2.3.3Active indicatorMigration, Displacement, and Rising Sea Levels
2.1Assessment and planning of health adaptation
2.2Enabling conditions, adaptation delivery, and implementation
2.3Vulnerabilities, health risk, and resilience to climate change
Indicator 2.3.3 · Adaptation
Migration, Displacement, and Rising Sea Levels
Sea-level rise can affect health through episodic flooding, permanent inundation, erosion, contamination of soil and drinking water, vector- and water-borne disease, threats to livelihoods, and adverse mental health impacts. As sea levels rise and populations grow in exposed areas, people may adapt where they live, relocate voluntarily or through forced displacement, or become unable to move despite increasing risks. The first part of this indicator tracks the number of people living in coastline areas within one meter of current sea levels, and therefore potentially exposed to the risk of future sea-level rise. The second part examines whether national policies recognise links between climate change, migration and (im)mobility, and health.
Headline finding
In 2025, 158.3 million people were living less than 1 m above current sea levels; as of December 2025, 59 national policies identified across 44 countries made links between climate change and migration while mentioning health
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Figure 1
Population Exposed To Sea Level Rise Risk
Coastline population living within 1 metre of current sea level in 2025, by country, Human Development Index (HDI) group, Lancet Countdown region, or World Health Organization (WHO) region. Landlocked countries with no coastline are shown in grey.
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Figure 2
Migration, Displacement, And Health
Number and percentage of national climate and migration policies that explicitly mention movement from a location, movement to a location, immobility, domestic movement, international movement, and health or well-being, by country, based on the 2025 assessment.
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About this indicator
Description
The first part of this indicator uses a bathtub model, overlaying future global mean sea level rise of 1m with coastal elevation to define areas of potential inundation, then uses gridded population data to estimate the current population at risk of exposure to 1m global mean sea level rise. The second part looking at national policies connecting climate change and migration reports on the number of national-level policies that include legislation for migrants related to climate change (including displaced and relocated peoples) and the number of such policies that mention health or well-being.
Data downloads
Caveats
Estimates of population exposure to global mean sea level rise vary according to the input datasets, timeframes and geographic scales, the parameters that are set for emissions and socioeconomic scenarios, and methods of analysis. Many factors, including adaptive strategies, influence population displacement due to sea level rise and some populations may not move due to lack of necessary resource to escape sites of risk or may remain in location due to social, cultural or political reasons. Additionally, other climate impacts and demographic factors contribute to migration into low-lying coastal sites. The analysis of national-level policies was mainly confined to those documents written in English, with a few other languages on occasion - the numbers reported must therefore be taken as the minimum.
Data sources
- GMSLR: Estimated global mean increases in sea-levels.
- Elevation: Coastal Digital Elevation Model (CoastalDEM)
- Hybrid gridded demographic data for the world.
- Global Administrative Areas (GADM) version 4.0.4, http://www.gadm.org/