Climate change and Miami: How is Miami adapting to rising sea levels?

A shrill industrial alarm buzzes inside the dimly lit hangar, warning everyone that an 8,400-horsepower machine made of 12 towering yellow fans is about to power up. Normally that’s a cue for everyone to get out of the way, but in hard hats and goggles, Steven Diaz and a half-dozen visiting scientists stand on a turntable, where the paths of the fans converge.

A high-pitched whine gets louder and is quickly overwhelmed by the sound of rushing air.

An unseen operator ramps the wind speed up to 30 miles per hour, and gusts whip at their clothes. It holds for a minute. Then the fans power down.

“He’s being conservative with this,” said Diaz, the site operations manager for this laboratory. Indeed, this is a tiny fraction of the power of these fans, which can drive winds up to 157 mph, the threshold for a Category 5 hurricane.

“I don’t think you would be able to stand on the turntable with the fans at full speed,” Diaz said dryly. “It would blow you back.”

The aptly named Wall of Wind at Florida International University in Miami is meant to blow back buildings. The hangar doors on the other side of the fans open out to a grass lot surrounded by netting to catch any stray debris. Here, inside the world’s most powerful hurricane simulator, scientists test structures, from scale models to full-size replicas, against the forces of nature. They inject water into the airflow to mimic downbursts and spray bubbles to track the eddies and currents. They watch with high-speed cameras and monitor pressure sensors to see how well different designs stand up to storms.

Steven Diaz, operations manager for the Wall of Wind, explains how the facility simulates hurricanes.

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The Wall of Wind can move air at speeds up to 157 miles per hour.

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Miami is at the water’s edge of understanding exactly how buildings fall apart under hurricanes and how to make them stand up to future storms. Results from labs like the Wall of Wind help officials decide where buildings can be built, what materials they need to use, and even what kinds of roofing nails are required.

The lab is part of a research initiative that emerged in the wake of Hurricane Andrew, a gargantuan storm that walloped South Florida in 1992. At the time, it was the most expensive and most destructive storm to ever hit the US. In response, city, county, and regional officials began updating building codes, while researchers brought a more scientific approach to the changing hazards in the region.

As rising average temperatures alter the realm of what’s possible, researchers are bracing for even more severe scenarios. FIU last year began upgrades to the lab to simulate winds up to 200 mph and storm surges as high as 20 feet, conditions that could afflict Miami in the future. From there, the process of testing, developing new codes, and deploying them in the real world will begin again.

By 2040, Miami will have sea levels anywhere from 10 to 17 inches above where they were in 2000, though studies this year found that sea levels have already risen around Florida faster than expected. When a cyclone rolls in, a few inches of sea level rise can lead to several more feet of storm surge — and billions of dollars more in damages.

Yet Miami is seeing a construction boom with tower cranes cropping up in thickets amid the high-rises, building taller on the coast’s notoriously soft, water-logged soil. Miami-Dade County recently reported a population decline, but it’s the first drop after decades of intense growth. From 2010 to 2020, the metro region’s population rose by more than 660,000, creating intense demand for offices, stores, hotels, and homes.

Construction is booming in Miami.

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Miami’s enduring magnetism in the face of growing risks from climate change has made it a laboratory in its own right, with experiments in how revised building codes, novel construction techniques, and resilient urban design fare in the real world, constrained by money and the practical needs of millions of people. Can Miami truly research, plan, design, and engineer its way through extreme heat, rising seas, and more devastating disasters?

The results of Miami’s experiments in adapting to climate change are critical for the rest of the country. More than 40 percent of the US population lives in a coastal county, and that number is growing. Nearly half of the country’s economic output is in sight of the shore, and without any interventions, the rising seas will displace millions of people. “The risks have been there, and with climate change, they’re going to intensify,” said James Murley, the chief resilience officer for Miami-Dade County. “That’s the same for any major urban area in the world.”

The extraordinary challenges of building in Miami, explained

The sand and the sea are powerful draws, but simply being next to the ocean introduces challenging conditions for buildings. Left unshielded or unmonitored, even massive structures can succumb to the elements.

