Time to Mainstream the Environment into Migration Theory?

As with all social processes, human migration is a dynamic process that requires regular theoretical reflection; this article offers such reflection as related to the role of the natural environment in contemporary migration research and theory. A growing body of evidence suggests that environmental contexts are increasingly shifting social and ecological realities in ways that are consequential to migration theory. We review some of this evidence, providing examples applicable to core migration theories, including neoclassical economic and migration systems perspectives, the "push-pull" framework, and the new economics of labor migration. We suggest that neglecting consideration of the natural environment may yield misspecified migration models that attribute migration too heavily to social and economic factors particularly in the context of contemporary climate change,. On the other hand, failure to consider migration theory in climate scenarios may lead to simplistic projections and understandings, as in the case of "climate refugees". We conclude that migration researchers have an obligation to accurately reflect the complexity of migration's drivers, including the environment, within migration scholarship especially in the context of global climate change.

Operationalizing and empirically identifying populations trapped in place by climate and environmental stressors in Mexico.

In this paper, we propose a guiding operational definition and corresponding set of empirical steps to identify and study trapped populations. Trapped populations consist of actors who are highly vulnerable to climate and environmental stressors given limited resources (economic, social, etc.), which limit their ability to adapt to these stressors in-situ or by choosing to migrate. Informed by both insights and omissions from prior theoretical and empirical research, we propose a guiding operational definition of trapped populations that appreciates and incorporates actors' limited resources and their migration intentions against the backdrop of climate and environmental stressors. As it should, our operational definition points to a specific set of operations, or steps, which can be followed to empirically identify and study trapped populations. Using data from the Mexican Family Life Survey (MxFLS), we detail the steps permitting both retrospective and prospective identification of trapped populations. We conclude by discussing the strengths and weaknesses of our operational definition and empirical approach, as well as possible extensions.

Exploring Rural-Urban Differences in Polygenic Associations for Health among Older Adults in the United States.

This paper contributes to research on health disparities among rural and urban residents by considering differences in the magnitude of genetic associations for physical health, mental health, and health behaviors across the two settings. Previous research has shown reduced genetic associations in rural compared to urban settings but none have utilized current genome-wide polygenic scores and none have focused on older adults. Using a sample of 14,994 adults from the 1992 to 2016 waves of the Health and Retirement Study our results suggest genetic associations for BMI (p<.018) and heart conditions (p < .023) are significantly reduced in rural compared to urban settings and we find weak evidence in support of this association for depression (p. < .065) and no evidence for smoking (p < 461). In sum, the weaker genetic associations in rural areas highlights the centrality of the social, economic, and built environment as a determinant of disparities.

Rural Population Health and Aging: Toward a Multilevel and Multidimensional Research Agenda for the 2020s.

The unique health and aging challenges of rural populations often go unnoticed. In fact, the rural United States is home to disproportionate shares of older and sicker people, there are large and growing rural-urban and within-rural mortality disparities, many rural communities are in population decline, and rural racial/ethnic diversity is increasing.Yet rural communities are not monolithic, and although some rural places are characterized by declining health, others have seen large improvements in population health. We draw on these realities to call for new research in five areas.First, research is needed to better describe health disparities between rural and urban areas and, because rural places are not monolithic, across rural America. Second, research is needed on how trends in rural population health and aging are affecting rural communities. Third, research is needed on the ways in which economic well-being and livelihood strategies interact with rural health and aging. Fourth, we need to better understand the health implications of the physical and social isolation characterizing many rural communities. Finally, we argue for new research on the implications of local natural environments and climate change for rural population health and aging.

Internal and International Mobility as Adaptation to Climatic Variability in Contemporary Mexico: Evidence from the Integration of Census and Satellite Data.

