Title : Statistically invisible: climate-related migration and the health data gap in sub-Saharan Africa
Abstract:
Rationale: Climate-related displacement in sub-Saharan Africa is now measured at scale, yet the health of those displaced is not: mobility data systems and health data systems have developed as parallel infrastructures that do not see each other's populations.
Objective: This critical review examines what is known about the health of populations displaced or migrating in the context of climate change in sub-Saharan Africa, and develops the argument that the central obstacle to knowledge and policy is infrastructural: the statistical invisibility of climate-affected movers.
Methods: This critical review synthesises peer-reviewed evidence, WHO/IOM/IDMC data sources and humanitarian surveillance (searched June-July 2026), reading the evidence through social science work on legibility, enumeration and the politics of data.
Results: Available evidence associates climate-related mobility with malnutrition, waterborne disease, psychosocial distress and deprivation of basic needs, with markedly gendered impacts and heterogeneous well-being outcomes of migration-as-adaptation. Yet displacement datasets rarely include health outcomes, health surveys rarely record displacement drivers, and climate attribution in operational data ranges from 3% to 99% across contexts. Health-system responses cluster in acute emergency delivery.
Conclusions: Populations rendered illegible to routine data systems are excluded from anticipatory health policy. Three low-cost modifications health modules in displacement tracking, mobility modules in health surveys, harmonised definitions would make climate-affected movers visible to research and planning.
Keywords: Climate Change; Migration; Internal Displacement; Sub-Saharan Africa; Health Inequalities; Data Infrastructure
