How huge parts of the US could become uninhabitable within decades — even so-called ‘climate havens’

The United States is no stranger to extreme weather, but the accelerating effects of climate change are pushing some regions closer to the brink of uninhabitability. From oppressive heat in the Southwest to rising sea levels and storm surges along the coasts, the challenges are diverse, daunting, and interconnected.

Masada Siegel, a consultant for FEMA and emergency management organizations, knows this reality well. A Phoenix native and mother of a 9-year-old son, Siegel has seen her hometown transform into a hostile environment. Last summer, Phoenix experienced 113 consecutive days over 100°F, the longest streak ever recorded. The average temperature that month was 97°F.

“In the summer at 116 degrees, you’re not laying out by the pool,” Siegel says. “You’re either in the pool, indoors, or in the shade. And then at a certain point, the pool is so hot, it feels like you’re in soup.”

Phoenix saw just 4.54 inches of rain last year — 2.52 inches below normal — and the lack of precipitation, as well as the increased heat, has thrown seasonal rhythms out of sync: “I have a lemon tree that’s flowering in January. My lime tree is flowering in January. They’re not supposed to flower until springtime.”

The changes aren’t just inconvenient; they’re impacting quality of life and mental health. “In Arizona, people get depressed in the summer, just like people in New York get Seasonal Affective Disorder in the winter,” Siegel adds. Many Arizonans now spend most of the summer indoors, and chronic Vitamin D deficiencies are becoming more common — especially in the south of the state — as a result.

Mikhail Chester, a climate adaptation and infrastructure expert from Arizona State University, highlights the long-term consequences of these changes. “Will things get worse? Yes, they will. I mean, we’re already seeing that,” he says. One of the simple reasons why things will get worse is because we haven’t immediately solved the climate change problem, and we’re still behaving in the same way we’ve done for decades: “So I drove my kids to school today in a gasoline car and I put CO2 into the atmosphere. And that will be there for 100 years.”

Too Hot to Handle: The Southwest

Phoenix isn’t the only city in the Southwest grappling with extreme heat and water shortages. Las Vegas and Los Angeles are also feeling the strain as the Colorado River — a lifeblood for millions in the region — shrinks due to rising temperatures, overuse, and a lack of snow migrating down from the Rocky Mountains. Without drastic changes to water management and conservation, these cities could face unsustainable conditions in the decades ahead.

This particular problem is urgent, as the current agreement about how to divide up water usage from the river ends in 2026. The river is not just used for water for desert households in Nevada and California; a lot of vegetation is grown using the water from the Colorado River — meaning that grocery prices could skyrocket if it’s cut off as a source.

Chester emphasizes that the cost of inaction is far greater than the cost of taking meaningful steps today. “If we allow these large-scale disasters to play out, the costs are significantly larger than mitigating emissions and, over time, mitigating the disasters and the cause of those disasters. That’s the conversation we need to be having.”

Too Old to Rebuild: New York

“Phoenix is a new city and New York is an old city, and I think that’s a really important starting point,” says Chester. “Phoenix is still growing out. New York is not, New York is mature.” That means New York City has infrastructure that was “in no way designed for the extremes of today,” and is too built-up to solve that problem.

That means that even though cities like Phoenix are experiencing more extreme weather right now, it’s also “much more appropriately designed for our extremes,” Chester adds, so “we tend to have fewer failures. We tend to have better reliability of our services.” Asphalt mixtures have been more thoughtfully designed. Power lines run underground, rather than through the air like in New York, where they are more vulnerable to being taken out by wind during a violent storm.

Over the next 20 years, some parts of New York and New Jersey may become uninhabited simply because the cost and stress of rebuilding partially destroyed infrastructure from flooding is no longer worth it to the residents.

Chester adds that this holds true for a lot of the U.S., particularly on the east coast, where infrastructure was first built: “Most major infrastructure systems in the United States were deployed right around the middle of the last century. Well, you know, here we are, it’s 2025, and they’ve gone through their initial lifespans. We’ve Band-Aided them together for another 20 or so years, and we just can’t keep Band-Aiding them anymore… They’re basically at the end of their first lifetime.”

Leave this creaky infrastructure in place as climate change gets worse, and Manhattan could be fully underwater by 2300. Several cities in Florida, including the entirety of the Everglades, would be looking at the same fate by 2050.

