Climate Shocks and Migration: An Agent-Based Modeling Approach.

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.

Changing crops in response to climate: virtual Nang Rong, Thailand in an agent based simulation.

The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely economic outcomes, but included elements of bounded rationality in dependence on household demography. The socioeconomic dynamics are endogenous in the system, and climate changes were added as exogenous drivers. Villages changed their agricultural effort in many different ways. Most villages reduced the amount of land under cultivation, primarily with reduction in jasmine rice, but others did not. The variation in responses to climate change indicates potential sensitivity to initial conditions and path dependence for this type of system. The differences between our virtual villages and the real villages of the region indicate effects of bounded rationality and limits on model applications.

Design of an Agent-Based Model to Examine Population-Environment Interactions in Nang Rong District, Thailand.

The design of an Agent-Based Model (ABM) is described that integrates Social and Land Use Modules to examine population-environment interactions in a former agricultural frontier in Northeastern Thailand. The ABM is used to assess household income and wealth derived from agricultural production of lowland, rain-fed paddy rice and upland field crops in Nang Rong District as well as remittances returned to the household from family migrants who are engaged in off-farm employment in urban destinations. The ABM is supported by a longitudinal social survey of nearly 10,000 households, a deep satellite image time-series of land use change trajectories, multi-thematic social and ecological data organized within a GIS, and a suite of software modules that integrate data derived from an agricultural cropping system model (DSSAT - Decision Support for Agrotechnology Transfer) and a land suitability model (MAXENT - Maximum Entropy), in addition to multi-dimensional demographic survey data of individuals and households. The primary modules of the ABM are the Initialization Module, Migration Module, Assets Module, Land Suitability Module, Crop Yield Module, Fertilizer Module, and the Land Use Change Decision Module. The architecture of the ABM is described relative to module function and connectivity through uni-directional or bi-directional links. In general, the Social Modules simulate changes in human population and social networks, as well as changes in population migration and household assets, whereas the Land Use Modules simulate changes in land use types, land suitability, and crop yields. We emphasize the description of the Land Use Modules - the algorithms and interactions between the modules are described relative to the project goals of assessing household income and wealth relative to shifts in land use patterns, household demographics, population migration, social networks, and agricultural activities that collectively occur within a marginalized environment that is subjected to a suite of endogenous and exogenous dynamics.

Social and Spatial Networks: Kinship Distance and Dwelling Unit Proximity in Rural Thailand.

We address a long hypothesized relationship between the proximity of individuals' dwelling units and their kinship association. Better understanding this relationship is important because of its implications for contact and association among members of a society. In this paper, we use a unique dataset from Nang Rong, Thailand which contains dwelling unit locations (GPS) and saturated kinship networks of all individuals living in 51 agricultural villages. After presenting arguments for a relationship between individuals' dwelling unit locations and their kinship relations as well as the particulars of our case study, we introduce the data and describe our analytic approach. We analyze how kinship - considered as both a system linking collections of individuals in an extended kinship network and as dyadic links between pairs of individuals -patterns the proximity of dwelling units in rural villages. The results show that in general, extended kin live closer to one another than do unrelated individuals. Further, the degree of relatedness between kin correlates with the distance between their dwelling units. Close kin are more likely to co-reside, a fact which drives much of the relationship between kinship relatedness and dwelling unit proximity within villages. There is nevertheless suggestive evidence of a relationship between kinship association and dwelling unit proximity among kin who do not live together.

Migrant remittances and the web of family obligations: ongoing support among spatially extended kin in North-east Thailand, 1984-94.

Exchanges of money, goods, and assistance among family/kin members are influenced by the intertwined lives of individuals and their family/kin. As people pass through the young adulthood years, acquiring obligations as spouses and parents, and migrating in search of economic opportunities, tensions can arise over existing obligations. Using rich longitudinal data from Northeast Thailand, we examined the role of family networks (origin and destination) on migrants' exchanges with family/kin. Our approach overcame many shortcomings of earlier studies, allowing us to 'see' the family social network arrayed in a broader network. We show that intra-family exchanges are influenced by marital status, the presence of children, having parents in the origin household, and having siblings depart from it. The results are stable across sensitivity tests that systematically include or exclude various familial links. In addition, reports provided by origin households on migrant remittances are consistent with reports from migrants themselves.

