The World at Six Billion
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United Nations
INTRODUCTION
According to the latest United Nations population estimates, world population reaches the six billion
mark on 12 October 1999, an historic milestone in the growth of world population. The marking of a world of
six billion just at the dawn of the new millennium is a convergence of events that is attracting widespread
global attention.
The World at Six Billion
was prepared in response to this attention. It provides in tabular and
graphic form salient characteristics of past, current and future world population growth.
The twentieth century has witnessed extraordinary population growth. During this century, world
population increased from 1.65 billion to 6 billion, and experienced both the highest rate of population growth
(averaging 2.04 per cent per year) during the late 1960s, and the largest annual increment to world population
(86 million persons each year) in the late 1980s.
The world population growth rate has fallen from its peak of 2 per cent per year to around 1.3 per cent
today. Nonetheless, world population will continue to increase substantially during the twenty-first century.
United Nations projections (medium fertility scenario) indicate that world population will nearly stabilize at
just above 10 billion persons after 2200. However, the twenty-first century is expected to be one of
comparatively slower population growth than the previous century, and be characterized by declining fertility
and the ageing of populations.
At the same time that the world population growth rate has declined from its peak, the average number
of children per couple has fallen from 4.9 to 2.7 and life expectancy at birth has risen from 56 years to 65
years. The share of the world’s population living in urban areas has increased from 36 per cent to 47 per cent
and the number of megacities of 10 million persons or more has grown from 5 to 18. The number of persons
who have moved to another country has risen to over 125 million today.
In the less developed regions, couples are currently having about two children less than couples did three
decades ago. Even though fertility has declined to relatively moderate levels in many developing countries, and to
below replacement level in some, a large and growing number of births are occurring annually, due to the
continued growth in the number of women of childbearing age; a legacy of past high fertility levels. In the more
developed regions, fertility declined from 2.4 births per woman during the late 1960s to an historic low of 1.6 for
the current period. In Europe, Northern America and Japan, the current fertility rate is 1.5 births per woman or
below.
In spite of the impressive gains in health and life expectancy that the world has exhibited during the past
decades, much remains to be done. Recent years has shown a devastating toll from AIDS in a number of
countries, particularly in sub-Saharan Africa. In addition, in some countries of Eastern Europe, the health
situation has been deteriorating and adult mortality, especially among males, has increased.
The twentieth century has witnessed the growth of urban centres and the concentration of population in
urban areas. Half of the world population is expected to be urban by 2006. Giant urban agglomerations are
becoming both more numerous and larger in size.
Another major transformation of the twentieth century has been population ageing. In 1999 there were
593 million persons aged 60 years or over in the world, comprising 10 per cent of the world population. By 2050,
this figure will triple to nearly 2 billion older persons, comprising 22 per cent of the world population. This
changing age structure will have wide-ranging economic and social consequences, affecting such factors as
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The World at Six Billion
United Nations
economic growth, savings and investment, labour supply and employment, pension schemes, and health and
long-term care. While once limited to developed countries, concern for the consequences of ageing has spread to
developing countries.
This publication provides a set of boxes, figures and tables that provides country and regional and
world-level data on population and demographic trends and corresponding population policies. The population
and demographic data are taken largely from the official United Nations population estimates and projections
prepared biennially by the Population Division for the United Nations system and are the consistent set of
population numbers utilized by the United Nations system. Projections are from the medium-fertility scenario.
Other scenarios, in particular the high and low, appear in other publications of the United Nations Population
Division. Policy information is from the Population Policy Data Bank maintained by the Population Division
for the United Nations. The full set of references used when compiling this publication is given in the
Bibliography section at the end of the volume.
These boxes, figures and tables are intended to provide readers with an overview of the startling
changes in the population and demography of the world during the twentieth century and earlier, and insight
into how the world’s demographics will change during the twenty-first century.
The World at Six Billion
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BOX 1. THE WORLD AT SIX BILLION: HIGHLIGHTS
1.
World population is estimated to cross the six billion threshold on October 12, 1999.
2.
World population is projected to cross the 7 billion mark in 2013; the 8 billion mark in 2028; the 9
billion mark in 2054. World population nearly stabilizes at just above 10 billion after 2200.
