Selected Results of the 2019 UN World Population Projections

2019 ◽  
Vol 45 (3) ◽  
pp. 689-694 ◽  
Keyword(s):  
Population Projections ◽  
World Population

Rapid Population Growth and Long-term Development

2020 ◽  
pp. 164-177
Author(s):  
Giovanni Andrea Cornia
Keyword(s):  
Population Growth ◽  
Resource Availability ◽  
Demographic Transition ◽  
Population Growth Rate ◽  
Physical Capital ◽  
Population Projections ◽  
World Population ◽  
Rapid Population Growth ◽  
The World

This chapter reviews population trends over the last two hundred years and population projections to the end of this century. In 2100 the world population will have stabilized but its geographical distribution will have substantially changed compared to 2015. The chapter then discusses the five stages of the demographic transition, and different neo-Malthusian and non-Malthusian theories of the relation between population growth and economic development. It emphasizes in particular the effects of rapid population growth on land and resource availability, human capital formation, population quality, the accumulation of physical capital, employment, wages, and income inequality. The effects of rapid population growth rate over a given period were found to change in line with the population size and density at the beginning of the period considered.

scholarly journals Invariant Causal Prediction for Nonlinear Models

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Christina Heinze-Deml ◽  
Jonas Peters ◽  
Nicolai Meinshausen
Keyword(s):  
Linear Models ◽  
Causal Model ◽  
Nonlinear Models ◽  
Causal Structure ◽  
Nonparametric Tests ◽  
Population Projections ◽  
World Population ◽  
Residual Distribution ◽  
Using Data

AbstractAn important problem in many domains is to predict how a system will respond to interventions. This task is inherently linked to estimating the system’s underlying causal structure. To this end, Invariant Causal Prediction (ICP) [1] has been proposed which learns a causal model exploiting the invariance of causal relations using data from different environments. When considering linear models, the implementation of ICP is relatively straightforward. However, the nonlinear case is more challenging due to the difficulty of performing nonparametric tests for conditional independence.In this work, we present and evaluate an array of methods for nonlinear and nonparametric versions of ICP for learning the causal parents of given target variables. We find that an approach which first fits a nonlinear model with data pooled over all environments and then tests for differences between the residual distributions across environments is quite robust across a large variety of simulation settings. We call this procedure “invariant residual distribution test”. In general, we observe that the performance of all approaches is critically dependent on the true (unknown) causal structure and it becomes challenging to achieve high power if the parental set includes more than two variables.As a real-world example, we consider fertility rate modeling which is central to world population projections. We explore predicting the effect of hypothetical interventions using the accepted models from nonlinear ICP. The results reaffirm the previously observed central causal role of child mortality rates.

scholarly journals Meeting the Sustainable Development Goals leads to lower world population growth

2016 ◽  
Vol 113 (50) ◽  
pp. 14294-14299 ◽  
Author(s):  
Guy J. Abel ◽  
Bilal Barakat ◽  
Samir KC ◽  
Wolfgang Lutz
Keyword(s):  
Sustainable Development ◽  
Reproductive Health ◽  
Population Growth ◽  
Sustainable Development Goals ◽  
Population Projections ◽  
Sensitivity Analyses ◽  
World Population ◽  
World Population Growth ◽  
Mortality Differentials ◽  
Development Goals

Here we show the extent to which the expected world population growth could be lowered by successfully implementing the recently agreed-upon Sustainable Development Goals (SDGs). The SDGs include specific quantitative targets on mortality, reproductive health, and education for all girls by 2030, measures that will directly and indirectly affect future demographic trends. Based on a multidimensional model of population dynamics that stratifies national populations by age, sex, and level of education with educational fertility and mortality differentials, we translate these goals into SDG population scenarios, resulting in population sizes between 8.2 and 8.7 billion in 2100. Because these results lie outside the 95% prediction range given by the 2015 United Nations probabilistic population projections, we complement the study with sensitivity analyses of these projections that suggest that those prediction intervals are too narrow because of uncertainty in baseline data, conservative assumptions on correlations, and the possibility of new policies influencing these trends. Although the analysis presented here rests on several assumptions about the implementation of the SDGs and the persistence of educational, fertility, and mortality differentials, it quantitatively illustrates the view that demography is not destiny and that policies can make a decisive difference. In particular, advances in female education and reproductive health can contribute greatly to reducing world population growth.