In 2021, the Champlain Towers South condominium in Surfside, north of Miami Beach, partially collapsed, killing 98 people. The National Institute of Standards and Technology is still conducting its investigation, which it expects to complete in spring 2024. However, the condominium complex previously reported structural damage to its concrete due to water leaks from its pool. Inspectors also found rebar corrosion due to relentless exposure to the salty coastal air and saltwater rising from the ground.

Investigators are still trying to figure out why the Champlain Towers South condominium partially collapsed in 2021, but early signs point to saltwater corrosion in its concrete.

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On top of this, the global climate is changing, and Florida is warming especially fast. The state’s average temperature rose more than 2 degrees Fahrenheit in the past decade, according to David Zierden, Florida’s state climatologist and a researcher at the Center for Ocean-Atmospheric Prediction Studies at Florida State University.

That has several major consequences for the Miami metropolitan area. Miami proper is home to 440,000 people. Miami-Dade County, which encompasses 34 cities including Coral Gables, Miami Beach, Doral, and Surfside, has more than 2.6 million residents. The metro region — spanning Miami, Fort Lauderdale, and West Palm Beach — includes more than 6 million residents.

Higher average temperatures mean more frequent and greater extreme heat events. Coupled with Miami’s legendary humidity, heat waves are already a potent health threat. By the middle of this century, Miami-Dade is poised to experience 134 days a year with a heat index above 100 degrees F, more than triple the rate between 1971 and 2000. Like many parts of the world, Miami just experienced its hottest July on record.

Ocean temperatures are rising too, at the surface and below. The waters around Florida this year reached the highest temperatures measured in more than a century, leading to coral bleaching and threatening other marine life. Hot water is also fuel for hurricanes. Patches of hot sea surface waters can cause these storms to rapidly intensify, a phenomenon that emerged in Hurricane Idalia as it made landfall in Florida’s Big Bend region in August. More recently, Hurricane Lee underwent one of the fastest rapid intensifications on record as it churned in the hottest Atlantic Ocean waters ever measured for the time of year.

Another climate change effect is that as air warms up, it can hold onto more moisture. That means when rainstorms occur, they dump a lot more water. An April rainstorm dumped a record-breaking 88 billion gallons of water on Fort Lauderdale, one-third of the city’s typical annual rainfall, leading to upward of 4 feet of flooding.

A tropical storm in June 2022 dropped 10 inches of rain on Miami, leading to extensive flooding.

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Rising temperatures also raise sea levels as ice caps melt and the water in the ocean expands. That means more flooding during king tides, abnormal but predictable high tides that occur in the region between September and November. King tides cause flooding, even when it’s bright and sunny out. They’re projected to occur more frequently, last longer, and reach further inland.

Higher sea levels also lead to more saltwater intrusion as salty ocean water enters fresh water supplies. This dynamic has accelerated as cities overdraw on groundwater. Rising sea levels also amplify storm surges, which are often the deadliest aspect of hurricanes. They occur when storms push seawater ashore, often worsened by torrential rainfall.

Together, this adds up to one of the most difficult environments in the world to build in, and the challenge is growing.

How Southeast Florida is trying to build, adapt, and thrive under climate change

At the same time, Miami residents have a lot of reasons to hold their ground. The region is a popular vacation spot, but it’s also an alluring place to live for students, families, and retirees.

The Miami region saw more than 26 million visitors in 2022.

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Some of the most valuable real estate is taking root in some of the most vulnerable areas. Last year, developers broke ground on the Waldorf Astoria tower in the Brickell business district, just a couple blocks from a flood zone off Biscayne Bay. The 100-story, 1,049-foot tower of skewed stacked cubes will be the tallest building in Florida when it’s completed in 2027.

“In what world does this make sense? Well, in a world where developers, profit, and business motivations are primary,” said Melissa Finucane, vice president of science and innovation at the Union of Concerned Scientists, who studies decision-making around environmental risks.

