Demographic Change and Immigration in Age-structured Epidemic Models

Immigration might be a remedy against the stress that low fertility causes to demographic and welfare systems. Sustained immigration, however, can alter both the demographic and epidemiological profiles of the receiving population. An age-structured SIR (susceptible-infective-recovered) model with realistic immigration under conditions of below replacement fertility is studied. Equilibria and threshold phenomena are characterized. The immigration profile and the epidemiological features of immigrants affect the reproduction number and the force of infection in the receiving population. Finally, an illustration is given, showing the potential effects of immigration for rubella control in Italy, by considering how the age profile of immigration influences the reproduction number of the disease.     

Demographic Responses And Population Change

Most Western societies have gone through a process of population change during the past 100-150 years. One important aspect is the socalled demographic transition: the shift from high to low birth and death rates, and accelerated growth resulting from the lag between falling mortality and falling fertility, in national populations. Equally important has been the "rural-to-urban" transition, which involved the migration of millions of people from rural areas. It is hypothesized, following the suggestion of Davis (Theory of the Multi-Phasic Demographic Response), that the adjustment in reproductive behavior made by a community in response to a rising "strain," such as that resulting from higher natural increase, is likely to differ depending upon the ease with which the community can relieve the strain through out migration. Relationships among such characteristics of modernization as intensity of industrialization, speed of urbanization, structural changes in the agricultural system, and declining fertility are implied. Case studies of England and Sweden lend support to the hypothesis: more rapid urban-industrial development, larger-scale movement from rural areas, and a delayed decline in the rural birth rate distinguish the English transition.     

人口转变的经济效应及其对中国经济增长持续性的影响

文章使用中国分省资料,对人口因素和经济增长之间的关系进行了实证研究。与其他跨国的经验研究类似,文章对中国分省资料的实证分析表明,人口因素对经济增长的影响是动态的。出生率增加对经济增长的负面影响越来越小;新增劳动力对中国经济增长的积极影响则越发明显。从维持经济持续增长源泉的角度出发,使人口政策实现动态调整已经具有一定的必要性。     

人口变动对气候变化的影响

人口与气候变化关系是一个非常缺乏研究的领域。本文总结近年有关人口变动对气候变化影响研究领域的状况,讨论不同研究方法和模型的应用成果及其局限性,特别介绍了应用整合评估模型iPETS对主要国家和地区温室气体排放预测结果,指出人口变动与经济发展、技术变动等都是人类影响气候变化的决定因素;人口变动的影响不只是人口规模的增减,人口和家庭户结构及其空间分布的变化也是应该考虑的内容;家庭户应该成为气候变化研究的人口分析单位;人口老化、城市化、家庭规模缩小等都是影响未来气候变化的重要人口因素。本研究提供了改进气候预测模型对人口变量处理方式的实例,指出了在制定减缓气候变化政策过程中考虑人口因素的重要性和可操作建议。     

The IMF on Policies Responding to Demographic Change

In its semiannual report World Economic Outlook, the International Monetary Fund presents its analysis of major economic policy issues and assessment of economic prospects, along with more detailed treatment of a selected current topic. The special topic in the 300-page report published in September 2004 is “The Global Demographic Transition,” treated in Chapter III of the document. An excerpt from the section of that chapter titled “Policies to Meet the Challenges of Global Demographic Change” is reproduced below with the permission of the IMF. Footnotes and the figure included in the excerpt have been renumbered. The title of Chapter III is “How Will Demographic Change Affect the Global Economy?” The tone of the discussion is set by the opening epigraph, a quotation from the UK's 1949 Report of the Royal Commission on Population: “It seems possible that a society in which the proportion of young people is diminishing will become dangerously unprogressive, falling behind other communities not only in technical efficiency and economic welfare, but in intellectual and artistic achievement as well.” Accordingly, the focus of the analysis, like that of the commentary by US Federal Reserve Chairman Alan Greenspan reprinted in the preceding Document item in this issue, is on the consequences of population aging and on the desirable policy responses to that process. The discussion broadly parallels Greenspan's but with a wider compass, including some consideration of the effects of aging in developing countries. It emphasizes the need for counteracting adverse effects of demographic change through a combination of policy measures, since “the size of the reforms” (such as increasing labor force participation, inducing later retirement, and attracting more immigrants) “that would be needed in any single area [is] sufficiently large that they would be politically and economically difficult to achieve.”     

