Migration and climate change: examining thresholds of change to guide effective adaptation decision-making

The implications of environmental change for migration are little understood. Migration as a response to climate change could be seen as a failure of in situ adaptation methods, or migration could be alternatively perceived as a rational component of creative adaptation to environmental risk. This paper frames migration as part of an adaptation response to climate change impacts to natural resource condition and environmental hazards. Thresholds will be reached by communities after which migration will become a vital component of an effective adaptation response. Such changes to migration patterns have the potential to undermine migration policy unless appropriate preparations are undertaken. This paper describes an approach to assist researchers to frame how climate change will influence migration by critically analysing how thresholds of fundamental change to migration patterns could be identified, primarily in relation to two case studies in Nepal and Thailand. Future policy for internal and international migration could be guided by the analysis of such thresholds of non-linear migration and resourced effectively to ensure that socio-economic and humanitarian outcomes are maximised.     

Household access to capital and its effects on drought adaptation and migration: a case study of rural Alberta in the 1930s

This article reports findings from an empirical study of the impacts of drought on rural households in southeastern Alberta, Canada during the 1930s. In that decade, extreme summer heat conditions and low precipitation levels led to repeated crop failures. These extreme climatic conditions coincided with economic recession, falling commodity prices, and rising unemployment to create widespread hardship and suffering across the rural population. Thousands of households adapted by leaving the drought-stricken region and migrating to more northerly regions unaffected by drought, often suffering still further hardship as they reestablished themselves in a new environment. Through secondary research of historical documents and interviews with surviving migrants and non-migrants, this study identifies how economic, human, and social capital influenced the adaptive capacity, adaptation decisions, and migration behavior of rural households and describes how institutional responses affected household adaptation. Differential access to capital in its various forms was a key factor that distinguished households that adapted via migration from those that did not. The findings from this study of historical environment-related population change provide insights that enhance our broader understanding of potential future migration responses to the impacts of anthropogenic climate change and important considerations for policy-makers and planners seeking to build adaptive capacity in rural populations.     

Thresholds in climate migration

Migration in response to climatic hazards or changes in climatic conditions can unfold in a variety of ways, ranging from barely observable, incremental changes in pre-existing migration flows to abrupt, non-linear population movements. The adoption of migration instead of in situ adaptation responses, and the high degree of variability in potential migration outcomes, in part reflects the presence of thresholds or tipping points within the processes of human-environment interaction through which climate adaptation and migration take place. This article reviews and makes linkages between existing research in climate adaptation, migration system dynamics, residential preferences, and risk perception to identify and explore the functioning and importance of thresholds. Parochial examples from the author’s published research on climate adaptation and migration in rural North America are used to illustrate. Six types of thresholds in response to climate hazards are identified: (1) Adaptation becomes necessary; (2) Adaptation becomes ineffective; (3) Substantive changes in land use/livelihoods become necessary; (4) In situ adaptation fails, migration ensues; (5) Migration rates become non-linear; and (6) Migration rates cease to be non-linear. Movement across thresholds is driven by context-specific characteristics of climate events, natural systems, and/or human systems. Transition from incremental to non-linear migration can be accelerated by people’s perceptions, by actions of influential individuals or groups, and by changes in key infrastructure, services, or other community assets. Non-linear climate migration events already occur at local and sub-regional scales. The potential for global scale, non-linear population movements later this century depends heavily on future greenhouse gas emission trends. The ability to identify and avoid thresholds that tip climate migration into a non-linear state will be of growing concern to policy makers and planners at all levels in coming decades. This article forms part of a special issue of this journal dedicated to the late Graeme Hugo, and the author draws heavily on past research by Professor Hugo and colleagues.     

Environmental hazard and migration intentions in a coastal area in Ghana: a case of sea flooding

Recently, there has been significant debate about whether ‘environmental migration’ can constitute a form of adaptation to environmental change, as opposed to forced or flight migration. The Foresight Report on Migration and Environmental Change (2011) suggested environmental factors are one driver of migration, as well as political, social, economic and demographic drivers, and that—under the right conditions—migration can be a form of adaptation to changing climatic conditions. However, this is dependent on migrants having adequate social and financial capital to undertake beneficial types of migration; it further argues that environmental change may result in ‘trapped populations’ whereby people who lack the necessary resources to re-establish livelihoods elsewhere may be left exposed to increasingly severe environmental shocks and stresses in situ. Research on the climate-migration nexus in West Africa has largely focused on out-migration from the semi-arid Sahel with more limited evidence about how sea flooding interacts with migration flows. This paper attempts to help fill this knowledge gap. Using data from a representative survey of households across three coastal communities in Ghana’s Volta River Delta, this paper concludes that exposure to sea flooding may not be a primary cause of out-migration as other community, economic and political factors influence migration intentions and decisions. Thus, it is important for planned adaptation interventions to be strengthened in situ to enable households, particularly farming households, sustain their livelihoods.     