PMG, the developer behind the Waldorf Astoria, says it’s bringing a suite of new technologies to endure Miami’s looming dangers, assuaging the worries of wealthy buyers. A two-bedroom condominium at the Waldorf Astoria starts at $2.8 million. More than 80 percent of the units have already been sold. Despite its innovations, the building exemplifies defiance in the face of increasing risk. PMG declined to comment for this story.

The construction site of the Waldorf Astoria tower in the Brickell business district of Miami.

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Miami leaders are also branding the city as a tech hub with aspirations to become a financial capital, pitching low business taxes, no state income tax, and lower levels of regulations than other metro regions. Those low taxes mean the local governments have to fund their operations with property taxes and taxes on tourists, creating an incentive for more development in popular coastal regions. The Miami metro region has a GDP topping $340 billion and rising. Its airports are gateways to the Caribbean and Latin America, and its ports are vital hubs for cargo and cruise ships.

All this development coupled with climate risks has forced Miami’s built environment to evolve. Architect Reinaldo Borges has a portfolio of buildings all over Florida, but Brickell — Miami’s steel-and-glass business district where the towering Waldorf Astoria is taking root — is his home turf. His firm designed the Infinity condominium tower, the 1060 Brickell Avenue condos, and the Megacenter storage and office complex in the neighborhood.

Architect Reinaldo Borges describes the climate-resilient design features of the skyscrapers in Miami’s Brickell business district.

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From the lobby of the Four Seasons, Borges noted that while the skyline may be the most visible feature of the neighborhood, Miami’s unique and subtle, climate-conscious design language is expressed at ground level.

Once you notice its expressions, you’ll see them everywhere: Many skyscrapers in the Brickell neighborhood have lobbies 8, 10, or 12 feet above the sidewalk. In other areas with older buildings, however, the entrances are below street level as sidewalks and roadways were rebuilt to higher elevations over the years. It’s rare that you would enter a building without climbing stairs or a ramp. Instead of glass storefronts at the sidewalk, buildings have vents for elevator shafts, HVAC systems, or entrances to parking garages.

These are adaptations in response to a looming threat. More than half of Miami-Dade County is 6 feet or less above sea level. “Brickell here is about 8 feet above sea level,” Borges said. “Walk towards the bay, and you’ll see that it’s downhill and it goes to 3 feet.” The neighborhood has flooded before, even when there wasn’t a hurricane blowing water inland. But when Hurricane Irma struck in 2017, it turned Brickell’s streets into rushing rivers.

Hurricane Irma in 2017 flooded streets throughout the Brickell neighborhood in Miami.

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So, architects have designed the offices and condos here to accommodate high water. They’ve installed laminated glass to withstand hurricane winds and gates to keep the storm surge off driveways. But as average temperatures rise, the water levels will climb. Even if the lobbies stay dry, the ground and basement level support structures will be inundated, possibly rendering elevators, air conditioners, parking garages, and backup power systems useless. The glass may not shatter, but the lights may not stay on.

“Just because you elevate the main level of a tower like this doesn’t mean that you’re solving all the problems and all the challenges of now and 100 years into the future,” Borges said.

How does an architect actually design a skyscraper in Miami, and how does a construction crew build it?

To build up, they must first dig down. That’s where the problems begin. The region has little bedrock suitable for heavy construction and a high water table, the height of the boundary where underground soil and rock are saturated with water. Dig a hole, and water will quickly seep in, if it doesn’t fill in from above first. Rather than building on concrete basement slabs or rafts, high-rise buildings in Miami are often built on piles — long vertical columns driven or screwed deep into the ground — or a combination of slabs and piles. Many buildings also use a technique called deep soil mixing, where construction crews blend cement directly into the surrounding soil, creating an impermeable “bathtub” around the substructure.

“Those foundation systems have a great track record,” said Thomas Leslie, a professor of architecture at the University of Illinois who studies skyscrapers. “They’re not cheap, but they work.”

