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Medical Hypotheses. 2003 Jul; 61(1):21-22.According to the United Nations, global fertility has declined in the last century as reflected by a decline in birth rates. The earth’s surface air temperature has increased considerably and is referred to as global warming. Since changes in temperature are well known to influence fertility we sought to determine if a statistical relationship exists between long-term changes in global air temperatures and birth rates. The most complete and reliable birth rate data in the 20th century was available in 19 industrialized countries. Using bivariate and multiple regression analysis, we compared yearly birth rates from these countries to global air temperatures from 1900 to 1994. A common pattern of change in birth rates was noted for the 19 industrialized countries studied. In general, birth rates declined markedly throughout the century except during the baby boom period of approximately 1940 to 1964. An inverse relationship was found between changes in global temperatures and birth rates in all 19 countries. Controlling for the linear yearly decline in birth rates over time, this relationship remained statistically significant for all the 19 countries in aggregate and in seven countries individually (p <0:05). Conclusions. The results of our analyses are consistent with the underlying premise that temperature change affects fertility and suggests that human fertility may have been influenced by change in environmental temperatures. (author's)
POPULATION BULLETIN OF THE UNITED NATIONS. 1989; (27):108-24.This paper reviews recent new trends in population structure in the world and its major regions in order to access the determinants of those trends and explore issues regarding the recent and projected changes in the age structure of population and the relationships of those changes to social and economic development. In particular, the paper compares the change in age structure projected by the Population Division of the UN Secretariat in its most recent 3 series--namely, those completed in 1984, 1986, and 1988. By and large, the most recent UN assessment projects that a larger proportion of the world population will be aged 60 and over in 2000 and 2025 than was previously estimated. Those changes in projections can be observed for the world and for the more developed countries as a whole, and for the regions of Africa, Latin America, Northern America, East Asia, Europe, and Oceania. While the recommendations of the International Conference on Population called attention to the importance of changes in population structure, this paper recommends urgent government action in planning social programs for the aged because of the greater eminence of population aging in many settings. The case of Japan is used to illustrate the growing importance of increases in life expectancy as a determinant of age structure changes (in relation to fertility decline), a point that is reinforced through a cruder decomposition of UN estimates and projections for several European countries. (author's)
In: UNFPA: 1986 report, [by] United Nations Fund for Population Activities. New York, New York, UNFPA, 1987. 6-31.The implications of population growth and prospects for the future are examined in a 1987 UNFPA report on the state of world population. Demographic patterns in developed and developing countries are compared, as well as life expectancy and mortality rates. Although most countries have passed the stage of maximum growth, Africa's growth rate continues to increase. Changes in world population size are accompanied by population distribution and agricultural productivity changes. On an individual level, the fate of Baby 5 Billion is examined based on population trajectories for a developing country (Kenya, country A), and a developed country of approximately the same size (Korea, country B). The report outlines the hazards that Baby 5 Billion would face in a developing country and explains the better opportunities available in country B. Baby 5 Billion is followed through adolescence and adulthood. Whether the attainment of 5 billion in population is a threat or a triumph is questioned. Several arguments propounding the beneficial social, economic, and environmental effects of unchecked population growth are refuted. In addition, evidence of the serious consequences of deforestation and species extinction is presented. The report concludes with an explanation of the developmental, health and economic benefits of vigorous population control policies, especially in developing countries.
Population and Development Review. 1984 Mar; 10(1):103-26.This paper presents some of the results of projections prepared by the World Bank in 1983 for all the world's countries. The projections (presented against a background of recent demographic trends as estimated by the United Nations) trace the approach of each individual country to a stationary state. Implications of the underlying fertility and mortality assumptions are shown mainly in terms of time trends of total population to the year 2100, annual rates of growth, and absolute annual increments. These indices are shown for the largest individual countries, for world regions, and for country groupings according to economic criteria. The detailed predictive performance of such projections is likely to be poor but the projections indicate orders of magnitude characterizing certain aggregate demographic phenomena whose occurrence is highly probable and set clearly interpretable reference points useful in discussing contemporary issues of policy. (author's)
Revue Tiers Monde. 1983 Apr-Jun; 24(94):305-24.This article discusses methodologies for arriving at population projections and predictions and their limitations, and presents short-term predictions for 1980-2000, longterm projections for 2000-2025, and very longterm projections for 2025-2100, which are highly speculative. The UN population projections for 210 countries and territories are provided by age and sex and by rural or urban status. The UN projections are prepared in 3 phases: 1) analysis of the quality of the basic data in different regions; 2) development of hypotheses concerning the evolution of fertility, mortality, and migration; and 3) separate projection of each component of growth. 4 variants, the medium, high, low, and constant fertility versions are usually prepared, of which the medium projection is considered most likely and that of constant fertility is included only for comparisons. The world crude reproduction rate fell from 2.41 in 1950 to 1.96 in 1975-80, and is expected to fall to 1.34 during 2000-2010 and to almost unity in the mid 21st century. Only Africa and Latin America are expected to have crude reproduction rates above replacement level in 2025. According to the medium projection, the world population will each 6.2 billion in 2000 and 10.4 billion in 2075, when it will be nearly stationary. Future growth in already developed countries will be minimal, but Third World countries, which had a population of 1.7 billion in 1950 and 3.3 billion in 1980, will have nearly 5 billion by 2000 and will stabilize at about 9.1 billion, representing 87% of total world population. About 40% will live in South Asia. The population in 2075 will be 1.2 billion in Latin America, 2.2 billion in Africa, and 1.7 billion in East Asia. The age structure of the future population will undergo considerable aging and the trend toward urbanization will accelerate.