3.
It has taken just 12 years for the world to add this most recent billion people. This is the shortest
period of time in world history for a billion people to be added.
4.
World population did not reach one billion until 1804. It took 123 years to reach 2 billion in 1927, 33
years to reach 3 billion in 1960, 14 years to reach 4 billion in 1974 and 13 years to reach 5 billion in
1987.
5.
The highest rate of world population growth (2.04 per cent) occurred in the late 1960s. The current
rate (1995-2000) is 1.31 per cent.
6.
The largest annual increase to world population (86 million) took place in the late 1980s; the current
annual increase is 78 million.
7.
Of the 78 million people currently added to the world each year, 95 per cent live in the less developed
regions.
8.
Eighty per cent of the world currently reside in the less developed regions. At the beginning of the
century, 70 per cent did so. By 2050, the share of the world population living in the currently less
developed regions will have risen to 90 per cent.
9.
The population of the world is ageing. The median age increased from 23.5 years in 1950 to 26.4
years in 1999. By 2050, the median age is projected to reach 37.8 years. The number of people in the
world aged 60 or older will also rise from the current one-of-ten persons to be two-of-nine by 2050.
Currently around one-of-five persons in the developed countries are aged 60 or older; in 2050 nearly
one-of-every three persons will be aged 60 or older.
10.
World life expectancy at birth is now at 65 years, having increased by a remarkable 20 years since
1950; by 2050 life expectancy is expected to exceed 76 years. However, in spite of these impressive
gains, recent years have shown a devastating toll from AIDS in a number of countries. In addition, in
some Eastern European countries, health has been deteriorating and mortality, particularly among
adult males, has been rising.
11.
Couples in developing countries today have on average 3 children each; thirty years ago they had six.
More than half of all couples in developing countries now use contraception.
12.
The number of persons who have moved to another country has risen to over 125 million migrants
today from 75 million in 1965.
13.
The world has become increasingly urban. Currently, around 46 per cent of the world population lives
in urban areas; the majority of the world’s population will be urban by 2006.
_______________
Source
: United Nations Population Division.
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BOX 2. WORLD POPULATION GROWTH
The rapid growth of the world population is a recent phenomenon in the history of the world. It is
estimated that 2000 years ago the population of the world was about 300 million. For a very long time the
world population did not grow significantly, with periods of growth followed by periods of decline. It
took more than 1600 years for the world population to double to 600 million.
The world population was estimated at 791 million in 1750, with 64 per cent in Asia, 21 per cent in
Europe and 13 per cent in Africa. By 1900, 150 years later, the world population had only slightly more
than doubled, to 1.7 billion. The major growth had been in Europe, whose share had increased to 25 per
cent, and in Northern America and in Latin America, whose share had increased to 5 per cent each.
Meanwhile the share of Asia had decreased to 57 per cent and that of Africa to 8 per cent. The growth of
the world population accelerated after 1900, with 2.5 billion in 1950, a 53 per cent increase in 50 years.
The rapid growth of the world population started in 1950, with reductions in mortality in the less
developed regions, resulting in an estimated population of 6.1 billion in the year 2000, nearly two-and-a-
half times the population in 1950. With the declines in fertility in most of the world, the global growth
rate of population has been decreasing since its peak of 2.0 per cent in 1965-1970. In 1999, the world’s
population stands at 6 billion and is growing at 1.3 per cent per year, or an annual net addition of 78
million people.
According to the medium variant of the
1998 Revision
of the official United Nations estimates and
projections, by 2050 the world is expected to have 8.9 billion people, an increase of nearly half over the
2000 population. By 2050, the share of Asia will be at nearly 60 per cent, that of Africa will have more
than doubled, to 20 per cent, and that of Latin America nearly doubled, to 9 per cent. Meanwhile the
share of Europe will decline to 7 per cent, less than one third its peak level achieved at the beginning of
the twentieth century. While in 1900 the population of Europe was three times that of Africa, in 2050 the
population of Africa will be nearly three times that of Europe.
The world population will continue to grow after 2050. The medium-fertility scenario from the
United Nations latest long-range population projections indicates that the world would reach 9.7 billion
by 2150 and nearly stabilize at just above 10 billion after 2200.