scholarly journals Fiscal Impacts of Demographic Transition in Pakistan

2021 ◽  
Vol 7 (1) ◽  
pp. 37-50
Author(s):  
Taqi Raza ◽  
Nabila Asghar ◽  
Farhat Rasul
Keyword(s):  
Demographic Transition ◽  
Pension System ◽  
Labour Force ◽  
Output Growth ◽  
Population Projections ◽  
World Population ◽  
Age Dependency ◽  
Fiscal Impacts ◽  
Age Dependency Ratio ◽  
The Impact

This study has examined the fiscal impacts of the demographic transition. Declining fertility rate and increasing life expectancy rate are expected to cause ageing in Pakistan. The population projections of United Nation’s World Population Prospects were used, for projecting the labour force, which uses different scenarios to project population namely low variant, medium variant and high variant scenario. The study found that projected labour force is expected to decline under the medium variant scenario. The study examined the impact of expected decline in labour force on output growth of Pakistan using growth accounting technique, and found that under medium variant scenario, Pakistan is expected to face a loss of 4% of GDP at the end of this century. On the expenditure side, this study attempted to measure the impact of demographic transition on pension expenditures. Due to the increase in the proportion of the dependent population pension expenditures are expected to rise from 1.2% of GDP in 2015 to 3.5% of GDP by the end of the century. Due to the increase in old-age dependency ratio and hike in pension expenditures of Pakistan pay-as-you-go pension system is expected to become fiscally unsustainable as fewer workers would be bearing the burden of aged population. This fact advocates transition from pay-as-you-go pension system to fully funded pension system.

scholarly journals GROWTH PERFORMANCE AND MANAGEMENT IN MIXED FOREST STANDS

2018 ◽  
Author(s):  
Heinz RÖHLE
Keyword(s):  
Climate Change ◽  
Mixed Forest ◽  
Biomass Productivity ◽  
Simulation Models ◽  
Forest Area ◽  
Population Projections ◽  
Forest Sector ◽  
Forest Conversion ◽  
World Population ◽  
Mixed Stands

In 2017, the global population stands at about 7.6 billion. Due to the medium variant of the population projections, developed by the UN, the world population will grow to nearly 10 billion by the middle of this century. As a consequence, the worldwide demand for wood will increase. Therefore, the forest sector has to develop concepts in order to cope with the increasing demand for wood, the altering environmental conditions and the challenge of climate change. Modified silvicultural treatment programs may contribute to solving these questions. Appropriate measures are the conversion of pure stands into mixed stands, the promotion of natural regeneration instead of artificial regeneration and the creation of structured forests consisting of indigenous or foreign tree species, which are better adapted to climate change and/or are growing faster. Mixed stands often exceed the volume as well as the biomass productivity of pure stands and increase the biodiversity of forest landscapes. Forest simulation models are a prerequisite for the management of mixed stands. They provide enhanced opportunities of planning for forest conversion and facilitate the decision support in forest practice. These model approaches support the development of goal oriented thinning programs and make it possible to test and optimize alternative silvicultural concepts without the establishment of experimental plots. The Bavarian State Forest Enterprise (Bayerische Staatsforsten) is managing 808731 ha of forest area in the southern part of Germany. Since 2005 this enterprise is converting pure, coniferous stands (> 200000 ha of forest area) into mixed, uneven-aged forests. A simulation program (single tree simulator) is used in order to achieve this goal.

scholarly journals Dimensions of global population projections: what do we know about future population trends and structures?

2010 ◽  
Vol 365 (1554) ◽  
pp. 2779-2791 ◽  
Author(s):  
Wolfgang Lutz ◽  
Samir KC
Keyword(s):  
Population Projections ◽  
World Population ◽  
Mortality Trends ◽  
Total Size ◽  
Future Fertility ◽  
Western Asia ◽  
The World ◽  
Global Population ◽  
Population Stabilization ◽  
Future Population

The total size of the world population is likely to increase from its current 7 billion to 8–10 billion by 2050. This uncertainty is because of unknown future fertility and mortality trends in different parts of the world. But the young age structure of the population and the fact that in much of Africa and Western Asia, fertility is still very high makes an increase by at least one more billion almost certain. Virtually, all the increase will happen in the developing world. For the second half of the century, population stabilization and the onset of a decline are likely. In addition to the future size of the population, its distribution by age, sex, level of educational attainment and place of residence are of specific importance for studying future food security. The paper provides a detailed discussion of different relevant dimensions in population projections and an evaluation of the methods and assumptions used in current global population projections and in particular those produced by the United Nations and by IIASA.

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