At ground level, the structure must shield its metal from saltwater corrosion. As rooflines rise, architects have to start to account for the wind. There are the ordinary prevailing winds that can rock a building back and forth, as well as the 200-mph gusts during hurricanes that can blow windows right out of their fixtures. Skyscrapers have to be designed to shed wind and the glass needs to be laminated so it protects the building envelope even if it shatters. The goal is to create a “wind load path” that moves the pressure from the roof to the ground.

Miami’s skyscrapers have to withstand hurricane-force winds and sometimes more than a dozen feet of storm surge.

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High rises in Brickell, Miami, seen from the ground on a cloudy day.

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Resilience against extreme weather has now become a selling point. The rising Waldorf Astoria tower boasts it will have Miami’s first tuned mass damper, a massive internal structure that functions like a pendulum to counteract Category 5 hurricane winds.

But even with all the investment in design, simulation, and building codes, things can still go wrong. The 645-foot Millennium Tower in San Francisco, inaugurated in 2009, is currently leaning 29 inches toward its northwest corner as the piles beneath it began to sink unevenly in the soft soil. Residents of New York City’s 432 Park Avenue condominiums — the third tallest residential building in the world at 1,396 feet — complained that high winds caused loud creaking and groaning, and at times forced elevators to shut down. With all the wind and water in Miami, the stakes are even higher.

Yet the bigger design challenge for Miami may be its smaller buildings, the far more common mid- and low-rise structures. Expensive new skyscrapers can be built like fortresses with modern materials to new resilience standards, but “when it comes to older homes, it’s not so simple,” said Ioannis Zisis, an associate professor at FIU who studies how wind affects structures. The aging, smaller, and cheaper buildings that house most people are far more vulnerable, especially if they were built before Hurricane Andrew.

Kobi Karp, an architect who designed the current tallest building in Miami, the 828-foot Panorama Tower, said that bringing older buildings up to date can be a delicate process. Buildings in Miami-Dade have to go through a recertification inspection process when they turn 25, 30, or 40 years old — depending on where and when they were built — and every 10 years thereafter. You can’t undo many past design decisions, and in many cases, you have to uphold them. The optimal strategy for older buildings is not necessarily to demolish and rebuild, but to recycle and retrofit, according to Karp. That positions the structure to better cope with the changing needs of its users, as well as the increasing pressures of the climate.

“I try to be careful about saying ‘future-proof’ and ‘hurricane-proof,’ because nothing is 100 percent,” Karp said. “Yet, what we have here is a great opportunity to recycle.”

From his office in the Wynwood district, Karp explained his work renovating the Surf Club in Surfside (a few blocks north of the collapsed Champlain Tower). The complex, completed in 1930, hosts a Four Seasons hotel, restaurant, spa, and residences. Karp had to preserve the historic structure and bring it up to code, which meant developing a new substructure to channel water away and using new materials to withstand hurricanes. In the process, the building was reimagined from a gated, private space to a historic building open to the public. “Before, it was an exclusionary private club,” Karp said. “We added a hotel function, which not only allowed us to be more financially efficient, but also it became more coherent to the community.”

The Surf Club in Surfside, Florida, was redesigned to become a more public space and to withstand hurricanes.

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Architect Kobi Karp points out the design features of the renovated Surf Club.

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As the needs of Miami residents evolve and the picture of the future under climate change grows sharper, architects, engineers, and city planners will have to regroup to anticipate what lies ahead and raise the bar for adaptation. That often proves to be as difficult as withstanding hurricane-force winds or a dozen feet of storm surge. “We are reactive. Our culture, our communities are reactive. The planning is very poor,” Borges said. “And so the proactive planning for these things, I have found it to be very inefficient, and very inadequate.”

Navigating climate change in Miami won’t be easy, or cheap

The most well-designed house or office tower doesn’t amount to much if the streets are flooded, electricity is cut off, or drinking water is contaminated. Miami is the only major metro area in the US that uses large numbers of septic tanks, which serve more than 100,000 homes and businesses. When the county floods, sewage reaches the surface, killing wildlife and sickening residents. Miami is also running out of places to store its waste, and a fire earlier this year shut down its main trash incinerator.

