Projections of countries’ future populations, broken down by age and sex, are widely used for planning and research. They are mostly done deterministically, but there is a widespread need for ...probabilistic projections. We propose a Bayesian method for probabilistic population projections for all countries. The total fertility rate and female and male life expectancies at birth are projected probabilistically using Bayesian hierarchical models estimated via Markov chain Monte Carlo using United Nations population data for all countries. These are then converted to age-specific rates and combined with a cohort component projection model. This yields probabilistic projections of any population quantity of interest. The method is illustrated for five countries of different demographic stages, continents and sizes. The method is validated by an out of sample experiment in which data from 1950–1990 are used for estimation, and applied to predict 1990–2010. The method appears reasonably accurate and well calibrated for this period. The results suggest that the current United Nations high and low variants greatly underestimate uncertainty about the number of oldest old from about 2050 and that they underestimate uncertainty for high fertility countries and overstate uncertainty for countries that have completed the demographic transition and whose fertility has started to recover towards replacement level, mostly in Europe. The results also indicate that the potential support ratio (persons aged 20–64 per person aged 65+) will almost certainly decline dramatically in most countries over the coming decades.
This paper analyzes characteristics, major driving forces and alternative management measures of land-use change in Kunshan, Jiangsu province, China. The study used remote sensing (RS) maps and ...socio-economic data. Based on RS-derived maps, two change matrices were constructed for detecting land-use change between 1987 and 1994, and between 1994 and 2000 through pixel-to-pixel comparisons. The outcomes indicated that paddy fields, dryland, and forested land moderately decreased by 8.2%, 29% and 2.6% from 1987 to 1994, and by 4.1%, 7.6% and 8% from 1994 to 2000, respectively. In contrast, the following increased greatly from 1987 to 1994: artificial ponds by 48%, urban settlements by 87.6%, rural settlements by 41.1%, and construction land by 511.8%. From 1994 to 2000, these land covers increased by 3.6%, 28.1%, 23.4% and 47.1%, respectively. For the whole area, fragmentation of land cover was very significant. In addition, socio-economic data were used to analyze major driving forces triggering land-use change through bivariate analysis. The results indicated that industrialization, urbanization, population growth, and China's economic reform measures are four major driving forces contributing to land-use change in Kunshan. Finally, we introduced some possible management measures such as urban growth boundary (UGB) and incentive-based policies. We pointed out that, given the rapidity of the observed changes, it is critical that additional studies be undertaken to evaluate these suggested policies, focusing on what their effects might be in this region, and how these might be implemented.
World population stabilization unlikely this century Gerland, Patrick; Raftery, Adrian E.; Ševčíková, Hana ...
Science (American Association for the Advancement of Science),
10/2014, Letnik:
346, Številka:
6206
Journal Article
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The United Nations (UN) recently released population projections based on data until 2012 and a Bayesian probabilistic methodology. Analysis of these data reveals that, contrary to previous ...literature, the world population is unlikely to stop growing this century. There is an 80% probability that world population, now 7.2 billion people, will increase to between 9.6 billion and 12.3 billion in 2100. This uncertainty is much smaller than the range from the traditional UN high and low variants. Much of the increase is expected to happen in Africa, in part due to higher fertility rates and a recent slowdown in the pace of fertility decline. Also, the ratio of working-age people to older people is likely to decline substantially in all countries, even those that currently have young populations.
Rural housing land accounted for 67.3% of China's total construction land in 2000. While there are numerous studies analyzing the loss of arable land due to urban sprawl, less attention has been paid ...to the study of rural housing land in China. This paper develops a theoretical framework for rural housing land transition in China. It introduces a research method, which is using the spatial differentiation in regional development for compensating the deficiencies in time-series data, to analyze the rural housing land transition in the Transect of the Yangtse River (TYR). Detailed land-use data and socio-economic data from both research institutes and government departments were used to test the following hypothesis on rural housing land transition. We assume that rural housing in every region will undergo specific stages—the proportion of rural housing in the increase of total construction land will decline gradually with the development of the local economy, and the end of the transition corresponds to a new equilibrium between rural housing and other construction activities. Five regional types of rural housing land change were defined according to an aggregation index used to reflect landscape patterns. The outcomes indicated that the share of rural housing in the increase of total construction land declines gradually from the upper reaches to the lower reaches of the Yangtse River, i.e. from Ganzi–Yushu to Luzhou–Diqing, Enshi–Chongqing, Tongling–Yichang and to Shanghai–Chaohu. Each region is in a different phase of the rural housing land transition, which corresponds to a particular socio-economic developmental level. Finally, some policy implications were discussed by applying this research to land management issues. The authors argue that there are problems in the current rural housing land managerial system in China, and that the Central Government needs to define uniform regulations for rural housing according to regional socio-economic developmental level, physical conditions and rural housing land transition phase.
