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How are the populations of the world likely to shift? Which countries will be impacted by sea-level rise? This paper uses a country-level agent-based dynamic network model to examine shifts in population given network relations among countries, which influences overall population change. Some of the networks considered include: alliance networks, shared language networks, economic influence networks, and proximity networks. Validation of model is done for migration probabilities between countries, as well as for country populations and distributions. The proposed framework provides a way to explore the interaction between climate change and policy factors at a global scale. 1 INTRODUCTION Human migration is an important research topic, with major economic effects (OECD 2014). At the same time, the decision to migrate is also determined by economic factors (Pew Research Center 2013). This intertwining effect is best captured by agent-based models, where agents interact with their environment, and changes in the environment affects the decisions of agents. Previous studies on human migration generally make simplistic assumptions about the decision model of migration, or do not consider fluctuations in birth/death rates, age distributions as well as networks ties between countries. With recent economic trends (Grant, Mark 2016), birth policy changes (Buckley, Chris 2015) and climate trends in mind, it is important to develop an agent-based model that is sensitive to these changes. In this work, we developed a country-level agent-based model which aims to mimic the agent's decision-making process for migration. This is done through consideration of a range of country networks, ranging from alliances to linguistic similarities to climate and migrant networks, just to name a few. Additionally, we initialize the age distributions of countries according to actual data (US Census Bureau 2016). The age distribution is then shifted throughout the simulation through an aging process, as well as actual births and deaths in population. We then validate our model against data for migration probabilities, and country-level observations (population and age distributions). The results are promising, as we illustrate through performance measures such as average of prediction error.
NCAR Technical Note NCAR/TN 508+STR, 47pp, 2014
The demographic features of a growing number of international migrants increasingly impacts socioeconomic development in various countries of the world. However, information on international migrant’s demographic characteristics is sparse. To develop the multiregional population/urbanization projections module of the NCAR Community Demographic Model (CDM) requires information on the age and gender composition of international migration streams. This paper reports on the methods used to generate the CDM International Migration dataset, which contains information on the age and gender profiles of international migrants with approximate global coverage. We use the raw data from the United Nations Global Migration Database (UNGMD) to derive the highest quality migrant stock for two time points closest to the year 2000. We reallocate the migrants into standardized age and gender categories by using information directly from the selected file, by borrowing information from files of other years, and by applying aggregated region-level information. After accounting for the impacts of mortality and fertility, we derive the age and gender profiles of net migrant flows between the two time points for each migration stream. The newly generated dataset contains age and gender profiles of international migrants for 3,713 country-level migration streams. Validation analyses against existing data sources and against the geographical, historical, and political context demonstrate reasonably high data quality. This data set not only meets our requirement for population projections, but can also be used for the study of international migration behavior among subgroups of various socioeconomic and environmental backgrounds.
Advances in Global Change Research, 2011
Past estimates of the numbers of migrants caused to relocate as a result of climate change have ranged from millions to billions worldwide. Attempts to quantify the numbers of people affected have commonly been based around calculating the numbers of 'environmental refugees' by projecting physical climate changes, such as sea-level rise or rainfall decline, on an exposed population. These studies generally make simplistic assumptions about the ability of individuals to cope with variations in climate. However, empirical evidence of environmentally induced migration have not supported such an approach with the recognition that migration decisions are usually not mono-causal but influenced by multiple factors involving complex spatial interactions under heterogeneous conditions. In this context, agent based modelling offers a robust method to model autonomous decision making in relation to migration. In this chapter we discuss the theoretical development of an agent-based modelling approach to climate change-migration studies using the example of Burkina Faso. In doing so we cover questions of emergence, validation, and bounded rationality related to quantitative migration studies.
2015
Cumulative causation of migration is widely accepted but its endogenous social networks rationale has been taken only implicitly but not explicitly. To address the challenge stemming from no observations of population-wide migrant networks we apply an agent-based model to China’s unprecedented rural-urban migration. Our model 1) sets up the census-derived initial condition of 313,355 individuals with their demographics and locational information in 1995; 2) constructs the initial migrant networks based on the actual family ties, family and village size distributions, and migrant stock in 1995; 2) uses parameters calibrated based on census, survey, and published data to model individual migratory actions under the influence of migrant networks; 4) builds micro-meso-macro feedback loops; 5) simulates migrant networks’ growth, decay and evolution; and 6) generate macro outcomes such as migrant stock distribution and emerging migration systems 1996-2000. Our paper will provide a complex...