Employment and Household Tasks of Japanese Couples, 1994-2009.

The paper examines changes in the relationship between employment and household tasks of Japanese couples, using data drawn from national cross-sectional surveys in 1994, 2000 and 2009 of persons aged 20-49 and from the 2009 follow-up of the 2000 survey. Wives' employment is structured by their husbands' employment time and earning power, as well as by their family situations including the presence and age of children and coresidence with parents. Housework hours of husbands, though very low, increased over time, while wives' hours decreased. Wives housework time decreases as their employment time increases. Marriage dramatically increases women's housework time but produces little change in men's time. Husbands' housework hours are positively correlated with reported marital satisfaction of both spouses.

Population Growth and Its Spatial Distribution as Factors in the Deforestation of Nang Rong, Thailand.

Frontiers constitute a major source of global land cover change hot spots, with forests and grass lands being converted into agricultural uses. As such, frontiers provide an opportunity to see how people manipulate the land and their lives in the context of social, cultural and environmental constraints. This paper examines frontier settlement and land cover change in Nang Rong district, Northeast Thailand for the last half century. It uses a Cellular Automata (CA) model to explore the land cover consequences of alternative patterns of settlement in a setting where people establish dwelling units in nucleated villages and work agricultural plots that surround villages. Forested land around the center of a village is converted into agricultural uses in an inverse relationship to the distance from the village center, but frequently modified by biophysical conditions. Land at the center of the village may be reforested after the village is established as a source of shade as well as fruit and other products. Model variation in land cover change is more sensitive to the spatial reach of village households than their temporal reach, suggesting the important role that technology plays in how villagers travel to their fields (walking versus motorized transit).

The Emergence of Two Distinct Fertility Regimes in Economically Advanced Countries.

Beginning in 2000, in economically advanced countries, a remarkable bifurcation in fertility levels has emerged, with one group in the moderate range of period total fertility rates (TFR), about 1.9, and the other at 1.3. The upper branch consists of countries in Northern and Western Europe, Oceania and the United States; the lower branch includes Central, Southern and Eastern Europe, and East and Southeast Asia. A review of the major theories for low fertility countries reveals that none of them would have predicted this specific bifurcation. We argue that those countries with fertility levels close to replacement level have institutional arrangements, and related policies, that make it easier, not easy, for women to combine the worker and mother roles. The institutional details are quite different across countries, suggesting that multiple combinations of institutional arrangements and policies can lead to the same country-level fertility outcome. Canada, the only exception to this bifurcation, illustrates the importance of the different institutional structures in Québec compared to the rest of Canada.

Contingent Work Rising: Implications for the Timing of Marriage in Japan.

Employment has become increasingly precarious in developed countries, meaning that, for many young adults, jobs provide neither benefits nor security, more work is part time, and employers are increasingly hiring workers from temporary help agencies and contract companies rather than as employees of their own company. These changes in employment relations have profound effects on gender roles and on family transitions of young adults, especially young men and in particular in countries such as Japan, where there are rigid family norms and the male-breadwinner tradition still prevails. The authors examined the effects of the experience of non-regular work on the timing of marriage and whether this differs by sex. Using recent life history data from Japan, they found that men working in non-regular jobs are especially likely to postpone marriage. The implications of the growth of precarious work for changes in work and family institutions in Japan are discussed.

From whom do older persons prefer support? The case of rural Thailand.

This study explores rural elderly preferences for support across a multi-dimensional measure of elderly care needs. Applying a framework developed in the U.S. to Thailand for the first time, five diverse types of support are considered: meal preparation, personal care, transportation, financial support, and emotional support. The emphasis is on preferences for care and not actual care received. The data are from focus group discussions conducted in seven villages in Nang Rong district, northeastern Thailand. Thailand and the study site represent the social and economic conditions faced by many rapidly industrializing places-where there has been a dramatic demographic transition (lowered fertility and substantial out-migration), growing numbers of older persons remaining in rural settings, and limited publically-financed elderly care or market-based elder care available for purchase. For this study, in each village, male and female older persons aged 60 and over participated in the focus group discussions. As part of the discussion, focus group participants were asked to rank their first four preferences by type of support. Male and female older persons' preferences were slightly different for genderized tasks. In addition, social closeness and geographical proximity mattered. Traditional matrilocal residence patterns contributed to the perceptions of the older persons. Neighbors were preferred when kin were not available. Preferences inform strategic choices by older persons given the context of available resources. Understanding preferences and strategic choices among the older persons can help policy makers tailor programs more effectively and efficiently, without jeopardizing elderly well-being.

