2008 Revision of World Population Prospects



2008 Revision of World Population Prospects

Key Findings

1. In July 2009, the world population will reach 6.8 billion, 313 million more than in 2005 or a gain of

78 million persons annually. Assuming that fertility levels continue to decline, the world population

is expected to reach 9.1 billion in 2050 and to be increasing by about 33 million persons annually at

that time, according to the medium variant.

2. Future population growth is highly dependent on the path that future fertility takes. In the medium

variant, fertility declines from 2.56 children per woman in 2005-2010 to 2.02 children per woman

in 2045-2050. If fertility were to remain about half a child above the levels projected in the medium

variant, world population would reach 10.5 billion by 2050. A fertility path half a child below the

medium would lead to a population of 8 billion by mid-century. Consequently, population growth

until 2050 is inevitable even if the decline of fertility accelerates.

3. In the more developed regions, fertility has increased slightly in recent years so that its estimated

level in 2005-2010, 1.64 children per woman, according to the 2008 Revision is higher than the onereported in the 2006 Revision (1.60 children per woman). As a result of the slightly higher projected

fertility and a sustained net in-migration averaging 2.4 million annually, the population of the more

developed regions is expected to increase slightly from 1.23 billion in 2009 to 1.28 billion in 2050.

4. The population of the 49 least developed countries is still the fastest growing in the world, at 2.3 per

cent per year. Although its rate of increase is expected to moderate significantly over the next

decades, the population of the least developed countries is projected to double, passing from 0.84

billion in 2009 to 1.7 billion in 2050. Growth in the rest of the developing world is also projected to

be robust, though less rapid, with its population rising from 4.8 billion to 6.2 billion between 2009

and 2050 according to the medium variant.

5. Slow population growth brought about by reductions in fertility leads to population ageing, that is, it

produces populations where the proportion of older persons increases while that of younger persons

decreases. In the more developed regions, 22 per cent of population is already aged 60 years or over

and that proportion is projected to reach 33 per cent in 2050. In developed countries as a whole, the

number of older persons has already surpassed the number of children (persons under age 15), and

by 2050 the number of older persons in developed countries will be more than twice the number of


6. Population ageing is less advanced in developing countries. Nevertheless, the populations of a

majority of them are poised to enter a period of rapid population ageing. In developing countries as

a whole, just 9 per cent of the population is today aged 60 years or over but that proportion will

more than double by 2050, reaching 20 per cent that year.

7. Globally, the number of persons aged 60 or over is expected almost to triple, increasing from 739

million in 2009 to 2 billion by 2050. Furthermore, already 65 per cent of the world’s older persons

live in the less developed regions and by 2050, 79 per cent will do so.

8. In ageing populations, the numbers of persons with older ages grow faster the higher the age range

considered. Thus, whereas the number of persons aged 60 or over is expected to triple, that of

persons aged 80 or over (the oldest-old) is projected to increase four-fold, to reach 395 million in

2050. Today, just about half of the oldest-old live in developing countries but that share is expected

to reach 69 per cent in 2050.

9. Although the population of all countries is expected to age over the foreseeable future, the

population will remain relatively young in countries where fertility is still high, many of which are

experiencing very rapid population growth. High population growth rates prevail in many

developing countries, most of which are least developed. Between 2010 and 2050, the populations

of 31 countries, the majority of which are least developed, will double or more. Among them, the

populations of Afghanistan, Burkina Faso, Niger, Somalia, Timor-Leste and Uganda are projected

to increase by 150 per cent or more.

10. In sharp contrast, the populations of 45 countries or areas are expected to decrease between 2010

and 2050. These countries include Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cuba, Georgia,

Germany, Hungary, Japan, Latvia, Lithuania, Moldova, Poland, the Republic of Korea, Romania,

the Russian Federation and Ukraine, all of which are expected to see their populations decline by at

least 10 per cent by 2050.

11. Population growth remains concentrated in the populous countries. During 2010-2050, nine

countries are expected to account for half of the world’s projected population increase: India,

Pakistan, Nigeria, Ethiopia, the United States of America, the Democratic Republic of Congo, the

United Republic of Tanzania, China and Bangladesh, listed according to the size of their

contribution to global population growth.

12. Fertility has continued to fall in the vast majority of countries in the less developed regions. The

number of developing countries with high fertility (5 children or more per woman) declined from

59 in 1990-1995 to 27 in 2005-2010, and their share of the world population dropped from 13 per

cent to 9 per cent. Over the same period, the number of developing countries with fertility levels

that do not ensure the replacement of the population increased from 15 to 38.

13. Most developed countries have had below-replacement fertility (below 2.1 children per woman) for

two or three decades. Among the 45 developed countries with at least 100,000 inhabitants in 2009,

42 had below-replacement fertility in 1990-1995 and 44 did in 2005-2010. However, between the

2000-2005 and 2005-2010, 34 developed countries experienced slight increases in fertility. For the

more developed regions as a whole, total fertility increased from 1.58 to 1.64 children per woman

between those two periods. Yet, in 2005-2010, 25 developed countries, including Japan and most of

the countries in Southern and Eastern Europe, still had fertility levels below 1.5 children per


14. In 2005-2010, the 76 countries with below-replacement fertility accounted for 47 per cent of the

world population. The most populous developing countries with below replacement fertility are

China, Brazil, Viet Nam, the Islamic Republic of Iran, Thailand and the Republic of Korea, in order

of population size.

15. Globally, total fertility is expected to fall from 2.56 children per woman in 2005-2010 to 2.02 in

2045-2050 according to the medium variant. However, in the more developed regions, total fertility

is projected to increase from 1.64 children per woman currently to 1.80 in 2045-2050. A major

reduction of fertility is projected for the group of least developed countries (from 4.39 to 2.41

children per woman) and the fertility of the rest of the developing world is expected to drop from

2.46 children per woman currently to 1.93 in 2045-2050, thus nearly converging to the fertility

levels by then typical of the developed world.

