Laxenburg, Austria – 9 October 1996 –The world's population, which has quadrupled over the past 80 years, may never double again, according to new population forecasts by the Population, Development and Environment Project at the International Institute for Applied Systems Analysis (IIASA).
According to the projections, there is a 66 percent chance that the world's population will not reach 11.5 billion – double today's population – within the next century, if ever. The projections are the first fully probabilistic ones ever released and reflect the impact of alternative assumptions for birth rates, migration and death rates. Based on expert opinions, the projections include confidence levels for global populations and go up to the year 2100. The projections and assumptions are clearly explained and substantively discussed in the Project's new, revised edition of "The Future Population of the World: What Can We Assume Today?" (ed. W. Lutz), just off press.
"The biggest factor affecting population growth is the continuing decline of fertility in most world regions," says Project Leader Wolfgang Lutz. Lutz says that as a whole, the world's population will probably increase from today's 5.8 billion to around 7.9 billion in 2020, 9.9 billion in 2050, and 10.4 billion by 2100, according to the Project's forecasts. However, four world regions – Pacific OECD countries, Eastern Europe, Western Europe, and the European part of the Former Soviet Union – are projected to experience population declines before 2050.
For example, over the course of the coming decades, population in the European part of the Former Soviet Union could decrease, according to the median projection, due to below-replacement fertility, relatively high mortality (especially for males), and near-term, net out-migration. By 2020, the population could fall from its current 238 million to 224 million. By 2050, the population may even fall to 187 million, and could fall to as low as 147 million by 2100.
In contrast, countries in North Africa and the Middle East are likely to experience dramatic population growth. According to projections, the population in these regions could double and possibly triple over the next 50 years due to current young age structures and high fertility levels. North Africa's 1995 population level of 162 million is likely to increase to 228 million by 2010 and to 439 million by 2050. The Middle East's 1995 population of 151 million is likely to grow to 234 million by 2010 and to 517 million by 2050.
Projections for North America reflect a slow but steady increase, climbing from 297 million in 1995 to 356 million in 2020, 405 million in 2050, and to 482 million in 2100, under the median
projection. The continued growth of the US population is largely fueled by the assumption of continued migration. In probabilistic terms, there is a 95 percent chance that the population of North America will grow to between 320 million to 400 million by 2020. Toward the end of the next century, the population may shrink only if migration is greatly restricted and if the USA has a long period of below-replacement fertility.
Lower birth rates affect not only the total population size, but also age distributions. The latter are likely to make a steady shift from a current, predominantly young population to an increasing proportion in the "over 60" age bracket, even in developing countries. For example, in 1995, 31.4 percent of the world's population was age 14 or younger. According to the Project's latest projections, the percentage will clearly fall over time, to a median percentage of 17.2 by 2100 (with 60 percent of all cases lying between 16 and 19 percent).
On the other hand, the proportion of those above age 60 will expand nearly three-fold, from a current 9.5 percent to 19.7 percent by 2050 and 26.8 percent by 2100 (under the most likely scenario). "This is going to have significant impacts on societies and cause serious problems with pension systems throughout the world," says Lutz.
Western Europe is likely to experience an increase in the proportion of those above age 60 from the current 18.6 percent to a very high 35 percent by 2100. The rapid aging is virtually certain: 95 percent of all projected cases lie between 28 percent and 44 percent for 2050. North America's current proportion of 16 percent above age 60 is likely to increase to 30 percent by 2050.
Another world region projected to see a dramatic aging of population is China and Centrally Planned Asia, whose proportion of those over 60 may go from a current 9.2 percent to 25 percent by 2050 (under the most likely scenario). "Within less than three decades, China's old-age dependency burden will be higher than North America's and about the same as that currently in Western Europe," explains Lutz, adding that to avoid serious problems in its pension system, China must take immediate and intensive actions.
"The Future Population of the World: What Can We Assume Today?", edited by Wolfgang Lutz, is published by Earthscan (ISBN 1 85383 349 5).
The International Institute for Applied Systems Analysis (Laxenburg, Austria) is a non-governmental research institution sponsored by a consortium of National Member Organizations in 17 nations. The Institute's research focuses on sustainability and the human dimensions of global change. The studies are international and interdisciplinary, providing timely and relevant information and options for the scientific community, policy makers and the public.
For more information, please contact:
Mary Ann Williams
Office of Public Information, IIASA, A-2361 Laxenburg, Austria;
phone: (+43 2236) 807 ext. 261; fax (+43 2236) 73 149;
william@iiasa.ac.at