World population is expected to increase by 2.6 billion over the next 45 years, from 6.5 billion today to 9.1 billion in 2050. Almost all growth will take place in the less developed regions, where today’s 5.3 billion population is expected to swell to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion.
These figures are from the 2004 Revision of the official United Nations population estimates and projections, released today by the Population Division of the Department of Economic and Social Affairs. The report provides crucial demographic information and population figures for the coming assessment of progress made towards achieving the Millennium Development Goals.
Other key findings of the 2004 Revision, which is based on the most recent national censuses, numerous specialized population surveys, and comprehensive review of past worldwide population trends and future prospects, include:
— By July 2005, the world will have 6.5 billion inhabitants, 380 million more than in 2000 or a gain of 76 million annually. Despite the lower fertility levels projected, by 2050 the world population is expected to reach 9.1 billion according to the medium variant and would still be adding 34 million persons annually by mid-century.
— Future population growth is highly dependent on the path that future fertility takes. In the medium variant, fertility declines from 2.6 children per woman today to slightly over 2 children per woman in 2050. If fertility were to remain about half a child above the levels projected in the medium variant, world population would reach 10.6 billion by 2050. A fertility path half a child below the medium would lead to a population of 7.7 billion by mid-century. That is, at the world level, continued population growth until 2050 is inevitable even if the decline of fertility accelerates.
— Because of its low and declining rate of population growth, the population of developed countries as a whole is expected to remain virtually unchanged between 2005 and 2050, at about 1.2 billion. In contrast, the population of the 50 least developed countries is projected to more than double, passing from 0.8 billion in 2005 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 4.5 billion to 6.1 billion between 2005 and 2050.
— Very rapid population growth is expected to prevail in a number of developing countries, the majority of which are least developed. Between 2005 and 2050, the population is projected to at least triple in Afghanistan, Burkina Faso, Burundi, Chad, Congo, Democratic Republic of the Congo, Timor-Leste, Guinea-Bissau, Liberia, Mali, Niger and Uganda.
— The population of 51 countries or areas, including Germany, Italy, Japan and most of the successor States of the former Soviet Union, is expected to be lower in 2050 than in 2005.
— During 2005-2050, eight countries are expected to account for half of the world’s projected population increase: India, Pakistan, Nigeria, Democratic Republic of the Congo, Bangladesh, Uganda, United States of America, Ethiopia, and China, listed according to the size of their contribution to population growth.
— In 2000-2005, fertility at the world level stood at 2.65 children per woman, about half the level it had in 1950-1955 ( 5 children per women ). In the medium variant, global fertility is projected to decline further to 2.05 children per woman.
— Average world levels result from different trends by major development group. In developed countries as a whole, fertility is currently 1.56 children per woman and is projected to increase slowly to 1.84 children per woman in 2045-2050. In the least developed countries, fertility is 5 children per woman and is expected to drop by about half, to 2.57 children per woman by 2045-2050. In the rest of the developing world, fertility is already moderately low at 2.58 children per woman and is expected to decline further to 1.92 children per woman by mid-century, thus nearly converging to the fertility levels by then typical of the developed world.
— In 2000-2005, fertility remains above 5 children per woman in 35 of the 148 developing countries, 30 of which are least developed countries, and the pace of decline in several countries of sub-Saharan Africa and South-Central Asia has been slower than anticipated. Overall, the countries with high fertility account for 10 per cent of the world population. In contrast, fertility has reached below-replacement levels in 23 developing countries accounting for 25 per cent of the world population. This group includes China, whose fertility during 2000-2005 is estimated at 1.7 children per woman.
— Fertility levels in the 44 developed countries, which account for 19 per cent of the world population, are currently very low. All except Albania have fertility below-replacement level and 15, mostly located in Southern and Eastern Europe, have reached levels of fertility unprecedented in human history ( below 1.3 children per woman ). Since 1990-1995, fertility decline has been the rule among most developed countries. The few increases recorded, such as those in Belgium, France, Germany, Netherlands and the United States, have been small.
— Global life expectancy at birth, which is estimated to have risen from 46 years in 1950-1955 to 65 years in 2000-2005, is expected to keep on rising to reach 75 years in 2045-2050. In the more developed regions, the projected increase is from 75 years today to 82 years by mid-century. Among the least developed countries, where life expectancy today is just under 50 years, it is expected to be 66 years in 2045-2050. Because many of these countries are highly affected by the HIV/AIDS epidemic, the projected increase in life expectancy is dependent on the implementation of effective programmes to prevent and treat HIV infection. In the rest of the developing world, under similar conditionalities, life expectancy is projected to rise from just under 66 years today to 76 years by mid-century.
