While you were worrying about rising sea levels…

Milder winters may also affect the territorial range of vectors — how far north different kinds of mosquitoes are able to survive.

Currently in southern Florida, “we have about a dozen species of mosquitoes that are not found farther north than the Everglades,” said Burkett-Cadena. “Many of these species are vectors of human pathogens.”

As winters grow milder further north, more of the Florida peninsula will become hospitable to these disease-carrying mosquitoes, Burkett-Cadena added.

Choosing to be prepared or unprepared

Historically, one consistently important factor in the spread of illnesses is the way human activity has interacted with the disease landscape – from the elimination of wetlands for agriculture several hundred years ago to the building of public health infrastructures in the modern age. The former destroyed breeding habitats for mosquitoes on a massive scale, functionally getting rid of entire species. The latter developed systems to monitor, fend off, and treat disease, ranging from simple measures like window screens to intricate systems for controlling mosquito populations, to hospitals ready to identify and react to disease outbreaks. 

Whether public health and other health care infrastructure is adequately funded will prove, scientists say, to be a critical determinant of how the consequences of a changing natural environment affect residents of the state.

Kevin Lafferty is a research ecologist with the U.S. Geological Survey who has cautioned that, rather than leading to blanket increases in disease, climate change may cause the incidence of some disease to decrease in some places. But Lafferty, too, thinks that public health readiness is ignored at society’s peril: “There are obviously going to be direct relationships between how we choose to invest in public health and the risk of infectious disease,” Lafferty said.

Independent of the complicated factors that Lafferty believes determine changes in the baseline risk of disease, he is certain on one point: across the board, risk will be worse than it otherwise would be in the absence of adequate investment in public health.

A real estate nightmare

Increased health problems are serious enough. But those problems have typically gone hand in glove with depressed real estate markets.

In 1997, the population of Churchill County in Nevada began to see an abnormal rate of pediatric leukemia. Lucas Davis, now an economics professor at the University of California, Berkeley studied the county and found that the health risk led to a significant decline in housing prices.

Davis and other experts interviewed by Remapping Debate agreed that a scenario in which communities in Florida become associated with disease outbreaks is analogous to other instances in which public health concerns, like proximity to toxic waste sites or power plants, put a dent in local real estate markets.

Davis noted that, for this to take place, individual outbreaks would need to be seen as part of a longer-term pattern. “If something really changes and all of a sudden some threshold is passed, and that really changes the risk in a community, then you could see an immediate, substantial impact” on housing values, he said.

Still, the threat of disease need not be incontrovertible to deliver a blow. Davis recounted how, in cancer clusters he’s studied, officials from the Center for Disease Control (CDC) would hold meetings to assure the population that the disease rates were a statistical anomaly and not an actual risk. Yet people remained skeptical.

“I think a reasonable thing the CDC gets asked at these meetings is, ‘Well, would you move your family to this community?’” Davis said. “The evidence does not have to be 100 percent verifiable for it to have impacts on perceptions and thus housing values.”

“It’s going to be about perceptions”

The key lies in people’s “demand functions” — the various factors that go into their assessment of how desirable a given location is as a place to live. One factor that could prove especially significant in Florida relates to the second-home market. If an increase in disease causes those seeking escape from wintertime cold to think twice about coming to Florida, they could easily substitute other destinations, thus causing a steep drop in Florida’s market for second homes.

“It’s going to be about people’s perceptions,” said Katherine Kiel, chair of the Department of Economics at the College of the Holy Cross in Massachusetts. “’How risky is it for me to move there? What other options do I have?’ If I’m pretty much indifferent between going to Florida and Arizona, and suddenly Florida has this other negative externality, I’m going to Arizona.”