储蓄投资行为及外部均衡中的人口结构效应——来自亚洲的经验证据

文章运用动态广义矩估计方法,分析亚洲人口年龄结构对储蓄率、投资率及经常账户的效应。结果发现:(1)人口结构对储蓄的效应存在,老年人口抚养比对储蓄率有显著负向影响,符合生命周期假说;(2)少儿抚养比与储蓄率无显著相关,少儿人口抚养质量与数量间存在替代效应;(3)老年人口抚养比效应对于外部均衡非常显著。老年化经济体对于经常账户逆差存在依赖,经常账户可以视为亚洲人口红利期高储蓄的国际缓存池和中转地。亚洲的经济增长、高储蓄与高顺差呈现梯队性的趋势,且与人口结构的变迁一致。这些发现可以从人口结构角度解释亚洲的高储蓄和高经常账户顺差及国际资本流动。所以,世界经济体应避免同周期的老年化,以保证经济的梯队发展和资源跨代跨国转移;同时,对于减少少儿人口来压缩社会负担的政策效果不能预期过高。     

人口转变的储蓄效应和增长效应--论中国增长可持续性的人口因素

人口转变是挑战中国经济持续增长的一个重要因素.在这个过程中,个人的生命周期和代际更替之间的相互叠加,通过劳动供给、储蓄和科技进步等渠道对长期经济增长施加影响.本文分析表明,人口转变使得中国从20世纪60年代中期开始享受人口红利,并一直持续到2015年前后.为了迎接人口老龄化冲击,中国需要通过扩大就业、加快人力资本积累和建立适合于中国国情的可持续的养老保障模式三条途径来充分挖掘未来潜在的人口红利,推动中国经济持续增长.     

人口转变、人口红利与经济增长可持续性--兼论充分就业如何促进经济增长

本文援引国际经验,把人口转变引致的不同人口年龄特征阶段看作是经济增长的一个额外源泉,或人口红利;论证了通过高储蓄率、充足的劳动力供给和低抚养比,中国人口转变对改革以来高速经济增长的贡献;揭示了人口红利即将消失的趋势,由此提出最大化促进就业是维持人口对经济增长正面效应的关键.     

Demographic Differentials and Demographic Integration of Turkish and Kurdish Populations in Turkey

The objectives of the study are threefold: (1) to provide estimates of the total populations and spatial distributions of different language groups in Turkey, (2) to test whether the commonly held belief that Turkish-speaking and Kurdish-speaking populations are “actors” of different demographic regimes is true, and (3) to assess whether a process of integration, in the form of intermarriage of Turks and Kurds is under way in Turkey. Data come mainly from the 2003 Turkish Demographic and Health Survey (TDHS-2003). Based on the assumption that the mother tongue composition of women is also representative of that of the whole population, the results of the TDHS-2003 imply that of the population of Turkey, 83% are Turkish-speaking, 14% are Kurdish-speaking, 2% are Arabic-speaking and the remaining 1% belong to other language groups. Results show that despite intensive internal migration movements in the last 50 years, strong demographic differentials exist between Turkish and Kurdish-speaking populations, and that the convergence of the two groups does not appear to be a process under way. Turks and Kurds do indeed appear to be actors of different demographic regimes, at different stages of demographic and health transition processes.     