Climate-related migration in rural Bangladesh: a behavioural model

Research into the climate change and migration nexus has often focussed solely on how people move in response to the impacts of variability and change in climate. This notion often ignores the nature of migration as a tried and tested livelihood choice amid a variety of socio-economic and environmental opportunities and limitations. This paper closely looks at the behavioural aspects of migration decision-making in Bangladesh in the context of changes in its economy, and, increasingly, exposure to the impacts of climate variability and change. We find that villagers in areas particularly affected by increasing climatic stresses and shocks are diversifying their traditional livelihood strategies by migrating. Environmental factors, including climatic stresses and shocks, often make such shifts even more necessary. Although the migrants’ primary motivation is better income, in effect, migration becomes an effective form of adaptation. Based on a qualitative study in three geographically distinct places of Bangladesh, we propose that migration is a socially acceptable behaviour that occurs in the context of perceived environmental change and climate variability. Migration decisions are mediated by a set of ‘behavioural factors’ that assesses the efficacy of different responses to opportunities and challenges, their socio-cultural acceptance and the ability to respond successfully. This understanding has policy relevance for climate change adaptation, in terms of both how migrants are perceived and how their movements are planned for.     

The safety net function of NTFPs in different agro-ecological zones of South Africa

Various South African studies have shown that rural households use NTFPs as safety nets in times of misfortune. However being focussed on one or two sites, they do not show the prevalence of NTFP use as safety nets across multiple sites. In addition, they do not show the use of NTFPs as safety nets by rural households in different agro-ecological zones. The results of the study showed that about 79% of the total households interviewed experienced at least one shock of some magnitude in the previous 12 months. The most experienced shocks were illness, death, crop failure, and hunger. The households employed various coping strategies in response to different types of shocks, with the three widely used strategies being assistance from friends and relatives, using cash savings, and using NTFPs. Households in low agro-ecological zones used NTFPs as safety nets more than households in high agro-ecological zones.     

Climate change and internal migration intentions in the forest-savannah transition zone of Ghana

Migration is at the centre of demographic research on the population–environment nexus. Increasing concerns about the impacts of environmental events on human population are fuelling interest on the relationship between migration and environmental change. Using data from the Climate Change Collective Learning and Observatory Network Ghana project, we employ binary logistic regression to examine migration intentions of households in response to major community stressors including climate-related ones. The results indicate that the type of community stressor that affects households most does not differentiate migration intentions in Ghana’s forest-savannah transition zone: Even though the majority of the respondents mentioned climate-related events as the stressor that affects them the most, such events do not appear to directly explain migration intentions. However, socio-demographic factors such as age, household size and current migration status are significant predictors of migration intentions, with younger household heads, heads of migrant households and heads of smaller households being relatively more likely to have migration intentions than other household heads. We conclude that migration drivers are multifaceted and deserve further research because even in areas with perceived environmental stress, climate-related events may not be the primary motivation for migration intentions.     

Household organization and the interregional variation of out-migration rates

Regional out-migration rates may depend on localized conditions, but the range of possibilities for migration decision making in multi person households includes processes in which the response to variations in localized conditions depends on household size. Analyses of migration rates for households indicate that larger households exhibit more extreme responses to variations in localized conditions and that this is an important source of variation in regional out-migration rates.     

The Impact of Migration and Remittances on Wealth Accumulation and Distribution in Rural Thailand

This article studies the impact of internal migration and remittance flows on wealth accumulation and distribution in 51 rural villages in Nang Rong, Thailand. Using data from 5,449 households, the study constructs indices of household productive and consumer assets with principal component analysis. The changes in these indices from 1994 to 2000 are modeled as a function of households’ prior migration and remittance behavior with ordinary least squares, matching, and instrumental variable methods. The findings show that rich households lose productive assets with migration, potentially because of a reduction in the labor force available to maintain local economic activities, while poor households gain productive assets. Regardless of wealth status, households do not gain or lose consumer assets with migration or remittances. These results suggest an equalizing effect of migration and remittances on wealth distribution in rural Thailand.     

Kidnap risks and migration: evidence from Colombia

Using a unique data set from the major Colombian cities collected between 2000–2003 and with information on more than 12,000 households, this paper studies the relationship between the kidnap risk a household faces with its migration decisions. We find evidence that exposure to such risk induces households to react sending some of their members to an international destination but not necessarily to a domestic one. Estimates are robust to the inclusion of several household characteristics usual in the migration literature, other crime risks, reported feelings of insecurity of the household, and an alternative measure of kidnap risk.     