The problem is that existing systems need updating and new systems need to be built to address climate change. And there doesn’t seem to be the will to do both: “You already have, as a backdrop, these systems that need major reinvestment. And there’s not the money out there to keep them going.”

Considering that natural disasters are becoming more common and we’re on a road toward that reality anyway, the best way to protect vulnerable coastal areas might be to work with the extreme weather, rather than against it. For instance, New York is building an armored dune across the Rockaways, and considering a $119 billion sea wall to protect lower Manhattan. Scottsdale, Arizona, considered implementing a similar structure to funnel water away from the city with solid concrete during the monsoon season a decade ago, but the residents rejected the idea, saying that it would be an eyesore. The city ultimately chose to build a series of parks and recreation areas instead.

Recently, researchers found that the abundant grass and vegetation in the new parks had actually managed to absorb more of the water than the planned concrete structure. Those who had championed the funnel had been blinded by the idea that nature could be defeated, rather than worked alongside — and we’re simply too far down the line to think that way now.

Rising Waters and Contamination in Florida

In Miami, sea-level rise and worsening hurricanes are creating a perfect storm. Streets regularly flood during “king tides,” and saltwater intrusion is threatening the city’s drinking water supply. As storms grow more intense, the cost of rebuilding — and the toll on residents — will continue to rise.

“In the Pacific Palisades, many people will be able to simply rebuild their homes without insurance,” Chester says of the recent fires that swept through Los Angeles. “Whereas in other parts of the US, people can’t afford to rebuild their home, should they have no insurance… Those dynamics will unfold and will absolutely be part of the financial calculus or where we choose to invest and where we choose not to. You’re starting to see states get more serious about where they encourage and discourage development.”

States like Florida will be at the forefront of this conversation, and will need to start spending significant amounts to protect their residents — but it’s unclear if the political will is there. That’s especially alarming considering that Miami is experiencing a boom in population and development, despite the fact that Miami-Dade County is set to become 60 percent submerged in the next 25 years.

Who Pays?: California’s Wildfire Problem

California’s wildfire season has grown longer, hotter, and deadlier, fueled by a combination of drought, extreme heat, and poor forest management. The fires aren’t just burning homes and landscapes; they’re also choking communities with smoke. Siegel, who covered the September 11 attacks and saw firsthand the long-term health effects on first responders, fears a similar epidemic could emerge among California firefighters and residents.

“I’m worried the firefighters working in California will develop lung problems from the air quality, just like we saw with 9/11 first responders,” she says.

Wildfires also contribute to a dangerous feedback loop — fires release massive amounts of carbon dioxide, which accelerates warming, which in turn makes conditions even more favorable for fires.

Again, it comes back to money. “Who pays?” says Chester, when talking about the damage caused by the most recent wildfires across the Pacific Palisades. “California is now laying bare the question. Is it the insurance company that pays? Is it the state or the federal government that pays?… And there’s no answer to these questions yet.”

“You’re gonna see the tension between states and insurers,” Chester adds. “They’re for-profit companies. So how are you gonna navigate this and tell them they have to insure under certain conditions if their business is maximizing profits? We’re about to see this discourse and tension play out.”

Many climate scientists are pessimistic about how this discourse might go, with one predicting that Los Angeles will simply hollow out and become “the world’s first ghost megalopolis” when — after the next decade or so of continued weather-related disasters — insurers refuse to protect housing in the area at all.

What Money Can’t Buy: Water Woes in the West

As water supplies dwindle, many western coast areas may find themselves forced to make hard choices about what’s sustainable. The cost of hauling water across vast distances could become prohibitive, driving people to leave — not because of the heat but because of the cost of survival.

One satellite community in Arizona already experienced this. Rio Verde Foothills, a suburb of Scottsdale, sued the city in 2023 after it cut the affluent community’s water off entirely. Extreme drought led Scottsdale to do so after it argued it needed the water to supply its own residents and couldn’t continue allowing private water trucks to deliver water to the wealthy Rio Verde community who had built their mansions in the nearby hills.

The Western United States faces sharp drops in rainfall by the 2050s

^{Map showing projected rainfall change in mm by the 2050s. Red areas will see decreased annual rainfall. Credit: The Revelator / Dipika Kadaba / CCAFS projections}

After a 10-month battle, water was brought back to the 500 households whose water supply had been suspended. The residents now have a shaky agreement with the Canadian water company EPCOR, whose new $10 million standpipe will take water from the Verde River. The agreement ends in December 2025.