Miami-Dade has already spent more than $1 billion on water and sewage systems under Mayor Daniella Levine Cava, who took office in 2020. According to one proposal, cleaning up septic tanks would cost $4 billion. The City of Miami’s stormwater master plan — comprising pumps, sea walls, pipes, and injection wells — is projected to cost $3.8 billion over the next four decades. The city also issued a $400 million bond to fund resilience projects, but has yet to fully allocate the money. “Even when we have the funds available, we don’t have the staff to deploy that capital,” said Aaron DeMayo, an architectural designer and urban planner in Miami.

The Five Park condominium tower in Miami Beach will be 518 feet tall when completed.

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Massive city-wide engineering efforts do have precedent. Faced with relentless mud and a cholera outbreak in the 19th century, Chicago began to lift its buildings up. Over 20 years, using screw jacks, Chicagoans raised buildings from 4 to 14 feet to make room for sewers beneath. The city also reversed the flow of the Chicago River to keep pollution out of Lake Michigan, its main source of drinking water.

Lake Michigan, however, isn’t rising or reaching hot-tub temperatures like the Atlantic Ocean, so Miami is still in uncharted waters when it comes to the pace and the scale of the shifts it must endure. DeMayo published his own proposal to build a region-wide network of levees, locks, green spaces, and barriers, effectively gating Biscayne Bay between Miami and Miami Beach to protect their respective shorelines from tides and storm surges.

And while many local officials, engineers, and architects think Miami can withstand the perils of a changing climate, a growing number of insurers think it can’t. This year, NOAA has tabulated five weather disasters that hit Florida and caused billion-dollar damages across states in the region. Early damage estimates for Hurricane Idalia are already in the tens of billions. It’s proven too much to bear for insurance companies like Farmers, which pulled up stakes in Florida earlier this summer, citing growing disaster risks across the state. Others like AAA have decided not to renew some insurance policies.

Another part of Miami’s challenge is political. Though neither of the two Floridians running for president say they believe that humans cause climate change, local officials are taking these problems seriously. Miami-Dade is part of the Southeast Florida Regional Climate Change Compact, working with three other counties to collaborate on overcoming the problems stemming from climate change and to chalk out the future. In 2021, Miami-Dade County named Jane Gilbert to be its chief heat officer, the first such position in the US.

But the pitch of limited government regulations runs counter to the need for strict building code enforcement. “This makes a huge difference in whether a building can withstand an intense hurricane or avoid flood damage,” said Eddie Seymour, a principal at Flux Architects in Miami. “Codes on the west coast of Florida are less stringent and it showed during Hurricane Ian last year.” That’s part of why Ian was the deadliest hurricane to make landfall in the mainland US since Hurricane Katrina in 2005.

Miami is also facing many of the same challenges of other metropolises: a shortage of affordable housing, outdated infrastructure, inadequate public transportation, inflation, and a slower than expected return to offices following the Covid-19 pandemic. These forces could reshape the makeup of the region before the rising waters will.

Miami’s shoreline is a powerful draw to the city and a major threat.

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Climate resilience efforts also need to extend beyond luxury shoreline properties to low- and mid-income areas, but adaptation expenses in the public and private sector are often passed down to residents, contributing to rising housing prices. That threatens to widen Miami’s rampant wealth inequalities, or create a situation where the people with the least means end up living in the most vulnerable neighborhoods.

All this adaptation effort is for naught if the world doesn’t address the core of the problem, humanity’s biggest uncontrolled experiment: rising greenhouse gas emissions from burning fossil fuels that are heating up the planet.

So from Miami’s grand climate change resilience experiment, one result is already clear: “There’s no one big fix,” said Murley, the Miami-Dade’s resilience officer. “You have to have a demonstrated commitment across everything that you do.” It’s a lesson every city by the sea would do well to heed as they all become laboratories for learning to survive a world unlike anything they’ve experienced before.