Coastal areas have long held dense settlement and economic activity; more than 40% of the world population lives within 100 kilometres of the coast. A new global study using satellite night-time lights shows many coastal communities moved inland over the past 30 years as climate hazards intensified.
The study, published in Nature Climate Change and led by researchers at Sichuan University with collaborators, mapped movements in 1,071 coastal regions across 155 countries. Overall, 56% of coastal regions retreated from the coast, 16% moved closer, and 28% remained stable; Africa and Oceania showed the highest shares of retreat.
Researchers conclude that retreat is linked more to social and infrastructural vulnerability than to the historical frequency of hazards. Nearly half of low-income regions are unable to retreat because they depend on coastal land for livelihoods, which leaves millions exposed to flooding and erosion.
Retreat is most common in middle-income countries, which often have some capacity and funds to support relocation but not enough to favour heavy protection. The authors note that night-time light data can miss settlements with limited electrification and call for more study to guide coastal planning.
Difficult words
- coastal — near the edge of the sea or ocean
- settlement — place where people live, like a town
- retreat — movement away from a place of danger
- hazard — something that can cause harm or dangerhazards
- vulnerability — state of being likely to be harmed
- livelihood — a way people earn money to livelivelihoods
- erosion — gradual loss of land by water or wind
- relocation — process of moving people to a new place
- electrification — process of providing electric power to places
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think it is better for people to move inland or to protect the coast? Give one reason for your opinion.
- How can limited electrification make it hard to study population changes with satellite night-time lights?
- What local jobs or reasons might stop low-income communities from leaving coastal areas?
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