Blue carbon and South Florida's coastal ecosystems

And now, for something a little less depressing than last week. (A little.)

Blue carbon and South Florida's coastal ecosystems

Image stolen from Wikipedia. Don't sue me.

What is blue carbon? The hint is in the name. We live on the blue planet, and so "blue" carbon is the carbon dioxide that is removed from the atmosphere by Earth's marine and coastal ecosystems: its marshes, its seagrass, its seaweed, its algae, and in Florida especially, its mangrove swamps. On a planet that's 70% covered in water, the ocean is naturally going to be its single greatest carbon sink, especially given that marine vegetation is extremely efficient at sequestering carbon; despite making up only about 0.05% of plant biomass on land, it captures and stores about the same amount of carbon dioxide per year as the other 99.95%. While rainforests on land are often described as "Earth's lungs", it is more accurate to say that the oceans, especially coastal ecosystems, are the true holders of that title.

Given the importance of marine ecosystems for balancing Earth's biosphere, their protection has naturally become a key component of environmental activism in coastal regions throughout the world, and there are few places where this is more true than in Florida. The Sunshine State, famous for its beaches, has numerous programs in place to protect its coastal ecosystems, including the Florida Coastal Management Program and the Office of Resilience and Coastal Protection. For Florida, protecting the coast isn't simply a matter of scenic beauty. In the 2018 gubernatorial election, Republican candidate Ron DeSantis distanced himself from the incumbent Republican governor Rick Scott's coastal management practices and ties to the sugar industry, whose agricultural practices created an enormous algae bloom that caused health problems in coastal communities like Cape Coral and drove tourists away from the beaches. Since the election, despite governing as a hard-right heir to Donald Trump in many ways, DeSantis notably takes a much softer and more moderate tone on environmental issues, allocating hundreds of millions of dollars to fighting algae blooms and restoring the Everglades. In Florida, coastal ecosystems are not an issue that one can so easily wave away, not when the threats to them, and by extension the livelihoods of millions of Floridians, are so potent and numerous.

Land development has long been one of the big killers of the coastal ecosystems that pull carbon dioxide out of the atmosphere. Because mangrove forests sit in or very close to areas where land developers want to build condos and shops to market to retirees and tourists, they often get bulldozed to make room. One unfortunate but, I will admit, karmic side effect of this is that the newly-constructed towns and cities thus created are often extremely vulnerable to flooding. Where mangrove forests were left in place, they have prevented billions of dollars in flood damage from hurricanes and other storms, serving as an natural levee system in a state that, with its limestone bedrock, cannot really build effective seawalls to protect its cities. During Hurricane Irma in 2017, for instance, it was estimated that mangroves prevented $1.5 billion in direct flood damages, and that areas with mangroves saw a quarter less damage than those without. Not only were buildings not constructed in the most vulnerable areas, but the mangroves protected the built-up areas behind them by stalling the storm surge.

Florida mangroves' status as a key component of Earth's marine life support system, of course, also make them vital for fighting climate change. Bulldozing mangroves means releasing that carbon into the atmosphere while preventing this key component of the carbon cycle from capturing more of it, with predictable consequences for coastal communities once the water rises. While coastal Florida is just one component of the global marine ecosystem, it is also a highly visible and vulnerable one, and state-level efforts to protect these blue carbon sources from overdevelopment could well serve as a model for the rest of the country- ah, what am I saying, DeSantis may talk a good game about protecting coastal ecosystems and fighting Big Sugar, but he still loves real estate development as much as any Florida politician.

Ironically, climate change may offer the best opportunity for the restoration of coastal Florida's blue carbon. In Staten Island, after Hurricane Sandy, several exposed and devastated coastal communities were abandoned and bulldozed after the storm came through, never to be rebuilt. Nature has since reclaimed them. In Florida, where insurance premiums are skyrocketing, a similar retreat from waterfronts could be caused by one hurricane too many. A buyout would be prohibitively expensive and would face stubborn opposition, but if storms and flooding convince people that coastal real estate in Florida is not worth it, a pullback would likely happen organically. In neighborhoods thus abandoned, rewilding programs, planting the seeds of new mangroves, could both restore lost ecosystems and protect the remaining populated areas away from the water.

It's a bitter strategy that sounds like something out of Thanos' book, but it might be what it takes.