POPULATION AND ENVIRONMENT

Child Fostering in a Changing Climate: Evidence from Sub-Saharan Africa
Ronnkvist S, Thiede BC and Barber E
An extensive social science literature has examined the effects of climate change on human migration. Prior studies have focused largely on the out-migration of working-age adults or entire households, with less attention to migration and other forms of geographic mobility among other age groups, including youth. In this study, we focus on the implications of climate variability for the movement of children by examining the association between climate exposures and the in- and out-fostering of children in sub-Saharan Africa. We link high-resolution temperature and precipitation records to data from the Demographic and Health Surveys for 23 sub-Saharan African countries. We fit a series of regression models to measure the overall associations between climate exposures and each outcome, and then evaluate whether these associations are moderated by socioeconomic status, the number of children in the household, and the prevalence of fostering in each country. Precipitation is positively associated with in-fostering overall, and these effects are especially strong among households who already have at least one child and in countries where child fostering is common. We find no overall relationship between either temperature or precipitation exposures and out-fostering, but we do detect significant effects among households with many children and those with more-educated heads. In sum, our findings suggest climate variability can influence child mobility, albeit in complex and in some cases context-specific ways. Given the socioeconomic and health implications of fostering, these results underline another pathway through which climate exposures can affect children's wellbeing. More broadly, this study shows that new attention to the links between climate variability, child fostering, and other understudied forms of spatial mobility is needed to fully understand the effects of climate change on human populations.
Rainfall, mothers' time use, and child nutrition: evidence from rural Uganda
Boyd CM
Care provision is a key component of women's time use with implications for the health and wellbeing of children. Shifting labor demands resulting from weather shocks may imply that women in developing countries have less time for care provision, potentially affecting their children's nutrition. Nonetheless, a broad literature focusing on the indirect impacts of climate change on child nutrition has yet to explore the mechanisms whereby this occurs, and whether mothers' time use is one of these mechanisms. Using the Uganda National Panel Survey, a unique data set that gathers data on farming activities, time use, and anthropometric measures, I analyze how rainfall variability affects mother's time use and whether time use is a mechanism whereby rainfall variability affects child nutrition in the short run (measured as weight-for-age and weight-for-height Z-scores). My results show that increased rainfall variability in the last month decreases mothers' time share in other household-related activities (e.g., fetching water), while it increases the probability of child wasting. Moreover, using mediation analysis, I find that none of the mothers' time-use variables appears to be a mediating factor between rainfall variability and child nutrition. These results suggest that mothers adjust their time use due to rainfall variability without jeopardizing their children's nutritional levels.
Examining the effects of cumulative environmental stressors on Gulf Coast child and adolescent health
Meltzer GY, Merdjanoff AA, Xu S, Gershon R, Emrich CT and Abramson DM
This study examines how community-level cumulative environmental stress affects child and adolescent emotional distress and chronic health conditions both directly and indirectly through stressors at the household, family, and individual levels. Data comes from the Women and their Children's Health (WaTCH) Study, which sought to understand the health implications of exposure to the 2010 Deepwater Horizon oil spill (DHOS) among a cohort of 596 mothers with children ages 10 to 17 in southeastern Louisiana. Community-level environmental stress was measured using a newly developed geospatial index. Household-level stressors included previous hurricane impacts, impacts of DHOS, degree of financial difficulty, and degree of housing physical decay. Family stressors included maternal depression, self-rated physical health, and degree of parenting stress. Child stress was based on perceived stress; child mental health was based on serious emotional disturbance; and child physical health was based on diagnosis of chronic illness. Structural equation modeling used weighted least squares means and variance and theta parameterization. Results showed a significant negative direct path between community-level cumulative environmental stress and child/adolescent serious emotional disturbance and chronic illness. However, the indirect relationship through household, family, and individual-level stressors was significant and positive for both child/adolescent serious emotional disturbance and chronic illness. These findings point to the centrality of the household and family in determining child and adolescent physical and mental health outcomes in communities exposed to frequent disasters and ongoing environmental stressors.
