Thursday, April 26, 2018

Miami's Residents Now Factor Climate Change Into Housing Costs

It's been known for some time, at least 35 years, that South Florida will be 'ground zero' when the rising seas from climate change begin to have their most serious impact. Indeed, the image produced giving a U.S. Geological survey map - with projected inundations by 2035, was actually published first in a Science Encyclopedia from 1981.

More recently, it's come to the attention of those who live in Miami or Miami -Dade (the greater metro area) that some areas flood during heavy rainfall and even on sunny days - when high tides known as "king tides" can swell the sea.

In fact, a 2016 study in the journal Ocean and Coastal Management found that the frequency of flooding increased significantly in Miami Beach between 2003 and 2016, with rain-induced events jumping 33 percent and tide-induced events soaring more than 400 percent.

How are tide-induced events generated and how are they connected to climate change? An examination of the diagram below can help which serves to illustrate tidal effects at Barbados:
No automatic alt text available.

It is not too difficult to see that the Moon would exert a pull, say  with force F1,   on the near point -  call it A on the Earth. By the same token, point B on the opposite side from A would be pulled  (say  with force F2) )nearer to the Moon than the water above it, thereby inducing a high tide at point B as well. In other words, two separate pulls, with F1 > F2,  resulting in two high tides at locations A  and B.  In this context one can appreciate the concept of differential gravitational pull.

Now, a "king tide" is the common term given to high ("spring") tides which occur when the Moon is at its closest position ("perigee") relative to the Earth.  The difference in distance works out to about 50,000 km or 30,000 miles.  That difference is enough to  generate a significant differential gravitational tidal pull at high tide - when the alignment is as shown.

In a normal situation such tides wouldn't constitute a flooding threat other than when the configuration occurs during a storm, e.g. hurricane. But to have it occur even on sunny days shows some other factor at work - and that other factor is incipient rising seas from climate change.  In effect, the sea level rise - even though it may only be measured in inches - is ample to flood the streets of Miami on sunny days if there is also a king tide on those days. 

That may still sound somewhat sketchy except now we have evidence from Miami property values that the rising seas from climate change  is factoring into realty assessments. Research published last Friday in the journal Environmental Research Letters  and reported in the WSJ (April 21-22, p. A3) shows that "single family homes in Miami Dade County are rising in value more slowly near sea level than at higher elevations."
Why is this? Well, it's entering into buyer considerations of possible "more frequent minor flooding in the short term and the challenge of reselling properties that  decades from now could be submerged. (Again, refer to the projected U.S. Geological survey map).''  The map of the Miami area showing effect of elevation on rate of price appreciation is shown below:
Where the more contrast colored purple section refers to greater effect on rate of appreciation.  The incredible conclusion of Harvard real estat4e professor (and author of the paper) Jesse Keenan, is that ordinary home owners are already factoring future sea level rise into their calculations.

 Reinforcing Keenan's work, the WSJ (ibid.) cites another new paper from researchers at the University of Colorado-Boulder and Pennsylvania State University. This paper "shows the trend in Miami is playing out across the country, with homes vulnerable to rising sea levels now selling at a 7 percent discount compared to similar but less expensive properties.".  In addition the paper "shows that the size of coastal discount has grown over time".  The same thing appears to be happening in Barbados, especially as hotels, beach houses now start to discount their rates after obvious sea level increase has eroded their once extensive beach fronts.

In the case of Miami it's an obvious testing ground for the vulnerability of housing markets to sea level rise- climate change because its elevation "is as little as 1 foot above sea level".

The WSJ cites one particular Miami native (Joel Fabelo) whose previous waterfront home "increasingly flooded in the final five days they lived there" - and "a half a dozen times each year when tides were especially high, water rose over the sea wall leaving mullets swimming on the lawn."

Are Miami's home owners loopy?  Are they too susceptible to global warming "blurtations"? Nope, they have their heads screwed on straight and they know what they know - and what they see with their own eyes. Moreover, like  nearly all the reinsurance companies (e.g.  Munich Re) they have climate change factored into their tables, costs, plans.  They better, because they will be ground zero as the planet's sea level continues its inexorable rise owing to melting ice caps, and the Greenland ice sheet.

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