Floods are driving millions to move as climate-driven migration patterns emerge

By | December 18, 2023

ST. LOUIS (AP) — Floods are driving millions of people to leave their homes, limiting growth in some affluent communities and accelerating decline in others, according to a new study that details how climate change and flooding are changing where Americans live.

In the first two decades of the 21st century, the threat of flooding convinced more than seven million people to avoid risky areas or leave risky places, according to an article Monday in the journal Nature Communications and research from the risk analysis organization First Street . Foundation.

Climate change is making major hurricanes more intense and increasing the amount of rain storms dump in the Midwest. And in the coming decades, researchers say millions more people will decide it’s too much to live with and leave.

First Street found that climate change creates winners and losers at the neighborhood and block level.

Zoom out to see the entire country and Americans seem to be ignoring the threat of climate change when deciding where to live. For example, Florida, vulnerable to rising sea levels and intense storms, is growing rapidly. But that ignores an important way in which people behave locally. Most moves are short range; people stay close to family, friends and jobs.

Jeremy Porter, chief research officer at First Street, said “there is more going on” than population growth in the Sun Belt states.

“People want to live in Miami. If you already live in Miami, you don’t say, ‘Oh, this property has a 9 (out of 10 for flood risk), let me move to Denver,'” Porter said. “They’ll say, ‘This property is a 9, but I want to live in Miami, so I’m going to look for a 6, a 7 or a 5 in Miami.’ You start thinking about the relative risk.’

That’s what First Street predicts over the next thirty years: blocks in Miami with a high chance of being hit by a major storm are more likely to see their populations decline, even as much of the city is expected to absorb more people.

Behind these findings is highly detailed data on flood risks, population trends and the reasons why people move, allowing researchers to isolate the impact of flooding even as local economic conditions and other factors motivate families to pick up the pieces and move elsewhere. They analyzed population changes in very small areas, down to the census block.

Some blocks have grown quickly and would have grown even faster if flooding were not a problem, First Street said. Expanding but flood-prone areas could have grown almost 25% more – and attracted about 4.1 million more people – if that risk had been lower. Researchers also identified areas where flood risk is driving or exacerbating population decline, which they called “climate abandonment areas.” About 3.2 million people left these neighborhoods due to flood risk over a twenty-year period.

When First Street extended to 2053, many of the new climate abandonment areas were in Michigan, Indiana, and other parts of the Midwest. Flood risk is just one factor driving this change and it doesn’t mean communities are emptying out, said Philip Mulder, a professor focused on risk and insurance at the University of Wisconsin-Madison.

“People can live in smarter places within those communities. That applies to Detroit as much as it does to Miami,” he said.

If people know that a house is prone to flooding, they are less likely to buy it. However, some states are not requiring the history of flooding to be made public, said Joel Scata, a senior attorney on the Natural Resources Defense Council’s climate adaptation team.

“Access to good information is very important in the real estate market,” said Scata.

Even for people who get help moving, the choice can be unbearable. Socastee, a community near Myrtle Beach, South Carolina, flooded not only when hurricanes hit, but sometimes when it rained heavily and water reached doorways and saturated yards. First Street’s data shows that Horry County won’t grow as quickly over the next 30 years because of flood risk.

A resident who has had to deal with repeated flooding said that when storms “make you sick” and take away your sense of security.

Terri Straka decided to leave the area, but had difficulty convincing her parents to do the same. Finally, she took them to a house for sale and said it could be their dream home. They reluctantly agreed to move.

“Being able to visualize what a future could look like is absolutely crucial for people who can move. They have to imagine a place and it has to be a real place that they can afford,” said Harriet Festing, executive director of the Anthropocene Alliance, which supports communities like Socastee affected by disasters and climate change.

Older people move less often and it takes money to move. If people don’t get enough help and don’t have the resources, they are more likely to stay in high-risk areas. When people start moving, it can create momentum for others to leave, leaving fewer residents to support a shrinking local economy, said Matt Hauer, a demographic expert and study author at Florida State University.

But there are also winners. Louisville, Kentucky, Detroit and Chicago, as well as several other major cities, have plenty of space with little flood risk, which will be attractive in the future, First Street found.

Mulder of the University of Wisconsin said of cities like Chicago, “They should not underestimate the relative advantages that come from being a safer place in a warming world.”


Fassett reported from San Francisco.


The Associated Press receives support from the Walton Family Foundation for reporting on water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environment

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