"Measuring the Environmental Context of Child Growth in Burkina Faso"
Rojas AJ, Gray CL and West CT
Child growth failure, as indicated by low height-for-age z-scores (HAZ), is an important metric of health, social inequality, and food insecurity. Understanding the environmental pathways to this outcome can provide insight into how to prevent it. While other studies have examined the environmental determinants of HAZ, there is no agreed upon best-practices approach to measure the environmental context of this outcome. From this literature, we derive a large set of potential environmental predictors and specifications including temperature and precipitation levels, anomalies, and counts as well as vegetation anomalies and trends, which we include using linear, nonlinear, and interactive specifications. We compare these measures and specifications using four rounds of DHS survey data from Burkina Faso and a large set of fixed effects regression models, focusing on exposures from the time of conception through the second year of life and relying on joint hypothesis tests and goodness-of-fit measures to determine which approach best explains HAZ. Our analysis reveals that nonlinear and interactive transformations of climate anomalies, as opposed to climate levels or vegetation indices, provide the best explanation of child growth failure. These results underline the complex and nonlinear pathways through which climate change affects child health and should motivate climate-health researchers to more broadly adopt measures and specifications that capture these pathways.
Drought and migration: An analysis of the effects of drought on temporary labor and return migration from a migrant-sending area in Nepal
Epstein A, Treleaven E, Ghimire D and Diamond-Smith N
Although the relationship between drought - a dimension of climate change - and migration has been explored in a number of settings, prior research has largely focused on out-migration and has not considered climate factors at the migrant destination. However, drought may impact not only out-migration, but also return migration, particularly in settings where temporary labor migration and agricultural reliance are common. Thus, considering drought conditions at origin and destinations is necessary to specify the effects of climate on migrant-sending populations. Using detailed data from the Chitwan Valley Family Study, a household panel study in a migrant-sending area in Nepal, we analyze the effect of drought at the neighborhood level on individual-level out-migration and drought at the origin district on return migration among adults from 2011 to 2017, assessing these associations among males and females separately. In mixed-effect discrete-time regressions, we find that neighborhood drought is positively associated with out-migration and return migration, both internally and internationally among males. Among females, drought is positively associated with internal out-migration and return migration, but not international migrations. We did not find an association between drought at the origin and return migration independent of drought status at the destination. Taken together, these findings contribute to our understanding of the complexity of the impacts of precipitation anomalies on population movement over time.
Migration and Fuel Use in Rural Zambia
Wu Y, Entwisle B, Sinai C and Handa S
What is the effect of migration on fuel use in rural Zambia? Opportunities to increase income can be scarce in this setting; in response, households may pursue a migration strategy to increase resources as well as to mitigate risk. Migrant remittances may make it possible for households to shift from primary reliance on firewood to charcoal, and the loss of productive labor through migration may reinforce this shift. This paper uses four waves of panel data collected as part of the Child Grant Programme in rural Zambia to examine the connection between migration and the choice of firewood or charcoal as cooking fuel and finds evidence for both mechanisms. Importantly, this paper considers migration as a process, including out- as well as return migration, embedding it in the context of household dynamics generally. Empirical results suggest that while migration helps move households away from firewood as a fuel source, return migration moves them back, but because firewood is more common, the overall effect of migration is to shift households away from primary reliance on firewood towards charcoal.
Climate anomalies and childhood growth in Peru
Nicholas K, Campbell L, Paul E, Skeltis G, Wang W and Gray C
Climate change has been linked to poor childhood growth and development through maternal stress, nutritional insults related to lean harvests, and exposure to infectious diseases. Vulnerable populations are often most susceptible to these stressors. This study tested whether susceptibility to linear growth faltering is higher among Peruvian children from indigenous, rural, low-education, and low-income households. High-resolution weather and household survey data from Demographic and Health Survey 1996-2012 were used to explore height-for-age -scores (HAZ) at each year of life from 0 to 5. Rural, indigenous children at age 0-1 experience a HAZ reduction of 0.35 units associated with prenatal excess rainfall which is also observed at age 4-5. Urban, non-indigenous children at age 4-5 experience a HAZ increase of 0.07 units associated with postnatal excess rainfall, but this advantage is not seen among rural, indigenous children. These findings highlight the need to consider developmental stage and social predictors as key components in public health interventions targeting increased climate change resilience.
