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TAMPA BAY, Fla. — Mark Luther’s dream home has a window that looks out to a world of water. He can slip out the back door and watch dolphins swim by his private dock. Shore birds squawk from nearby nests in giant mangroves.

He said it’s hard to imagine ever leaving this slice of paradise on St. Petersburg’s Bayou Grande, even though the water he adores is starting to get a little creepy.

Over the 24 years since he moved into the house, the bayou has inched up a protective sea wall and crept toward his front door. As sea level rises, a result of global warming, it contributes to flooding in his Venetian Isles neighborhood and Shore Acres, a neighboring community of homes worth as much as $2.5 million, about 70 times per year.

“Why stay?” asked Luther, an oceanographer who knows perfectly well a hurricane could one day shove 15 feet of water into his living room. “It’s just so nice.”

Tampa Bay is mesmerizing, with 700 miles of shoreline and some of the finest white sand beaches in the nation. But analysts say the metropolitan area is the most vulnerable in the United States to flooding and damage if a major hurricane ever scores a direct hit.

A Boston firm that analyzes potential catastrophic damage reported that the region would lose $175 billion in a storm the size of Hurricane Katrina. A World Bank study called Tampa Bay one of the 10 most at-risk areas on the globe.

Yet the bay area — greater Tampa, St. Petersburg and Clearwater — has barely begun to assess the rate of sea-level rise and address its effects. Its slow response to a major threat is a case study in how American cities reluctantly prepare for the worst, even though signs of impacts from climate change abound all around.

State leaders could be part of the reason. Republican Gov. Rick Scott’s administration has reportedly discouraged employees from using the words “climate change” in official communications. Last month, the Republican-controlled state legislature approved bills allowing any citizen to challenge textbooks and instructional materials, including those that teach the science of evolution and global warming.

The sea in Tampa Bay has risen naturally throughout time, about an inch per decade. But in the early 1990s, scientists say, it accelerated to several inches above normal, so much that recent projections have the bay rising between six inches and more than two feet by the middle of the century and up to nearly seven feet when it ends. On top of that, natural settling is causing land to slowly sink.

Sea-level rise worsens the severity of even small storms, adding to the water that can be pushed ashore. Hard rains now regularly flood neighborhoods in St. Petersburg, Tampa and Clearwater.

(Zoeann Murphy/The Washington Post)

By a stroke of gambler’s luck, Tampa Bay hasn’t suffered a direct hit from a hurricane as powerful as a category 3 or higher in nearly a century. Tampa has doubled down on a bet that another won’t strike anytime soon, investing billions of dollars in high-rise condominiums along the waterfront and shipping port upgrades and expanding a hospital on an island in the middle of the bay to make it one of the largest in the state.

Once-sleepy St. Petersburg has gradually followed suit, adorning its downtown coast with high-rise condominiums, new shops and hotels. The city is in the final stages of a plan to build a $45 million pier as a major attraction that would extend out into the bay.

Worried that area leaders weren’t adequately focused on the downside of living in a tropic, the Tampa Bay Regional Planning Council reminded them of the risks by simulating a worst-case scenario hurricane, a category 5 with winds exceeding 156 mph, to demonstrate what would happen if it entered the Gulf of Mexico and turned their way.

The fictitious Phoenix hurricane scenario projects that wind damage would destroy nearly half a million homes and businesses. About 2 million residents would require medical treatment, and the estimated death toll, more than 2,000, would top the number of people who perished from Hurricane Katrina in Louisiana and Mississippi.

Florida’s most densely populated county, Pinellas, could be sliced in half by a wave of water. The low-lying county of about a million is growing so fast that there’s no land left to develop, and main roads and an interstate connecting it to Tampa get clogged with traffic even on a clear day.

“If a hurricane 4 or 5 hit us,” St. Petersburg City Council Chairman Darden Rice said, referring to the two highest category storms, “there’s no doubt about it. The plan is you’d better get out of Dodge.”

Tampa Mayor Bob Buckhorn’s warning was even starker. Standing outside City Hall last year, he described what would happen if a hurricane as small as a category 3 with 110 mph to 130 mph winds hit downtown.

“Where you’re standing now would be 15 feet under water,” he said.