Global Warming

Now that global warming has happened, what do we do about it?
 
Sea levels are rising.  Do we spend billions on dikes and levees?  Or do we encourage lowland-using activities to relocate to higher ground?
 
Major rivers are likely to change their courses.  Do we spend billions on trying to confine the rivers?  Or do we relocate our river-dependent industries?
 
Agricultural zone boundaries are much farther north than they were forty years ago.  Do we spend billions trying to force nature to do our bidding?  Or do we learn to grow different crops, and grow our old crops in different places?
 
Formerly well-watered places are now arid, and formerly dry places are now suffering excess rainfall.  Same pair of questions.  Spend billions on dubious technology or learn to relocate?
 
Our current tax structure and land-ownership pattern makes relocation unduly difficult.  Land is too expensive to buy but too cheap to own for long term.  Relocation means abandoning now-worthless land that was initially bought at great cost, and buying new land at even greater cost.
 
Landowners are not making much from this scheme.  The only winners are banks who loan ever-increasing amounts of money for bigger and bigger mortgages.
 
What if we got smart and levied high real estate taxes on the location value of land, thus making it impractical to own land that's not immediately needed?  It seems that initial purchase prices of land would be greatly decreased.  Land that becomes worthless to to changes in the natural world would be much easier to abandon because new land could be more readily bought elsewhere.  The only losers would be banks, who would no longer have a market for huge land-purchase mortgages.
 
Of course there's still a need to curtail human activities that needlessly result in unnecessary global warming, but a more dynamic land usage pattern is going to be a necessary part of any solution.