Climate variability and migration in the Philippines

How sudden- versus slow-onset environmental events affect self-identification as an environmental migrant: Evidence from Vietnamese and Kenyan survey data

In response to changing climatic conditions, people are increasingly likely to migrate. However, individual-level survey data reveal that people mainly state economic, social, or political reasons as the main drivers for their relocation decision-not environmental motives or climate change specifically. To shed light on this discrepancy, we distinguish between sudden-onset (e.g., floods and storms) and slow-onset (e.g., droughts and salinity) climatic changes and argue that the salience of environmental conditions in individuals' migration decisions is shaped by the type of climate event experienced. Empirically, we combine individual-level surveys with geographic information on objective climatic changes in Vietnam and Kenya. The empirical evidence suggests that sudden-onset climate events make individuals more likely to link environmental conditions to their migration decision and, hence, to identify themselves as "environmental migrants." Regression analyses support these results and are consistent with the view that slow-onset events tend to be linked with migration decisions that are more economically motivated.

Societal determinants of flood-induced displacement

What explains human consequences of weather-related disaster? Here, we explore how core socioeconomic, political, and security conditions shape flood-induced displacement worldwide since 2000. In-sample regression analysis shows that extreme displacement levels are more likely in contexts marked by low national income levels, nondemocratic political systems, high local economic activity, and prevalence of armed conflict. The analysis also reveals large residual differences across continents, where flood-induced displacement in the Global South often is much more widespread than direct human exposure measures would suggest. However, these factors have limited influence on our ability to accurately predict flood displacement on new data, pointing to important, hard-to-operationalize heterogeneity in flood impacts across contexts and critical data limitations. Although results are consistent with an interpretation that the sustainable development agenda is beneficial for disaster risk reduction, better data on societal consequences of natural hazards are critically needed to support evidence-based decision-making.

Evolution trend and hot topic measurement of climate migration research under the influence of climate change

Introduction

Global climate change, which is characterized by climate warming, has become one of the most prominent risk problems in society at present. Climate migration brings many accompanying problems to the environment, economy, politics, society, and culture. It is of great theoretical and practical significance to study the internal relationship between climate change and population migration.

Methods

The data were extracted from the Web of Science core collection database (WOS) and China Knowledge Network database (CNKI). A total of 785 documents and 157 documents in the field of climate migration from 2008 to 2021 were selected as analysis samples. Word frequency analysis, clustering analysis, sudden word detection analysis, and other methods were extensively used to build the evolution trend map of climate migration using CiteSpace visual bibliometric software.

Results

It is concluded that climate migration research has experienced three stages of development: initial exploration stage (2008-2011), development enrichment stage (2012-2017), and system deepening stage (2018).The hot topics of climate migration include: (1) different types of climate migration research; (2) Quantitative model research on climate migration; (3) Climate justice research. Different types of climate migration include 7 main types: (1) migration caused by sea level rise; (2) Resettlement caused by flood disaster; (3) Migration due to worsening drought; (4) Migration caused by extreme climate events; (5) Voluntary migration due to climate change discomfort; (6) Project resettlement caused by climate change response engineering measures; (7) Migrants whose livelihoods are broken due to climate change.

Discussion

The study points out that climate migration research is an interdisciplinary research field, which needs joint research by scholars from different academic backgrounds. In the future climate migration research, 1) strengthen the prediction ability of climate change population migration model; 2) Make use of China’s beneficial exploration in the migration fields such as engineering resettlement, ecological resettlement and poverty alleviation resettlement to formulate climate migration policies, regulations and strategic planning; 3) Establish a database cloud platform related to climate change and population migration; 4) Strengthen the exchange and cooperation between Chinese researchers in the field of climate migration and international scientific research institutions.

