World population

The world population is the total number of living humans on Earth at a given time. As of July 8 2008, the world's population is believed to be approximately 6,708,700,100. In line with population projections, this figure continues to grow at rates that were unprecedented before the 20th century, although the rate of increase has almost halved since its peak of 2.2 percent per year, which was reached in 1963. The world's population, on its current growth trajectory, is expected to reach nearly 9 billion by the year 2042.

Population figures

Censuses taken between 300–400 CE showed over 50 million people living in the combined eastern and western Roman empire.(citation Dr. Kenneth W. Harl, tulane.edu)

Below is a table with historical and predicted population figures shown in millions. The availability of historical population figures varies by region. (Note: These projections here are not kept up to date.) Please see World population estimates for more figures.

World historical and predicted populations (in millions)

Region	1750	1800	1850	1900	1950	1999	2050	2150
World	791	978	1,262	1,650	2,521	5,978	8,909	9,746
Africa	106	107	111	133	221	767	1,766	2,308
Asia	502	635	809	947	1,402	3,634	5,268	5,561
Europe	163	203	276	408	547	729	628	517
Latin America and the Caribbean *	16	24	38	74	167	511	809	912
Northern America *	2	7	26	82	172	307	392	398
Oceania	2	2	2	6	13	30	46	51

World historical and predicted populations by percentage distribution

Region	1750	1800	1850	1900	1950	1999	2050	2150
World	100	100	100	100	100	100	100	100
Africa	13.4	10.9	8.8	8.1	8.8	12.8	19.8	23.7
Asia	63.5	64.9	64.1	57.4	55.6	60.8	59.1	57.1
Europe	20.6	20.8	21.9	24.7	21.7	12.2	7.0	5.3
Latin America and the Caribbean *	2.0	2.5	3.0	4.5	6.6	8.5	9.1	9.4
Northern America *	0.3	0.7	2.1	5.0	6.8	5.1	4.4	4.1
Oceania	0.3	0.2	0.2	0.4	0.5	0.5	0.5	0.5

Estimated world population at various dates (in thousands)

Year	World	Africa	Asia	Europe	Latin America *	Northern America*	Oceania	Notes
70,000 BCE	2
10,000 BCE	1,000
9000 BCE	3,000
8000 BCE	5,000
7000 BCE	7,000
6000 BCE	10,000
5000 BCE	15,000
4000 BCE	20,000
3000 BCE	25,000
2000 BCE	35,000
1000 BCE	50,000
500 BCE	100,000
1	200,000
1000	310,000
1750	791,000	106,000	502,000	163,000	16,000	2,000	2,000
1800	978,000	107,000	635,000	203,000	24,000	7,000	2,000
1850	1,262,000	111,000	809,000	276,000	38,000	26,000	2,000
1900	1,650,000	133,000	947,000	408,000	74,000	82,000	6,000
1950	2,518,629	221,214	1,398,488	547,403	167,097	171,616	12,812
1955	2,755,823	246,746	1,541,947	575,184	190,797	186,884	14,265
1960	2,981,659	277,398	1,674,336	601,401	209,303	204,152	15,888
1965	3,334,874	313,744	1,899,424	634,026	250,452	219,570	17,657
1970	3,692,492	357,283	2,143,118	655,855	284,856	231,937	19,443
1975	4,068,109	408,160	2,397,512	675,542	321,906	243,425	21,564
1980	4,434,682	469,618	2,632,335	692,431	361,401	256,068	22,828
1985	4,830,979	541,814	2,887,552	706,009	401,469	269,456	24,678
1990	5,263,593	622,443	3,167,807	721,582	441,525	283,549	26,687
1995	5,674,380	707,462	3,430,052	727,405	481,099	299,438	28,924
2000	6,070,581	795,671	3,679,737	727,986	520,229	315,915	31,043
2005	6,453,628	887,964	3,917,508	724,722	558,281	332,156	32,998**
Year	World	Africa	Asia	Europe	Latin America *	Northern America*	Oceania	Notes

* Northern America indicates the northern countries and territories of North America: Canada, the United States, Greenland, Bermuda, and St. Pierre and Miquelon. This should not be confused with the term "North America" which typically includes Mexico. The United Nations data includes Mexico as part of Latin America.

