26 February 2003


Press Release



NEW YORK, 26 February (UN Population Division) -- The newly released 2002 Revision of the official United Nations population estimates and projections breaks new ground in terms of the assumptions made on future human fertility and the impact of the HIV/AIDS epidemic.  For the first time, the United Nations Population Division projects that future fertility levels in most developing countries will likely fall below 2.1 children per woman, the level needed to ensure the long-term replacement of the population, at some point in the twenty-first century.  By 2050, the medium variant of the 2002 Revision projects that three out of every four countries in the less developed regions will be experiencing below-replacement fertility.

With respect to HIV/AIDS, the 2002 Revision anticipates a more serious and prolonged impact of the epidemic in the most affected countries than in previous revisions.  The impact of the disease is explicitly modeled for 53 countries, up from the 45 considered in the 2000 Revision.  The dynamics of the epidemic, as estimated by the Joint United Nations Programme on HIV/AIDS (UNAIDS), are assumed to remain unchanged until 2010.  Thereafter, prevalence levels are assumed to decline in a manner consistent with modifications of behaviour that reduce the rates of recruitment into the high risk groups as well as the chances of infection among those engaging in high risk behaviour.  The resulting HIV prevalence levels remain relatively high until 2010 and then decline, but are still substantial by mid-century.

As a consequence of these changes, the 2002 Revision projects a lower population in 2050 than the 2000 Revision did:  8.9 billion instead of 9.3 billion according to the medium variant.  About half of the 0.4 billion difference in these projected populations results from an increase in the number of projected deaths, the majority stemming from higher projected levels of HIV prevalence.  The other half of the difference reflects a reduction in the projected number of births, primarily as a result of lower expected future fertility levels.

The 2002 Revision confirms key conclusions from previous revisions.  Despite the lower fertility levels projected and the increased mortality risks to which some populations will be subject, the population of the world is expected to increase by 2.6 billion during the next 47 years, from 6.3 billion today to

8.9 billion in 2050.  However, the realization of these projections is contingent on ensuring that couples have access to family planning and that efforts to arrest the current spread of the HIV/AIDS epidemic are successful in reducing its growth momentum.  The potential for considerable population increase remains high.  According to the results of the 2002 Revision, if fertility were to remain constant in all countries at current levels, the total population of the globe could more than double by 2050, reaching 12.8 billion.  Even a somewhat slower reduction of fertility than that projected in the medium variant would result in

additional billions of people. Thus, if women were to have, on average, about half a child more than according to the medium variant, world population might rise to 10.6 billion in 2050 as projected in the high variant.

The increasing diversity of population dynamics among the countries and regions of the world is evident in the results of the 2002 Revision.  Whereas today the population of the more developed regions of the world is rising at an annual rate of 0.25 per cent, that of the less developed regions is increasing nearly six times as fast, at 1.46 per cent, and the subset of the 49 least developed countries is experiencing even more rapid population growth (2.4 per cent per year).  Such differences, although somewhat dampened, will persist until 2050.  By that time, the population of the more developed regions will have been declining for 20 years, whereas the population of the less developed regions will still be rising at an annual rate of 0.4 per cent.  More importantly, the population of the least developed countries will likely be rising at a robust annual rate of over 1.2 per cent in 2045-2050.

As a result of these trends, the population of more developed regions, currently at 1.2 billion, is anticipated to change little during the next

50 years.  In addition, because fertility levels for most of the developed countries are expected to remain below replacement level during 2000-2050, the populations of 33 countries are projected to be smaller by mid-century than today (e.g., 14 per cent smaller in Japan; 22 per cent smaller in Italy, and between

30 and 50 per cent smaller in the cases of Bulgaria, Estonia, Georgia, Latvia, the Russian Federation and Ukraine).

The population of the less developed regions is projected to rise steadily from 4.9 billion in 2000 to 7.7 billion in 2050 (medium variant).  Particularly rapid growth is expected among the least developed countries whose population is projected to rise from 668 million to 1.7 billion despite the fact that their fertility is projected to decline markedly in the future (from 5.1 children per woman today to 2.5 children per woman in 2045-2050).  With sustained annual growth rates higher than 2.5 per cent between 2000 and 2050, the populations of Burkina Faso, Mali, Niger, Somalia, Uganda and Yemen are projected to quadruple, passing from 85 million to 369 million in total.

Large population increments are expected among the most populous countries even if their fertility levels are projected to be low.  Thus, during 2000-2050, eight countries (India, Pakistan, Nigeria, the United States, China, Bangladesh, Ethiopia and the Democratic Republic of Congo, in order of population increment) are expected to account for half of the world’s projected population increase.