Climatic Conditions and Infant Care: Implications for Child Nutrition in Rural Ethiopia
Randell H, Grace K and Bakhtsiyarava M
We examine the relationships between climatic conditions, breastfeeding behavior, and maternal time use in Ethiopia. Infant feeding practices are important predictors of child nutrition that may be affected by a number of factors including mother's time engaging in agricultural labor, food security, cultural beliefs, and antenatal care. We use panel data from the Living Standards Measurement Study to investigate linkages between climatic conditions during a child's first year of life and year prior to birth and duration of exclusive breastfeeding. We then explore one potential mechanism: women's agricultural labor. Results indicate that rainfall during the primary agricultural season-kiremt-in a child's first year of life plays an important role in duration of exclusive breastfeeding. Experiencing 25 cm of average monthly kiremt rainfall, versus 5 cm, is associated with a 20-percentage-point decrease in the likelihood of being exclusively breastfed for the recommended six months. More kiremt rainfall is associated with a greater number of days that women spend planting and harvesting, and at high levels of rainfall women with infants do not engage in significantly fewer days of agricultural labor than those without infants. Lastly, we find that during the year before birth, greater rainfall during kiremt as well as the dry season is associated with a lower likelihood of six months of exclusive breastfeeding, potentially due to the early introduction of complementary foods. Our findings indicate that agricultural labor demands may in part drive breastfeeding behaviors, leading to "sub-optimal" feeding practices in the short-term, but resulting in improved household food security in the longer-term.
The Differential Influence of Geographic Isolation on Environmental Migration: A Study of Internal Migration Amidst Degrading Conditions in the Central Pacific
Roland HB and Curtis KJ
This study investigates how geographic isolation interacts with declining environmental and economic conditions in Kiribati, an island nation wherein which limited access to financial resources amidst degrading environmental conditions potentially constrain capital-intensive, long distance migration. We examine whether geographic isolation modifies the tenets of two dominant environmental migration theses. The environmental scarcity thesis suggests that environmental degradation prompts migration by urging households to reallocate labor to new environments. In contrast, the environmental capital thesis asserts that declining natural resource availability restricts capital necessary for migration. Results show that the commonly applied environmental scarcity thesis is less valid and the environmental capital thesis is more relevant in geographically isolated places. Findings indicate that geographic isolation is an important dimension along which migration differences emerge. As overall environmental and economic conditions worsen, likelihoods of out-migration from less remote islands increase whereas likelihoods of out-migration from more isolated islands decrease.
Drought and migration: a case study of rural Mozambique
Yoo SH and Agadjanian V
Migration is commonly seen as a last resort for households impacted by climate shocks, given the costs and risks that migration typically entails. However, pre-existing labor migration channels may facilitate immediate migration decisions in response to climate shocks. This study explores the relationship between migration and droughts in a rural Sub-Saharan setting from which men commonly migrate in search of non-agricultural employment. We use data from the Men's Migrations and Women's Lives project, which includes a longitudinal household panel conducted in rural Mozambique between 2006 and 2017, and combine it with the Standardized Precipitation Evapotranspiration Index, a high-resolution climate measure. The fixed-effect models assess the lagged impact of droughts on the labor migration status of male household heads. We find an immediate increase in migration following a drought, peaking in the first year, then diminishing in the second year, with a slight resurgence in the third year. However, by the sixth-year post-drought, the likelihood of being a migrant turns negative. These findings demonstrate the complex associations of climate shocks with labor migration in low-income rural settings.
Climate change and non-migration - exploring the role of place relations in rural and coastal Bangladesh
Rabbani MMG, Cotton M and Friend R
Of growing research and policy interest are the experiences of people living under conditions of climate change-induced environmental stress, which either are unable to migrate (sometimes described as a 'trapped population') or are seemingly unwilling to do so (sometimes described as the 'voluntarily immobile'). This paper problematises and expands upon these binary categories: examining the complex dimensionality of non-migration as a form of place relations, explored through qualitative study of rural and coastal Bangladeshi communities. Through 60 semi-structured interviews of individuals from four communities in the Kalapara region, the analysis proffers four qualitatively derived and inter-related dimensions of voluntary and involuntary non-migration framed as a form of place relations. These four dimensions concern the following: (1) livelihood opportunities, (2) place obduracy, (3) risk perceptions, and (4) social-structural constraints, with the interplay between these elements explaining diverse non-migratory experiences. In our analysis, 'place obduracy' is introduced as a concept to describe the differential speed of environmental change and socio-cultural adaptation responses to explain non-migratory experiences. Our discussion provides insight into how to best support non-migrant people's adaptive capacity in the face of growing climate emergency.
