Over Our Heads?

By Craig Pittman Photography by Ted Mase January 1, 2009

asset_upload_file883_31571.jpgThe evidence is there. You can’t see it while sunbathing on Siesta Key’s sugary sands, or searching Venice Beach for shark’s teeth, or strolling around St. Armands Circle. But it’s there.

The sea level is rising. Slowly but surely, day after day, it’s creeping a little higher, and it’s changing the way everything in Florida looks.

There’s no question it’s happening. The question is: What are you going to do about it? That’s a question of greater urgency for residents of the Sarasota-Bradenton area than anywhere else in the Southeast. It’s especially relevant for the folks driving up and down U.S. 41 and 301.

Take this step by step. Start with Ernie Estevez out at Mote Marine Laboratory.

Estevez, a Tampa native with a Ph.D., has worked at Mote Marine Laboratory since 1979. He doesn’t need to look for clues along the beach near his office on Sarasota’s City Island. He’s seen the evidence in the tidal charts.

People have been recording the highs and lows of Florida’s tides since the 1930s. In some places, like the Keys, the record goes back even further, to the 1800s. Put all the high tide lines on a single chart, and they climb a jagged path upward, like a tricky mountain trail that grows more treacherous as it scales an unseen peak. The lines show that, over the past seven decades, Florida’s high tides have crept higher, ever higher.

This is not some theory that can be debated, says Estevez. The charts are an authentic, documented record that the sea level is rising, and has been for some time. In some places around the state, Estevez says, it’s been a mere two inches a century. In others, though, it’s nearly a foot a century.

“Eight inches a century—that’s the average,” says Estevez, a former president of the Florida Academy of Sciences who has been writing about the rising sea level since the early 1990s. “The average is pretty reliable.”

Sea levels have risen and fallen around Florida for centuries, spurred by natural geological shifts. At Little Salt Spring, a picturesque natural pool in North Port, archaeologists diving down 40 feet find ancient relics from the humans and animals who once visited the pool for a cool drink. The location of the spear points and mastodon teeth shows that 10,000 years ago, Florida’s sea level was much lower—30 or 40 feet below where it is now.

But now the rate of the sea level’s rise is increasing beyond what the natural rate would be, and that puts Florida—and the 80 percent of the population living near the coast—right on the front lines for dealing with climate change.

Gary Mitchum is a soft-spoken University of South Florida professor who monitors satellite readings worldwide. The satellites log the high and low tides across the entire surface of the earth. "Then we can add it up and average it," Mitchum explains.

Over the past 50 years, the global average for sea level rise is about two millimeters a year, Mitchum says. That works out to seven-hundredths of an inch a year. But in the past 15 years, he adds, "We’re seeing rates that are more like three millimeters." In other words, the worldwide rate of sea level rise has increased to more than a tenth of an inch a year.

"Now the question becomes, are we seeing a natural fluctuation in the system, or is it manmade?" Mitchum says.

In other words: Is this a sign of global warming? Although some members of Congress disagree, the majority of scientists say yes—and humans are the cause. An international panel of scientists affiliated with the United Nations (the group that shared the Nobel Peace Prize with Al Gore) has agreed that humans are changing the climate. President George W. Bush asked the National Academy of Sciences to double-check the U.N. group’s conclusion, and the academy agreed with the U.N.

Since then, the heads of science academies in more than 10 other countries have chimed in, too, signing a letter urging the world’s leaders to take global warming and sea level rise seriously. The National Oceanic and Atmospheric Administration (NOAA for short) as well as the National Aeronautics and Space Administration and the Environmental Protection Agency all agree that it’s happening.

Here’s the short course on global warming: Greenhouse gases such as carbon dioxide trap the sun’s heat in the atmosphere, altering the climate. Some projections say the temperature worldwide will rise by 2.5 degrees Fahrenheit to 10.4 degrees Fahrenheit by the end of this century. It’s already begun. The annual average temperature in the Southeast has risen by 2 degrees Fahrenheit since 1970, NOAA says.

To find the cause, you have to look to the 1800s. Prior to the start of the Industrial Revolution, the amount of carbon dioxide in the atmosphere was about 280 parts per million by volume (ppmv). The breathing of animals and humans produced most of the carbon dioxide in the atmosphere. That amount of carbon dioxide could be balanced out by trees and plants that absorbed it and produced oxygen.