_______________
Source
: United Nations Population Division.
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T
ABLE
1. W
ORLD POPULATION
,
YEAR
0
TO NEAR STABILIZATION
Year
Population
(in billions)
0
1000
1250
1500
1750
1800
1850
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
1999
2000
2010
2020
2030
2040
2050
2100
2150
Near stabilization (after 2200)
0.30
0.31
0.40
0.50
0.79
0.98
1.26
1.65
1.75
1.86
2.07
2.30
2.52
3.02
3.70
4.44
5.27
5.98
6.06
6.79
7.50
8.11
8.58
8.91
9.46
9.75
Just above 10 billion
Source
: United Nations Population Division.
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T
ABLE
2. P
OPULATION OF THE WORLD AND ITS MAJOR AREAS
, 1750-2150
Major area
1750
1800
1850
1900
1950
1999
2050
2150
A. Population size (millions)
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
B. Percentage distribution
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
Source
: United Nations Population Division.
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Figure 1. Long-term world population growth, 1750 to 2050
0
20
40
60
80
100
0
2
4
6
8
10
1750
1800
1850
1900
1950
2000
2050
Billions
Millions
Annual increments
Population size
Population increment
Population size
Source
: United Nations Population Division.
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BOX 3. WORLD POPULATION MILESTONES
World Population reached
:
1 billion in
1804
2 billion in 1927 (123 years later)
3 billion in
1960 (33 years later)
4 billion in
1974 (14 years later)
5 billion in
1987 (13 years later)
6 billion in
1999 (12 years later)
World Population may reach
:
7 billion in
2013 (14 years later)
8 billion in
2028 (15 years later)
9 billion in
2054 (26 years later)
10 billion in
2183 (129 years later)
Source
: United Nations Population Division.
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United Nations
T
ABLE
3. P
OPULATION SIZE AND COMPONENTS OF GROWTH BY MAJOR AREA
, 1995-2000
Births
Deaths
Net
migration
Total
growth
Major area
Population
1999
(thousands)
(annual average, in thousands)
World total
5 978 401
129 810
52 072
0
77 738
More developed regions
1 185 174
13 224
11 951
1 971
3 243
Less developed regions
4 793 227
116 586
40 121
-1 971
74 494
Africa
766 623
28 115
10 331
-287
17 496
Asia
3 634 279
77 953
27 492
-1 207
49 254
Europe
728 934
7 493
8 248
950
195
Latin America and the Caribbean
511 345
11 554
3 245
-471
7 838
Northern America
307 202
4 172
2 528
930
2 574
Oceania
30 018
527
227
81
381
Source
: United Nations Population Division.
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Figure 2. World population growth rates: past estimates and medium-, high-
and low-fertility variants, 1950-2050
Growth rate (per cent)
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
1950-
1955
1955-
1960
1960-
1965
1965-
1970
1970-
1975
1975-
1980
1980-
1985
1985-
1990
1990-
1995
1995-
2000
2000-
2005
2005-
2010
2010-
2015
2015-
2020
2020-
2025
2025-
2030
2030-
2035
2035-
2040
2040-
2045
2045-
2050
High
Medium
Low
Source
: United Nations Population Division.
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United Nations
T
ABLE
4. C
URRENT LEVELS OF POPULATION GROWTH
,
MORTALITY
,
FERTILITY
AND CONTRACEPTIVE USE
,
BY MAJOR AREAS
Major area
Population
size, 1999
(millions)
Population
growth rate,
1995-2000
(per cent)
Life
expectancy at
birth,
1995-2000
(years)
Total fertility
rate, 1995-2000
(average number
of children per
woman)
Contraceptive
use, 1990s
(per cent of
currently
married
women)
World
5 978
1.3
65
2.7
58
More developed regions
1 185
0.3
75
1.6
70
Less developed regions
4 793
1.6
63
3.0
55
Africa
767
2.4
51
5.1
20
Asia
3 634
1.4
66
2.6
60
Europe
729
0.0
73
1.4
72
Latin America and the Caribbean
511
1.6
69
2.7
66
Northern America
307
0.8
77
1.9
71
Oceania
30
1.3
74
2.4
64
Source
: United Nations Population Division.