Sunday, December 04, 2016

Global Warming, the beach and risk

Barry Ritholz had a blurb on his blog asking people to lay down
a marker by buying coastal property if they thing AGW isn't
a real problem.
Several years ago we bought a condo on the beach in Florida.
I worry about hurricanes, and I've followed weather and hurricanes
since I could read and my father gave me a book on the history of
hurricanes by the corp of Engineers.  (around 1975)  One of things postulated
in that book and by Nash Roberts (famous New Orleans Hurricane guy)
is that hurricanes peak in 30 year cycles.  That cycle is probably related
to the PDO cycle, but meteorologists in the 70's didn't know about the
PDO cycle, Nash would say throughout my childhood that we were in the
low part of the cycle.  Things picked up in the 90's with Andrew, then
were roaring until 2008 and have pretty much stopped for the past 8 years.

We made a bet that the risk to owning a beach condo for the next 10 years
or so is pretty low due to low hurricane activity.   I also have a side bet with
someone who expects it to flood due to rising sea levels.   I know a little about
geology and know that barrier islands with active beaches should grow
if there is a source of sand and rising sea levels.  The real risk is that the beach
will grow so long that it will be too far to walk back to replenish beers.

The reality is that man has leveed the rivers so that most sediment is transported
too far offshore to be caught in the alongshore current, so beaches are eroding but
are being built up just as fast by the county dredging sand from offshore.

We'll probably look at selling in 3 or 4 years or maybe moving to a higher floor
or increasing our insurance, the hurricane activity should start ramping up then.
Sea level will continue to increase as it has for the past 200 years, rebounding from
the little ice age.  The answer to that problem will be less control of natural rivers,
accepting flooding in some areas (Mississippi Delta) to build land from sediment.

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