The past 50 years witnessed a remarkable reduction of fertility levels in the less developed regions, with total fertility falling from six to three children per woman.  Over the next 50 years, fertility in less developed regions is expected to reach replacement level in 2030-2035 and fall below it thereafter.  However, average fertility in the less developed regions as a whole is still expected to be slightly above two children per woman in 2045-2050, mainly because of the increasing heterogeneity of population dynamics among developing countries.  Thus, the 49 least developed countries are expected to have a total fertility of 2.5 children per woman in 2045-2050, well above replacement level.  That is, the 2002 Revision foresees that by mid-century there will still be a significant number of countries where the transition to very low fertility will not be completed.

Increasing diversity is also evident with respect to future mortality levels.  At the world level, life expectancy at birth is likely to rise from

65 years today to 74 years in 2045-2050.  But whereas more developed regions, whose life expectancy today is estimated at 76 years, will see it rise to

82 years, that of less developed regions will remain considerably below, reaching 73 years by mid-century (up from 63 years today).  In the group of least developed countries, many of which are highly affected by the HIV/AIDS epidemic, life expectancy today is still below 50 years and is not expected to exceed 67 years by 2050.  So, although the gap in life expectancy between the different groups of countries is expected to narrow, major differences in the probabilities of survival will remain evident by mid-century.

The 2002 Revision indicates a worsening of the impact of the HIV/AIDS epidemic in terms of increased morbidity, mortality and population loss.  Although the probability of being infected by HIV is assumed to decline significantly in the future (particularly after 2010), the long-term impact of the epidemic remains dire.  Over the current decade, the number of excess deaths because of AIDS among the 53 most affected countries is estimated at 46 million and that figure is projected to ascend to 278 million by 2050.  Despite the devastating impact of the HIV/AIDS epidemic, the populations of the affected countries are generally expected to be larger by mid-century than today, mainly because most of them maintain moderate fertility levels.  However, for the seven most affected countries in southern Africa, where current HIV prevalence is above 20 per cent, the population is projected to increase only slightly, from 74 million in 2000 to 78 million in 2050, and outright reductions in population are projected for Botswana, Lesotho, South Africa and Swaziland.

The deeper reductions of fertility projected in the 2002 Revision result in a faster ageing of the population of developing countries than in previous revisions.  Globally, the number of older persons (60 years or over) will nearly triple, increasing from 606 million in 2000 to nearly 1.9 billion by 2050.  Whereas six of every 10 of those older persons live today in less developed regions, by 2050, eight of every 10 will do so.  An even more marked increase is expected in the number of the oldest-old (80 years or over) at the global level:  from 69 million in 2000 to 377 million in 2050.  In less developed regions, the rise will be from 32 million to 265 million, again implying that most oldest old will live in less developed countries by 2050.

In more developed regions, the population aged 60 or over currently constitutes 19 per cent of the population; by 2050 it will account for 32 per cent of the population.  The elderly population has already surpassed the child population (persons aged 0-14) and by 2050 there will be 2 elderly persons for every child.  In the less developed regions, the proportion of the population aged 60 or over will rise from 8 per cent in 2000 to close to 20 per cent in 2050.

Increases in the median age, the age at which 50 per cent of the population is older and 50 per cent is younger than that age, reflect the ageing of the population.  At the world level, the median age rose by scarcely three years between 1950 and 2000, from 23.6 years to 26.4 years largely because most populations in less developed countries remained young.  Over the next 50 years, however, the world’s median age will rise by nearly 10 years, to reach 37 years.  Among developed countries, 17 are expected to have a median age of 50 years or more, with Japan, Latvia and Slovenia (each with a median age of about 53 years), and the Czech Republic, Estonia, Italy, Singapore and Spain (each with a median age of about 52 years) leading the list.  At the other end of the spectrum,

Angola, Burkina Faso, Mali, Niger, Somalia, Uganda and Yemen expect to have very young populations, with median ages lower than 23 years in 2050.

International migration is projected to remain high during the first half of the century.  The more developed regions are expected to remain net receivers of international migrants, with an average gain of about 2 million per year over the next 50 years.  Averaged over the 2000-2050 period, the main net gainers of international migrants are the United States (1.1 million annual net migrants), Germany (211,000), Canada (173,000), the United Kingdom (136,000) and Australia (83,000), whereas the major net senders are China (-303,000 annual net number of migrants), Mexico, (-267,000), India (-222,000), the Philippines (-184,000) and Indonesia (-180,000).

A more detailed summary of the key findings of the 2002 Revision is available as World Population Prospects:  The 2002 Revision, Highlights (United Nations, February 2003).  This document will be posted on the Population Division’s web site at  The full results of the 2002 Revision will be issued in a series of three volumes and a wall chart that are under preparation as well as in electronic format.

For further information on the 2002 Revision, please contact Joseph Chamie, Director, Population Division, New York, NY 10017, USA; tel:  (212) 963-3179, fax:  (212) 963-2147).

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For information media. Not an official record.