As rising seas erode buildings, it's getting riskier to live on the coast

MIAMI – Samuel Schrager looks out on the parking lot of his condo that was built in 1967. After a week of afternoon downpours amid hurricane season, it's flooded. Again.

Signs of climate change are everywhere, he says. Even on some sunny days, he can't get to parts of the barrier island where he lives because they are underwater.

"It's here, it's real," said Schrager, 72, president of the condo association at the Keys Biscayne building where his family has owned a unit for five decades.

Long before the horrific collapse of Champlain Towers South, which authorities so far say killed 64 people with 76 still missing, Schrager encouraged his neighbors to fix up their aging building to mitigate the impact of climate change.

"You have salt, you have sea level rise, which is impacting the foundations of these buildings," said Schrager. "In our building, we have been proactive, but I don't have eyes that can see underground."

While the cause of Champlain Towers South is not yet known, experts say a combination of factors likely contributed to the failure. In South Florida, where the sea is almost 5 inches higher than it was in 1993, they say climate change is undoubtedly on the list.

Engineers and scientists who study the changing environment say whether or not the Champlain collapse ends up having a direct link to global warming, future problems with coastal buildings are assured.

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"If you want to live in coastal areas, there's a risk. And that risk is getting riskier because of sea level rise," said Zhong-Ren Peng, a professor of design, construction and planning at the University of Florida in Gainesville.

But for now, many property owners simply aren't motivated to contend with the inevitable.

Cruz Otazo, 72, who owns a unit in Schrager's building, says she one of the few concerned with the impact of climate change in buildings across the city – and pushing for it to be addressed.

"There are a lot of people in denial," she said. "They don't care because they say, 'I'll be dead by then.'"

'A complete reset'

Salt water is corrosive, as shipbuilders have long known. Today coastal areas face an environment nothing like the one developers built for in the 1980s and 90s, said Peng, who directs the UF's International Center for Adaptation Planning and Design.

"If you designed a building 40 years ago, then you won't have used the right materials to resist corrosion" because it wasn't an issue then, he said. It is now.

Long term, the South Florida coast may be poised for "a complete reset," said Albert Slap, president of Coastal Risk Consulting, a climate adaptation technology and consulting company in Plantation.

About 22% of Miami-Dade County homeowners believe sea level rise will "have a great impact" on them personally, a recent survey by the University of Florida found. That number jumps to 50% when considering the impact on future generations.

Some changes already are underway. Miami plans to spend more than $3.8 billion to build seawalls to fortify its coastline against more frequent flooding and storm surges. The city of Miami Beach is raising streets 2 feet to combat increasingly common "sunny day" flooding. In towns along the coast, new high rises sometimes come with above-ground garages and living space built even higher to safe from the ever-rising ocean.

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More defensive measures against rising tides will come, said Slap, who works with property owners, local governments and homeowner associations. Some say older buildings in prime locations eventually will be knocked down, replaced by higher ones designed with sea level rise in mind.

"It would be possible to still have habitation in that area, but it will be more expensive because you've basically taken a lot of middle-class, single-family homes that were built in the ’60s, ’70s, or maybe the ’80s, knocked them all down and put up high rises," he said.

For Marvin Wilmoth, vice mayor of North Bay Village, a small municipality near Surfside, where the Champlain Towers fell, it's a matter of leadership and explaining to residents changes are urgent.

"The estimated costs of preparing for climate change are such that it creates real angst among some homeowners given structural changes and raising floor elevations are expensive endeavors," said Wilmoth. "Our elected officials and leaders need to take that into account when making decisions regardless of the ramifications."

A changing coastline

Climate change can attack buildings in several ways. In South Florida, the sea is rising, the land is porous and stronger, wetter hurricanes are coming.

In the case of Surfside and many other recently built-up coastal areas, mangrove forests that protected against erosion were cut down. Bays were dredged of rock and sand which was used as fill to create more buildable land. The underlying rock is limestone, topped with sand as thin as 3 feet or as much as a few dozen feet deep.