The problem, as Masada Siegel sees it, is that people keep moving to Arizona — 250,000 in the past year alone — and building communities like the Rio Verde Foothills, despite the fact that the state’s infrastructure is now struggling to absorb them. Eventually, even extremely rich residents will find that there are some things money can’t buy.

Too Cold: Arctic Blasts in Chicago

While heat is the dominant threat in the southern U.S., extreme cold events are a growing concern in the Midwest. Cities like Chicago have experienced record-breaking cold snaps caused by disruptions in the polar vortex. These sudden, intense freezes strain energy grids, endanger lives, and make everyday life perilous.

Although winters in general will trend warmer in the Midwest due to climate change, this disruption of the temperature between such areas and the North Pole allows freezing air to travel downwards and suddenly dump vortexes on places like Chicago. That’s why the Midwest in general will see less severe cold day-to-day in the winter, but more severe cold events that suddenly take down infrastructure and threaten lives.

Of course, rising temperatures in general will also mean hotter summers in cities that were built to insulate heat rather than to keep it out — and flooding will be a problem, too. Chicago, which is built on a former swamp, could begin to sink with enough flooding.

The Midwest is particularly important to consider because it’s often thought of as a “climate haven” or “climate refuge” — somewhere people can depend upon to be less affected by global warming. The idea that northern or midwestern states and cities can function as little havens among the climate chaos is outdated and now generally thought of as wrong, most experts say today.

Air Quality and Geopolitics: Why You Can’t Just Move to Vermont

For many Americans, the idea of relocating to escape climate impacts seems appealing in theory but impractical in reality. As Siegel puts it: “Would I move somewhere? It was 116 degrees in October [in Phoenix]. But the problem is, my sister came to visit from Florida, and Florida’s hot too. So, where do you go? Wildfires in California, [air quality problems] in New York… You can’t just run somewhere.”

Even if northern states like Vermont or Minnesota seem like safer havens, mass migration isn’t a realistic solution for the millions of people in at-risk areas, she adds: “Not all the millions and millions of people in the southern parts of the United States are gonna be able to do that.”

Chester agrees, and cautions against the narrative that suggests simply moving north can solve people’s problems: “I’ve seen the studies that show certain areas are less risky than others — Minnesota looks great, or whatever… but then you get these massive Canadian wildfires that dump terrible air quality on the northern U.S. for prolonged periods of time. There’s no insulating yourself from these risks. The geopolitical boundaries that we often default to, to think about how we make decisions are not relevant when it comes to air quality.”

Stuck Between Threats: Nowhere to Run

There is “a time for retreat” in certain, extreme circumstances, Chester adds — but that shouldn’t be the first port of call. Instead, we should start accepting that some disasters will happen, and rebuild around that fact.

In New York City, for instance, “you can’t rip out everything and put in new infrastructure for a hundred different reasons,” he says. “So you are going to experience flooding and failure. And you need to mitigate those consequences.” That means accepting that floods will happen and telling communities how to deal with it — for instance, reaching out to diabetic people to educate them on how to refrigerate insulin when you don’t have power. And where infrastructure can be altered — where sewer lines can be widened, or power lines can be moved underground, or critical parts of a building can be moved to higher floors — then it should be.

“The costs of failure are way more than the cost of doing something about it,” Chester adds. “You can’t turn away from, for example, the LA wildfires or New York City flooding and say there’s no cost to those events playing out. The costs are astronomical.”

For Chester, climate action isn’t just about economics; it’s about setting an example. He put solar panels on his house — not necessarily to save money but to send a message to his children. He wants them to know “this is something we do. This is important,” he says.

Chester underscores the personal stakes of taking action now: “If my kids — three, five, and seven — live to the average age, they should be alive at 2100 at the end of the century. The decisions that we are making today will set them up for success or failure on the planet.”

For Siegel and her family, moments of joy still emerge, even amid the challenges. “When it did rain a few months ago, my son went out onto the patio and started making rain angels… When it rains, we go outside and play in the rain ‘cause we’re so happy that it’s raining.”

But those fleeting moments underscore the urgency of action. Siegel adds: “In Arizona, when it rains, it’s the top story. Everyone’s excited.” A climate future where rain is rare and heat is unrelenting isn’t just an Arizona problem — it’s a global one. And when it happens, the communities affected won’t have the luxury of saying their politics precludes them from believing it.