Despite warnings from scientists, rising sea levels still seem little more than a distant, imperceptible threat, a phenomenon whose change is measured in centimeters over decades.
Nowhere is that reflected more than in peninsular Florida, where cities and counties continue to approve hundreds of luxury homes, hotels and condos on exposed barrier islands and slowly receding coastlines.
In the past two years, though, widespread flooding from Tropical Storm Debby and Hurricane Sandy has prompted a growing realization among planners that government agencies can no longer ignore rising sea levels, which scientists warn will result in destruction of habitat, loss of farmland, increased salt-water intrusion and more severe and frequent flooding.
In Hillsborough County, officials from the Tampa Bay Regional Planning Council are working with researchers from the University of Florida and hoping to prove that investing in preventive planning will save millions of dollars in flood mitigation in years to come. In South Florida, Broward, Miami-Dade, Monroe and Palm Beach counties have formed a compact to collaborate on planning and responses to rising seas and extreme weather.
Pinellas County officials recently began a study to identify what parts of the county are most vulnerable to sea-level rise.
“From there, we’ll begin to see what Pinellas County government can do to address the vulnerabilities that affect the service we deliver and the infrastructure of the county,” said Larry Arrington, the county’s director of strategic planning and initiatives.
Counties and cities are still a long way from adopting politically difficult policies such as restricting development in coastal areas. In fact, the North Carolina General Assembly last year passed a bill prohibiting state planners from considering rising sea levels in coastal planning.
Nevertheless, the recently released report from the National Climate Assessment and Development Advisory Committee warned that state and local governments in coastal areas need to start preparing for the effects of climate change, particularly rising sea levels.
“You can see they are encouraging all levels of government to begin studying the issues better as they impact on a local basis,” said Arrington.
Sea level rise is not new. Worldwide, the mean sea level has risen by about 3.5 inches since the 1950s, said Don Chambers, an associate professor in the College of Marine Science at the University of South Florida St. Petersburg and an expert on the physics of sea-level rise.
Scientists are predicting that the melting of glaciers and of ice shelves in Greenland and Antarctica from global warming will accelerate that process, said Chambers.
Estimates of how much the sea will rise vary, but even conservative projections point to mean sea level rising by about 3 feet by the end of the century, Chambers said.
That may sound far off, but the effects will likely be felt much sooner.
Higher tides will accelerate erosion of beaches and the deterioration of sea walls, raps and groins. Salt water will penetrate deeper into groundwater, making freshwater springs undrinkable and causing more backflows of sewage systems.
Flooding from storm surges and high-tide events will become more frequent, too.
“It’s not going to be an isolated event,” Chambers said. “It will be every single year.”
Sea-level rise would seem to be a global problem and beyond the resources of local governments to solve.
However, researchers at the University of Florida’s College of Design, Construction and Planning are working on strategies that coastal communities can adopt to limit damage and ensure essential services continue to operate.
The study upon which Pinellas officials have embarked is a necessary first step to identify the schools; roads; hospitals; infrastructure, such as sewers and water plants, and emergency-service providers that are most vulnerable, said Zhong-Ren Peng, a University of Florida professor of urban and regional planning.
After that, the decisions get difficult.
As the threat of flooding becomes more apparent, coastal communities will have to make decisions about which areas of the coastline will need to be protected, he said.
Coastal communities may have to designate coastal land as not suitable for development, despite the wishes of land owners.
Cities and counties could even be forced to buy back properties in vulnerable areas, Peng said. That could be cheaper than continuing to provide utilities and services in flood-prone areas.
Peng is one year into a project centered on the Tampa Bay region, examining the economic impact of sea level rise. He also hopes to produce a model to help government agencies calculate whether investment in infrastructure such as sea walls and the loss of revenue from limiting coastline development will save money in the long run.
“In the end, it [local government] has the authority to do coastal planning and zoning,” he said. “[The] federal government will not micromanage it on that level.”
Making the changes necessary to protect communities from sea-level rise likely will be a hard sell.
Counties and cities would lose out on potential property tax revenues in the short-term if they limit development. Developers and businesses that benefit from tourism are likely to fight zoning changes that block coastline development, a concern that was reflected at a recent Pinellas County Commission meeting.
“We want to still make sure that we create jobs and we have economic development,” said Commissioner Karen Seel. “If you’re putting the word out there that the sky is falling down and we’re going to sink into the ocean, it has an impact on our tourists and it has an impact on our economy.”
In the wake of Hurricane Sandy, a few larger cities have already begun taking steps to protect services from severe weather events, said Kathryn Frank, an assistant professor in the department of urban and regional planning at the University of Florida.
That includes New York, which is paying for subway improvements to prevent a repeat of the flooding from Sandy that ground many subway lines to a halt.
So far, though, most coastal communities have yet to spend significantly on mitigating sea-level rise, Frank said.
That may only change when repeated flooding and other damage makes coastal development no longer viable.
“We have been doing things that increase our vulnerability for a financial gain,” she said. “At some point it will be very difficult to afford it the costs will become more apparent.”