Actually the longer cycles of 100 years or more are more important than 20 to 30 or 40 years. Part of the reason we know that there has been glacier melting is because of satellite pictures from NASA. Well 100 years ago we didn't have pictures so we have no idea whether they were melting or gaining or anything else. But if we go from 1990 until 2090 we can get a better idea.
As far as South Florida being uninhabitable that is an opinion not based on any facts. You could call it a theory. I'm not sure how old you are but I'm willing to bet South Florida isn't going to be uninhabitable by the time you pass away if you live to be 85 or whatever.
Many climatologists have predicted things that they've had to retract. Things like "the Arctic will soon be ice free", they've had to retract saying it would be ice free by 2030. In fact Al Gore said in 2009 that it would be ice free in 5 to 7 years from then. That obviously proved not to be true.
People also said that polar bears would become extinct. But they've actually increased by at least 8000 since the 1960s.
Some scientists also have said that climate change would cause global massive food shortages. Barack Obama echoed this claim. Actually during the last decade food production has skyrocketed.
I want to reiterate the fact you would have to be very ignorant to not realize that climate change is real. The issue I have and many others is continuing to cause people to fear without these things coming to fruition and then again pushing the goal posts back. This is also very ignorant. And some of it is just to be "right", which is really stupid by the way.