As sea levels rise, salt water pushes in from the ocean and permeates the ground, a process called saltwater intrusion. This can cause the ground to shift.

That's one reason some buildings in the area, including the Champlain Towers South, have been sinking since the 1990s, according to a study in 2020 by Shimon Wdowinski, a professor in the Department of Earth and Environment.

That salt water also can deteriorate foundations not built to withstand it. While concrete may seem solid, to water it's not, said Matthys Levy, a consulting engineer, professor at Columbia University and author of “Why Buildings Fall Down: How Structures Fail.”

That seawater slowly soaks into the concrete, bringing with it chloride ions that penetrate into reinforced steel bars inside. The steel corrodes and expands, effectively breaking the concrete from the inside out, said John Scully, a corrosion specialist at the University of Virginia.

Another issue is increasing tidal flooding. King tides occur several times a year in coastal areas when the sun and moon align, increasing the gravitational pull that produces normal tides.

With a higher sea level, the tides push further inland, bringing the corrosive effects of salt water to buildings that often weren't built to withstand them.

"For hundreds of years being close to the beach has been a part of the sales pitch," said Adam Sobel, a professor of physics and climate science at Columbia University. "Now the segment of the population that’s worried about flooding and risk, they’re not viewing the coast in the same way."

Flocking to the shore

Americans love coastal living. In 2020, nearly 30% of the U.S. population lived in coastline counties, an increase of 40% since 1960, according to the U.S. Census Bureau.

Change in that beckoning landscape is hard to fathom, said Klaus Hans Jacob, a disaster and climate expert at Columbia University's Lamont-Doherty Earth Observatory.

"Sea level rise has been nonexistent practically for the last 10,000 years, so it's very difficult for us to come to grips with," he said.

Masses of buildings are not expected to start failing any time soon, experts say, but eventually, thousands of structures along the coast will require extensive – and expensive – remediation to keep them safe.

In Florida, many elected officials have been loath to enforce building practices that take climate change into account.

The question is whether political and economic will exist to make the necessary fixes before more calamities occur.

Jacob thinks it will take "multiple" Hurricane Sandy-level events to make Americans face the scope of the problem. The "Superstorm" that made landfall in New Jersey eight years ago killed 159 people, caused $65 billion in damage and damaged or destroyed at least 650,000 homes.

"We're in denial about what we're facing," he said.

Sobel thinks the shift will start with buyers.

"The market has its own feedbacks. Somebody decides it isn’t worth it and then others pay attention. People are not thinking about it and then all of the sudden the psychology changes," said Sobel, who is creating computer models for the insurance industry on how to incorporate climate change into views of hurricane risk.

Coastal areas don't have to become uninhabitable before it comes to a crisis, he said. “Once the marketplace starts to fully contend with the scope of what’s coming, it could cause a collapse of confidence long before it’s physically untenable."

It's already beginning, said Benjamin Keys, a professor of finance and real estate at the University of Pennsylvania’s Wharton School. Florida's real estate markets began to diverge after Hurricane Sandy.

"Since 2013, near coastal markets are down 20% relative to less exposed coastal markets," he said. The effect is strongest in areas of Florida with the highest number of residents from the Northeast, which took the brunt of the 2012 hurricane.

Long term, climate change will make it more expensive to live in coastal areas. Anything can be built, for a price. That means longtime Florida residents like Ashley Toussant may be priced out.

Toussant, 41, is a teacher who lives in Little Haiti, a working-class Miami neighborhood home to Caribbean immigrants for decades. The area, a few miles west of Biscayne Bay, is perched on some of the highest ground in all of Miami-Dade County – between 7 and 14 feet above sea level.

According to some sea level rise predictions, the neighborhood could one day be Miami's new South Beach.

Developers and real estate investors already have begun to buy in the neighborhood. Toussant says after the collapse of the condo tower in Surfside, he fears the gentrification and displacement will intensify.

"Now with this catastrophe," he said, "you're going to get those people that actually live along the shoreline pushing inland."

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This article originally appeared on USA TODAY: Miami condo collapse shows risk of climate change to coastal living