Lessons from hurricanes bode poorly for our future

The end of the 2018 hurricane season is a good time to take a step back and see what we've learned from recent storms.

In the last two years, 18 North Atlantic hurricanes struck the U.S., five of which were very dangerous by any measure. It is not unreasonable to assume that these powerful storms are the beginning of the "new normal" - the impact of a warming ocean on hurricane intensity.

In 2017, an unprecedented three "superstorms" - Harvey, Irma and Maria - hit the U.S. coast. Harvey tied Katrina as the most destructive hurricane since 1900, damaging 130,000 homes ($125 billion) and dumping a national-record 60 inches of rain on Houston, a city spectacularly unprepared for flooding. Irma struck eight Caribbean islands, Cuba, southwest Florida, and skimmed past the Florida Keys, destroying 25 percent of the buildings there ($53 billion). Maria ripped through Puerto Rico, causing devastation over much of the island ($90 billion) and killing an estimated 2,975 people.

Things didn't let up in 2018 as Florence and Michael came ashore, both superstorms in my view. Florence ($19 billion) produced a state-record rainfall of 35 inches in North Carolina and caused more damage than the two North Carolina hurricanes (Floyd and Matthew) combined. Michael ($11 billion) nearly destroyed Mexico Beach, Florida, and had the third-lowest air pressure ever measured in the U.S., behind the 1900 Galveston storm and Katrina.

Recognizing the probable relationship between global climate change and this increasingly severe storm activity, the time has come to take stock of our coastal development along the Atlantic and Gulf coasts. Not only will we likely suffer through a continuing string of more intense storms, but also contend with a rising sea level. Yet, development continues along the U.S. shoreline, placing more people and property in harm's way. It is time for that to cease.

Already, sea level rise fears are having an impact on near-beach house prices. I think a true crash in prices is just around the corner because of four factors:

1. Federal flood insurance is likely to become actuarial (start paying for itself), which will make beach home ownership considerably more expensive because the costs of insurance will more accurately reflect the risks of living along the coast.

2. Beach nourishment, now the preferred way to deal with shoreline erosion and save houses, will likely become much less important because of sand shortage and shorter beach life spans due to rising seas and bigger storms.

3. Increasingly there is public concern about taxpayers paying much of the cost (millions of dollars per mile) of beach nourishment. "Why should I pay since I wasn't the one to build next to the beach? It's a form of welfare for the rich."

4. Common sense will prevail when the public recognizes that the houses being repaired today are just being set up for the next storm. Does it make sense to simply rebuild after every storm, when much of the cost is at taxpayers' expense?

And what can be done with the big cities? Miami is likely doomed and will need to be abandoned, in part because the low-lying city is perched on top of very porous limestone through which the sea will rise. Fort Lauderdale is not much better. Tampa and St. Petersburg are vulnerable because the "right" storm (coming across the shoreline in a northeasterly direction) will cause immense damage to these low-lying cities. By orders of magnitude, the state of Florida leads the way in numbers of cities and towns threatened by the sea.

Cities not on barrier islands, like Boston, New York, Philadelphia, Los Angeles and Seattle, can possibly be saved, at least for a while, by construction of massive sea walls.

We are not Holland, which has a coastline about 1,500 miles long. In that small country, there is nowhere to retreat from a rising sea, which means intense engineering is required for national survival. The U.S., with 94,571 miles of coastline to protect, cannot afford the Dutch approach and, instead, we must move homes and communities away from much of the coastline.

Orrin H. Pilkey is the James B. Duke Professor Emeritus of Earth and Ocean Sciences at Duke University's Nicholas School of the Environment.