18th century are estimates, and thus the margin of error for the total number of humans who have ever lived should be in the billions, or even tens of billions of people.

[edit] Further resources

• There is a map that is rescaled in order to display every country according to its population size. It is available at the University of Sheffield Worldmapper.^[56]
• Population patterns and trends can be explored on the GeoHive interactive world atlas.^[57]

[edit] References

[edit] See also

[edit] External links

• World Population Prospects (United Nations Population Division).
• Year-by-Year World Population Estimates: 10,000 B.C. to 2007 A.D.
• World Population
• The Population Project
• Optimum Population Trust
• State of World Population 2007 report 27 June, 2007 - United Nations Population Fund
• World Population Day United Nations: 11 July
• The Day of 6 Billion official homepage
• World Population Prospects. URL accessed on April 7, 2005.
• World Population Counter
• Trend of growth rate with total global population
• The World in Balance Transcript of two-part PBS' Nova on World Population
• BBC (1999). UN chief welcomes six billionth baby. URL accessed on March 7, 2005.
• Central Intelligence Agency (2004). CIA The World Factbook 2004. URL accessed on February 13, 2005.
• United Nations (2001). United Nations Population Information Network. URL accessed on February 13, 2005.
• United States Census Bureau (2004). Historical Estimates of World Population. URL accessed on February 13, 2005.
• PopulationData.net (2005). PopulationData.net - Information and maps about populations around the world.
• GeoHive GeoHive.com - World Statistics including population and future predictions.
• Population Reference Bureau www.prb.org - News and issues related to population.
• (French) World Population Clock (2005). WorldPopClock.com - World population clock.
• Population Counter. Real time counter..
• Population Information on population, population growth, population problems, population statistics, and population figures.
• World maps, including maps of population from Year 1 to Year 2300
• Live World Population
• Berlin Institute for Population and Development [[3]]
• World Population from the US Census Bureau in an interactive Excel dashboard