"Once you exceed the 50 per cent threshold, you begin to lose working families and working households,'' Murray said. ``We already see it: A decline in working families, a decline in Miami-Dade in owner households in certain income categories.''
Regardless of income or wealth, everyone with a stake in South Florida faces the potentially dire consequences of climate change. Locals have grown accustomed to the flooding that submerges low-lying intersections and sidewalks on sunny days. Experts warn that as the seas rise further, flooding may become permanent, turning streets into canals, endangering access to drinking water and eroding the man-made beaches that have long drawn people to Miami.
"There is a disconnect - there's a real estate bubble, and then there's where we see sea level rise going,'' said Henry Briceno, who studies the effects of rising sea levels through the Southeast Environmental Research Center at Florida International University. ``That's what really worries me: The rush to make money right away without thinking of the future and who is going to pay.''
Yet to many wealthy international buyers, the opportunities appear to outweigh those risks.
Because so many of her clients now own Miami property, Sao Paulo-based interior designer Brunete Fraccaroli recently bought a condo at One Paraiso, a 53-story tower with a beach club slated to be finished next year. She expects her Florida clientele to grow as Brazil's plight intensifies.
Analysts say the South American country may be headed for its longest downturn in more than a century. Operating losses and labour strikes have battered the state oil company, Petrobras. Government spending cuts have failed to curb the deficit. Political corruption has left the country in chaos.
"We think that the Brazilian real is going to drop more and more - it's going to be worse,'' said Fraccaroli, who also stars in her country's reality TV show ``Rich Women.''
The influx of rich foreigners has led to changes in sales at foreign-owned businesses with Miami outposts. One is Artefacto, a high-end furniture maker with multiple outlets in Brazil and Miami. CEO Paulo Bacchi said he sees his customers buying furniture for larger homes compared with prior years, which suggests to him that they plan to stay in Florida longer. It's a point echoed by other business people who say tourists are now staying for months instead of weeks.
For some transplants from South America, there's also a welcome lifestyle change. They can flash their wealth in Miami instead of hiding it for fear of criminals, expatriates say. Women can wear their diamonds instead of burying them in their purses. Bulletproof cars are no longer necessary.
"Every single city in South America - there is a basic problem of safety on the streets,'' Bacchi said. ``Here in Miami, you can drive convertibles.''