We describe a Bayesian projection model to produce country-specific projections of the total fertility rate (TFR) for all countries. The model decomposes the evolution of TFR into three phases: ...pre-transition high fertility, the fertility transition, and post-transition low fertility. The model for the fertility decline builds on the United Nations Population Division's current deterministic projection methodology, which assumes that fertility will eventually fall below replacement level. It models the decline in TFR as the sum of two logistic functions that depend on the current TFR level, and a random term. A Bayesian hierarchical model is used to project future TFR based on both the country's TFR history and the pattern of all countries. It is estimated from United Nations estimates of past TFR in all countries using a Markov chain Monte Carlo algorithm. The post-transition low fertility phase is modeled using an autoregressive model, in which long-term TFR projections converge toward and oscillate around replacement level. The method is evaluated using out-of-sample projections for the period since 1980 and the period since 1995, and is found to be well calibrated.
The relationship between economic development and environmental quality is a debated topic. Environmental Kuznets curve (EKC) is one prominent hypothesis, positing an inverted U-shaped ...development–environment relationship. Here we test this hypothesis using data from Shenzhen, People's Republic of China. Established in 1980 as the first special economic zone in China, Shenzhen has developed from a small village into a large urban-industrial agglomeration with the highest income level in the country. The enormous expansion of infrastructure, industrial sites and urban settlements has profoundly changed the local environment. We utilize environmental monitoring data from Shenzhen on concentration of pollutants in ambient air, main rivers, and near-shore waters from 1989 to 2003. The results show that production-induced pollutants support EKC while consumption-induced pollutants do not support it.
Population momentum and the demand on land and water resources Fischer, Günther; Heilig, Gerhard K.; Fischer, Günther ...
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
07/1997, Letnik:
352, Številka:
1356
Journal Article
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Future world population growth is fuelled by two components: the demographic momentum, which is built into the age composition of current populations, and changes in reproductive behaviour and ...mortality of generations yet to come. This paper investigates, by major world regions and countries, what we know about population growth, what can be projected with reasonable certainty, and what is pure speculation. The exposition sets a frame for analysing demographic driving forces that are expected to increase human demand and pressures on land and water resources. These have been contrasted with current resource assessments of regional availability and use of land, in particular with estimates of remaining land with cultivation potential. In establishing a balance between availabilty of land resources and projected needs, the paper distinguishes regions with limited land and water resources and high population pressure from areas with abundant resources and low or moderate demographic demand. Overall, it is estimated that two-thirds of the remaining balance of land with rainfed cultivation potential is currently covered by various forest ecosystems and wetlands. The respective percentages by region vary between 23% in Southern Africa to 89% in South-Eastern Asia. For Latin America and Asia the estimated share of the balance of land with cultivation potential under forest and wetland ecosystems is about 70%, in Africa this is about 60%. If these were to be preserved, the remaining balance of land with some potential for rainfed crop cultivation would amount to some 550 million hectares. The regions which will experience the largest difficulties in meeting future demand for land resources and water, or alternatively have to cope with much increased dependency on external supplies, include foremost Western Asia, South-Central Asia, and Northern Africa. A large stress on resources is to be expected also in many countries of Eastern, Western and Southern Africa.
This note analyzes China's provincial diversity from two perspectives. First, the regional gross domestic products of China's 31 mainland provinces are compared with the national GDP of other ...countries. This demonstrates that China's most advanced provinces and urban areas have per capita GDP levels comparable to those of Sweden and Singapore. On the other hand, China's least developed provinces have a standard of living similar to those of Sudan and Honduras. The second part of the analysis demonstrates that China's economic diversity is not unique. In fact, European countries exhibit almost the same degree of income diversity as do Chinese provinces.
The author analyzes five anthropogenic driving forces of land-use change in China: population growth, urbanization, industrialization, changes in lifestyles and consumption, and shifts in political ...and economic arrangements and institutions. The intention is to demonstrate the broad range of factors other than biogeophysical conditions that will affect future land-use patterns in China. A first set of statistical data was collected to analyze these demographic and socioeconomic trends. The author also includes new estimates on China's cultivated land area, indicating that it is more seriously underreported in official statistics than previously acknowledged.
Asiaten und Afrikaner werden die demographische Zukunft des Planeten Erde bestimmen. Damit wird sich von vielen weitgehend unbemerkt eine Zeitenwende bis zum Ende dieses Jahrhunderts vollzogen haben. ...Vor allem das demographische Gewicht der Europäer wird drastisch zurückgehen – und es ist noch weitgehend ungeklärt, wie sich dies auf die ökonomische, geostrategische und ökologische Situation der Welt auswirken wird.
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