Climate change and city size: the role of temperature difference in the spatial distribution of China's population

This paper examines the relationship between climate change and the spatial distribution of population in China. We establish a two-way fixed effects model to investigate the role of temperature difference in the spatial distribution of China's population. We find that the annual variation of temperature has an impact on city size in both large and small cities, and that city size tends to shrink as the temperature difference increases. Meanwhile, we also find that the population in the cities located south of Qinling-Huaihe Line and Aihui-Tengchong Line (Hu's Line) is more sensitive to temperature effects, and that the temperature difference has a significant negative effect on city size. Similarly, the same results are found for prefecture-level cities with low administrative levels. Considering the endogeneity between temperature change and city size, we adopt an instrumental variable using latitude to perform a more robust empirical analysis, the results of a series of robustness tests support these conclusions.

“Central” and “peripheral” adaptation pathways of entangled agrifood systems transformations

In the agrifood systems of developing countries, local adaptation actions and pathways often interact with other climate and development responses, creating new trade-offs, uncertainties, and potentially maladaptive outcomes. While knowledge on the interacting pathways of adaptation is expanding, previous studies have focused on complex systems dynamics, and studies that address the human, social, and political forces that drive the cascading of risks between different coupled social-ecological systems are few. This paper aims to examine climate adaptation trade-offs, uncertainties, and maladaptation through an interdisciplinary analysis of two interacting pathways of transformational adaptation in the Philippines: the post 2004 disaster rural transformations in the coconut-producing municipality of Infanta and a state-led urban water resilience strategy for the capital region of Metro Manila. Data were collected from January 2021 to March 2022 through ethnographic field visits, participant observation, focus group discussions, semi-structured interviews, geospatial analysis, multicriteria mapping sessions, and review of planning documents and secondary data sources. Key findings suggest that the pathways of transformation and their entanglement are rooted in historical processes of change and that maladaptation is contingent on the political relations between the “central” and “peripheral” pathways. Overall, the paper offers a significant contribution to adaptation research in the agrifood systems of developing countries as it calls for a deeper kind of collective reflexivity and action that can transform narrow notions and practices of resilience and sustainable development.

The Childhood Origins of Climate-Induced Mobility and Immobility

The literature on climate exposures and human 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. After developing this conceptual framework, we evaluate the corresponding hypotheses using a big data approach, analyzing 20 million individual georeferenced records from 81 censuses implemented across 31 countries in tropical Africa, Latin America, and Southeast Asia. For each world region, we estimate regression models that predict lifetime migration (a change in residence between birth and ages 30-39) as a function of temperature and precipitation anomalies 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 of lower socioeconomic status are most vulnerable. Finally, we compare our main results with models using alternative measures of climate exposures. 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 the hypothesized human capital mechanism.

As California burns: the psychology of wildfire- and wildfire smoke-related migration intentions

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11111-022-00409-w.

Exploring the Climate Temperature Effects on Settlement Intentions of Older Migrants: Evidence from China

Permanent migration across provinces in China has become an important strategy for Chinese older people to respond to a temperature-unfriendly place of residence in late life. However, the relation between temperature effects and permanent settlements of older migrants remains unclear. Based on the data obtained from China Migrants Dynamic Survey, this paper examined how four temperature effects (i.e., cold effect, heat effect, temperature gap effect, and temperature zone effect) play a role in shaping older migrants’ intentions to settle permanently in a destination place by conducting logistic regression analysis. Our findings show that: (1) extreme cold (rather than extreme heat or mild temperature) was found to have significant effects on settlement intentions of older people; (2) relative winter temperature between origin and destination places rather than absolute winter temperature in the destination place has a significant positive effect on the settlement intentions; (3) spatially, older migrants tend to migrate to geographically adjacent temperature zones. Our findings will inform a more effective planning and allocation of services for supporting older people by better understanding trends and intentions of older migrants.