Farming Systems and Rural Out-Migration in Nang Rong, Thailand and Chitwan Valley, Nepal.

Using data from two post-frontier rural settings, Nang Rong, Thailand (N=2,538) and Chitwan Valley, Nepal (N=876), this paper examines agricultural push factors determining the outmigration of young people age 15 to 19. We focus on different dimensions of migration, including distance and duration. Our study examines a wide array of agricultural determinants, each with its own potential effect on migration. These determinants include land tenure, crop portfolios, animal husbandry activities, and use of farm inputs. We link these proximal causes to two underlying mechanisms: risk and amenities. We examine these determinants using separate models across settings. Our results indicate that agricultural factors are significant determinants of migration in both contexts. However, different factors operate in different settings, indicating the importance of contextual variation in explaining the manner in which risks and amenities influence agricultural determinants of migration.

Land Suitability Modeling using a Geographic Socio-Environmental Niche-Based Approach: A Case Study from Northeastern Thailand.

Understanding the pattern-process relations of land use/land cover change is an important area of research that provides key insights into human-environment interactions. The suitability or likelihood of occurrence of land use such as agricultural crop types across a human-managed landscape is a central consideration. Recent advances in niche-based, geographic species distribution modeling (SDM) offer a novel approach to understanding land suitability and land use decisions. SDM links species presence-location data with geospatial information and uses machine learning algorithms to develop non-linear and discontinuous species-environment relationships. Here, we apply the MaxEnt (Maximum Entropy) model for land suitability modeling by adapting niche theory to a human-managed landscape. In this article, we use data from an agricultural district in Northeastern Thailand as a case study for examining the relationships between the natural, built, and social environments and the likelihood of crop choice for the commonly grown crops that occur in the Nang Rong District - cassava, heavy rice, and jasmine rice, as well as an emerging crop, fruit trees. Our results indicate that while the natural environment (e.g., elevation and soils) is often the dominant factor in crop likelihood, the likelihood is also influenced by household characteristics, such as household assets and conditions of the neighborhood or built environment. Furthermore, the shape of the land use-environment curves illustrates the non-continuous and non-linear nature of these relationships. This approach demonstrates a novel method of understanding non-linear relationships between land and people. The article concludes with a proposed method for integrating the niche-based rules of land use allocation into a dynamic land use model that can address both allocation and quantity of agricultural crops.

Why do people postpone parenthood? Reasons and social policy incentives.

BACKGROUND: Never before have parents in most Western societies had their first children as late as in recent decades. What are the central reasons for postponement? What is known about the link between the delay of childbearing and social policy incentives to counter these trends? This review engages in a systematic analysis of existing evidence to extract the maximum amount of knowledge about the reasons for birth postponement and the effectiveness of social policy incentives. METHODS: The review followed the PRISMA procedure, with literature searches conducted in relevant demographic, social science and medical science databases (SocINDEX, Econlit, PopLine, Medline) and located via other sources. The search focused on subjects related to childbearing behaviour, postponement and family policies. National, international and individual-level data sources were also used to present summary statistics. RESULTS: There is clear empirical evidence of the postponement of the first child. Central reasons are the rise of effective contraception, increases in women's education and labour market participation, value changes, gender equity, partnership changes, housing conditions, economic uncertainty and the absence of supportive family policies. Evidence shows that some social policies can be effective in countering postponement. CONCLUSIONS: The postponement of first births has implications on the ability of women to conceive and parents to produce additional offspring. Massive postponement is attributed to the clash between the optimal biological period for women to have children with obtaining additional education and building a career. A growing body of literature shows that female employment and childrearing can be combined when the reduction in work-family conflict is facilitated by policy intervention.

