It won’t just be the sun’s heat making skin look older at the beach, scientists predict.
Rising seas will lead to a surge in young people migrating away from the coasts, and their new study estimates the shift could result in the median ages of coastal communities climbing to as much as 10 years older by 2100.
And the trend will be global in scope: With costal populations projected to surpass one billion people this century, worldwide, rising sea levels due to climate change are expected to force hundreds of millions of people further inland.
Worse, coastal population drain is likely to be 5.3 to 18 times higher than expected, the researchers said, based on new estimates accounting for the indirect migration of doctors and service workers sure to follow young migrants to their new homes.
‘Who could be left behind in these environmentally precarious areas?’ the new study’s lead author asked of this coastal youth flight.
‘Older people,’ he said, ‘and, in particular, older women.’
Rising seas will lead to a surge in young people migrating away from coastal US counties (red-to-yellow, above) to counties further inland (blue-to-green above). The new study estimates that the median age of coastal communities may climb to as much as 10 years older by 2100
Worse, researchers found those numbers are likely to be 5.3 to 18 times higher than expected (above map), based on estimates that account for factors like the indirect migrations of doctors, teachers and other service workers sure to follow young migrants to their new homes
Sociologist Matt Hauer, the study’s lead author and an associate professor at Florida State University, expressed the hope that these new predictive models will help local communities prepare for sharp disruptions in vital services like health care.
‘If a municipality were to plan for climate migrants based on a given climate impact, they should really plan for 10x the change in the total population!’ Hauer posted to X.
Hauer and his colleagues incorporated a variety of demographic data and harder-to-predict secondary effects into their study, combining that with standard flood hazard models and a county-by-county US migration model.
Their work built off of 40 years of environmental migration patterns across the US.
‘Scientists generally model climate migrants as age-less and sex-less individuals,’ the team wrote the new paper, published in the Proceedings of the National Academy of Sciences.
‘[They are] omitting the well-established relationship between migration propensity and demographic characteristics.’
The researchers expect that both coastal ‘sender’ communities and their inland ‘destination’ community counterparts could wind up flat-footed by these massive population shifts, thanks to these unexpected secondary effects.
‘Imagine young families moving out of areas like Miami,’ Hauer pointed out in a statement, ‘and moving to other locations and starting a family there.’
‘In the destination communities where populations are increasing you’ll need more dentists, doctors, service workers, construction workers, etc.,’ Hauer said. ‘So by people moving, you affect other people’s likelihood of moving. You get a demographic amplification.’
‘Who could be left behind in these environmentally precarious areas?’ the new study’s lead author asked of this coastal flight: ‘Older people and, in particular, older women’
Young adults leaving an area is also likely to speed up any increase to the average age in one of these neglected beach towns, Hauer said, as those who remain are unlikely to start new families there themselves.
‘Because migration is most likely to occur in more youthful populations,’ he noted, areas experiencing accelerated out-migration could face accelerated population aging.’
Miami-Dade in Florida was one of the counties the study expect to be hardest hit by these migrations.
The researchers predict that about 28,300 people will have intentionally migrated away from the area by 2100 — but the total demographic decline due to these other factors is likely to be as much as 243,900 less people.
Dare County in North Carolina, similarly, was modelled to experience roughly 8,500 departing residents due to climate, but a total of 39,900 less people due to secondary effects by this century’s end.
San Mateo County in California, and Brazoria and Galveston counties in Texas, also neared the top of the list of those estimated to experience the most severe declines and a flight of young citizens.
‘Relatively small displacements,’ the team wrote, ‘can cascade into considerably larger demographic changes.’
Sunshine Jacobs, a study co-author and a doctoral student with FSU’s Department of Sociology, noted that even with the many new factors included in their model, the new findings are only one slice of the coming climate migration crisis.
‘We only looked at sea level rise,’ as Jacobs pointed out.
‘Imagine other hazards that we know cause people to move, like heat events, wildfires and economic hazards,’ she added. ‘The future uses and implications of the model are amazing.’