Mauritania’s internal migration dynamics and trends in response to rainfall variability and change1

The northwest African country of Mauritania is a vast, desert territory, which was historically been dominated by pastoral nomads. Since independence in 1960, the country has witnessed a dramatic sedentarization of its nomadic population, as well as settlements in and movements to urban centers. This vast sedentarization movement coupled with internal and interregional migration has resulted in the growth of Mauritania’s urban population from less than 10 percent of the total population in 1965 to nearly 90 percent in 2013. Factors that have caused this rapid urbanization, include the droughts that spanned the late 1960s through to the early 1980s, and the turbulent transformation of Mauritania’s political economy. The aim of this study is to determine and examine internal migration flows to analyze the relationship between long-term rainfall changes and dynamic spatial demographic shifts in terms of movements toward urban centers. In this regard, we propose an assessment approach that integrates official statistics from the decennial census and rainfall data, with available socioeconomic variables, to characterize interregional migration flows. Our result confirms that rates of interregional migration remain elevated and are expected to increase. In 2013, 702,575 individuals were documented as having participated in interregional migration, comprising 17.5 percent of the total population. In comparison, there were 477,814 individuals, which migrated inter-regionally in 2000, and 208,039 in 1988. These results demonstrate distinct interactions between climate variability and interregional migration in Mauritania throughout the past four decades.

Population Responses to Environmental Change: Looking Back, Looking Forward

Over the past two decades, population researchers have engaged in a far-reaching and productive program of research on demographic responses to changes in the natural environment. This essay "looks back" to the origins of these developments, identifying pivotal agenda-setting moments in the 1990s and tracing the impact on contemporary research. The essay also "looks forward" to identify critical gaps and challenges that remain to be addressed and to set an agenda for future research on population responses to environmental change. It recommends that the multidimensionality of environmental contexts and change be fully embraced, long run as well as short term effects be investigated, variability in the effects of environmental change in relation to social institutions, policy implementation, and environmental context be examined, movement between contexts as well as change in situ as sources of environmental change be considered, and interconnections among demographic processes in response to environmental change be explored. Taking these steps will position demographers to contribute significantly to a larger and deeper understanding of environmental change and its consequences, locally, regionally, and globally.

Identifying the natural and anthropogenic factors influencing the spatial disparity of population hollowing in traditional villages within a prefecture-level city

In developing countries, the phenomena of rural depopulation have been an intense continuing, which have become a major bottleneck for the sustainable revitalization of traditional villages. However, the factors influencing the spatial disparity of population hollowing (SDPH) in traditional villages within a prefecture-level city have not been fully quantitatively researched. Based on the factors that influence general villages, this study incorporated historical and cultural factors related to traditional village characteristics to construct a targeted influencing factor index system and then identified the key factors by applying the geo-detector method. With the percentage of resident population (PRP) used as a metric, this study examined Lishui, one of China's traditional village agglomeration regions, as an example to explore SDPH in traditional villages. The results of this study were revealed in the following. (1) The average PRP value in traditional villages in Lishui was 0.68, with clear spatial disparities between the northern region (0.73) and the southern region (0.57). (2) The factors driving the SDPH included both natural and anthropogenic factors; of these, altitude, the number of public facilities, and the number of communication base stations were the most significant influencing factors. In contrast, historical and cultural factors have relatively low impacts. (3) The interaction relationships of pair factors were often enhanced on a bivariate basis, with the highest enhanced impact occurring from the interaction of two variables: the degree of intangible cultural inheritance and altitude. (4) The intervals of the variables leading to the hollowing of the population above a moderate level can be detected. This method can effectively analyze the factors influencing SDPH in traditional villages; can help reveal the interaction impact of pair factors; and can help identify the factors' risk intervals.

Climate-related migration and population health: social science-oriented dynamic simulation model

BACKGROUND

Social science models find the ecological impacts of climate change (EICC) contribute to internal migration in developing countries and, less so, international migration. Projections expect massive climate-related migration in this century. Nascent research calls to study health, migration, population, and armed conflict potential together, accounting for EICC and other factors. System science offers a way: develop a dynamic simulation model (DSM). We aim to validate the feasibility and usefulness of a pilot DSM intended to serve as a proof-of-concept and a basis for identifying model extensions to make it less simplified and more realistic.

METHODS

Studies have separately examined essential parts. Our DSM integrates their results and computes composites of health problems (HP), health care (HC), non-EICC environmental health problems (EP), and environmental health services (ES) by origin site and by immigrants and natives in a destination site, and conflict risk and intensity per area. The exogenous variables include composites of EICC, sociopolitical, economic, and other factors. We simulate the model for synthetic input values and conduct sensitivity analyses.

