Southern Florida has few options to adapt to sea-level rise
Too much salt-water, not enough fresh water and more severe hurricanes threaten existence of Southern Florida towns
Thankfully 2018’s hurricane season has been milder than the 2017, when seven long-standing records were shattered. But it’s not just increased severity of hurricanes that are challenging the continued existence of southern Florida’s towns and city. They are being hit multiple ways and it’s going to get worse. Some likely will disappear entirely in the coming decades. Others will turn into playgrounds for the rich with imported workers from poorer countries.
What are the challenges that southern Florida is facing?
Sea-level rise is accelerating. Despite the claims of the ‘skeptics’ in the room, there’s going to be significant sea-level rise by 2050 and it will be worse by 2100. The IPCC 5 excluded some research because it didn’t have a good explanation for observed changes. The follow-on research has been done and the next IPCC report is expected to increase average sea-level rise in its scenario from a median of 2 ft or 60 cm to a median of about 3.3 ft or 1 meter by 2100.
Florida will see more than average sea level-rise. That median is average sea-level rise across the entire ocean surface. Just as a global average temperature increase is felt unequally in different parts of the world, so sea-level rise is felt unequally. The closer to the equator a place is, the higher the sea-level rise (all else being equal). That’s in part due to thermal expansion of water due to increased warmth but also due to centripetal force. But it’s also due to the gravitational attraction of the polar ice caps. As they melt, they lose the hold they had on nearby water and it flows further toward the equator as well. And finally, there are the effects of ocean currents, prevailing winds and the like. They have accounted in the past several years in Florida in much accelerated sea-level rise, closer to an inch a year or 20 mm than the 3.2 mm ‘skeptics’ like to talk about.
Florida’s land is subsiding. This is a slow motion reaction to the loss of continental glaciers 20,000 years ago. They pushed down on the center of the continent and the edges puffed up a bit. Now they are subsiding, but more on the softer east coast than the rockier west coast. As a result, Florida is sinking at the same time the seas are rising.
The 2017 hurricane season is a harbinger of what is to come. The hurricanes that occurred were more intense. This isn’t rocket science. Hurricane intensity is fed by warmth which is increased over warmer water. Hurricane damage is a combination of wind speed and rain, and warmer water means more water vapor which in turn falls out of the sky. The 33 trillion gallons of rain over Houston weren’t normal. The multiple Cat 5 hurricanes in the Atlantic weren’t normal. And Florida is Ground Zero for hurricane landings from the Gulf and from the Atlantic. On average, there will be more severe hurricanes and more rain from them. Asia has already seen a significant increase in number and severity of typhoons hitting land due to global warming, and this is likely to be repeated for Florida, but with greater damage due to higher sea levels.
Florida has a limestone problem that makes holding back the sea impossible and is likely to eliminate fresh water. Limestone is lovely stuff, but it’s basically a rock sponge. Water travels through it quite nicely. It’s permeable. And the Biscayne Aquifer, southern Florida’s source of fresh water, is just fresh water held in the limestone sponge. As sea levels increase, more salt water soaks into the sponge and impinges on the fresh water. The Aquifer is going to become increasingly brackish and in the next few decades it’s highly likely that there will be substantially diminished fresh water available in southern Florida leading to much higher prices for it.
So, Florida is going to run short of fresh water, have sea water flowing over its next-to-shore infrastructure and when it gets it by hurricanes, it’s going to be hit harder.
Not a good combination. They keep voting for people who refuse to deal with the causes of global warming, so they are going to have to continue to live with worse results of global warming. Avoidance is no longer an option, so adaptation is all Florida has going for it.
How resilient is Florida?
Resilience is the modern response to adaptation, not hardening. The ability to gracefully deal with challenges as they arise is second-best to avoiding them, but is much better than trying to fortify to the point of unbreakability.
Resilience is a multi-factorial concern. Let’s look at McKinsey’s US state ranking data for Florida and pull out the resiliency impacting ones.
Health care in the bottom third of the USA is a problem. With more hurricanes and less fresh water, health will be impacted and poorer health care means lower resiliency as Floridians will be spending more time dealing being unhealthy and dealing with that than dealing with cleanup.
Economic strength and fiscal stability are good. Money helps with resiliency quite a bit. The richer parts of Florida such as St. Petersburg will probably be okay, one way and another. The poorer parts, not so much.
Infrastructure close to the top 20% is good for resiliency, one hopes. It depends on what is behind the ranking. Good infrastructure that’s underwater doesn’t help anybody.
Crime being bad is an issue for resiliency. If you are worried about your neighbors looting your store or your house, you are less likely to be spending time helping the community adapt, all else being equal.
So that’s a mixed bag. As for specific adaptation, there are only a handful of actual tactics available.
What specific things can Florida towns do?
Move inland: Put in place zoning laws that the lowest-level parts of seaside towns are off limits for building. Find money to buy out the owners in those low-lying areas and help them move to higher ground. It’s already happening in Louisiana, with an entire town being moved. In Canada, the BC city of Surrey is going to buy all of the properties in the expensive, seaside neighborhood of Crescent Beach and abandon the area to the sea.
Barrier islands, marshlands and dunes: When hurricanes and storm swells come, it’s good to have something between developed areas and the sea. That’s where barrier islands, marshlands and robust dunes with some vegetation on them are very helpful. Helping those natural elements remain in place is very useful. Recreating them is important. And really difficult with sea-level rise. Goodbye seaside homes, hello long walks from parking lots to get to beaches.
Dredging for beach sand: Keep spending more money every year to put sand back on the beaches. A 2015 assessment indicated a strong positive ROI for beach preservation, but it ignored the shortage of sand leading to higher prices and — tellingly — didn’t mention climate change, global warming or sea-level rise anywhere. As the ROI assessment pointed out, Florida’s beaches are its biggest draw for tourists, mentioned that hurricanes caused problems for beaches but ignored the elephant in the room. Finally, as the costs are split relatively equally between municipal, state and federal budgets, it’s likely that increasingly costly beach reclamation will drop from some budgets or be constrained.
Accept the inevitable and disappear: Southern Florida is in for an increasingly tough time over the coming decades. Like the people who never went back to Florida, Houston or New Orleans after the major hurricanes, move somewhere else and don’t look back.
Southern Florida and the Keys even more so likely will become pockets of rich resorts interspersed with squalor over the coming decades. Shipped in water and booze will keep the smaller number of richer vacationers happy, but where will the workers come from? Probably, like Mar-a-Lago, they’ll import them from other countries and put them up in dormitories.