Men’s Migration and Women’s Fertility in Rural Mozambique

Labor migration profoundly affects households throughout rural Africa. This study looks at how men’s labor migration influences marital fertility in a context where such migration has been massive while its economic returns are increasingly uncertain. Using data from a survey of married women in southern Mozambique, we start with an event-history analysis of birth rates among women married to migrants and those married to nonmigrants. The model detects a lower birth rate among migrants’ wives, which tends to be partially compensated for by an increased birth rate upon cessation of migration. An analysis of women’s lifetime fertility shows that it decreases as the time spent in migration by their husbands accrues. When we compare reproductive intentions stated by respondents with migrant and nonmigrant husbands, we find that migrants’ wives are more likely to want another child regardless of the number of living children, but the difference is significant only for women who see migration as economically benefiting their households. Yet, such women are also significantly more likely to use modern contraception than other women. We interpret these results in light of the debate on enhancing versus disrupting effects of labor migration on families and households in contemporary developing settings.     

Do Rainfall Deficits Predict U.S.-Bound Migration from Rural Mexico? Evidence from the Mexican Census

Environmental and climatic changes have shaped human mobility for thousands of years and research on the migration-environment connection has proliferated in the past several years. Even so, little work has focused on Latin America or on international movement. Given rural Mexico’s dependency on primary sector activities involving various natural resources, and the existence of well-established transnational migrant networks, we investigate the association between rainfall patterns and U.S.-bound migration from rural locales, a topic of increasing policy relevance. The new economics of labor migration theory provides background, positing that migration represents a household-level risk management strategy. We use data from the year 2000 Mexican census for rural localities and socioeconomic and state-level precipitation data provided by the Mexican National Institute for Statistics and Geography. Multilevel models assess the impact of rainfall change on household-level international out-migration while controlling for relevant sociodemographic and economic factors. A decrease in precipitation is significantly associated with U.S.-bound migration, but only for dry Mexican states. This finding suggests that programs and policies aimed at reducing Mexico-U.S. migration should seek to diminish the climate/weather vulnerability of rural Mexican households, for example by supporting sustainable irrigation systems and subsidizing drought-resistant crops.     

Environmental Influences on Human Migration in Rural Ecuador

The question of whether environmental conditions influence human migration has recently gained considerable attention, driven by claims that global environmental change will displace large populations. Despite this high level of interest, few quantitative studies have investigated the potential effects of environmental factors on migration, particularly in the developing world and for gradual but pervasive forms of environmental change. To address this, a retrospective migration survey was conducted in rural Ecuador and linked to data on topography, climate, and weather shocks. These data were used to estimate multivariate event history models of alternative forms of mobility (local mobility, internal migration, and international migration), controlling for a large number of covariates. This approach is generalizable to other study areas and responds to calls for the development of more rigorous methods in this field. The results indicate that adverse environmental conditions do not consistently increase rural out-migration and, in some cases, reduce migration. Instead, households respond to environmental factors in diverse ways, resulting in complex migratory responses. Overall, the results support an alternative narrative of environmentally induced migration that recognizes the adaptability of rural households in responding to environmental change.     

Seasonal migration of rural labor in India

The impact of seasonal migration has been overlooked by students of migration. A unique data set collected in Dungarpur – one of the less developed districts of India – allows us to closely examine both the determinants and impact of seasonal migration. Detailed information was gathered from all members of 624 households, thus enabling analyses at both individual and household levels. The findings indicate that seasonal migration among rural laborers is wide-spread. Rural households in India use migrant labor offered by their members to improve their well-being by both reducing the impacts of inferior conditions and by raising household's income levels. Migrant labor is a compensating mechanism used by households to reduce their disadvantageous position. Migrant households are characterized by lower education levels, lower levels of income from agriculture, and by an inferior geographical location. However, those households sending migrant labor are found to have higher income levels than those not sending migrant labor. Income from migrant labor accounts for almost 60% of total annual income of households sending at least one migrant laborer. Such findings are in accordance with explanations derived from the `new economics of migration'. We can thus learn that migration-related decisions should not evaluated only on the basis of utility maximization of individual migrants, but also on the basis of risk reducing by households.     

