Research uncovers reason for mass migration: 'There's more to the story'

The effects of a warming planet are altering how people decide where to live, with millions of people avoiding flood-risk areas, according to a new study. 

What happened?

Research from the risk analysis organization First Street Foundation has found that more than 7 million Americans either moved away from areas prone to flooding or chose to avoid them since 2000, according to a summary of the research posted on the foundation's website.

The researchers looked at flood data between 2000 and 2023 and found that flooding is stifling growth in prospering cities and accelerating declines in struggling areas.

If you look at state-level data, it may appear that people are ignoring climate change when they decide where to live. For example, Florida, vulnerable to rising seas and hurricanes, is still growing quickly. However, "there's more to the story," Jeremy Porter, head of research for First Street, said, as quoted by The Salem News. 

"People want to live in Miami," he said. "If you live in Miami already, you're not going to say, 'Oh, this property is a 9 (out of 10 for flood risk), let me move to Denver. They are going to say, 'This property is a 9, but I want to live in Miami, so I'm going to look for a 6 or a 7 or a 5 in Miami.' You are going to think about relative risk."

Why is this research concerning?

In the past year, historic flooding has battered communities across the globe. For example, in January 2024, it was reported that the Congo River had risen to its highest level in over 60 years, leading to hundreds of deaths in the Democratic Republic of the Congo (DRC) in the preceding months. Thousands more people were displaced.

In Italy, heavy rains in October 2023 caused Lake Como to overflow from its banks and flooded Milan, causing significant damage. Heavy rainfall across the region also spurred mudslides in Tuscany, and strong winds in Venice led to one of the highest local tides on record.

The effects of flooding on human populations are only expected to get worse, too. According to the World Resources Institute, the number of people affected by floods will double between 2010 and 2030.

"Climate change is increasing the likelihood of extreme flooding — and particularly in urban areas," Valeriy Ivanov, a University of Michigan researcher unaffiliated with the First Street study, said in a press release. "In the past four decades, 99% of U.S. counties were impacted by flooding, and since 2000, there have been 1,782 flood related fatalities."

What's being done about flood risk?

Ivanov is co-leading a five-year initiative that will help to predict and communicate flood risk, thanks to a $7.5 million grant from the Office of Naval Research. The project will utilize the expertise of researchers in science, technology, and the humanities and will seek to answer questions such as, "What information do leaders need to make decisions about evacuation?"

Some cities are also taking precautions to protect themselves from flooding. A Vancouver, Canada team hopes to revamp the city's waterfront area to take advantage of floodwaters. The plan includes vertical extensions of flood-adaptive townhouses with community terraces and mid-rise buildings with public spaces that allow for flooding without permanent damage, as well as "floating habitat islands" and mixed-use spaces on stilts.

Venice has another solution — a system of 78 hinged steel floodgates along the seafloor. While experts are unsure how well it can hold up against a warming planet, it did save the city from the 2023 storm that ravaged the rest of the country.

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