Movin' On Up: Fueled by Climate Change, Florida's Mangroves Creep North

Vital cogs in coastal ecosystems, mangroves act as both coastal defense barriers against hurricanes and nursery grounds for spawning fish.

Fueled by Climate Change, Florida's Mangroves Creep North

(Photo: Richard Soberka/Getty Images)

Sal holds a Political Science degree from the George Washington University. He's written about all things environment since 2007.

Searching for tangible proof that global warming is real, and not some hoax conjured up by the liberal media machine?

Well, look no farther than Florida’s Atlantic coastline: Over the last three decades, it’s gained more than 3,000 acres of mangrove forest, according to a comprehensive survey of satellite data recently published in the journal Proceedings on the National Academy of Sciences.

The study’s authors considered sea level rise, land use, rainfall amounts, and changes in the mean temperature as possible explanations for the northern expansion but found no correlation. Only a reduced frequency of cold snaps below 25 degrees, which kill off mangrove saplings, was associated with the growth of mangroves along a stretch of the Sunshine State between Cape Canaveral and St. Augustine.

Take Titusville, Fla. Situated roughly halfway between Miami and Jacksonville, the town experienced “an average of 1.2 fewer days per year with extreme-cold temperatures between 2006 and 2011 than between 1984 and 1989,” reports the Associated Press.

Mangroves are a form of wetland—trees and shrubs that grow where tropical seawater overlaps land. As integral cogs in coastal ecosystems, they provide a litany of ecological services—acting as everything from coastal defense barriers against hurricanes and tsunamis to nursery grounds for spawning fish.

They also lend a much needed hand in the fight against global warming: Mangroves are carbon safes that capture carbon dioxide and store it for hundreds of years. A 2011 study found that mangrove forests store up to four times more carbon per hectare than other tropical forests.

They’re disappearing en masse, though; more than a third of the planet’s mangroves have vanished between 1980 and 2000—mostly because of coastal development and the rise of industrial shrimp farming.

So the Florida mangrove expansion must be a good thing, right? Not so fast: The lead author of the Florida study says it’s too early to tell what long-term effect the northern migration might have on the state’s ecology.

“The expansion isn’t happening in a vacuum,” said Scott Cavanaugh, a postdoctoral fellow at Brown University. “There’s an enormous amount of uncertainty as to what these changes mean for the food webs.”

Still, it’s a climatological Escher drawing that’s irresistible: Climate change drives growth of the thing that mitigates climate change. Try getting your head around that one.

Or click the link below, and try to do something about it.

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