** This figure is disputed.

Rate of increase

Different regions have different rates of population growth, but in the unusual case of the 20th century, the world saw the biggest increase in its population in human history due to medical advances and massive increase in agricultural productivity made by the Green Revolution.

In 2000, the United Nations estimated that the world's population was then growing at the rate of 1.14% (or about 75 million people) per year, down from a peak of 86 million per year in 1987. 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. The 2007 CIA factbook increased this to 211,090 people every day.

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

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.

Population growth which exceeds the carrying capacity of an area or environment results in overpopulation. Conversely, such areas may be considered "underpopulated" if the population is not large enough to maintain an economic system; however, many who do not view overpopulation as a serious problem fail to consider the sustainability of economic systems, the environmental degradation caused, and the ecological footprint of the existing population.

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 2075.

• 

  Population (est.) 10,000 BCE – 2000 CE.

• 

  Population (est.) in log y scale

• 

  World population 1950–2000

• 

  Increase rate 1950–2000

Milestones

World population estimates milestones .

Population (in billions)	1	2	3	4	5	6	7	8	9
Year	1804	1927	1961	1974	1987	1999	2011	2024	2042
Years elapsed		123	34	13	13	12	12	13	18

These numbers show that the world's population has tripled in 72 years, and doubled in 38 years up to the year 1999. Including some more estimates, 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.

		Starting at 250 millions							Starting at 375 millions
Population (in billions)		0.25	0.5	1	2	4	8		0.375	0.75	1.5	3	6
Year		950	1600	1804	1927	1974	2024		1420	1720	1875	1961	1999
Years elapsed			650	204	123	47	50			300	155	86	38

Population distribution

Asia accounts for over 60% of the world population with almost 3.8 billion 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 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 21 million.

The 15 most populous nations

Approximately 4.3 billion people live in these 15 countries, representing roughly two-thirds of the world's population. If added together, all nations in the European Union, with 494 million people – about 7.3% of world's population in 2006 – would be third in the list below.

Country	Population (millions)	Percentage (of world)
China	1,321	19.84%
India	1,132	16.96%
United States	304	4.56%
Indonesia	232	3.47%
Brazil	187	2.80%
Pakistan	163	2.44%
Bangladesh	159	2.38%
Nigeria	148	2.22%
Russia	142	2.13%
Japan	128	1.92%
Mexico	107	1.60%
Philippines	89	1.33%
Vietnam	84	1.31%
Germany	82	1.23%
Egypt	81	1.13%
Total	4,356	65.32%

Ethnicity

The world is made up of hundreds of thousands of ethnic groups, and due to mass migration across the planet over millennia, it is impossible to tell how many people belonging to a certain ethnic group inhabit the earth. 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').

Demographics of youth

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

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 160 million-per-year raw births after 1995, the time it took to reach the next billion reached its fastest pace (only 12 years), as world population reached 6 billion people in 1999, when at the beginning of the decade, the reaching was designated for the year 2000, by most demographers. People aged 7 through 17 make up these births, today.

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 because 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 17 to 22 make up these births, today.

Forecast of world population

U.S. Census Bureau estimates

Year	Population (in billions)
2010	6.9
2020	7.7
2030	8.4
2040	9.0
2050	9.5

In the long run, the future population growth of the world is difficult to predict. 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.

Alternately, 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 United States Census bureau revision from June 18, 2008 has increased its projections further, to beyond 9.5 billion in 2050.

Other projections of population growth predict that the world's population will eventually crest, though it is uncertain exactly when or how. In some scenarios, the population will crest as early as the mid-21st century at under 9 billion, due to gradually decreasing birth rates, (the "low variant" of ), The "high variant" from the same source gives a population between 10 and 11 billion in 2050.