A machine learning analysis of drought and rural population change on the North American Great Plains since the 1970s
McLeman R, Grieg C, Heath G and Robertson C
Machine learning techniques have to date not been widely used in population-environment research, but represent a promising tool for identifying relationships between environmental variables and population outcomes. They may be particularly useful for instances where the nature of the relationship is not obvious or not easily detected using other methods, or where the relationship potentially varies across spatial scales within a given study unit. Machine learning techniques may also help the researcher identify the relative strength of influence of specific variables within a larger set of interacting ones, and so provide a useful methodological approach for exploratory research. In this study, we use machine learning techniques in the form of random forest and regression tree analyses to look for possible connections between drought and rural population loss on the North American Great Plains between 1970 and 2020. In doing so, we analyzed four decades of population count data (at county-size spatial scales), monthly climate data, and Palmer Drought Severity Index scores for Canada and the USA at multiple spatial scales (regional, sub-regional, national, and county/census division levels), along with county level irrigation data. We found that in some parts of Saskatchewan and the Dakotas - particularly those areas that fall within more temperate/less arid ecological sub-regions - drought conditions in the middle years of the 1970s had a significant association with rural population losses. A similar but weaker association was identified in a small cluster of North Dakota counties in the 1990s. Our models detected few links between drought and rural population loss in other decades or in other parts of the Great Plains. Based on R-squared results, models for US portions of the Plains generally exhibited stronger drought-population loss associations than did Canadian portions, and temperate ecological sub-regions exhibited stronger associations than did more arid sub-regions. Irrigation rates showed no significant influence on population loss. This article focuses on describing the methodological steps, considerations, and benefits of employing this type of machine learning approach to investigating connections between drought and rural population change.
As California burns: the psychology of wildfire- and wildfire smoke-related migration intentions
Berlin Rubin N and Wong-Parodi G
Climate change impacts and rapid development in the wildland-urban interface are increasing population exposure and vulnerability to the harmful effects of wildfire and wildfire smoke. The direct and indirect effects of these hazards may impact future mobility decisions among populations at risk. To better understand how perceptions and personal experience inform wildfire- and smoke-associated migration intentions, we surveyed a representative sample of 1108 California residents following the 2020 wildfire season. We assessed the associations between threat appraisal, coping appraisal, personal experience, migration intentions, the impact of wildfire and smoke on migration intentions and place satisfaction, and the potential likelihood of future migration. Results indicate that roughly a third of our sample intended to move in the next 5 years, nearly a quarter of whom reported that wildfire and smoke impacted their migration decision at least a moderate amount. Prior negative outcomes (e.g., evacuating, losing property) were associated with intentions to migrate. Perceived susceptibility and prior negative outcomes were associated with a greater impact of wildfire and smoke on migration intentions. For those intending to remain in place, prior negative outcomes were associated with a greater impact of wildfire and smoke on place satisfaction, which was in turn associated with a greater reported likelihood of future migration. Our findings suggest that perceptions of and experiences with wildfire and smoke may impact individual mobility decisions. These insights may be leveraged to inform risk communications and outreach campaigns to encourage wildfire and smoke risk mitigation behaviors and to improve climate migration modeling.
Spatial heterogeneity in drinking water sources in the Greater Accra Metropolitan Area (GAMA), Ghana
Tetteh JD, Templeton MR, Cavanaugh A, Bixby H, Owusu G, Yidana SM, Moulds S, Robinson B, Baumgartner J, Annim SK, Quartey R, Mintah SE, Bawah AA, Arku RE, Ezzati M and Agyei-Mensah S
Universal access to safe drinking water is essential to population health and well-being, as recognized in the Sustainable Development Goals (SDG). To develop targeted policies which improve urban access to improved water and ensure equity, there is the need to understand the spatial heterogeneity in drinking water sources and the factors underlying these patterns. Using the Shannon Entropy Index and the Index of Concentration at the Extremes at the enumeration area level, we analyzed census data to examine the spatial heterogeneity in drinking water sources and neighborhood income in the Greater Accra Metropolitan Area (GAMA), the largest urban agglomeration in Ghana. GAMA has been a laboratory for studying urban growth, economic security, and other concomitant socio-environmental and demographic issues in the recent past. The current study adds to this literature by telling a different story about the spatial heterogeneity of GAMA's water landscape at the enumeration area level. The findings of the study reveal considerable geographical heterogeneity and inequality in drinking water sources not evidenced in previous studies. We conclude that heterogeneity is neither good nor bad in GAMA judging by the dominance of both piped water sources and sachet water (machine-sealed 500-ml plastic bag of drinking water). The lessons from this study can be used to inform the planning of appropriate localized solutions targeted at providing piped water sources in neighborhoods lacking these services and to monitor progress in achieving universal access to improved drinking water as recognized in the SDG 6 and improving population health and well-being.