Migration provides a strategy for rural Mexican households to cope with, or adapt to, weather events and climatic variability. Yet prior studies on "environmental migration" in this context have not examined the differences between choices of internal (domestic) or international movement. In addition, much of the prior work relied on very coarse spatial scales to operationalize the environmental variables such as rainfall patterns. To overcome these limitations, we use fine-grain rainfall estimates derived from NASA's Tropical Rainfall Measuring Mission (TRMM) satellite. The rainfall estimates are combined with Population and Agricultural Census information to examine associations between environmental changes and municipal rates of internal and international migration 2005-2010. Our findings suggest that municipal-level rainfall deficits relative to historical levels are an important predictor of both international and internal migration, especially in areas dependent on seasonal rainfall for crop productivity. Although our findings do not contradict results of prior studies using coarse spatial resolution, they offer clearer results and a more spatially nuanced examination of migration as related to social and environmental vulnerability and thus higher degrees of confidence.

Native Americans: Where in Environmental Justice Research?

While the last two decades have seen important theoretical, empirical, and policy advancements in environmental justice generally, much remains to be done regarding Native Americans. Unique political and cultural dynamics shape the study and pursuit of environmental justice (EJ) in Native American communities. This review summarizes Native American EJ issues based on a cross-disciplinary search of over 60 publications. In so doing, we discuss the unique nature of Native American EJ in terms of conducting research and working toward reducing the continuation of historical trauma associated with environmental ills, the types of strategies used in Native American EJ research, and issues of Native American climate justice. We conclude with discussion of remaining knowledge gaps and future research needs.

Swimming and Gendered Vulnerabilities: Evidence from the Northern and Central Philippines.

Men and women's vulnerability to disasters is different and often related, in part, to cultural norms that influence gendered behaviors and abilities. In this study we focus on gender differences in swimming abilities, which, in the case of tsunamis have resulted in far greater female mortality rates. We present results on swimming ability by gender for 940 residents of coastal rural communities in the northern and central Philippines. We also examine cross-generational transmission of swimming abilities to shed light on future vulnerability. Results reveal men are far more likely than women to swim and, importantly, parents who can swim are more likely to have children who can swim. In this way, differences in swimming ability among today's adults may perpetuate vulnerabilities within future generations.

Domestic and International Climate Migration from Rural Mexico.

Evidence is increasing that climate change and variability may influence human migration patterns. However, there is less agreement regarding the type of migration streams most strongly impacted. This study tests whether climate change more strongly impacted international compared to domestic migration from rural Mexico during 1986-99. We employ eight temperature and precipitation-based climate change indices linked to detailed migration histories obtained from the Mexican Migration Project. Results from multilevel discrete-time event-history models challenge the assumption that climate-related migration will be predominantly short distance and domestic, but instead show that climate change more strongly impacted international moves from rural Mexico. The stronger climate impact on international migration may be explained by the self-insurance function of international migration, the presence of strong migrant networks, and climate-related changes in wage difference. While a warming in temperature increased international outmigration, higher levels of precipitation declined the odds of an international move.

Amplification or suppression: Social networks and the climate change-migration association in rural Mexico.

Increasing rates of climate migration may be of economic and national concern to sending and destination countries. It has been argued that social networks - the ties connecting an origin and destination - may operate as "migration corridors" with the potential to strongly facilitate climate change-related migration. This study investigates whether social networks at the household and community levels amplify or suppress the impact of climate change on international migration from rural Mexico. A novel set of 15 climate change indices was generated based on daily temperature and precipitation data for 214 weather stations across Mexico. Employing geostatistical interpolation techniques, the climate change values were linked to 68 rural municipalities for which sociodemographic data and detailed migration histories were available from the Mexican Migration Project. Multi-level discrete-time event-history models were used to investigate the effect of climate change on international migration between 1986 and 1999. At the household level, the effect of social networks was approximated by comparing the first to the last move, assuming that through the first move a household establishes internal social capital. At the community level, the impact of social capital was explored through interactions with a measure of the proportion of adults with migration experience. The results show that rather than amplifying, social capital may suppress the sensitivity of migration to climate triggers, suggesting that social networks could facilitate climate change adaptation in place.

Climate Change as Migration Driver from Rural and Urban Mexico.