But with the advent of coal-fired factories—followed by the rise of the internal combustion engine and the proliferation of cars and trucks—that all changed, producing more carbon dioxide than the globe’s plant life could absorb. The current level of carbon dioxide in the world’s atmosphere is now greater than 380 parts per million by volume, and it increases every year.

A 2008 study by the Brookings Institution blamed some of the increase on suburban sprawl and limited public transportation. Each of those puts a lot more cars on the road, all of them spewing greenhouse gases. The think tank ranked the carbon footprint of the nation’s top 100 metropolitan areas, and the report produced a nasty surprise: The Sarasota-Bradenton-Venice metropolitan area produced more greenhouse gases per person than anywhere else in Florida, more than Miami, Jacksonville or Tampa-St. Petersburg. It even surpassed far more populated areas such as Atlanta and New York.

The source of those emissions: homeowners’ power usage—cranking that air conditioner, for instance—and all the cars and trucks clogging the highway.So how does a traffic jam on U.S. 301 help create a global crisis that threatens to submerge Florida?

The answer is twofold. The first part is easy: Heat melts ice. As the temperature rises, mountainous glaciers in Greenland, Iceland and other cold locales melt. U.S. Geological Survey scientists have been keeping careful records of three glaciers in Alaska and Washington state for 50 years, and in August announced that their observations show all three have been melting faster than they should be, all because of climate change. All three have shrunk by the greatest margin during the past 15 years.

As the frozen water that was above the sea turns liquid and flows downhill, it raises the world’s sea level. But that’s not the main cause of sea level rise.

The bigger factor is something called "thermal expansion." Water, like other materials, expands as it gets warmer. The warmer global temperature makes the upper level of the ocean warmer, too.

Last summer, NOAA scientists reported that the world’s ocean surface temperature was the warmest ever for June, breaking the previous high mark set in 2005. The global temperature records date back to 1880.

As a result, the water expands, pushing the sea level higher. "We are seeing an acceleration [of sea level rise] due to the heating of the ocean," Mitchum, the USF expert, says.Some activists trying to stir the public to take action on global warming have painted nightmarish scenarios about a rapid increase in the rate of sea level rise. They flash around maps that show whole cities inundated in a decade or so. Those scenarios go beyond what the science shows, at least for now.

At this point no one can say for sure how much the rate will accelerate. The U.N. panel of experts has predicted an increase of half a foot to 2.6 feet by 2100, but some scientists worry that that prediction is too conservative.

The wild card is how fast the Greenland and West Antarctica ice sheets melt. Computer models showing how fast those ice sheets would turn to liquid have proven to be far too conservative. They’re melting faster than expected.

For now, Florida State University scientists estimate that the sea level around Florida will rise a quarter to a third of a foot in the next 20 years. That doesn’t sound like a lot—it’s less than the projections of the United Nation’s global warming experts for the worldwide average rise in sea level. But when the land is as flat as it is in Florida, even a small increase can be a problem. A one-foot rise in the sea level can cause the shoreline to move inland by 2,000 to 10,000 feet. A 2007 study by an FSU geology professor found that Florida’s beaches are already losing on average more than four feet a year because of sea level rise.

That’s bad news for anyone living on a barrier island like Siesta Key, Casey Key or Longboat Key. A rising sea erodes the sandy beaches more quickly. Beach erosion, which already costs Florida more than $600 million per year, is likely to increase.

There are additional impacts as well. As the shoreline recedes, the threat posed by hurricane storm surges increases. If the sea is a lot closer to the dwellings and stores built along what’s left of the shore, those buildings are far more likely to be swept away. That makes Florida’s 1,350 miles of coastline extremely susceptible to the effects of climate change, a fact that Gov. Charlie Crist mentions frequently in explaining his strong interest in the subject. "Florida is more vulnerable to rising ocean levels and violent weather than any other state," he said in a 2007 speech.

Some areas of Florida’s shoreline are more vulnerable than others. The rising sea is already causing profound environmental changes in wetland areas along the Gulf coast.Jack Putz got a call about the dying trees in 1992. Could he please check on what was wrong? At first Putz, a University of Florida botany professor, thought the palm trees had fallen victim to some sort of disease he hadn’t seen before.

But as he studied the problem, he made a troubling discovery. The palms at Waccasassa Bay Preserve State Park in rural Levy County were toppling over because rising saltwater from the Gulf of Mexico had crept up the beach. Now the

saltwater was swamping their roots. Without freshwater, the trees died.

As the trees die and fall over, Putz says, "You can see the forest changing to marsh." Eventually the marsh will take over, he adds, and there will be nothing left

of the wild palms but inundated stumps.