— Mortality in Eastern Europe has been increasing since the late 1980s. In 2000-2005 life expectancy in the region, at 66.6 years, was lower than it had been in 1955-1960 ( 67.2 years ). Particularly affected by rises in mortality are countries such as the Russian Federation or Ukraine, partly because of the spread of HIV.
— Twenty-five years into the HIV/AIDS epidemic, 60 countries are highly affected by the epidemic and the impact of the disease is evident in terms of increased morbidity and mortality and slower population growth. In Southern Africa, the region with the highest prevalence of the disease, life expectancy has fallen from 62 years in 1990-1995 to 48 years in 2000-2005, and is projected to decrease further to 43 years over the next decade before a slow recovery starts. As a consequence, population growth in the region is expected to stall between 2005 and 2020. In Botswana, Lesotho and Swaziland, the population is projected to decrease as deaths outnumber births. In most of the other developing countries affected by the epidemic, population growth will continue to be positive, as their moderate or high fertility more than counterbalances the rise in mortality.
— The primary consequence of fertility decline, especially if combined with increases in life expectancy, is population ageing, whereby the share of older persons in a population increases relative to that of younger persons. Globally, the number of persons aged 60 years or over is expected almost to triple, increasing from 672 million in 2005 to nearly 1.9 billion by 2050. Whereas 6 out of every 10 of those older persons live today in developing countries, by 2050, 8 out of every 10 will do so. An even more marked increase is expected in the number of the oldest-old ( persons aged 80 years or over ): from 86 million in 2005 to 394 million in 2050. In developing countries, the rise will be from 42 million to 278 million, indicating that by 2050 most oldest-old will live in the developing world.
— In developed countries, 20 per cent of today’s population is aged 60 years or over, and by 2050 that proportion is projected to be 32 per cent. The elderly population in developed countries has already surpassed the number of children ( persons aged 0-14 ), and by 2050 there will be two elderly persons for every child. In the developing world, the proportion of the population aged 60 or over is expected to rise from 8 per cent in 2005 to close to 20 per cent by 2050.
— Increases in the median age, the age at which 50 per cent of the population is older and 50 per cent younger than that age, are indicative of population ageing. Today, just 11 developed countries have a median age above 40 years. By 2050, there will be 90 countries in that group, 46 in the developing world. Population aging, which is becoming a pervasive reality in developed countries, is also inevitable in the developing world and will occur faster in developing countries.
— Countries where fertility remains high and has declined only moderately will experience the slowest population ageing. By 2050, about 1 in 5 countries is still projected to have a median age under 30 years. The youngest populations
will be found in least developed countries, 11 of which are projected to have median ages at or below 23 years in 2050, including Angola, Burundi, Chad, Democratic Republic of the Congo, Equatorial Guinea, Guinea-Bissau, Liberia, Niger and Uganda.
— During 2005-2050, the net number of international migrants to more developed regions is projected to be 98 million. Because deaths are projected to exceed births in the more developed regions by 73 million during 2005-2050, population growth in those regions will largely be due to international migration.
— In 2000-2005, net migration in 28 countries either prevented population decline or doubled at least the contribution of natural increase ( births minus deaths ) to population growth. These countries include Austria, Canada, Croatia, Denmark, Germany, Italy, Portugal, Qatar, Singapore, Spain, Sweden, United Arab Emirates and United Kingdom
— In terms of annual averages, the major net receivers of international migrants are projected to be United States ( 1.1 million annually ), Germany ( 204,000 ), Canada ( 201,000 ), United Kingdom ( 133,000 ), Italy ( 120,000 ) and Australia ( 100,000 ). The major countries of net emigration are projected to be China ( -333,000 annually ), Mexico ( -304,000 ), India ( -245,000 ), Philippines ( -180,000 ), Pakistan ( -173,000 ) and Indonesia ( -168,000 ).
A more extensive discussion of the key findings of the 2004 Revision is available in World Population Prospects: The 2004 Revision, Highlights ( United Nations, February 2005 ), which can be found on the web site of the Population Division/DESA at www.unpopulation.org. The full results of the 2004 Revision will be issued in a series of three volumes and a wall chart that are currently under preparation. Data on particular countries can also be accessed online at the web site of the Population Division.