Studies investigating migration as a response to climate variability have largely focused on rural locations to the exclusion of urban areas. This lack of urban focus is unfortunate given the sheer numbers of urban residents and continuing high levels of urbanization. To begin filling this empirical gap, this study investigates climate change impacts on U.S.-bound migration from rural and urban Mexico, 1986-1999. We employ geostatistical interpolation methods to construct two climate change indices, capturing warm and wet spell duration, based on daily temperature and precipitation readings for 214 weather stations across Mexico. In combination with detailed migration histories obtained from the Mexican Migration Project, we model the influence of climate change on household-level migration from 68 rural and 49 urban municipalities. Results from multilevel event-history models reveal that a temperature warming and excessive precipitation significantly increased international migration during the study period. However, climate change impacts on international migration is only observed for rural areas. Interactions reveal a causal pathway in which temperature (but not precipitation) influences migration patterns through employment in the agricultural sector. As such, climate-related international migration may decline with continued urbanization and the resulting reductions in direct dependence of households on rural agriculture.

The Environmental Dimensions of Migration.

Research on the environmental dimensions of human migration has made important strides in recent years. However, findings have been spread across multiple disciplines with wide ranging methodologies and limited theoretical development. This article reviews key findings of the field and identifies future directions for sociological research. We contend that the field has moved beyond linear environmental "push" theories towards a greater integration of context, including micro-, meso-, and macro-level interactions. We highlight findings that migration is often a household strategy to diversify risk (NELM), interacting with household composition, individual characteristics, social networks, and historical, political and economic contexts. We highlight promising developments in the field, including the recognition that migration is a long-standing form of environmental adaptation and yet only one among many forms of adaptation. Finally, we argue that sociologists could contribute significantly to migration-environment inquiry through attention to issues of inequality, perceptions, and agency vis-à-vis structure.

Undocumented migration in response to climate change.

In the face of climate change induced economic uncertainty, households may employ migration as an adaptation strategy to diversify their livelihood portfolio through remittances. However, it is unclear whether such climate migration will be documented or undocumented. In this study we combine detailed migration histories with daily temperature and precipitation information for 214 weather stations to investigate whether climate change more strongly impacts undocumented or documented migration from 68 rural Mexican municipalities to the U.S. during the years 1986-1999. We employ two measures of climate change, the warm spell duration index (WSDI) and the precipitation during extremely wet days (R99PTOT). Results from multi-level event-history models demonstrate that climate-related international migration from rural Mexico was predominantly undocumented. We conclude that programs to facilitate climate change adaptation in rural Mexico may be more effective in reducing undocumented border crossings than increased border fortification.

Measuring the Environmental Dimensions of Human Migration: The Demographer's Toolkit.

In recent years, the empirical literature linking environmental factors and human migration has grown rapidly and gained increasing visibility among scholars and the policy community. Still, this body of research uses a wide range of methodological approaches for assessing environment-migration relationships. Without comparable data and measures across a range of contexts, it is impossible to make generalizations that would facilitate the development of future migration scenarios. Demographic researchers have a large methodological toolkit for measuring migration as well as modeling its drivers. This toolkit includes population censuses, household surveys, survival analysis and multi-level modeling. This paper's purpose is to introduce climate change researchers to demographic data and methods and to review exemplary studies of the environmental dimensions of human migration. Our intention is to foster interdisciplinary understanding and scholarship, and to promote high quality research on environment and migration that will lead toward broader knowledge of this association.

Wildfire-Migration Dynamics: Lessons from Colorado's Fourmile Canyon Fire.

The number of people living in wildfire prone wildland-urban interface (WUI) communities is on the rise. Yet, no prior study has investigated wildfire-induced residential relocation from WUI areas after a major fire event. To provide insight into the association between socio-demographic and socio-psychological characteristics and wildfire related intention to move, we use data from a survey of WUI residents in Boulder and Larimer Counties, Colorado. The data were collected two months after the devastating Fourmile Canyon fire destroyed 169 homes and burned over 6,000 acres of public and private land. Although working with a small migrant sample, logistic regression models demonstrate that survey respondents intending to move in relation to wildfire incidence do not differ socio-demographically from their non-migrant counterparts. They do, however, show significantly higher levels of risk perception. Investigating destination choices shows a preference for short distance moves.