"People have a hard time accepting that this is happening here," says Putz. Seeing the dying palms of Waccasassa, he says, "brings a global problem right into our own back yard."

Something similar is happening at Rookery Bay Preserve near Naples, according to preserve administrator Gary Lytton of the state Department of Environmental Protection.

By comparing aerial photos of the area from the 1920s to what’s there now, Lytton and his staff could see how the rising sea has changed the preserve. Saltwater mangroves have slowly crept in and replaced freshwater marshes—marshes that are important habitat for a variety of bird and fish species. Without that habitat, those animals are likely to move on.

"You can see an ecological shift that’s taking place," Lytton says. "We’re beginning to lose freshwater wetland habitat."

The sea level’s rise is often difficult to detect along urban coastlines because seawalls and renourished beaches can blunt the impact or make it harder to see, says Mike Savarese, a Florida Gulf Coast University marine science professor. The impact is more obvious in undeveloped areas such as state and national parks. In those natural areas, "We’re seeing some real indications of a change out there," according to Savarese.

To study past sea level fluctuations, Savarese has been pulling out core samples from around the Ten Thousand Islands area of Everglades National Park. By using carbon dating, he can see how old the different layers are. It paints a clear picture of what has been happening, he says.

The seas around Florida have risen and fallen for tens of thousands of years, while the land itself remained fairly stable. At one point the state’s coastline lay somewhere out in the middle of what is now the Gulf of Mexico. At another point, the shore was a line of dunes along what’s now the center of the state.

The core samples that Savarese has dug out show that the sea that receded from Florida’s shores thousands of years ago is beginning to come back, naturally and slowly.

"Prior to the 1800s, the rates are fairly constant," Savarese explains. That rate varied from about 1 1/2 to three inches a century. But since the Industrial Revolution, the sea level is increasing by a rate of 15 to nearly 20 inches per century along that part of the Florida coast.

One of the most surprising discoveries is what Savarese found amid the maze of marshes and mangroves that form the Ten Thousand Islands: inland tidal pools that are "growing in size and increasing in number. They should eventually come together and form a new body of water. We’re creating a new set of bays inland of our own." Should this trend continue, Savarese says, it could lead to a scenario where "The Ten Thousand Islands drown and the coastline becomes much more open. It would create a very different kind of ecology."

If that continues, Lytton sees a clear downside for the state’s economy.

"Florida generates over $4 billion a year from sportfishing, and think about all the related businesses that tie in to that," he says. Since those fish need those disappearing wetlands for habitat, "if we begin to lose our coastal wetland ecosystems, it’s going to begin to have a serious impact."

So then the question becomes: What can Florida do about it? Al Hine’s answer is blunt: Adapt.Hine, a folksy Ph.D. from the University of South Florida, doesn’t buy the Chicken-Little scenarios. Sure, the sea is rising—but slowly. So here’s the good news: There’s still time to make changes, to figure out how to deal with the problem.

"My general message is, we don’t have to run for the hills," says Hine, a geological oceanographer with USF’s marine science program. "We’ve got some time. We don’t have to go into apocalyptic mode right now."

But we do have to take some action, he says. If we do nothing, rising sea levels are going to be a serious problem for our children or, more likely, our grandchildren, Hine says. So it’s good that scientists have figured out now what’s going on, in time for our generation to act.

Right now, everyone may be moving too slowly because they get confused about taking action on sea level rise vs. taking action on other issues. Hine says he recently was invited to join in a panel discussion of sea level rise at a Sarasota conference. He showed up armed with slides and graphs and charts about the sea level, but everyone else on the panel wasn’t prepared to talk about that topic. Instead they wanted to talk about what they were doing to cut back on producing greenhouse gases.

That’s not unusual. A Pew Center study in 2007 found that hundreds of cities across the United States were drawing up plans to deal with climate change, but most were focused only on trying to reduce their carbon emissions. Few were looking at how to deal with the rising sea.

While Florida law attempts to prod local governments into planning for the future, nothing in the law requires addressing the impact of sea level rise. A survey by FSU found that most coastal communities don’t look beyond 10 years down the road—not a sufficiently distant horizon to be alarmed by such a slow-moving threat.

The study found that "sea level rise is not on the menu of immediate concerns" by government planners, and that situation is unlikely to change unless state officials start explicitly requiring planners to consider it in mapping out future growth.

