The Future is Now for Sea Level Rise in South Florida
It’s not unusual for Keith London to run into people who doubt that global warming is really such a big deal. “I tell them, ‘the ocean is rising,’ ” he said. “They say, ‘so?’ It drives you crazy.”
London is no scientist; he’s a city commissioner in Hallandale Beach, Fla., a municipality of about 37,000 that sits on the Atlantic coast between Fort Lauderdale and Miami. But he talks to scientists and engineers all the time as part of his job, and the story they tell him isn’t pretty. “The average elevation in Florida is 6 feet,” London said. “Some places are as little as 3 feet above sea level. And sea level is going to rise as all that ice in the Arctic melts.”
ON THE FRONT LINES
Keith London: City commissioner, Hallandale Beach, Fla.
Katharine Hayhoe: Climate scientist, and professor at Texas Tech University
Abigail Borah: 21-year-old Middlebury junior
Edward Lu: Astrophysicist and electrical engineer
Michael Mann: Climatologist and physicist
For places like Hallandale Beach, along with much of South Florida, that’s a big problem — not just off in the future, the way climate change feels to some people, but right now. The sea has already risen more than a foot in this area over the past century, and new research by Climate Central shows that some 2.4 million Floridians are at risk of flooding from even a moderate hurricane-driven storm surge. The odds of a catastrophic 100-year flood by 2030 are now 2.6 times higher than they would have been without global warming.
Mindful of the danger, public officials in Monroe, Broward, Miami-Dade, and Palm Beach counties — Democrats and Republicans alike — have organized the Southeast Florida Regional Climate Compact to coordinate their responses. But local governments have already been dealing with the effects of the rising sea, and Hallandale Beach is a perfect example.
“The two biggest issues,” London said, “are potable water and sewage treatment.” Hallandale Beach, like much of the region, draws water from the Biscayne Aquifer, an immense natural subsurface reservoir that supplies 1.3 billion gallons of fresh water every day for drinking, cooking, bathing and more.
Since the ground is relatively porous, though, the rising ocean has been pushing it’s way under the beaches and into the reservoir. “Seven-eighths of our wells,” London said, “have had saltwater intrusion.” The only solution: drill more wells several miles inland, at a cost of $3 million, probably on the golf course in the neighboring town of Hollywood. “This is a big investment for a city with a $100 million annual budget,” he said. “It should hold us for 30-50 years.”
Hallendale Beach water tower. Credit: HallendaleBeachfl.gov
Then there’s the torrential rainfall — another consequence of global warming that’s already becoming apparent, and which is likely to get worse. “We’ve had a couple of major storm events recently,” London said. “In ’09, we literally had 18 inches of rain in 30 hours.”
It’s not just the stuff that falls directly on Hallandale Beach itself. “If it rains out [to the west] in Plantation or Miramar, the water ends up here,” London said. “If it rains in Hollywood or Fort Lauderdale [to the north] it flows south.” To deal with the inundation, the city is building a $15 million injection well to shunt the stormwater 150 feet underground, untreated. “Luckily,” London said, a bit facetiously, “the aquifer is already compromised.”
For the city’s sewer system, the problem is both ocean intrusion and age. “We’re a 70-year-old city and the pipes are crumbling, partly because they’re being corroded by salty groundwater,” London said. The groundwater seeps into the pipes, putting an extra burden on sewage processing that London estimates at about $2 million per year. On top of that, the system currently operates by gravity, with sewage flowing downhill until it reaches the plant. As groundwater levels rise with sea level, the city will have to resort to pumping — another big expense.
Finally, there’s the ocean itself, creeping higher every year as ice melts and the water itself swells as it warms. The main threat here not the loss of a few feet of beachfront, or a slightly higher water level in the canals that crisscross the city. It’s the inundation that happens when a hurricane pushes a wall of water inland. When Hurricane Katrina slammed ashore in New Orleans in 2005, it was the storm surge, not the wind or rain, that destroyed much of the city.
Admittedly, Katrina’s surge of nearly 30 feet above sea level was a U.S. record, and not likely to be repeated anytime soon. It wouldn’t take anything close, however, to devastate South Florida. “I’ve lived here since ’79,” London said, “and we’ve been very blessed. We’ve had wind-event hurricanes, but very few water-event hurricanes. As the crow flies, I’m less than a quarter mile from the ocean. With a 6-foot surge, my house might be gone.” So, he said, would the first floors of many of Hallandale Beach’s oceanfront high-rises.
One stopgap solution might be to artificially create the sort of vegetation-rich sand dunes that can partly absorb the impact of storm surges, but, while London remembers at least three rounds of beach replenishment during his time in the city, there’s been no attempt to build dunes. “People don’t want to see palm trees where they could put a beach towel,” London said, but simply refurbishing a flat beach is, he argues, “the definition of futility. People are extremely short-sighted.”
So London has pushed a small-scale project that won’t interfere with anyone’s towel. He’s gotten a grant from the Florida Department of Transportation for a pilot project to plant mangroves in the brackish water of some of his city’s canals. “It’s relatively small,” he said, “just a couple of acres.” The plants will not only absorb some of the impact of storm surges, but they also tend to filter pollutants out of the water, and provide habitat for fishes and nesting places for birds.
It’s an extremely modest effort, but London hopes people will see the benefit, and support the project’s expansion. And whatever pundits and politicians say to challenge climate science, he doubts that his colleagues in other South Florida cities and towns are paying much attention. “I do hear people on talk shows say this is phony science,” he said. ”But the people I tend to be at meetings with — most of us are on the same page.”
Like London, they can’t afford to debate arcane science when the evidence of climate change is right at their front doors.