Simple answer with horrible consequences, discontinue all FEMA insurance. This of course will never happen because many elected representatives from both parti

Simple answer with horrible consequences, discontinue all FEMA insurance. This of course will never happen because many elected representatives from both parties have coastal properties that require it in order to get a mortgage. But if you did the above, it really doesn't matter whether climate change is real or not, all the risk will be on the homeowner going forward. That ought to be enough to change behavior in the long run.