Coastal residents around the world are relocating inland away from coastlines as sea levels rise, a new international study shows.
But the poorest regions are forced to stay where they are or move closer to the rising sea, it adds.
The findings were contained in the study, published in Nature Climate Change, which analysed 27 years (1992–2019) of satellite night light data taken from 1071 coastal regions across 155 countries.
COASTAL STUDY FINDINGS
- The population in 56% of regions analysed had relocated inland.
- People in 28% of regions had stayed put.
- The population in 16% of the regions moved closer to the coast.
The trend of moving closer to the coast was the highest in South America (17.7%) then in Asia (17.4%), Europe (14.8%), Oceania (13.8%), Africa (12.4%) and North America (8.8%).
(Social media posts have included videos of beachfront stilt houses washing out to sea along the Outer Banks in North Carolina.)
The study’s lead author is Xiaoming Wang, an adjunct Professor with the Monash University’s Department of Civil and Environmental Engineering.
He says relocation is largely driven by economic vulnerability and ability to respond.
“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,” he says.
“In poorer regions, people may have to be forced to stay exposed to climate risks to live or (they have) no capacity to move. These communities can face increasingly severe risk in a changing climate.”
The Pacific Island nations of Oceania have the closest settlements to the coast globally due to their island geography.
“In Oceania, we see a common reality where wealthier and poorer communities are likely to relocate towards coastlines in addition to moving inland,” Prof. Wang says.
“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 growing coastal hazards.”
The study also highlights concerns that overconfidence in protective measures like seawalls encourages risky development close to the coast.
“It is interesting to note that high-income groups also had a relatively higher likelihood to remain on coastlines, such as in Europe and North America.
“This can be due to their capacity and wealth accumulated in coastal areas,” Adjunct Prof. Wang said.
The study warns that relocation inland may become unavoidable as sea levels rise and climate change intensifies.
“Relocating away from the coast must be part of a long-term climate strategy,” he says.
“The rationale for policy and planning to relocate people requires meticulous consideration of (the) economic and social implications across individuals, communities and regions,” Prof Wang says.
“Alongside climate change mitigation, it needs to be combined with efforts to reduce coastal hazard exposure and vulnerability, improve informal settlements, balance coastal risks with livelihoods and maintain sustainable lifestyles in the long-term.
“Without this, coastal adaptation gaps will continue to be widened and leave the world’s poorest behind.”
ABOUT THE STUDY
The study is an international collaboration on climate adaptation research between Prof. Wang, the Institute for Disaster Management and Reconstruction at Sichuan University, and researchers from Denmark and Indonesia.
The study focused on how communities cope with recurring coastal threats and highlights gaps in adaptation in need of urgent attention.