Gov. Crist appointed a Climate Action Team to suggest ways Florida can deal with the changes threatened by global warming. When it comes to sea level rise, the team’s October 2008 report focused on such tactics as building a better system for monitoring local changes. Hine contends that now is the best time for Floridians to start planning ahead, not just for measuring the changes but also how to adapt to them.

Rising sea levels are going to affect everything from the elevation of roads and bridges to the sources of our drinking water. Roads and bridges will have to be built higher to avoid being inundated, especially when hurricanes threaten. As for the drinking water: The salty sea will intrude on the freshwater underground where most Floridians get their water. That means finding other sources, such as building expensive desalination plants.

Dealing with the consequences of a rising sea will also require making some tough decisions about where we live and play in our beach-centric state, Hine says. Barrier islands—the geologic equivalent of the bumpers on a car—are lined with condominiums and high-rise hotels. The barrier islands are likely to be the one developed part of the state to wind up under water in the foreseeable future—not a lot of water, mind you, but enough to make it inconvenient or even unhealthy to build there. Sewer plants on those vulnerable areas could flood, and sewer lines could be washed away.

Homeowners might be inclined to build seawalls. If they already have seawalls, their inclination will be to build them higher. But Hine says it’s time to consider something that sounds like heresy in Florida. He calls it "a strategic retreat from the coastline."

It’s time to start directing new construction away from the beaches, Hine says. Time to halt taxpayer-subsidized flood insurance for houses on barrier islands. Time to say "no" to expensive federal beach renourishment projects.

After all, like the foolish man’s house in the Bible that was built upon the sand, the rising sea will soon wash it all away.

Craig Pittman, who covers environmental issues for the St. Petersburg Times, is co-author with Matthew Waite of Paving Paradise: Florida’s Vanishing Wetlands and the Failure of No Net Loss, and author of the forthcoming Manatee Insanity: Inside the War Over Florida’s Most Famous Endangered Species, both published by the University Press of Florida.

Sarasota Underwater

When and where the rising seas will affect our town.Anyone reading about sea level rise has to wonder: Where will it happen? And if you live along Florida’s coast, you can’t help but ask: Will it happen in my town? In my neighborhood? Along my street?

The fact is, it’s hard to say exactly what’s going to be inundated with any precision. But there are a few signs to look for, say the experts.

Low-lying areas, of course, are more vulnerable than uplands. If you’re already in a flood-prone area, chances are it will only get worse. If you’ve already had to build a seawall, chances are you’ll need to make it taller.

In the Sarasota area, for instance, Ernie Estevez of Mote Marine Laboratory predicts that the mainland shore in Sarasota is high enough not to face any real threat from sea level rise for quite some time. Same thing with waterfront property north of Osprey, he says. But in Venice, along Dona and Roberts Bay, the land is low enough that an increase in the sea level is likely to cause problems. And of course anyone living on a barrier island like Siesta Key, Casey Key or Longboat Key is in the danger zone, since a rising sea erodes the sandy beaches more quickly.

It’s not just the bayfront and beaches that are likely to be in trouble, Estevez says. Along the Myakka River, from U.S. 41 to the Charlotte County line, is lots of low-lying property. The surging sea will push into the freshwater flow of the river, shoving the river levels higher. More and more, the river will overflow its banks.

"A lot of wetlands in that area will notice a change in the sea level before other areas," Estevez says.

But nobody can say how soon all this will happen. It all depends on the rate of sea level rise. Look at Mote Marine, which is on City Island near St. Armands Circle. Its first floor is currently six feet above sea level.

The Environmental Protection Agency has come up with three scenarios—low, moderate and high—for how fast the glaciers will melt, boosting tides. Using the high rate, Estevez says, it would take 150 years for high tides to reach Mote’s first floor. Using the moderate rate would lengthen the time to 273 years. And if the low rate is the right one, then it will be 527 years before Mote’s employees will have to swim through the front door.


But a rising global temperature is doing more than just pushing the seas higher. It’s also making hurricanes more intense, according to a report last year from the U.S. Geological Survey. That means higher wind speeds, heavier rainfall—and stronger storm surges. And if the sea is already closer to the buildings than it was before, a stronger storm surge could far more easily turn a high tide into Florida’s version of a tsunami.

Endless Summer

The number of days per year with peak temperature over 90º F is expected to rise significantly, especially under a higher emissions scenario as shown in the map at right. By the end of the century, projections indicate that North Florida will have more than 165 days (nearly six months) per year over 90º F, up from roughly 60 days in the 1960s and 1970s. The increase in very hot days will have consequences for human health, drought and wildfires.Source: U.S. Global Change Research Program

Dutch Lessons

How the Netherlands sees economic opportunity in sea level rise.