Population and Environment, 2016
This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative and quantitative analyses of a well-studied demographic field site, Nang Rong district, Northeast Thailand. With this model, we simulate patterns of migration under four weather regimes in a rice economy: 1) a reference, 'normal' scenario; 2) seven years of unusually wet weather; 3) seven years of unusually dry weather; and 4) seven years of extremely variable weather. Results show relatively small impacts on migration. Experiments with the model show that existing high migration rates and strong selection factors, which are unaffected by climate change, are likely responsible for the weak migration response.
Ruhr Economic Paper 471, 2014
In this paper an agent-based model of endogenously evolving migrant networks is developed to identify the determinants of migration and return decisions. Individuals are connected by links, the strength of which declines over time and distance. Methodologically, this paper combines parameterization using data from the Mexican Migration Project with calibration. It is shown that expected earnings, an idiosyncratic home bias, network ties to other migrants, strength of links to the home country and age have a signifi cant impact on circular migration patterns. The model can reproduce spatial patterns of migration as well as the distribution of number of trips of migrants. It is shown how it can also be used for computational experiments and policy analysis.
The polish migration review (Polski Przegląd Migracyjny), 2017
The text is an attempt to estimate changes in the potential sources and targets of international migration (countries with a modern population quantity of more than 5 million were taken into account) in accordance with the prognoses of change of population quantity until 2050. The author attempted to estimate the change in the “difference of potentials of an available population by countries”. The research leans on three scenarios of demographic development as offered by the UN – low, medium and high. To the best of the author’s knowledge, the model created by the author is one of the few models of global international migration based on a synergistic approach. With the help of the created model in the course of consistent iterations, matrices were developed of paired indexes of the mutual attractiveness of countries for migrants for every fifth year from 2020 to 2050. Based on these matrices and in accordance with the UN’s proposed scenarios of demographic development, three scenarios were constructed for forecasting trends and volumes of legal migration for every five years to 2050 among all countries taken into consideration. The predicted values were determined for the total number of international migrants in each of the countries by 2050. The conclusion is that there are stable migration directions which are not limited to the direction of “South – North”. It was also determined that there is no fundamental difference in the forecasted migration directions according to each of the UN scenarios. The results of the forecasting and some supplementary materials to this article are available online.
2008
In this paper we analyze the demographic factors that influence the migration dynamics of recent immigrants to The Netherlands. We show how we can allow for both permanent and temporary migrants. Based on data from Statistics Netherlands we analyze both the departure and the return from abroad for recent non-Dutch immigrants to The Netherlands. Results disclose differences among migrants by migration motive and by country of origin and lend support to our analytical framework. Combining both models, for departure and returning, provides the probability that a specific migrant ends-up in The Netherlands. It also yields a framework for predicting the migration dynamics over the life-cycle. From the obtained insight in the dynamic composition of migrants in the country important policy implications can be derived, including admission procedures for different countries and/or migration motives.
2024
Climate change will have significant impacts on all aspects of human society, including population movements. In some cases, populations will be displaced by natural disasters and sudden-onset climate events, such as tropical storms. In other cases, climate change will gradually influence the economic, social, and political realities of a place, which will in turn influence how and where people migrate. Planning for the wide spectrum of future climate-related mobility is a key challenge facing development planners and policy makers. This article reviews the state of climate-related migration forecasting models, based on an analysis of thirty recent models. We present the key characteristics, strengths, and weaknesses of di erent modeling approaches, including gravity, radiation, agent-based, systems dynamics and statistical extrapolation models, and consider five illustrative models in depth. We show why, at this stage of development, forecasting models are not yet able to provide reliable numerical estimates of future climate-related migration. Rather, models are best used as tools to consider a range of possible futures, to explore systems dynamics, to test theories or potential policy e ects. We consider the policy and research implications of our findings, including the need for improved migration data collection, enhanced interdisciplinary collaboration, and scenarios-based planning.