Post-disaster (im)mobility aspiration and capability formation: case study of Southern California wildfire
Tinoco N
Scholarship on the environmental dimensions of migration demonstrates the complex interplay of climatic and non-climatic factors which combine to create a potential for migration. Yet in times of environmental crisis or change, not everyone aspires to or is capable of moving to reduce their vulnerability. When, why, and how populations vulnerable to hazard risks decide not to migrate remains a significant gap in our understanding of the migration-environment relationship. Analysis of data from 38 qualitative interviews shows how Los Angeles County residents-after surviving the 2018 Woolsey Fire-developed aspirations to stay and/or rebuild, depending on the attachments and meanings associated with their communities. This paper also seeks to clarify the concept of capabilities to stay by considering separately the capabilities to return and rebuild from the capabilities to cultivate preparedness. Many who stayed also worked to strengthen community resilience to alleviate concerns of future wildfire risk. Some residents expressed individual commitments to stay and defend homes during future fires, while well-equipped volunteer fire brigades have proliferated in more affluent areas. Community mobilizations pressured local government and fire services to address the perceived institutional failure during previous fire responses and fostered feelings of collective efficacy among residents which increased their confidence to remain in high wildfire risk communities.
Extreme events, educational aspirations, and long-term outcomes
Iwo R, Frankenberg E, Sumantri C and Thomas D
The 2004 Indian Ocean tsunami was an extremely destructive event in Aceh, Indonesia, killing over 160,000 people and destroying infrastructure, homes, and livelihoods over miles of coastline. In its immediate aftermath, affected populations faced a daunting array of challenges. At the population level, questions of how the disaster affected children's and parents' aspirations for education and whether it permanently disrupted schooling progression are critical in understanding how shocks affect human capital in the short and long term. We use longitudinal data from the Study of the Tsunami Aftermath and Recovery (STAR) to examine how disaster exposure affects educational aspirations and eventual attainment. We find that damage to one's community depresses aspirations in the short term but that this weakens with time. With respect to educational attainment 15 years after the event, children's aspirations, parents' education, and family socioeconomic status are more important determinants of whether children complete high school and go on to tertiary schooling than disaster exposure. While these results likely reflect, at least in part, the successful post-tsunami reconstruction program, they also establish enormous resilience among survivors who bore the brunt of the tsunami.
Climate Mobility and Development Cooperation
Stojanov R, Rosengaertner S, de Sherbinin A and Nawrotzki R
Development cooperation actors have been addressing climate change as a cross-cutting issue and investing in climate adaptation projects since the early 2000s. More recently, as concern has risen about the potential impacts of climate variability and change on human mobility, development cooperation actors have begun to design projects that intentionally address the drivers of migration, including climate impacts on livelihoods. However, to date, we know little about the development cooperation's role and function in responding to climate related mobility and migration. As such, the main aim of this paper is to outline the policy frameworks and approaches shaping development cooperation actors' engagement and to identify areas for further exploration and investment. First, we frame the concept of climate mobility and migration and discuss some applicable policy frameworks that govern the issue from various perspectives; secondly, we review the toolbox of approaches that development cooperation actors bring to climate mobility; and third, we discuss the implications of the current Covid-19 pandemic and identify avenues for the way forward. We conclude that ensuring safe and orderly mobility and the decent reception and long-term inclusion of migrants and displaced persons under conditions of more severe climate hazards, and in the context of rising nationalism and xenophobia, poses significant challenges. Integrated approaches across multiple policy sectors and levels of governance are needed. In addition to resources, development cooperation actors can bring data to help empower the most affected communities and regions and leverage their convening power to foster more coordinated approaches within and across countries.
