Human settlements around the world are shifting away from the sea as rising waters and stronger coastal hazards take hold. But new research shows millions in poorer regions are unable to move, and in some cases are being pushed even closer to the shore.
The findings come from an international study published on September 22, 2025, in Nature Climate Change. The research examined satellite nighttime light data from 1992 to 2019 across 1,071 coastal regions in 155 countries.
According to the analysis, 56 percent of regions saw populations moving inland, but 26 percent remained in place and 16 percent edged closer to the coast. Researchers linked the differences to income levels and the capacity of communities to adapt to rising risks.
Lead author Xiaoming Wang, an adjunct professor at Monash University’s Department of Civil and Environmental Engineering, said the study is the first to map global population shifts away from coastlines.
“For the first time, we’ve mapped how human settlements are relocating from coasts around the world,” Wang said. “It’s clear that moving inland is happening, but only where people have the means to do so.”
The study found that low-income regions, particularly in Africa and Asia, often lacked the resources to move inland. In 46 percent of these areas, people either stayed in place or moved closer to the water, despite the risks.
“In poorer regions, people may be forced to remain exposed to climate risks because they cannot afford to move,” Wang said. “These communities face increasingly severe risks in a changing climate.”
The data showed regional differences in the scale of migration. South America saw the largest proportion of people shifting toward the coast, at 17.7 percent. Asia followed closely at 17.4 percent, with Europe at 14.8 percent, Oceania at 13.8 percent, Africa at 12.4 percent, and North America at 8.8 percent.
In Oceania, researchers noted that both wealthier and poorer communities were likely to remain close to the sea. Wang explained this was tied to economies that depend heavily on coastal access. “In Oceania, we see a reality where both groups move towards coastlines, in addition to relocating inland,” he said.
The study also found that wealthier regions, such as parts of Europe and North America, were more likely to stay on coastlines. Researchers said that wealth, infrastructure, and accumulated investments in coastal property encouraged communities to remain despite increasing risks.
“High-income groups have a higher likelihood of staying on coastlines because they rely on protections such as flood levees and have more capacity to adapt,” Wang said. “But this reliance can create overconfidence and encourage risky development.”
Coastal hazards are expected to intensify as sea levels rise. The researchers warned that relocation inland may become essential in the future, but it will carry social and economic consequences.
“Relocating away from the coast must be part of a long-term climate strategy,” Wang said. “Planning to relocate people requires careful consideration of economic and social impacts across individuals, communities, and regions.”
The authors stressed that adaptation strategies must address inequalities. Communities without resources to move will need support to reduce their exposure to climate risks.
“Alongside mitigation, adaptation must reduce coastal exposure, improve informal settlements, and balance livelihoods with risk,” Wang said. “Without this, adaptation gaps will widen and the world’s poorest will be left behind.”
The study was carried out by Monash University in collaboration with the Institute for Disaster Management and Reconstruction at Sichuan University, as well as researchers in Denmark and Indonesia. The team used nearly three decades of satellite data to track settlement changes and match them against climate hazards.
By showing where communities are moving and where they are trapped, the researchers say they have identified the regions most in need of urgent attention. Their findings underline a growing challenge: adapting to a future where coastlines will be under greater threat, and where the poorest may bear the greatest risks.
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