结构转变、制度变迁下的人口红利与经济增长

已有的对人口红利影响经济增长的实证研究未将结构和制度的重大变革纳入模型,这与东亚及我国经济增长的现实不符。本文通过在模型中纳入结构转变和制度变迁变量,用1978～2008年的数据进行误差修正分析,计算出在结构转变和制度变迁的背景下,我国人口红利及各要素对经济增长的影响。结果发现,固定资产投资对我国经济增长的影响程度最大,其次是技术进步,第三是制度变迁,结构变化的影响也很显著。人口红利的影响也较显著,但是其对经济增长解释力度较小。因此随着人口红利的逐渐消失,未来的经济增长更需要依靠投资、技术进步、结构变迁和制度变革。     

Poverty,Inequality, and Fertility: The Contribution of Demographic Change to Global Poverty Reduction

Global poverty has fallen dramatically over the past decades. In many developing countries, this transformation was accompanied by rapid improvements in demographic outcomes, such as falling child mortality and fertility. Yet, recent theorizing and empirical research into the causes of global poverty reduction has mostly omitted demographic factors. This paper aims to fill this gap by testing for effects of demographic variables on poverty. Using time series data for 140 countries, we document a strong effect of lagged fertility on country-specific poverty rates. This effect is robust across several specifications and data sets. It appears to be stronger in countries with larger fertility differentials, in the early transition stages. The proposed mechanism behind this result is a “Kuznets curve-type” expansion of fertility inequality at the onset of the demographic transition. We conclude by calling for a stronger inclusion of demographic variables in the distribution-sensitive analysis of global poverty.     

Demographic pattern in history

The study deals with the relationship of population’ to historical processes. Six aspects are selected for consideration: (1) The pattern of demographic factors which help to cause the persistence of particular human physical types in given localities. (2) Social control to maintain population within subsistence limits. (3) The conditions in which such control breaks down. (4) Migration. (5) Major trends in population history. (6) The influence of population on historical development.     

Demographic and agricultural survey

Cooperation between the government of Laos and the United Nations Fund for Population Activities began early in 1976 with the approval of an emergency project to strengthen statistical services and the planning of a demographic and agricultural survey to be conducted in 1978. It is hoped that this survey will lay the foundations for a demographic census to be conducted in 1980.     

Demographic challenges and health in Germany

Demographic challenges are affecting the health care system in Germany and globally: a growing aging population; low birth rates; sociopolitical, women’s health, and health care economic issues; and immigration. During a recent Fulbright Scholar program, scholars from several disciplines including demography, sociology, medicine, and nursing examined these demographic challenges facing Germany and other industrialized countries. Enormous challenges exist for industrialized and developing countries related to these demographic changes, the complexity of health care economics, and population issues. In Germany, the shifting population demographics are affecting health care, financing of the German health care system, and the growth of immigrant populations.     

中国人口转变、人口红利与经济增长的实证

我国人口年龄结构的变动使得劳动负担逐渐下降,这对于储蓄水平的上升和劳动力投入效率的提高具有显著的促进作用;我国劳动负担比与经济增长呈现出明显的负相关,劳动负担比每下降1个百分点,经济增长将提高1.06个百分点,在过去的30年里劳动负担降低累计带来的经济增长占总增长的27.23%。通过计量检验证明人口年龄结构变动所产生的促进经济增长的人口红利是存在的。由此我们推断,由于未来的人口年龄结构变动趋向人口老龄化,劳动负担逐步上升,这将会对未来的经济增长造成制约。利用未来10～20年时间较轻的劳动负担的机遇期,我们应当建立良好的教育、人力资本投资、社会保障等方面的制度以及制定积极的人口政策,调整当前生育政策、适时执行宏观经济政策(劳动就业政策)来应对已发生的、正在进行的人口变动,使我国的经济继续保持强有力的增长态势。     

云南人口机会窗口与人口红利收获研究

该文首先分析了云南人口机会窗口的特征和给社会经济发展带来的潜在机遇,第二部分指出由于劳动就业压力、资本市场不健全和老龄化问题突出等阻碍着我们获取人口红利,最后对收获人口红利的支撑体系进行了简要探讨。