2017
Migration has always been a fundamental component of human history. During last decades several researchers have derived models for predicting mass migrations. This paper critically reviews the theories and models qualitative structural and mathematical modelling of migration. It analyses the institutional causes of migration at the origin and the impacts of migration on destination. Migration as a consequence of climate change is also considered and modelled. Comparisons of different modelling processes provide a better understanding of migration modelling itself and the subsequent synthesis of models and variables show the differences and complementarities. The critical analysis conducted will greatly facilitate development of new more comprehensive models for migration in the future.
The Journal of Defense Modeling and Simulation: Applications, Methodology, Technology, 2018
Climate change has the potential to displace large populations in many parts of the developed and developing world. Understanding why, how, and when environmental migrants decide to move is critical to successful strategic planning within organizations tasked with helping the affected groups, and mitigating their systemic impacts. One way to support planning is through the employment of computational modeling techniques. Models can provide a window into possible futures, allowing planners and decision makers to test different scenarios in order to understand what might happen. While modeling is a powerful tool, it presents both opportunities and challenges. This paper builds a foundation for the broader community of model consumers and developers by: providing an overview of pertinent climate-induced migration research, describing some different types of models and how to select the most relevant one(s), highlighting three perspectives on obtaining data to use in said model(s), and the consequences associated with each. It concludes with two case studies based on recent research that illustrate what can happen when ambitious modeling efforts are undertaken without sufficient planning, oversight, and interdisciplinary collaboration. We hope that the broader community can learn from our experiences and apply this knowledge to their own modeling research efforts.
Revista Latinoamericana de Población
We analyze migration and demographic changes among the six countries of North America (NA) and the Northern Triangle of Central America (NTCA, i.e. Guatemala, Honduras and El Salvador). Together, they comprise a long-standing South-North migration stream, with the United States (US) and Canada being the main destinations for Mexico and the NTCA. Studies that analyze the demographic effects of international migration in origin and destination countries have been limited. In order to fill this gap and explain the implications of recent changes in migration trends and demographic dynamics of the six countries, we study the interrelationship between future changes in the age structure associated with different migration scenarios. We use data from the United Nations World Population Prospects 2017 to compare the main demographic indexes and age structure indicators under two prospective scenarios: with and without migration. Current and projected population dynamics suggest convergence ...
In this paper a method to model and forecast international immigration, emigration and net migration by age and sex is proposed. This method is based on Lee’s 1993 model, which is an extension of the well-known Lee-Carter model (Lee & Carter, 1992). The method proposed allows forecasting migration consistently with the whole population dynamic in the sense that it incorporates sustainable migration levels. This sustainability is incorporated through a logistic transformation of total migration, and it allows constraining the migration’s fluctuation and thus avoiding negative values in a total population forecast. The method is applied to recent estimates of Mexican immigration, emigration and net migration by age and sex from 1960 to 2010 made by the Mexican Society of Demography (SOMEDE, 2011). The predictive power of the model is tested forecasting the period 1991 to 2010 and comparing the results with estimates for such period.
Population Studies
Young adults migrate more than older people. As populations in many countries get older, this may affect out-migration-and thus immigration to other countries. This is not usually accounted for in projections of future immigration, even though considerable ageing is expected globally. We show how United Nations projections of future age profiles in origin regions can be combined with those regions' emigration rates by age group to improve national projections of immigration to a destination country, exemplified by Norway. Using various methods for projecting future migration, we show that projected immigration tends to be lower when taking expected ageing in origin regions into account. This may have a considerable effect on population projections: for Norway, taking changing age profiles in origin regions into account in immigration projections would have an effect on the projected population of Norway equivalent to that of reducing the fertility assumptions by 0.1 children per woman.
SNE Simulation Notes Europe
Demographic developments are not only a point of interest on national but also on sub-national level where migration rates are typically much higher compared to international movements. This article presents several models for the simulation of the impact national and international migration has on regional population development. Hereby we contribute to the research field of demographic modelling as we demonstrate pros and cons of the different modelling strategies when trying to parametrize the models with real-world data. Since the influence of an individual's age and sex on its mobility is a common feature discussed in literature, the models developed mainly focus on these influences. While the first models use decoupled migration processes, one additional approach is designed to take into account an individual's wish of moving to a particular place and not being distributed to a random region. All models are further enhanced with a region-specific external migration tool.
