Coastal Flooding—A $1 Trillion Annual Headache Come 2050

Three American cities are especially at risk to incur damages: New York, New Orleans, and Miami.

Coastal Flooding—A $1 Trillion Annual Headache Come 2050

After Hurricane Sandy, vehicles in a lower Manhattan parking structure remain submerged due to coastal flooding. (Photo: Adrees Latif/Reuters)

Sal holds a Political Science degree from the George Washington University. He's written about all things environment since 2007.

"Sell. Sell now. Get out while you can still find a sucker to take the four walls and roof off your hands."

This was what I wrote a little more than a month ago to the 1.4 million coast-dwelling Americans after a report in the journal Nature Climate Change found that the number of people at risk from hurricane storm surges could double if the natural defenses (kelp forests, coral reefs, etc.) protecting U.S. coastlines were lost because of global warming.

Well, that very same journal is out with another coastal study, and the results, while not as injurious, are nevertheless ominous: Flooding in cities near coasts could total one trillion annually by 2050. That’s a trillion—with a "t"—every year starting mid-century.

Three American cities are especially at risk to incur damages: New York, New Orleans, and Miami.

"If we did nothing about the risk, the flood damages in coastal cities would grow to huge amounts. So that's really not an option," said study co-author Robert Nicholls, a coastal engineering professor at the University of Southampton in England.

The seed for Nicholls' study was planted in the days after Hurricane Katrina. He told LiveScience:

Nicholls and his colleagues realized that scientists had little idea which cities around the world were most vulnerable to flooding. So the team compiled data on 136 coastal cities with more than 1 million residents, looking at the elevation of the cities, the population distribution and the types of flood protection they had, such as levees or storm-surge barriers. They then combined that data with forecasts of sea level rise, ground sinking due to groundwater depletion, as well as population growth projections and economic forecasts of gross domestic product (GDP). From there, they used the depth of water flooding a city to estimate the cost of the damage.

The study wasn't all doom and gloom; it did come with some advice that, if followed, could reduce the annual losses to only $52 billion (italics all mine). This preventative cocktail includes: increasing the height of levees, erecting storm-surge barriers, making buildings flood-resistant, or converting flood-prone, low-lying areas to parks or football fields.

Fifty-two billion dollars is a lot. But it's a heckuva lot less than one trillion annually, and its light-years less than what it would cost to rebuild major cities every time a major flood or hurricane decided to make an appearance every five years.

And consider a 2005 report which found that for every $1 FEMA spends on hazard mitigation, the country earns $4 in benefits.

New York City, ravaged by Hurricane Sandy in October 2012, seems to be taking this advice to heart, unveiling a rebuilding plan on Monday, August 19, which takes climate change very, very seriously. From the Hurricane Sandy Rebuilding Task Force:

No single solution or set of actions can anticipate every threat, but decision makers at all levels must recognize that climate change and the resulting increase in risks from extreme weather have eliminated the option of simply building back to outdated standards and expecting better outcomes after the next extreme event.

After all, what fiscal sense does it make to reconstruct New York's coast—or any battered coast, for that matter—right now with infrastrucutre that, because of rising sea waters, will be ineffective in 15 years anyway?

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