Living by the sea? Climate change is about to dramatically age our coastal population, a study says

It won't just be the heat of the sun that makes skin look older on the beach, scientists predict.

Rising seas will lead to a wave of young people moving away from coastal areas, and their new study estimates that this shift could mean the average age of coastal communities will be as much as ten years older by 2100.

And the trend will be global in scope: With the coastal population expected to surpass one billion people this century, rising sea levels due to climate change are expected to push hundreds of millions of people further inland worldwide.

Worse, coastal population drains are likely to be 5.3 to 18 times higher than expected, the researchers said, based on new estimates that take into account the indirect migration of doctors and service workers who are sure to follow young migrants to their new homes .

'Who could be left behind in these ecologically precarious areas?' asked the lead author of the new study on this youth flight along the coast.

'Elderly,' he said'and especially older women.'

Worse, researchers found that these figures are likely 5.3 to 18 times higher than expected (above the map), based on estimates that take into account factors such as the indirect migrations of doctors, teachers and other service providers that certainly bring young migrants to their new house will follow.

Sociologist Matt Hauer, lead author of the study and associate professor at Florida State University, expressed hope that these new predictive models will help local communities prepare for sharp disruptions in vital services such as health care.

'If a municipality were to plan climate migrants based on a certain climate impact, it would actually have to take into account 10x the change in the total population!' Hauer posted on X.

Hauer and his colleagues incorporated a variety of demographic data and harder-to-predict secondary effects into their study, in combination with standard flood hazard models and a U.S. migration model by province.

Their work built on 40 years of environmental migration patterns in the US.

“Scientists generally model climate migrants as ageless and sexless individuals,” the team wrote in the new paper, published in the Proceedings of the National Academy of Sciences.

'[They are] omitting the established relationship between migration tendencies and demographic characteristics.”

The researchers expect that both coastal “sender” communities and their inland “destination” community counterparts could be left flat-footed by these massive population shifts, thanks to these unexpected secondary effects.

“Imagine young families moving from areas like Miami,” Hauer noted in one rack“and move to other locations and start a family there.”

“In the destination communities where the population is increasing, you need more dentists, doctors, service workers, construction workers, etc.,” Hauer said. 'By moving you influence the chance that others will move. You get a demographic boost.'

'Who could be left behind in these ecologically precarious areas?' The lead author of the new study asked about this coastal flight: 'Older people and especially older women'

Young adults leaving an area are also likely to accelerate the rise in the average age in one of these neglected beach towns, Hauer said, because those who remain are unlikely to start new families there of their own.

“Because migration is most likely to occur in more youthful populations,” he noted, areas experiencing accelerated outmigration may experience accelerated population aging.”

Miami-Dade, Florida was one of the counties most likely to be affected by these migrations, according to the study.

The researchers predict that by 2100, about 28,300 people will have deliberately migrated from the area – but the total demographic decline due to these other factors is likely to be as many as 243,900 fewer people.

Similarly, in Dare County, North Carolina, it was modeled that there would be approximately 8,500 outgoing residents due to climate, but a total of 39,900 fewer people by the end of this century due to secondary impacts.

San Mateo County in California, and Brazoria and Galveston counties in Texas, also neared the top of the list of counties estimated to experience the most severe decline and a flight of young citizens.

“Relatively small shifts,” the team wrote, “can culminate in significantly larger demographic changes.”

Sunshine Jacobs, co-author of the study and doctoral candidate in FSU's Department of Sociology, noted that even with the many new factors incorporated into their model, the new findings represent only part of the coming climate migration crisis.

“We only looked at sea level rise,” as Jacobs noted.

“Imagine other hazards that we know cause people to move, such as heat events, wildfires and economic hazards,” she added. 'The future applications and implications of the model are astonishing.'