Florida is slipping under water. And as global climate change steadily encroaches upon the Florida Keys, the Nature Conservancy is wondering why it should even bother saving land that will end up under water.

KEY WEST, Florida — Jody Thomas’s Key West home lies just across the street from the town cemetery, the island’s highest point.

That it sits just 18 feet above sea level is an indication of just how low-lying — and thus how vulnerable — this stretch of islands off Florida’s southern coast are.

Across the world, the temperature at the surface of the sea rose nearly 1 degree Fahrenheit during the 20th century.

As the waters continue to warm, they will expand.

Thomas, the director of the Nature Conservancy’s Southern Florida Conservation Region, and a colleague, Chris Bergh, rolled out a laminated chart on Thomas's wooden floor and showed why they’re worried.

The map showed the elevation of Big Pine Key, a low-lying island up the Keys where Bergh lives and where the Nature Conservancy, a nonprofit dedicated to protecting nature and preserving wildlife, is a partner in a deer refuge.

Four smaller maps showed the same island under different levels of rising water.

The first depicted the expected sea level rise by the end of this century under the most optimistic conditions, a scenario that assumes the world cooperates to aggressively fight climate change. Under that scenario, the seven-inch rise had flooded 16 percent of the island. Water would be sloshing through some streets and presumably the ground floor of many houses.

The next two maps were based on more realistic assumptions, and in these projections the sea rises accordingly.

Under a scenario of rapid world economic growth with little attention to climate change — the track the planet is currently on — waters would rise two feet.

In this scenario, waves would wash over more than half the island.

Bergh’s final map reflected the work of the German climatologist Stefan Rahmstorf, who junked the computer models and simply projected current trends to the end of the century. In this case, Big Pine Key was almost entirely under the sea, just a grid of rooftops and a scattering of highlands rising above the waves.

“The important thing is that we don’t know where we’re going to fall on this spectrum,” Bergh said. “And storm surges and abrupt changes could make it happen much more quickly.”

The Nature Conservancy has joined with the National Marine Sanctuary and others to study coral bleaching in hopes of finding ways to mitigate or adapt to the stresses of climate change. But increasingly they’re turning their attention to what lies onshore.

“We’re having conversations that we never dreamed of having,” Thomas said. “The Nature Conservancy has got to start saying, ‘Okay, what’s our investment worth to us, and should we continue investing?’”

“We’re not buying land here anymore,” Bergh said. “Where sea levels have been rising, there are winners and losers. It’s certainly worse for us who live on the island. And it’s worse for the terrestrial species.

“But all that then becomes marine environment. Once this is underwater, we still care about it. It will still be part of the Nature Conservancy’s mission when there’s coral there and fish there rather than deer and plants.

“If we can take the energy and money that we would have spent buying land to prepare the terrestrial environment to be a good future marine environment, that’s a really worthwhile thing to do. So if we have a toxic waste dump, get it cleaned up now before it goes underwater and spills out into the future marine environment,” Bergh added.

“Our strategy," Thomas said, "is to use this place as an example of why we should try to minimize the impacts of climate change and minimize the inputs that create it."

“And also to use it as a place to figure out how to adapt,” she added. “We’ll be an experiment, and other people can see it and learn.” 

Forecast: The global consequences of climate change

Part 1: Why America Should Care
The Florida Keys are shrinking
Can insurance cover the costs of climate change?
Who will be able to afford to live on the coast?

Part 2: The Spread of Disease
Pathogens find new habitats
Countries could backslide into poverty
How disease relates to carbon dioxide

Part 3: The Arctic Melt
Easier passage through the Arctic
A scramble for control of the Arctic
Opening the Arctic to damage

(Stephan Faris is the GlobalPost environment correspondent. Click here to buy his new book, "Forecast: The Consequences of Climate Change, from the Amazon to the Arctic, from Darfur to Napa Valley.")

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