16. The median age, that is, the age that divides the population in two halves of equal size, is an

indicator of population ageing. Globally, the median age is projected to increase from 29 to 38 years

between 2009 and 2050. Europe has today the oldest population, with a median age of nearly 40

years, which is expected to reach 47 years in 2050.

17. The median age is higher in countries that have been experiencing low fertility for a long time. In

2010, 19 developed countries or areas are expected to have a median age of 40 years or higher, up

from 11 in 2005. In addition, among developing countries or areas, median ages above 40 were

reached in Hong Kong SAR China and Singapore. The pervasiveness of population ageing will

increase by 2050 when all 45 developed countries are projected to have median ages higher than 40

years and 43 developing countries will also have similarly high median ages. Whereas today abou

7 per cent of the world population lives in countries where median ages are 40 years or higher, the

equivalent proportion in 2050 is projected to be 43 per cent.

18. Countries where fertility remains high and has declined only moderately will experience the slowest

population ageing. By 2050, slightly fewer than one in five countries is projected to have a median

age under 30 years (37 countries). The youngest populations will be found among the least

developed countries, eight of which are projected to have median ages below 25 years in 2050,

including Afghanistan, Chad, Guinea-Bissau, Niger, Somalia, Uganda, United Republic of Tanzania

and Zambia.

19. Increasing longevity also contributes to population ageing. Globally, life expectancy at birth is

projected to rise from 68 years in 2005-2010 to 76 years in 2045-2050. In the more developed

regions, the projected increase is from 77 years in 2005-2010 to 83 years inn 2045-2050, while in

the less developed regions the increase is expected to be from 66 years currently to 74 years by midcentury.

20. Life expectancy remains low in the least developed countries, at just 56 years in 2005-2010, and

although it is projected to reach 69 years in 2045-2050, realizing such increase is contingent on

reducing the spread of HIV and combating successfully other infectious diseases. Similar

challenges must be confronted if the projected increase of life expectancy in the rest of the

developing countries, from under 68 years today to 76 years by mid-century, is to be achieved.

21. A major concern is that most developing countries are unlikely to meet the goal of reducing underfive

mortality by two-thirds between 1990 and 2015, as called for in the Millennium Development

Goals. According to the 2008 Revision, 134 of the 151 developing countries with more than

100,000 inhabitants in 2009 will not reach that goal. Furthermore, 59 developing countries, located

mainly in sub-Saharan Africa or belonging to the group of least developed countries, are projected

to have in 2015 an under-five mortality higher than 45 deaths per 1000, the less demanding target

set by the Programme of Action of the International Conference on Population and Development.

22. Among the more developed regions, Eastern Europe has the lowest life expectancy and it has

experienced reductions in life expectancy at birth since the late 1980s. In 2005-2010 life expectancy

in the region increased somewhat but at 69.2 years was lower than it had been in 1965-1970 (69.6

years). Despite having recorded some recovery since the late 1990s, Moldova, the Russian

Federation and Ukraine have currently the lowest life expectancies among developed countries

(below 70 years).

23. Although the HIV/AIDS epidemic continues to be a major issue of concern in the global health

agenda, adult HIV prevalence reached a peak over the past decade or so in at least two thirds of the

58 countries considered to be most affected by the epidemic and a growing number of them are

reaching and maintaining lower prevalence levels. Nevertheless, in countries where prevalence has

been high, the impact of the epidemic in terms of morbidity, mortality and slower population

growth continues to be evident. Thus, in Southern Africa, the region with the highest prevalence of

the disease, life expectancy has fallen from 61 years in 1990-1995 to 52 years in 2005-2010 and is

only recently beginning to increase. Nevertheless, life expectancy in the region is not expected to

recover the level it had in the early 1990s before 2045. As a consequence, the growth rate of the

population in the region has plummeted, passing from 2.4 per cent annually in 1990-1995 to 0.6 per

cent annually in 2005-2010 and is expected to continue declining for the foreseeable future.

24. Given the low fertility prevailing in developed countries, deaths are expected to exceed births over

the foreseeable future. Consequently, the population of the more developed regions would be

World Population Prospects: The 2008 Revision xiii

decreasing if the excess of deaths over births were not counterbalanced by a net migration gain.

During 2010-2050, the net number of international migrants to more developed regions is projected

to be 96 million, whereas the excess of deaths over births is 58 million, implying an overall growth

of 38 million.

25. In 2005-2010, net migration in nine countries or areas more than doubled the contribution of natural

increase (births minus deaths) to population growth: Belgium, Macao SAR China, Luxembourg,

Malta, Qatar, Singapore, Slovakia, Slovenia and Spain. In addition, in a further 11 countries or

areas, net migration counterbalanced totally or in part the excess of deaths over births. These

countries are: Austria, the Channel Islands, Croatia, the Czech Republic, Germany, Greece,

Hungary, Italy, Japan, Portugal and the Russian Federation.

26. In terms of annual averages, the major net receivers of international migrants during 2010-2050 are

projected to be the United States (1.1 million annually), Canada (214,000), the United Kingdom

(174,000), Spain (170,000), Italy (159,000), Germany (110,000), Australia (100,000) and France

(100,000). The major countries of net emigration are projected to be Mexico (-334,000), China

(-309,000 annually), India (-253,000), the Philippines (-175,000), Pakistan (-161,000), Indonesia

(-156,000) and Bangladesh (-148,000). Although the current economic crisis may reduce migration

flows in comparison to those registered over the recent past, the major economic and demographic

asymmetries that will persist are likely to remain powerful generators of international migration

over the medium-term future.


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