Has the world survived the population bomb? A 10-year update
Lam D
Between 1960 and 2011, world population grew from 3 to 7 billion, an unprecedented rate of population growth that will never be seen again. In spite of the addition of 4 billion people in just 51 years, the world experienced some of the biggest improvements in living standards in human history, with declines in poverty and improvements in food production per capita in all major regions. This paper looks at the period since 2011, during which the world added another billion people. Progress has continued in many areas, with food production continuing to grow faster than population and with continued declines in the proportion of the population in poverty in all regions. Not all trends are positive, however. Progress in food production has slowed, with recent declines in food production per capita in Africa. Prices of food and other commodities have recently hit historic highs. Climate change is a challenge to progress in combatting hunger and poverty, especially in Africa. While climate change will make it harder to meet the needs of Africa's continued population growth in this century, the paper shows that the countries with the highest population growth account for a very small share of global CO emissions. The record of the last six decades suggests that progress can be made to reduce poverty and hunger, even while world population continues to grow, but continued progress will require solutions to climate change that mainly target high-income and middle-income countries.
Impacts of rainfall shocks on out-migration are moderated more by per capita income than by agricultural output in Türkiye
Delacrétaz N, Lanz B, Delju AH, Piguet E and Rebetez M
Rural populations are particularly exposed to increasing weather variability, notably through agriculture. In this paper, we exploit longitudinal data for Turkish provinces from 2008 to 2018 together with precipitation records over more than 30 years to quantify how variability in a standardized precipitation index (SPI) affects out-migration as an adaptation mechanism. Doing so, we document the role of three potential causal channels: per capita income, agricultural output, and local conflicts. Our results show that negative SPI shocks (droughts) are associated with higher out-migration in rural provinces. A mediated-moderator approach further suggests that changes in per capita income account for more than one quarter of the direct effect of droughts on out-migration, whereas agricultural output is only relevant for provinces in the upper quartile of crop production. Finally, we find evidence that local conflict fatalities increase with drought and trigger out-migration, although this channel is distinct from the direct effect of SPI shocks on out-migration.
The effect of social network sites usage in climate change awareness in Latin America
Gómez-Casillas A and Gómez Márquez V
Using data from the Latinobarómetro (Latin Barometer) survey of 2017 to analyze the effect of social network site usage on climate change awareness in 18 Latin American countries, this article makes three contributions. First, it offers results on the socioeconomic determinants of climate awareness in a region of the world where there is scant published evidence in this regard. Second, it shows the effect of social media consumption on climate change awareness by assessing the role of each of the most popular sites: YouTube, Facebook, Instagram, Twitter, LinkedIn, WhatsApp, Snapchat, and Tumblr. Third, it assesses the effects of multi-platform consumption. The results show that YouTube has the strongest and most robust positive and statistically significant effect on climate change awareness, followed by Instagram, Twitter, and WhatsApp, while being a multi-platform user also has a positive and statistically significant effect on climate change awareness. The implications of these findings for understanding the role of social media in the development of environmental awareness are discussed.
Environmental shocks and migration among a climate-vulnerable population in Bangladesh
Freihardt J
Various studies predict large migration flows due to climatic and other environmental changes, yet the ex post empirical evidence for such migration is inconclusive. To examine the causal link between environmental changes and migration for a population residing along the Jamuna River in Bangladesh, an area heavily affected by floods and riverbank erosion, I relate the respondents' self-reported affectedness by environmental changes, their migration aspirations, and their capability to move to their migration likelihood. The analysis relies on a unique quasi-experimental research design based on original survey panel data of 1604 household heads. I find that erosion significantly and substantively increases the likelihood to migrate, leading to more than a doubling of the migration likelihood compared to the unaffected control group. Flooding has a significant effect only if it causes severe and irreversible impacts. Moreover, erosion affectedness increases the likelihood of moving permanently, with the whole household, and to a rural location. Individual, temporary moves to urban locations, by contrast, are primarily driven by low socio-economic status. Those who move with the whole household migrate mostly less than five kilometers. These findings call for a more nuanced understanding of the complex environment-migration nexus.