Saving New York From Sea-Level Rise Could Cost $120 Billion

It could cost more than $120 billion to protect New York City from rising seas and storm surges expected by the end of this century, according to a Rutgers University expert on climate change effects on sea level.
But the risk to New York is even higher: almost $170 billion in property losses alone.
Bob Kopp, associate director of the Rutgers Energy Institute, offered what he called this "rough guesstimate" of costs at the University of Chicago last week in response to queries by Chicago economics professor Michael Greenstone, former chief economist for President Obama’s Council of Economic Advisers.
"You know we're going to spend every single dollar to protect Manhattan," Greenstone said.
Kopp outlined the risks before he priced the solution.
"In New York City itself you’ve got about $170 billion worth of property (at risk), which is why Michael says we’ll spend anything to protect it," he said. "You’ve got about a million people, about a third of whom are high social vulnerability. You’ve got about 400,000 homes, a whole bunch of EMS stations, fire stations and hospitals. So this is what’s threatened."
In fact, according to Climate Central, $168 million worth of New York City property is at risk of flooding from a nine-foot rise in sea level, 930,000 people live in those areas in 400,000 housing units, alongside 65 fire and EMS stations and 28 hospitals.
But inundation is not the only threat.
"There’s two things that happen with sea level rise," Kopp said. "First of all there are areas that get permanently flooded, but for most of the world the most significant effect is that it takes a smaller storm surge or even smaller tidal range to cause flooding from extreme water levels. And we care about this particularly in New Jersey the last three years because of our experience with Superstorm Sandy."
To keep New York City's average cost for annual flood damages where it is today, Kopp said, the city would have to install almost a meter of flood protection by 2030 and 2.5 meters by 2100.
New York hasn't estimated what protection would cost, but one coastal municipality has. Three years ago The Canadian Province of British Columbia estimated the cost to build flood defenses along 250 km of shoreline surrounding metro Vancouver.
One meter of flood protection, they estimated, would protect 2.3 million people and 2,880 square miles, and it would cost $9.5 billion.
"Assuming it scales with population, let’s call that about $50 billion per meter in New York City," Kopp said. "So, this 2.5 meter projection, I would roughly guestimate something on the order of $120 to $150 billion."
"That's a crude order of magnitude. It's something we're looking at more."
The number is likely to change with further analysis, Kopp cautioned during a seminar hosted by the Energy Policy Institute of Chicago, but "just to give you a scale, you're talking about projects in the tens of billions of dollars."
Worldwide, about one in 20 people—380 million—live within six vertical meters of the ocean, in areas vulnerable to flooding from sea-level rise and storm surge.
Koop, an expert in understanding uncertainty in climate change, has been working with colleagues at Rutgers and Princeton to solidify the sea-level record and project likely outcomes.
"The result of our analysis is that from 1901 to 1990, global mean sea level rose about 1.2 mm per year or about half an inch per decade. And that over the last 20 years there's been about a 2.5-fold acceleration in the rate of sea-level rise," he said.
"We can conclude with 95 percent probability that this increase was faster than any increase in the previous 26 centuries."