By David KlementHolland sees economic opportunities galore in the marketplace that global warming will create. Having battled the North Sea since their ancestors first settled its low-lying shores around 800 A.D., the Dutch know a thing or two about water management, international trade, wetland reclamation and lifestyle quality—all conducted behind 25-foot dikes that keep the "water wolf," the North Sea, at bay.

But it isn’t just rising sea levels that the Dutch fear. Already they attribute frequent weather aberrations that have caused heavy flooding throughout Europe to climate change. And they believe this is only the beginning. Heavier rainfall will create flooding, droughts will dry up fresh water supplies, and rising temperatures will affect crops.

Yet the Dutch are marching boldly into the uncertain new world of glacial meltdowns, flooding and droughts that a warming planet will produce, not just to protect their people but because they see economic benefits in doing so. From a massive expansion into the North Sea of the Port of Rotterdam (already the second-busiest in the world) to research into "smart soils" for dike-building and pinpoint weather forecasting, the Dutch are capitalizing on the technology and science of climate change. Some adaptations a Florida delegation observed in 2008 included injections of biological organisms to enhance dike stability, data collection to forecast weather by square-mile quadrants, huge hydraulic projects to control water, and planned dike overflows to mitigate flood damage.

IBM is aggressively investing in cutting-edge research in The Netherlands to prepare it to prosper in a warmer, more watery world. It’s establishing a Center of Excellence in Holland that will gather and apply cutting-edge technology for a variety of applications to benefit its clients—which include governments like Holland.

Deltares, an international company, is a major player in water research in Holland. Last year the company joined with the Rijkswaterstaat, the National Ministry of Transport, Public Works and Water Management, and provincial water boards to establish the International Deltares Institute to combine its scientific expertise in water management with that of the Dutch government. When fully operational, it will employ 800 people.

Areas that Deltares is researching include harbors and coastal engineering, wave dynamics, flood management and hydrology, river engineering, desalination plants, even something called "coastal morphodynamics and mud."

Few projects are as ambitious as the Port Rotterdam expansion, called Maasvlakte 2. It will expand the port by nearly 2,500 acres by pushing back the North Sea nearly four square miles, at a cost of some $5 billion, to capitalize on the container shipping boom.

But the city of Rotterdam itself is deep into "Waterplan 2," a multi-pronged strategy to bolster its defenses from the impact of climate change while also transforming the somewhat gritty industrial city into a utopia of parks, lakes and canals befitting the label "Rotterdam Water City 2030." That vision for Rotterdam’s makeover by 2030 involves many environmentally friendly strategies such as green roofs, water squares and gardens, floating houses, transforming dikes to double duty as water barriers and "urban balconies," plus new nature preserves and trails.

Seeing the destruction caused in New Orleans by flooding after Hurricane Katrina, the Dutch have devised a new strategy for handling floodwater called "Ruimte voor de Rivier"—Space for the Rivers. It’s a 10-year, multi-national program started in 2006 to enhance flood protection and environmental improvement of the nation’s western delta, initially budgeted at $3.4 billion. Instead of simply raising the dikes higher, as the Dutch have done for centuries, this plan focuses on giving the rivers more space to expand and thus to handle greater volumes of water in flooding periods. It is among the most complex public works projects ever undertaken.

The project will enlarge river beds, remove groins and other obstacles that retard river flow, deepen the forelands in certain areas to accommodate more water, and actually give up some precious polders (dike-enclosed land areas) by removing dikes. Homeowners who will be affected by subsequent flooding will be compensated, as will farmers who lose agriculture productivity due to flooding anticipated to occur once a year.

For a people who have been building dikes to hold back water for 1,200 years, destroying dikes to allow floodwater to spread into farms and homesites has to come as a culture shock—not to mention a heavy financial burden in a country that already spends fully 1 percent of its GNP on water management.

The author, the former director of the Institute for Public Policy and Leadership at the University of South Florida Sarasota-Manatee, was recently oppointed to the Florida Public Service Commission.


Helpful Web sites about sea level change.Florida’s Oceans Council on climate change and sea level rise: United States Geological Survey tracks the effects of climate change on Florida’s natural areas: Florida Energy and Climate Commission:

National Academy of Sciences’ reports on climate change:

The science academies of the G8 countries, plus Brazil, China, India, Mexico, and South Africa, all call for quick global action on climate change:

Filed under
Show Comments