Journal of the Royal Statistical Society Series A: Statistics in Society, 2016
Summary Age and sex patterns of migration are essential for understanding drivers of population change and heterogeneity of migrant groups. We develop a hierarchical Bayesian model to estimate such patterns for international migration in the European Union and European Free Trade Association from 2002 to 2008, which was a period of time when the number of members expanded from 19 to 31 countries. Our model corrects for the inadequacies and inconsistencies in the available data and estimates the missing patterns. The posterior distributions of the age and sex profiles are then combined with a matrix of origin–destination flows, resulting in a synthetic database with measures of uncertainty for migration flows and other model parameters.
2000
This Discussion Paper is issued within the framework of IZA's research area Mobility and Flexibility of Labor Markets. Any opinions expressed here are those of the author(s) and not those of the institute. Research disseminated by IZA may include views on policy, but the institute itself takes no institutional policy positions.
Historical Methods 48(3), 113-127, 2015
Although data for the total number of international migrant flows is now available, no global dataset concerning demographic characteristics, such as the age and gender composition of migrant flows exists. This paper reports on the methods used to generate the CDM-IM dataset of age and gender specific profiles of bilateral net (not gross) migrant flows. We employ raw data from the United Nations Global Migration Database and estimate net migrant flows by age and gender between two time points around the year 2000, accounting for various demographic processes (fertility, mortality). The dataset contains information on 3,713 net migrant flows. Validation analyses against existing data sets and the historical, geopolitical context demonstrate that the CDM-IM dataset is of reasonably high quality.
Despite being a top concern on global agenda, global-scale, high resolution quantification of net-migration and its major drivers, is still missing for recent decades. We created a global dataset of annual net-migration between 2000–2019 (~ 10km grid), based on reported and here-downscaled sub-national birth and death ratios. We show that globally, internal migration has increased rapidly, dominating over international migration. Around 50% of world’s urban population lived in urban areas where migration accelerated urban population growth, while a third of global population lived in provinces where rural areas experienced positive net-migration. Finally, we show that socio-economic factors play a more important role than climatic ones to explain the migration patterns globally. By capturing migration patterns not only between but also within countries, socio-economic and geophysical zonings, our study highlights the importance of sub-national analysis of migration – a necessity for...
per, both from a global perspective and from a national perspective. Several economic, political and social implications of aging and aging-related demographic shifts are explored using System Dynamics models as scenario generators for Exploratory System Dynamics Modeling and Analysis. In Exploratory System Dynamics Modeling and Analysis, a plethora of uncertainties (pertaining to model structures, functions, scenarios, parameters) are used to generate thousands of plausible transient scenarios. The dynamic complexity of the resulting 'ensemble of future worlds' is analyzed to find robust policies. The national model is used to explore plausible effects on the sustainability of (Dutch) national health and social security systems, the economy, and the housing sector. Deep uncertainty related to the national model was dealt with during an Exploratory Group Model Specification and Simulation workshop by generating and using alternative hypotheses for major uncertainties. Moreover, the global model is used to test the feasibility of the national model in the international context.
Plausible dynamics of a major demographic shift-(societal) aging-is studied in this paper, both from a global perspective and from a national perspective. Several economic, political and social implications of aging and aging-related demographic shifts are explored using System Dynamics models as scenario generators for Exploratory System Dynamics Modeling and Analysis. In Exploratory System Dynamics Modeling and Analysis, a plethora of uncertainties (pertaining to model structures, functions, scenarios, parameters) are used to generate thousands of plausible transient scenarios. The dynamic complexity of the resulting 'ensemble of future worlds' is analyzed, ultimately in view of finding robust policies. The national model is used to explore plausible effects on the sustainability of (Dutch) national health and social security systems, the economy, and the housing sector. Deep uncertainty related to the national model was dealt with during an Exploratory Group Model Specification and Simulation workshop by generating and using alternative hypotheses for major uncertainties. Moreover, the global model is used to test the feasibility of the national model in the international context.
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