Child-care availability and fertility in Norway.

The child-care and fertility hypothesis has been in the literature for a long time and is straightforward: As child care becomes more available, affordable, and acceptable, the antinatalist effects of increased female educational attainment and work opportunities decrease. As an increasing number of countries express concern about low fertility, the child-care and fertility hypothesis takes on increased importance. Yet data and statistical limitations have heretofore limited empirical tests of the hypothesis. Using rich longitudinal data and appropriate statistical methodology, We show that increased availability of child care increases completed fertility. Moreover, this positive effect of child-care availability is found at every parity transition. We discuss the generalizability of these results to other settings and their broader importance for understanding variation and trends in low fertility.

Order Amidst Change: Work and Family Trajectories in Japan.

Substantial family and work macro-level change has been occurring in Japan. Examples include a decline in the availability of jobs that afford lifetime protection against unemployment, an increase in jobs that do not carry benefits such as a pension, an increase in age at marriage and at first birth, and an increase in marital dissolution. Using life history data from the 2000 National Survey on Family and Economic Conditions, young Japanese appear to have responded to these macro-level changes in a fairly orderly manner. Marriage and childbearing have been postponed, but marriage still precedes childbearing. Education is completed prior to starting work. For men, once work commences they continue working. For women, the classic conflict between work and family roles is evident. For men and women in both the family and work spheres Japanese young adults have more orderly life course trajectories than American young adults.

Institutions and the transition to adulthood: Implications for fertility tempo in low-fertility settings.

The number of countries experiencing very low fertility has been rising in recent years, garnering increasing academic, political and media attention. There is now widespread academic agreement that the postponement of fertility is a major contributing factor in the very low levels of fertility that have occurred, and yet most policy discussions have been devoted to increasing the numbers of children women have. We discuss factors in three institutions-the educational system, the labour market and the housing market-that may inadvertently have led to childbearing postponement. We highlight important components of the timing of childbearing, including its changing place within the transition to adulthood across countries and the significance of the demands of childbearing versus childrearing. Using illustrations from Europe, North America, Japan, Australia and New Zealand, we argue that the following all lead to younger childbearing: 1) an open education system whereby it is relatively easy to return to school after having dropped out for a while; 2) a shorter, smoother, easier school-to-work transition; 3) easier re-entry into the labour market after having taken time out for childrearing or any other reason; 4) greater capability of integrating childrearing into a career; 5) easier ability to obtain a mortgage with a moderately small down payment, moderately low interest rate and a long time period over which to repay the loan; and 6) easier ability to rent a dwelling unit at an affordable price. Conversely, reversing any or all of these factors would lead, other things being equal, to postponement of childbearing.

Case studies, cross-site comparisons, and the challenge of generalization: comparing agent-based models of land-use change in frontier regions.

Cross-site comparisons of case studies have been identified as an important priority by the land-use science community. From an empirical perspective, such comparisons potentially allow generalizations that may contribute to production of global-scale land-use and land-cover change projections. From a theoretical perspective, such comparisons can inform development of a theory of land-use science by identifying potential hypotheses and supporting or refuting evidence. This paper undertakes a structured comparison of four case studies of land-use change in frontier regions that follow an agent-based modeling approach. Our hypothesis is that each case study represents a particular manifestation of a common process. Given differences in initial conditions among sites and the time at which the process is observed, actual mechanisms and outcomes are anticipated to differ substantially between sites. Our goal is to reveal both commonalities and differences among research sites, model implementations, and ultimately, conclusions derived from the modeling process.

Measuring housing quality in the absence of a monetized real estate market.

Measuring housing quality or value or both has been a weak component of demographic and development research in less developed countries that lack an active real estate (housing) market. We describe a new method based on a standardized subjective rating process. It is designed to be used in settings that do not have an active, monetized housing market. The method is applied in an ongoing longitudinal study in north-east Thailand and could be straightforwardly used in many other settings. We develop a conceptual model of the process whereby households come to reside in high-quality or low-quality housing units. We use this theoretical model in conjunction with longitudinal data to show that the new method of measuring housing quality behaves as theoretically expected, thus providing evidence of face validity.