Climate change and the defend versus retreat decision

The unpredictability of extreme weather and rising sea levels will change the cost of living in certain parts of the planet.  Skyrocketing flood insurance premiums and stricter building standards will require homeowners and governments to make very difficult decisions that fundamentally ask - - "Do we continue to defend certain areas at increasing risk in the era of climate change or do we move into an abandon and retreat mode?"

The New York Times addresses this today in Rebuilding After Sandy, But to Costly New Rules.  A paragraph to ponder:

"So in the most devastated communities, families are being forced to make difficult financial calculations: can they afford the new flood insurance premiums, which, at worst, can reach as high as $30,000 a year?  Do they have the money to rebuild their homes to the government's new specifications?  Does it even pay to stay?"

Flooding since Noah has always been about the X, Y, and Z axis in a geographical context.  Rising sea levels and increased flooding potential, especially in coastal areas, requires communities, homeowners, and businesses to focus more sharply on the Z axis.  Consider the following from the same article:

"The insurance premiums are determined, in part, by where your home stands relative to that base.  The higher you go, of course, the less you pay.  Consider a single-family home in a zone with a moderate to high risk of a flood, that has a flood policy with $250,000 of coverage.  If the home is four feet below the base flood elevation, the homeowner would pay an annual premium of about $9,500 according  to FEMA.  But if the home was elevated to the base, the premium would cost $1,410.  Hoist the home three feet higher, and the premium would drop $427."

This was the example provided in the article - - annual flood increase goes to $31,000 per year.  If you raise the house 5 1/2 feet, the insurance drops to $7,500.  If you can raise the house a total of 7 1/2 feet, the rate drops to $3,500 per year.  So staying at your current X and Y location requires very difficult decisions in the Z axis - - especially if a 5 1/2/ foot movement costs you $150,000. 

Defend versus retreat.  Defend, with increased public liabilities, much higher flood insurance, and engineers focused on the Z axis versus retreat, with huge economic costs, unpredictable social change, and mass relocations that might result in foreclosures and bankruptcy.  Defend versus retreat - - and don't overlook the local, state, and national politics associated with all of this.

We are heading toward a century filled with very difficult and complex defend versus retreat decisions.