Heterogeneous climate effects on human migration in Indonesia

We examine the effect of anomalous temperatures, rainfall levels, and monsoon timing on migration outcomes in Indonesia. Using panel data from the Indonesian Family Life Survey and high-resolution climate data, we assess whether intra- and inter-province moves are used as a response to climatic shocks. We evaluate the relative importance of temperature, rainfall, and monsoon timing for migration. Only temperature and monsoon timing have significant effects, and these do not operate in the direction commonly assumed. Estimated effects vary according to individuals’ gender, membership in a farm household, and location. We also analyze climate effects on sources of household income, which highlights the multi-phasic nature of household responses. Results undermine narratives of a uniform global migratory response to climate change and highlight the heterogeneous use of migration as a response to such changes. By extending previous research on environmentally induced migration in Indonesia, we also highlight the sensitivity of estimates to alternative climate and migration measures.     

气候变化对宁夏生态脆弱地区农牧民生计的影响及适应策略

气候变化对人类生产生活的影响随地区和人群的不同而不同,其中对生态脆弱地区的贫困人群影响尤为特殊。本文以受干旱影响的典型区域一宁夏生态脆弱地区农牧民生计为例．试图通过对宁夏回族自治区5个县／市／区294户农牧家庭开展的问卷调查和访谈研究．分析气候变化对当地农牧民生产、生活和生存状况的具体影响内容及影响的程度．探讨农牧民应对气候变化的主要的生计适应措施。结果显示农牧民心理上的自我调适是人们在脆弱的状态下应对气候变化的前提,并通过多样化的生计方式、外出务工、自主性迁移等自适应方式来适应气候变化对农牧民生计带来的种种影响．同时生态脆弱地区气候变化的应对也离不开政府大环境背景下的制度设计和政策支持。     

Erratum to: Heterogeneous climate effects on human migration in Indonesia

We examine the effect of anomalous temperatures, rainfall levels, and monsoon timing on migration outcomes in Indonesia. Using panel data from the Indonesian Family Life Survey and high-resolution climate data, we assess whether intra- and inter-province moves are used as a response to climatic shocks. We evaluate the relative importance of temperature, rainfall, and monsoon timing for migration. Temperature and monsoon timing have significant effects, and these do not operate in the direction commonly assumed. Estimated effects vary according to individuals’ gender, membership in a farm household, and location. We also analyze climate effects on sources of household income, which point to the multi-phasic nature of household responses. Results undermine narratives of a uniform global migratory response to climate change and highlight the heterogeneous use of migration as a response to such changes. By extending previous research on environmentally induced migration in Indonesia, we also highlight the sensitivity of estimates to alternative climate and migration measures.     

The impacts of climate variability on household welfare in rural Mexico

In light of the expected increase in weather variability from climate change, we examine the impact of weather shocks, defined as rainfall or growing degree days more than a standard deviation from their respective long-run means, on household consumption per capita. The analyses suggest that both rainfall and temperature shocks affect both food and non-food consumption. Furthermore, the results show that a household’s ability to protect its consumption from weather shocks depends on the climate region and when in the agricultural year the shock occurs. Especially, households in arid climates are not fully protected from weather shocks occurring during the beginning of the wet season (April, May, June). The results highlight the necessity to account for the underlying climatic variation as well as to carefully define the shocks.     

The impact of extreme weather events on education

This paper provides new evidence on the long- and medium-term impact of extreme weather events on education. Our focus is on Mongolia, where two extremely severe winters caused mass livestock mortality. We use household panel data with information on households’ preshock location, combined with historic district-level livestock census data and climate data. Our econometric strategy exploits exogenous variation in shock intensity across space and time, using a difference-in-differences approach. Results indicate that individuals who experience the shock while of schooling age and living in severely affected districts are significantly less likely to complete mandatory education, both in the long and medium terms. The effects are driven by individuals from herding households, while no significant effects are found for individuals from nonherding households. This finding renders it unlikely that extreme winters affect education through school closures during extreme climatic conditions, to which all children were exposed. Moreover, there is no evidence for a differential impact of extreme weather events by gender. This suggests that the effects are not mainly channeled through increased child labor in herding but rather they are related to reductions in household income.     

International Migration and the Education of Children: Evidence from Lima,Peru

The issue of whether emigration has consequences for the education of children who remain behind in the country of origin occupies an increasingly prominent place in the agendas of both scholars and policy makers. The conventional wisdom is that the emigration of family members may benefit children by relaxing budget constraints through remittances that can be used to cover educational expenses. However, the empirical evidence on the overall effect of migration is inconclusive. This is due in part to a substantive emphasis on remittances in the literature, as well as the inability of some studies to deal satisfactorily with the endogeneity of household migration decisions in comparing outcomes across migrant and non-migrant households. Using Peruvian data from the Latin American Migration Project (LAMP), we apply an innovative instrumental variable technique to evaluate the overall effect of migration on educational attainment and schooling disruption among the children of immigrants. In contrast to conventional wisdom, our results suggest that a higher household risk of immigration has deleterious consequences for the education of children who remain behind.