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Study tracks settlement shifts in 1,071 coastal regions across 155 countries
56% of regions saw populations moving inland between 1992 and 2019
Poorer regions in Africa and Asia often stayed put or moved closer to the sea
Wealthier areas more likely to retreat inland or build coastal protections
Researchers warn adaptation gap is widening as climate risks intensify
Rising sea levels and intensifying coastal hazards are driving people away from the shorelines, yet in low-income regions millions remain stuck, or even move closer to the sea, according to a global study.
The research, published in the journal Nature Climate Change on September 22, 2025, examined 1,071 coastal regions across 155 countries.
While 56 per cent of regions saw populations shifting inland between 1992 and 2019, the poorest areas, often the most vulnerable, were unable to move and in some cases were forced closer to the coast, heightening their exposure, the researchers found.
The findings are based on three decades of satellite nighttime light data. While most migration inland occurred in places facing rising coastal risks, the study found that 26 per cent of coastal populations stayed put and 16 per cent moved closer to the shoreline.
South America accounted for the highest proportion of people moving towards the coast (17.7 per cent), followed by Asia (17.4 per cent), Europe (14.8 per cent) and Oceania (13.8 per cent). Africa saw 12.4 per cent of its coastal population relocate closer to the sea, while North America recorded 8.8 per cent.
The relocation was mainly driven by the vulnerability of the population and their capacity to respond to the crisis. The study noted links between communities shifting away from coasts associated with their previous experiences of coastal climate hazards.
Lead author Xiaoming Wang, an adjunct professor at Monash University’s Department of Civil and Environmental Engineering and one of the authors of the paper, said: “For the first time, we've mapped how human settlements are relocating from coasts around the world. It's clear that moving inland is happening, but only where people have the means to do so.”
People in poorer regions, with little or no capacity to cope with climate risks, are forced to remain exposed to extreme weather and high climate threats, Wang underlined.
In 46 per cent of low-income regions, particularly in Africa and Asia, populations either stayed in place or edged nearer the shore, revealing the large adaptation gap in addressing future climate change risks, the study said.
The study also noted stark contrasts in Oceania and Australia, where wealthier and poorer communities alike moved closer to the coast, reflecting dependence on coastal economies.
Communities staying close to the coast were often found to have more structural protections including flood levees and better capacity to adapt. But the study noted concerns that such protective infrastructure instilled overconfidence among populations and supported risky development closer to the coast.
Wang said, “On one hand, the movement closer to coastlines can expose vulnerable populations to the impacts of storms, erosion, and sea-level rise. On the other hand, it can expose those wealthy communities to the growing coastal hazards.”
The authors concluded that relocation inland may become essential as sea levels rise and climate impacts intensify. Relocating away from the coast must be a long term climate adaptation strategy as relocating human population implies economical and social impacts across individuals, communities and regions, the researcher pointed out.
Wang said: “Alongside mitigation, adaptation must reduce coastal exposure, improve informal settlements and balance livelihoods with risk. Without this, adaptation gaps will only widen and leave the world’s poorest behind.”