* Florida is supposed to be mostly wetland. People didn't like that, so they drained most of the wetland. Trouble is, that's where the freshwater came from. So now they are short of freshwater because their ancestors did something stupid. That means one thing that needs to be done is to restore the wetlands and thus the flow of freshwater.
* Florida is also a giant sponge. That means any shortage of freshwater in the land gets replaced with saltwater from the surrounding ocean. See above re: the need to restore wetlands.
* Hurricanes and other violent storms swipe through that area all the time. Now, Florida used to have some protection from mangroves, reefs, and other things that are now mostly gone due to humans removing them as a nuisance. This leaves the area much less protected, which means every storm surge penetrates farther inland, turning more freshwater to saltwater. In order to reduce this aspect of the problem, restore the mangroves and reefs.
* But no matter what they do, Florida is fucked anyway. Climate change makes Florida one of the most fucked over places on Earth, second only to island nations that will be completely sunk. This is what North America will look like after the ice finishes melting. What Florida? It's all underwater. But it won't take nearly that long to drive out the population. Florida already has a problem with sunny day floods, which imposes high costs that can ruin businesses.
We have the technology to restore wetlands, mangrove swamps, and oyster reefs. That would fix the shortage of freshwater in the medium term and would slow the advance of climate change. However, we do not have the technology to stop and reverse climate change. We are not even doing most of what we could be doing for damage control. Given those factors, our remaining choices are to evacuate Florida, let everyone there die, or change a land-based population to a water-based population via platforms, floating cities, boats, etc. In light of people's reluctance to move and the general governmental incompetence leading to these problems in the first place, I predict that large numbers of people will die.
Things you can do about this:
* Promote restoration of wetlands, mangrove swamps, and oyster reefs. Even though these won't solve the problem, they will slow it down and buy us time, thus minimizing the total damage and casualties.
* Vote Green, or at least look for candidates interested in salvaging what's left of our environment instead of destroying it. While even the best politicians cannot stop climate change, they can make a big difference in how bad it gets, how fast, and how many people die horrible preventable deaths because of it.
* If you do not live in Florida, stay out of it. If you are in Florida and can leave, do so. At this point if you own property there, people will currently pay you good money for it. This will not continue for much longer. As conditions continue to worsen, growth will slow, stop, gradually reverse -- and then there will come a massive crash as most Florida property becomes worthless, probably following a major storm or other disaster. To map this curve, don't watch the businesses or politicians; watch the "Insurance" companies, who have to pay for damages. When the "Insurance" bugs out, the shit is about to hit the fan. (Consider a map of disaster areas. Few places are safe from all, but some disasters are smaller and more survivable than others.) Plan accordingly with the resources available to you.