The Childhood Origins of Climate-Induced Mobility and Immobility

Abstract

The existing literature on climate change and migration has focused largely on assessing short-term responses to temperature and precipitation shocks. In this paper, we suggest that this common “coping strategies” model can be extended to account for mechanisms that link environmental conditions to migration behavior over longer periods of time. We argue that early-life climate exposures may affect the likelihood of migration from childhood through early adulthood by influencing parental migration, community migration networks, human capital development, and decisions about household resource allocation, all of which are correlates of geographic mobility. We evaluate this expectation empirically using a “big data” approach, analyzing georeferenced records from 81 censuses implemented across 31 countries in tropical Africa, Latin America, and Southeast Asia. For each world region, we estimate multivariate regression models that predict lifetime migration through ages 30-39 as a function of temperature and precipitation in early life, defined as the year prior to birth through age four. Results suggest that early-life climate is systematically associated with changes in the probability of lifetime migration in most regions of the tropics, with the largest effects observed in sub-Saharan Africa. In East and Southern Africa, the effects of temperature shocks vary by sex and educational attainment and in a manner that suggests women and those with lower socioeconomic status are most vulnerable to climate shocks. Finally, we compare our main results with models using alternative measures of climate exposure. This comparison suggests climate exposures during the prenatal period and first few years of life are particularly (but not exclusively) salient for lifetime migration, which is most consistent with our proposed human capital mechanism.

Child Fostering in a Changing Climate: Evidence from Sub-Saharan Africa

“…We express these measures as z-scores 6 (i.e., climate anomalies), with reference to all other one-year periods in each cluster's climate history . These measures are locally meaningful since they are produced with respect to community-specific averages, should be uncorrelated with baseline climate, and as such have been shown to be stronger predictors of demographic outcomes than unstandardized climate values (Gray & Wise 2016;Thiede et al 2022).…”

“…The conceptual framework underpinning most of this prior research largely assumes that migration is used as an economic livelihood strategy (Thiede et al 2022), undertaken to diversify income and mitigate climate-induced income shocks. However, migration is not only a means of securing income.…”

Climate Exposures and Household Dynamics in Sub-Saharan Africa

“…Such standardized climate values are known as climate anomalies and are commonly used in the population-environment literature (Thiede, 2022). They are often preferred over unstandardized temperature and precipitation levels because they capture locally meaningful deviations from normal, are not associated with baseline climate, and are stronger predictors of demographic outcomes than raw values (Call & Gray, 2020;Gray & Wise, 2016;Mueller et al, 2020;Nordkvelle et al, 2017;Thiede et al, 2022b). We take two approaches to measuring climate exposures in our analyses: our first model for each outcome uses the anomalies as predictors, while the second model includes four categorical variables that indicate whether temperature and precipitation anomalies were, respectively, one standard deviation above the mean (i.e., positive shocks) or below the mean (i.e., negative shocks).…”