RESULTS

The simulation results refer to generic origin and destination sites anywhere on Earth. The effects' sizes are likely inaccurate from a real-world view, as our input values are synthetic. Their signs and dynamics are plausible, internally consistent, and, like the sizes, respond logically in sensitivity analyses. Climate migration may harm public health in a host area even with perfect HC/ES qualities and full access; and no HP spillovers across groups, conflict, EICC, and EP. Deviations from these conditions may worsen everyone's health. We consider adaptation options.

CONCLUSIONS

This work shows we can start developing DSMs to understand climate migration and public health by examining each case with its own inputs. Validation of our pilot model suggests we can use it as intended. We lay a path to making it more realistic for policy analysis.

Climate anomalies, land degradation and rural out-migration in Uganda

Globally, rural livelihoods are increasingly challenged by the dual threats of land degradation and climate change. These issues are of particular concern in sub-Saharan Africa, where land degradation is believed to be severe and where climate change will bring higher temperatures and shifts in rainfall. To date, however, we know little about the relative effects of these various potential environmental stressors on migration. To examine these processes, we link longitudinal data from 850 Ugandan households with environmental data on soils, forests, and climate, and then analyze these data using approaches that account for potential spatial and temporal confounders. Our findings reveal that climate anomalies, rather than land degradation, are the primary contributor to environmental migration in Uganda, with heat stress of particular importance. Short hot spells increase temporary migration, an element of a diversified household livelihood strategy, while long-term heat stress induces permanent migration through an agricultural livelihoods pathway.

Climate Change and Migration: New Insights from a Dynamic Model of Out-Migration and Return Migration

In popular accounts, stories of environmental refugees convey a bleak picture of the impacts of climate change on migration. Scholarly research is less conclusive, with studies finding varying effects. This paper uses an agent-based model (ABM) of land use, social networks, and household dynamics to examine how extreme floods and droughts affect migration in Northeast Thailand. The ABM explicitly models the dynamic and interactive pathways through which climate-migration relationships might operate, including coupled out and return streams. Results suggest minimal effects on out-migration but marked negative effects on return. Social networks play a pivotal role in producing these patterns. In all, the portrait of climate change and migration painted by focusing only on environmental refugees is too simple. Climate change operates on already established migration processes that are part and parcel of the life course, embedded in dynamic social networks, and incorporated in larger interactive systems where out- and return migration are integrally connected.

The changing climate-migration relationship in China, 1989-2011

A persistent concern about the social consequences of climate change is that large, vulnerable populations will be involuntarily displaced. Existing evidence suggests that changes in precipitation and temperature can increase migration in particular contexts, but the potential for this relationship to evolve over time alongside processes of adaptation and development has not been widely explored. To address this issue, we link longitudinal data from 20 thousand Chinese adults from 1989-2011 to external data on climate anomalies, and use this linked dataset to explore how climatic effects on internal migration have changed over time while controlling for potential spatial and temporal confounders. We find that temperature anomalies initially displaced permanent migrants at the beginning of our study period, but that this effect had reversed by the end of the study period. A parallel analysis of income shares suggests that the explanation might lie in climate vulnerability shifting from agricultural to non-agricultural livelihood activities. Taken together with evidence from previous case studies, our results open the door to a potential future in which development and in-situ adaptation allow climate-induced migration to decline over time, even as climate change unfolds.

Spatial and Temporal Dimensions of Weather Shocks and Migration in Nepal

Research shows that environmental shocks can influence migration. However, studies vary widely in the shocks and type of migration measured, the context, and the strength and direction of environmental effects. In addition, existing theories provide opposing predictions for this relationship. There is a clear need for further theoretical development in the climate-migration literature. This study, in rural Nepal, examines four types of weather shocks, over various time frames, on four types of migration. Results suggest that the most substantial influence of weather shocks is not in a wholesale increase or decrease in migration. Instead, weather shocks are related to changes in the type of migration used, resulting in less long-term and more short-term migrations in the population. We use the Ready-Willing-and-Able perspective to make sense of these patterns.