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Health and migration in the context of a changing climate: A systematic literature assessment

A doctor examines a woman patient at a mobile health clinic in Pakistan


Climate change and climate variability interact with political, economic, social, demographic, and other environmental drivers to change the scale and patterns of human migration, and, specifically, climate-migration.Climate change is considered an important driver of migration; however, the term ‘climate-migrant’ and its synonyms remain legally and scientifically contested. In the context of accelerating climate change and breaches to other planetary boundaries, there is an urgent need to better understand how migrant health can be protected and promoted in the context of a changing climate to manage safe and orderly migration.

The specific objectives of this systematic assessment were as follows:

  1. To synthesize empirical evidence about the climate change-migration-health nexus.
  2. To identify the methodologies and research questions.
  3. To determine the study settings, populations, mobility responses, and health outcomes.
  4. To identify knowledge gaps and clusters (aggregated knowledge) in the evidence base.
  5. To define both positive and negative health impacts of climate-related migration on populations as well as climate impacts on health that drive mobility responses and how relationships between climate-related migration and health relate to circumstances (e.g. vulnerabilities) and interventions (e.g. planned relocation)

While research has focused on the separate dyads of i) climate change and migration, and ii) climate change and health, limited consideration has been given to the nexus between climate change, migration, and health. This assessment synthesizes research that has investigated this relationship since 1990.This assessment will be of significance given the high levels of climate-related migration anticipated in the future, and the limited consideration to date of specific aspects of the adaptive potential of climate-change-related migration, especially in terms of health.

* The text below provides a summary of the open access paper “Health and migration in the context of a changing climate: A systematic literature assessment” published in Environmental Research Letters in September 2020. For much more detail you can read the full paper here.

Methods and Tools

The systematic assessment protocol was registered with the international systematic literature review platform Prospero on August 29, 2018. The protocol was developed in consultation with the IOM Migration Environmental and Climate Change Division, and as part of a coordinated effort by Environmental Research Letters to synthesize evidence in preparation for IPCC AR6.

Following an a priori protocol and with the assistance of a subject librarian, systematic searches were conducted in four academic databases (PubMed, Scopus, Ovid Medline, and Global Health) and Google Scholar for empirical studies investigating migration and health in the context of climate change with any study design between 1990 – 2018. The search results underwent a two-stage screening process and the eligible studies were subjected to quality appraisal using a mixed methods appraisal tool. Data extraction and a meta-synthesis followed producing outputs deemed most useful for policy, practice, and further research.

For the purposes of this synthesis research, ‘climate change’ was defined as a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. ‘Health’ was defined broadly to include physical, mental, and social components and due to the population health nature of this assessment, was extended to include food security and water security, and water, sanitation, and hygiene. ‘Migration’ was defined as the movement of persons away from their place of habitual place of residence, either across an international border or within a state regardless of legal status, degree of choice, causes of movement, or length of stay.


While the strengths of this research include blinded study selection and quality appraisal as well as the extensive search in four literature databases, there were several limiting factors such as the following:

  1. The inclusion of English and German studies published in academic journals, which may have led to selection bias.
  2. The exclusion of grey literature, which may have led to the omission of some important findings.
  3. Ambiguity in reporting within eligible studies, which may have led to over or underestimation of methodological quality.
  4. Although the inclusion of all three elements of the climate-migration-health nexus was required for inclusion in this assessment, some studies still focused on a ‘dyad’ within the nexus, whereby climate change was considered, but either migration or health was underexplored. Subsequently, extractable data for these underexplored elements was at times inadequate and required interpretation.

Key Findings

The registered protocol and search strategy revealed 1,904 studies of which 180 were screened in fulltext and 50 were included in the meta-synthesis. Overall, the methodological and reporting quality of the included studies was high. This assessment produced five main findings:

  1. there is a paucity of empirical research investigating the climate-health-migration nexus;
  2. the relationships between migration and health in the context of climate change are strongly heterogeneous and global findings are unlikely to emerge;
  3. studies have examined diverse health issues associated with migration in the context of climate change including changing patterns of infectious disease, non-communicable disease, psychosocial conditions, and access to health care;
  4. food and water security are important mediators between climate change, human mobility, and health outcomes;
  5. there is no consistent approach to integrating climate data in studies exploring migration and health in the context of climate change.

Although migrant health and climate-related health risks are significant population health concerns, there has been limited consideration of the complex connections between climate change, migration, and health. Considering climate change threatens decades of global health gains, health equity, and human rights, there is significant impetus to better understand how migrant health can be protected and promoted in the context of accelerating climate change. This understanding requires transdisciplinary research, consensus on how to integrate climate data, understanding of the pathways via which climate impacts shape mobility, and policy-relevant research.

This assessment indicates that there are potentially important intersections between climate, health, and migration and that further research is required to better understand this nexus. There is also no uniform or global solutions for this nexus given the heterogeneous nature of the climate change, migration, and health relationship. To date and based on this assessment, it seems important that research and policy related to migration also consider the links between climate change and health and that migration is considered a determinant of health in climate change and health research.

Areas for further research

This assessment identified some well-represented knowledge clusters that are amenable to synthesis via systematic review; however, underrepresented areas of research would benefit from further primary research, including the health considerations for trapped populations, the mental health impacts of climate-related migration, and the gendered health impacts of climate-related migration. Further research could analyze the question of quality in terms of climate data integration in climate change-related public health research. Finally, research could examine how the syndemic of climate change, obesity, and undernutrition interacts with non-communicable disease management and migration.

Suggested Citation

Schwerdtle, P. N., Mcmichael, C., Mank, I., Sauerborn, R., Danquah, I., & Bowen, K. (2020). Health and migration in the context of a changing climate: A systematic literature assessment. Environmental Research Letters. doi:10.1088/1748-9326/ab9ece

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