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).

UN estimates (in thousands).

Year	World	Africa	Asia	Europe	Latin America	US and Canada	Oceania
2010	6,830,283	984,225 (14.4%)	4,148,948 (60.7%)	719,714 (10.5%)	594,436 (8.7%)	348,139 (5.1%)	34,821 (0.5%)
2015	7,197,247	1,084,540 (15.1%)	4,370,522 (60.7%)	713,402 (9.9%)	628,260 (8.7%)	363,953 (5.1%)	36,569 (0.5%)
2020	7,540,237	1,187,584 (15.7%)	4,570,131 (60.6%)	705,410 (9.4%)	659,248 (8.7%)	379,589 (5.0%)	38,275 (0.5%)
2025	7,851,455	1,292,085 (16.5%)	4,742,232 (60.4%)	696,036 (8.9%)	686,857 (8.7%)	394,312 (5.0%)	39,933 (0.5%)
2030	8,130,149	1,398,004 (17.2%)	4,886,647 (60.1%)	685,440 (8.4%)	711,058 (8.7%)	407,532 (5.0%)	41,468 (0.5%)
2035	8,378,184	1,504,179 (18.0%)	5,006,700 (59.8%)	673,638 (8.0%)	731,591 (8.7%)	419,273 (5.0%)	42,803 (0.5%)
2040	8,593,591	1,608,329 (18.7%)	5,103,021 (59.4%)	660,645 (8.0%)	747,953 (8.7%)	429,706 (5.0%)	43,938 (0.5%)
2045	8,774,394	1,708,407 (19.5%)	5,175,311 (59.0%)	646,630 (7.4%)	759,955 (8.7%)	439,163 (5.0%)	44,929 (0.5%)
2050	8,918,724	1,803,298 (20.2%)	5,217,202 (58.5%)	653,323 (7.3%)	767,685 (8.6%)	447,931 (5.0%)	45,815 (0.5%)

Predictions based on our growing population

Although Thomas Malthus, in 1798, incorrectly predicted that population growth would eventually outrun food supply by the middle of the 19th century, food prices in the early 21st century have finally risen sharply on a global scale with serious malnutrition spreading widely in step. In 1968, Paul R. Ehrlich reignited this argument with his book The Population Bomb, which predicted that "in the 1970s and 1980s hundreds of millions of people will starve to death", and helped give the issue significant attention throughout the 1960s and 1970s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Simon.

On the opposite end of the spectrum there are a number of people who argue that today's low fertility rates in Europe, North America, Japan and Australia, combined with mass immigration, will have severe negative consequences for these countries.

Child poverty has been linked to people having children before they have the means to care for them. More recently, some scholars have put forward the Doomsday argument applying Bayesian probability to world population to argue that the end of humanity will come sooner than we usually think.

It should be noted that between 1950 and 1984, as the Green Revolution transformed agriculture around the globe, 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. The peaking of world hydrocarbon production ( Peak oil) may test Malthus and Ehrlich critics. As of May 2008, increased farming for use in biofuels, world oil prices at over $120 a barrel, global population growth, climate change, loss of agricultural land to residential and industrial development, and growing consumer demand in China and India have pushed up the price of grain. Food riots have recently taken place in many countries across the world.

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).

Number of humans who have ever lived

Estimates of the total number of people who have ever lived range approximately from 45 billion to 125 billion. Many of the more robust estimates fall into the range of 90 to 110 billion humans. It is impossible to make a precise count of the number of human beings who have ever lived for the following reasons:

• 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.

• 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 exists 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. Even with the advent of agencies such as the United States Bureau of the Census, reliable census methods and technologies continue to evolve. All estimates 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.

"Guesstimating the number of people ever born... requires selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period..."

According to one set of calculations based on 2002 data:

• The number who have ever been born is around 106 000 000 000.
• The world population in mid-2002 was approximately 6 215 000 000
• The percentage of those ever born who were living in 2002 was approximately 5.8%